Which tree flowers are pollinated by bats. Bats pollinate durians. Pollination by bats. Chiropterophilia

25.10.2019

In the temperate zones, the pollination of flowers is in most cases done by insects, and it is believed that the lion's share of this work falls on the bee. However, in the tropics, many species of trees, especially those that bloom at night, rely on bats for pollination. Scientists have proven that "bats that feed on flowers at night ... apparently play the same ecological role that hummingbirds play during the day."

The leaf-nosed bat (Leptonycteris nivalis), in search of nectar, sticks its tongue into the flower of the cereus and gets dirty in the pollen, which it then transfers to other flowers.

This phenomenon has been studied in detail in Trinidad, Java, India, Costa Rica, and many other places; observations revealed the following facts:

In Ghana, a female bat visits the inflorescences of Parkia clappertontana.

1. The smell of most flowers pollinated by bats is very unpleasant for humans. This applies primarily to the flowers of Oroxylon indicum, baobab, as well as some types of kigelia, parkia, durian, etc.

2. Bats come in different sizes - from animals smaller than a human palm to giants with a wingspan of more than a meter. The little ones, launching long red tongues into the nectar, either soar above the flower, or wrap their wings around it. Big bats stick their muzzles into the flower and begin to quickly lick the juice, but the branch sinks under their weight, and they fly up into the air.

3. Bat-attracting flowers belong almost exclusively to three families: Bignonia (Bignoniacea), Mulberry Cotton (Bombacaceae) and Mimosa (Leguminoseae). The exception is Phagrea from the Loganiaceae family and the giant cereus.

Rat "tree"

The climbing pandanus (Freycinetia arborea), found in the Pacific Islands, is not a tree, but a liana, although if its many trailing roots can find suitable support, it stands so straight that it looks like a tree. Otto Degener wrote about him:

“Freycinetia is quite widespread in the forests of the Hawaiian Islands, especially in the foothills. It is not found anywhere else, although more than thirty related species have been found on the islands located to the southwest and east.

The road from Hilo to Kilauea Crater is teeming with yeye ( Hawaiian name for climbing pandanus. - Approx. transl.), which are especially conspicuous in summer when they bloom. Some of these plants climb the trees, reaching the very tops - the main stem wraps around the trunk with thin aerial roots, and the branches, bending, get out into the sun. Other individuals crawl along the ground, forming impenetrable plexuses.

The woody yellow stems of the yeye are 2-3 cm in diameter and are surrounded by scars left from fallen leaves. They produce many long adventitious aerial roots of almost the same thickness along the entire length, which not only supply the plant with nutrients, but also enable it to cling to a support. The stems branch every meter and a half, ending in bunches of thin glossy green leaves. The leaves are pointed and covered with spines along the edges and along the underside of the main vein ...

The method developed by the yeye to ensure cross-pollination is so unusual that it is worth talking about in more detail.

Freycinetia bracts are popular with field rats. Crawling along the branches of a plant, rats pollinate flowers.

During the flowering period, bracts consisting of a dozen orange-red leaves develop at the ends of some yeye branches. They are fleshy and sweet at the base. Three bright plumes stick out inside the bract. Each sultan consists of hundreds of small inflorescences, which are six combined flowers, of which only tightly fused pistils have survived. On other individuals, the same bright stipules develop, also with sultans. But these plumes do not carry pistils, but stamens in which pollen develops. Thus, the yeye, dividing into male and female individuals, completely secured themselves from the possibility of self-pollination ...

Inspection of the flowering branches of these individuals shows that they are most often damaged - most of the fragrant, brightly colored fleshy leaves of the bract disappear without a trace. They are eaten by rats, which, in search of food, move from one flowering branch to another. Eating fleshy bracts, rodents stain their whiskers and hair with pollen, which then falls on the stigmas of females in the same way. Yeye is the only plant in the Hawaiian Islands (and one of the few in the world) that is pollinated by mammals. Some of its relatives are pollinated by flying foxes - fruit-eating bats that find these fleshy bracts tasty enough.

Ant trees

Some tropical trees are attacked by ants. This phenomenon is completely unknown in the temperate zone, where the ants are just harmless bugs that climb into the sugar bowl.

Everywhere in the rain forests there are countless ants of the most varied sizes and with the most varied habits - ferocious and gluttonous, ready to bite, sting, or in some other way destroy their enemies. They prefer to settle in trees and for this purpose they choose certain species in the diverse plant world. Almost all of their chosen ones are united by the common name "ant trees". A study of the relationship between tropical ants and trees has shown that their union is beneficial for both parties ( For lack of space, we shall not here deal with the part played by ants in the pollination of certain flowers or in the dispersal of seeds, nor with the ways in which certain flowers protect their pollen from ants.).

Trees shelter and often feed ants. In some cases, trees secrete lumps of nutrients, and ants eat them; in others, the ants feed on tiny insects, such as aphids, that live off the tree. In forests that are subject to periodic flooding, trees are especially important for ants, as they save their homes from flooding.

Trees undoubtedly extract some nutrients from the debris that accumulates in ant nests - very often an aerial root grows into such a nest. In addition, ants protect the tree from all kinds of enemies - caterpillars, larvae, grinder bugs, other ants (leaf cutters) and even from people.

Regarding the latter, Darwin wrote:

“The protection of the foliage is provided ... by the presence of entire armies of painfully stinging ants, whose tiny size only makes them more formidable.

Belt, in his book The Naturalist in Nicaragua, gives a description and drawings of the leaves of one of the plants of the Melastomae family with swollen petioles and indicates that, in addition to small ants living on these plants in large numbers, he noticed dark-colored Aphides several times. In his opinion, these small, painfully stinging ants bring great benefits to plants, as they protect them from enemies that eat leaves - from caterpillars, slugs and even herbivorous mammals, and most importantly, from the ubiquitous sauba, that is, leaf-cutting ants, which, according to he said, they are very afraid of their small relatives.

This union of trees and ants is carried out in three ways:

1. In some ant trees, the twigs are hollow, or their core is so soft that the ants, arranging a nest, easily remove it. Ants look for a hole or a soft spot at the base of such a branch, if necessary, gnaw their way and settle inside the branch, often expanding both the inlet and the branch itself. Some trees even seem to prepare entrances for ants in advance. On thorny trees, ants sometimes settle inside the thorns.

2. Other ant trees place their tenants inside the leaves. This is done in two ways. Usually ants find or gnaw the entrance at the base of the leaf blade, where it connects to the petiole; they climb inside, pushing the top and bottom covers of the sheet apart, like two pages glued together - here's your nest. Botanists say that the leaf "invaginates", that is, it simply expands, like a paper bag, if you blow into it.

The second way of using leaves, which is observed much less often, is that ants bend the edges of the leaf, glue them together and settle inside.

3. And finally, there are ant trees that do not themselves provide dwellings for ants, but instead ants settle in those epiphytes and vines that they support. When you stumble upon an ant tree in the jungle, you usually don't waste time checking whether the ant streams are coming from the leaves of the tree itself or from its epiphyte.

Ants in the branches

Spruce detailed his introduction to ant trees in the Amazon:

“Ant nests in the thickening of the branches are in most cases on low trees with soft wood, especially at the base of the branches. In these cases, you will almost certainly find ant nests either at each node or on the tops of the shoots. These anthills are an expanded cavity inside the branch, and communication between them is sometimes carried out along the passages laid inside the branch, but in the overwhelming majority of cases - through covered passages built outside.

A sprig of Cordia nodosa is a ready home for ants.

Cordia gerascantha almost always has pouches at the point of branching, in which very vicious ants live - the Brazilians call them "takhi". C. nodosa is usually inhabited by small fire ants, but sometimes takhi. Perhaps the fire ants were the first inhabitants in all cases, and the takhs are pushing them out.

All tree-like plants of the buckwheat family (Polygonaceae), Spruce continues, are affected by ants:

“The entire core of each plant, from the roots to the apical shoot, is almost completely scraped out by these insects. Ants settle in a young stem of a tree or shrub, and as it grows, releasing branch after branch, they make their moves through all its branches. These ants all seem to belong to the same genus, and their bite is extremely painful. In Brazil they are called "tahi" or "tasiba" and in Peru "tangarana", and in both these countries the same name is commonly used for both the ants and the tree in which they live.

In Triplaris surinamensis, a fast-growing tree throughout the Amazon, and in T. schomburgkiana, a small tree in the upper Orinoco and Ca-siquiare, the thin, long tube-like branches are almost always perforated with many tiny holes that can be found in the stipule of almost every leaf. This is the gate, from which, at a signal from the sentinels constantly walking along the trunk, a formidable garrison is ready to appear at any second - as a carefree traveler can easily see from his own experience, if, seduced by the smooth bark of a takhi tree, he decides to lean against it.

Almost all tree ants, even those that sometimes descend to the ground during the dry season and build summer anthills there, always keep the above-mentioned passages and bags as their permanent homes, and some species of ants do not leave trees at all all year round. Perhaps the same applies to ants who build anthills on a branch of foreign materials. Apparently, some ants always live in their aerial dwellings, and the inhabitants of the tokoki (see p. 211) do not leave their tree even where they are not threatened by any floods.

Ant trees exist throughout the tropics. Among the most famous is the cecropia (Cecropia peltata) of tropical America, which is called the "trumpet tree" because the Waupa Indians make their wind pipes from its hollow stems. Ferocious Azteca ants often live inside its stems, which, as soon as the tree is swayed, run out and. pounce on the daredevil who disturbed their peace. These ants protect cecropia from leaf cutters. The internodes of the stem are hollow, but they do not communicate directly with the outside air. However, near the apex of the internode, the wall becomes thinner. A fertilized female gnaws through it and hatches her offspring inside the stem. The base of the petiole is swollen, outgrowths are formed on its inner side, which the ants feed on. As the outgrowths are eaten, new ones appear. A similar phenomenon is observed in several related species. Undoubtedly, this is a form of mutual accommodation, as evidenced by the following interesting fact: the stem of one species, which is never "ant-like", is covered with a wax coating that prevents leaf cutters from climbing it. In these plants, the walls of the internodes do not become thinner and edible outgrowths do not appear.

In some acacias, the stipules are replaced by large spines swollen at the base. In Acacia sphaerocephala in Central America, ants enter these spines, clean them of internal tissues and settle there. According to J. Willis, the tree provides them with food: "Additional nectaries are found on the petioles, and edible outgrowths are found on the tips of the leaves." Willis adds that any attempt to damage the tree in any way causes the ants to pour out in masses.

The old riddle of which came first, the chicken or the egg, is repeated in the example of the Kenyan black gall locust (A. propanolobium), also known as the whistling thorn. The branches of this small shrub-like tree are covered with straight white thorns up to 8 cm long. Large galls form on these thorns. At first, they are soft and greenish-purple, and then harden, blacken, and ants settle in them. Dale and Greenway report: “The galls at the base of the thorns... are said to be due to ants that gnaw them from the inside. When the wind hits the holes of the Gauls, a whistle is heard, which is why the name "whistling thorn" arose. J. Salt, who examined the galls on many acacias, found no evidence that their formation was stimulated by ants; the plant forms swollen bases, and the ants use them.

Ant tree in Ceylon and southern India is Humboldtia laurifolia from the legume family. In him, cavities appear only in flowering shoots, and ants settle in them; the structure of non-flowering shoots is normal.

Considering the South American species of Duroia from the madder family, Willis notes that in two of them - D. petiolaris and D. hlrsuta - the stems are swollen right under the inflorescence, and ants can enter the cavity through the resulting cracks. A third species, D. saccifera, has anthills on leaves. The entrance, located on the upper side, is protected from rain by a small valve.

Gauls on a "whistling thorn" in Africa (close-up).

Corner describes the different types of macaranga (locally called mahang), the main ant tree of Malaya:

“Their leaves are hollow, and ants live inside. They gnaw their way out in the shoot between the leaves, and in their dark galleries they keep a mass of aphids, like herds of blind cows. The aphids suck the sugary sap of the shoot, and their bodies secrete a sweetish liquid that the ants eat. In addition, the plant produces so-called "edible outgrowths", which are tiny white balls (1 mm in diameter), which consist of oily tissue - it also serves as food for ants ... In any case, ants are protected from rain ... If you cut escape, they run out and bite ... Ants penetrate young plants - winged females gnaw their way inside the shoot. They settle in plants that have not reached even half a meter in height, while the internodes are swollen and look like sausages. The voids in the shoots arise as a result of the drying of the wide core between the nodes, like in bamboos, and the ants turn individual voids into galleries, gnawing through the partitions in the nodes.

J. Baker, who studied ants on macaranga trees, discovered that it was possible to cause a war by bringing two trees inhabited by ants into contact. Apparently, the ants of each tree recognize each other by the specific smell of the nest.

Ants inside leaves

Richard Spruce points out that spreading tissues and integuments, which form suitable sites for the emergence of ant colonies, are found mainly in some South American melastomas. The most interesting of these is the tokoka, whose numerous species and varieties grow in abundance along the banks of the Amazon. They are found mainly in those parts of the forest that are flooded during floods of rivers and lakes or during rains. Describing bags formed on leaves, he says:

“The leaves of most species have only three veins; some have five or even seven; however, the first pair of veins always departs from the main one about 2.5 cm from the base of the leaf, and the bag occupies precisely this part of it - from the first pair of lateral veins down.

Enlarged leaf (Dischidia rafflesiana) cut open. You can see the ant's nest and the roots of the creeper.

This is where the ants settle in. Spruce reported that he found only one species - Tososa planifolia - without such swellings on the leaves, and trees of this species, as he noticed, grow so close to rivers that they are undoubtedly under water for several months of the year. These trees, in his opinion, “cannot serve as a permanent residence for ants, and therefore the temporary appearance of the latter would not leave any imprint on them, even if instinct did not force the ants to avoid these trees altogether. Trees of other species of Tosos, growing so far from the shore that their tops remain above the water even at the moment of its highest rise, and therefore suitable for the constant habitation of ants, always have leaves with bags and are not free from them in any of the seasons. . I know this from bitter experience, for I have had many skirmishes with these belligerent bugs when I damaged their dwellings while collecting specimens.

Normal small and invaginated (enlarged) leaves of Dischidia rafflesiana (Singapore).

Bag-like dwellings of ants also exist in the leaves of plants of other families.

Like birds, bats' body surfaces are not smooth, so they have a great ability to retain pollen. They also fly fast and can travel long distances. Pollen from plants located at a distance of 30 km was found in the faeces of bats. Therefore, it is not surprising that bats are good pollinators.

The first conscious observations of bats visiting flowers were made by Bürk in the Biitenzorg (now Bogor) Botanical Garden. He observed that fruit-eating bats (probably Cynopterus) visited the inflorescences of Freycinetia insignis, a plant now known to be entirely chiropterophilic, in contrast to its closely related ornithophilous species.

Later, some authors described other cases, and the example of Kigelia (Kigelia) has become a classic. As early as 1922, Porsche was expressing certain considerations regarding chiropterophilia, noting its characteristic features and predicting many possible examples.

Thanks to the work of van der Pijl in Java, Vogel in South America, Jaeger, and Baker and Harris in Africa, bat pollination has now been identified in many plant families. It turned out that some plants, previously considered ornithophilous, are pollinated by bats (for example, species of Marcgravia).

Bats are generally insectivorous, but herbivorous bats independently appeared in both the Old and New Worlds. Perhaps the evolution went through frugivorousness to the use of flowers for food. Fruit-eating bats are known in two suborders inhabiting different continents, while African Pteropinae are characterized by a mixed diet. Like hummingbirds, nectar feeding is thought to have evolved from hunting insects in flowers.

Hart's observations in Trinidad in 1897 on Bauhiniamegalandra and Eperuafalcata are often mentioned in the literature, confusingly with incorrect conclusions.

Relationships between fruit and flower feeding Megalochiroptera are still partly dystropic. In Java, Cynopterus has been found to eat Durio flowers and parts of Parkia inflorescences.

In eastern Indonesia and Australia, Cynopterus and Pteropus destroy many Eucalyptus flowers, indicating hitherto unbalanced pollination conditions.

Macroglossinae are more adapted to the flower than even hummingbirds. In the stomachs of these animals caught in Java, only nectar and pollen were found, the latter in such large quantities that its accidental use is completely excluded. Obviously, pollen is in this case a source of protein, which their ancestors received from fruit juice. In the Glossophaginae, the use of pollen, although found, seems to be less significant.

Howell is of the opinion that Leptonycteris satisfies its protein requirements from pollen, and the protein in the pollen is not only of high quality, but also in sufficient quantity. She also states that the chemical composition of the pollen of flowers pollinated by bats is adapted to the use of it by these animals and differs from the composition of the pollen of related species that are pollinated by other animals. This can be seen as a floral part of the co-evolution of the chiropterophilia syndrome. Until now, the issue of African fruit-eating bats that swallow pollen has not been clarified.

The class of flowers pollinated by bats has been found to have an early side branch of evolution, forming its own subclass, for which the only pollinator is Pteropineae. In these flowers, solid food (with a characteristic odor) is represented only by specialized structures. There is neither nectar nor large masses of pollen. Freycinetiainsignis has a sweet bract, the Bassia species is a very sweet and easily separating corolla. Perhaps another species of Sapotaceae, namely the African Dumoriaheckelii, also belongs to this subclass.

The possibility of bat pollination of the white-flowered tree strelitzia (Strelitzianicolai) in the eastern region of Cape Cod needs to be investigated.

Nectar-eating New World bats are typically found in the tropics, but some migrate to the southern US during the summer, visiting cacti and agaves in Arizona. There is no record of bat pollination in Africa from the north of the Sahara, while Ipomoeaalbivena in South Pansbergen in South Africa just grows in the tropics. In Asia, the northern limit of bat pollination is in the northern Philippines and Hainan Island, with a small

Pteropinae extends beyond the latitude of Canton. The Eastern Pacific border runs in a sharp ridge through the Caroline Islands to Fiji. Macroglossinae are known to have visited flowers in Northern Australia (introduced by Agave), but the native Adansoniagregorii has all the characteristics of chiropterophilia; therefore, chiropterophilia must also exist on this continent.

Knowing the characteristics of pollination by bats can help in solving the mysteries of the origin of plants. The chiropterophilic flower of Musafehi is evidence that the species was introduced to Hawaii, where there are no bats. Chiropterophilia could have taken place in his homeland, New Caledonia, from where, as established by several botanists, he comes from.

Nectar-eating bats are characterized by a variety of adaptations. Thus, the Macroglossinae of the Old World have adapted to life on flowers, namely, they have decreased in size (the mass of Macroglossus minimus is 20–25 g), they have reduced molars, a long muzzle, and a very elongated tongue with long soft papillae at the end.

Similarly, some species of the New World Glossophaginae have a longer snout and tongue than their insectivorous relatives. Musonycterisharrisonii has a tongue length of 76 mm and a body length of 80 mm. Vogel believes that the hairs of the Glossophaga's coat are particularly well adapted to carrying pollen, since they are equipped with scales similar in size to those on the hairs that cover the belly of a bumblebee.

The physiology of Megachiroptera's sense organs deviates from what we usually see in bats. The eyes are large, sometimes with a folded retina (allowing rapid accommodation), with many rods but no cones (causing color blindness). In night photographs, fruit-eating Epomopsfranqueti show huge eyes, almost the same as those of a lemur. Smell perception probably plays a more important role than usual (large nasal cavities separated by septa), and the sonar (hearing) apparatus is less developed. According to Novik, sonar location organs are present in Leptonycteris and other pollinating Microchiroptera. In American bats with a mixed diet - nectar, fruits and insects - the sonar apparatus is intact. They make long flights with very short visits to sometimes rather poor flowers with a less rigid corolla (in this case, soaring visits are more often observed).

Macroglossinae have a powerful flight, which at first glance resembles the flight of swallows. Some species can hover in much the same way as hummingbirds. Similar data have been obtained for the Glossophaginae.

The presence of a certain harmony between the flower and animals in structure and physiology allows you to create the concept of the existence of a special type of flower pollinated by bats. Secondary self-pollination in Ceiba, or even parthenocarpy, as in cultivated Musa, can only cause harm.

It is noteworthy that although the development of chiropterophilia in America occurred independently and probably much later than elsewhere, and although the bats in question developed as an independent lineage rather late, the basic features that make up the syndrome of chiropterophilia are the same throughout the world. In all regions, bat-pollinated flowers and flower-pollinating bats are mutually adapted. This indicates common features in the physiology of all the bats under consideration. Sometimes, the development of chiropterophilia in different lines may also be based on common features of plant families.

Many flowers open shortly before dark and fall off in the early morning. Since the times of activity of diurnal birds and dusky bats, as well as the opening times of flowers pollinated by birds and bats, overlap, it is not surprising that some chiropterophilous plants are visited by birds. Werth apparently never made nocturnal observations and therefore lists Ceiba and Kigelia in the list of ornithophilous plants, although birds only plunder these flowers.

Flowers pollinated by bats are similar in appearance to flowers pollinated by hummingbirds, but only more pronounced. Flagellifloria (pendulifloria) is often observed, with flowers hanging freely on long hanging stems (Adansonia, Parkia, Marcgravia, Kigelia, Musa, Eperua). This is most evident in some species of Misipa, in which shoots up to 10 m long or more bring attraction elements out of the foliage.

In Markhamia, Oroxylum there is also a pincushion type with tight stems that lift the flowers up. The giant agave blossom speaks for itself. Favorable is also the pagoda-like structure of some Bombacaceae.

The phenomenon of chiropterophilia also explains why caulifloria, best adapted to visiting bats, is practically limited to the tropics, with only 1,000 cases found. Good examples are Cres "centia, Parmentiera, Durio and Amphitecna. In many genera (Kigelia, Misipa), flagellifloria and caulifloria are observed simultaneously in the same species; in other cases, these signs occur in different species.

Caulifloria is a secondary phenomenon. Its ecological nature is consistent with the results of studies of its morphological basis. Numerous cases had no taxonomic morphological, anatomical and physiological commonality.

In most examples of cauliflory where the flower was not chiropterophilous, another connection with bats was found, namely chiropterochory, the dispersal of seeds by fruit-eating bats. In this case, bats had an earlier and more widespread effect on tropical fruit, including color, position, and smell. This older syndrome corresponds exactly to the newer chiropterophilia syndrome. Basicaulicarpy may also be related to saurochory syndrome (seed dispersal by reptiles), a phenomenon older than angiosperms.

The sequence of flowering periods is necessary for both the plant and the bats. In Java, on large plantations of Ceiba, which has a certain flowering period, bats visited the flowers only in places close to gardens with Musa, Parkia, etc., where they could feed when Ceiba was not in bloom.

In general, the relatively young nature of chiropterophily is reflected in the distribution of bat-pollinated flowers among plant families. So, in Ranales, bats eat fruits, but do not visit flowers. Pollination of flowers by bats occurs in highly evolutionarily advanced families ranging from the Capparidaceae and Cactaceae, and is concentrated mainly in the Bignoniaceae, Bombacaceae and Sapotaceae. Many cases are completely isolated.

Some families (Bombacaceae and Bignoniaceae), characterized by chiropterophilia, apparently developed independently of each other in the Old and New Worlds, probably on the basis of some kind of preadaptations. It may also have happened in some genera, such as Misipa and especially Parkia, which Baker and Harris considered from the point of view of the noted representations.

Similarly, Bignoniacae and Bombacaceae, like Misipa and Musa, are characterized by some intermediate types which are pollinated by both birds and bats. Bombaxmalabaricum (Gossampinusheptaphylla) is ornithophilous, but not completely so it has open red cup-shaped daytime flowers. The flowers of this plant, however, have a bat-smell, which is characteristic of the chiropterophilic related species valetonii. In Java, malabaricum flowers are neglected by bats, but in the tropical regions of southern China they are eaten by Pteropinae. Chiropterophilia appears to have evolved from ornithophilia in the Bignoniaceae; Bombacaceae and Musa have probably reverted and subtropical species are being pollinated by birds. The transition from hawk-pollinated flowers in Cactaceae has already been considered.

It is still too early to try to quantify the links and their genetic implications. Sometimes bats (especially the slow Pteropinae) confine themselves to a single tree, resulting in self-pollination. Macroglossinae, characterized by rapid flight, make circles around trees, and apparently remember spatial relationships very well. However, in the study of pollen on wool and especially large accumulations of pollen in the stomachs, it was found that they are not characterized by constancy to flowers. It is also not clear how genetic purity is maintained in related chiropterophilic species, such as the wild species Musa, or whether it is maintained at all.

Introduction

Each organism, including plants, has the ability to reproduce its own kind, which ensures the existence of a species in space and time, sometimes for a very long time. With the loss of the ability to reproduce, species die out, which has repeatedly occurred in the course of the evolution of the plant world.

Plants reproduce both sexually and asexually. Sexual reproduction consists in the fact that two cells, called gametes, merge, and, in addition to the fusion of protoplasms, the fusion of nuclei is necessary for sexual reproduction. Thus, the fusion of nuclei is the most important stage of the sexual process, otherwise called fertilization.

Pollination plays a major role in plant reproduction. Pollination is the process of transferring pollen grains from the stamens to the stigma of the pistil. This process can occur with the help of various factors, both biotic and abiotic.

In this paper, we will consider the definition of pollination, its types. Cross-pollination and morphological adaptations of plants to it will be considered and studied in more detail.

The purpose of the course work is to consider and study the morphological adaptations of angiosperms to cross-pollination.

1. Review the definition of pollination.

2. Study the types of pollination.

3. Consider cross-pollination in more detail.

4. Consider the morphological adaptations of plants to cross-pollination.

Chapter 1. Pollination as a way of reproduction of angiosperms

1.1 Pollination as a mode of reproduction

Pollination is the process of transferring pollen grains from the stamen to the stigma of the pistil. This process can occur with the help of various factors, both biotic and abiotic.

In classical works on the ecology of pollination, two concepts are distinguished: autogamy, or self-pollination, in which pollen from the same flower falls on the stigma. If the flowers are on the same plant, pollination is called heitenogamy, if on different plants - xenogamy.

There are no sharp differences between these variants of pollination. Geitenogamy is genetically equivalent to autogamy, but requires the participation of certain pollinators, depending on the structure of the flower. In this respect, it is similar to xenogamy. In turn, xenogamy can be identical to autogamy if the pollinated plants belong to the same clone, i.e. arose as a result of vegetative reproduction of one maternal individual.

In this regard, pollination is reduced to two types: autogamy, or self-pollination, and cross-pollination.

1.2 Autogamy, or self-pollination

This type of pollination is characteristic only of bisexual flowers. Autogamy can be random or regular.

Random autogamy is not uncommon. It is difficult to enumerate all the factors contributing to its implementation. It is only important that there is a physiological compatibility of pollen grains and the stigma of the pistil.

Regular autogamy can be gravitational if the pollen grain, due to its gravity, falls on the stigma from the anther located above it. The carriers of pollen grains inside the flower can be raindrops, small insects - thrips, which settle in the flower. The most common is contact autogamy, in which the opening anther comes into contact with the stigma of the pistil (hoof). Autogamy is closely related to the time factor and environmental conditions. In Dortmann's lobelia (Lobelia dortmanna) (see Fig. 1), it occurs before flowering, although it develops chasmogamous flowers with external attributes to attract pollinators.

Figure 1 - Lobelia Dortmann (Lobelia dortmanna)

In the small mousetail (Myosurus minimus L.) (see Fig. 2), self-pollination occurs in the first half of flowering, later it is impossible. In flowers in which self-pollination occurs before flowering, certain elements are often reduced. The extreme degree of such reduction is represented by cleistogamous flowers.

Figure 2 - Small mousetail (Myosurus minimus L.)

In oxalis (Oxalis) (see Fig. 3), about a month after flowering, when seeds are already developing in their ovaries, small (up to 3 mm) cleistogamous flowers appear with perianth in the form of small scales. An important feature of the cleistogamous flower is that anthers never open in it, but pollen tubes grow from the pollen grains in them, piercing the anther wall and growing towards the stigma, often bending at the same time. The stigma is often located at the top of the ovary, there is no style.

Figure 3 - Common Oxalis (Oxalisacetosella)

Often, cleistogamy is optional and appears in plants only under certain weather conditions. This is found in plantain chastukha (Alismaplantago-aguatica), sundew, feather grass, in which cleistogamous flowers develop during soil drought and low temperatures. In wheat, chasmogamous flowers are formed in warm, humid weather, and cleistogamous in dry and hot weather.

In most cases, cleistogamy occurs in unstable habitat conditions unfavorable for cross-pollination.

1.3 Cross-pollination

Cross-pollination, or allogamy, is a type of pollination in angiosperms in which pollen from the androecium of one flower is transferred to the stigma of the pistil of another flower.

There are two forms of cross-pollination:

1. Geitonogamy (adjacent pollination) - pollination in which pollen from a flower of one plant is transferred to the stigma of the pistil of another flower on the same plant;

2. Xenogamy - cross-pollination, in which pollen from the flower of one plant is transferred to the stigma of the pistil in the flower of another plant.

With the help of cross-pollination, genes are exchanged, which maintains a high level of heterozygosity in the population, determines the unity and integrity of the species. With cross-pollination, the possibilities of recombination of genetic material increase, more diverse genotypes of offspring are formed as a result of the combination of hereditarily diverse gametes, therefore, more viable than with self-pollination, offspring with a greater amplitude of variability and adaptability to various conditions of existence. Thus, cross-pollination is biologically more beneficial than self-pollination, therefore it was fixed by natural selection and became dominant in the plant world. Cross-pollination exists in over 90% of plant species.

Cross-pollination can be carried out both biotically (with the help of living organisms) and abiotic (through air or water currents).

Cross-pollination is carried out in the following ways:

a) Anemophily (pollination by wind)

b) Hydrophilia (pollination with water)

c) Ornithophilia (pollination by birds)

d) Chiropterophilia (pollination by bats)

e) Entomophily (pollination by insects)

Chapter 2. Morphological adaptations of plants to cross-pollination.

2.1 Anemophily or wind pollination

Wind-pollinated plants often grow in large clusters, for example, hazel thickets, birch groves. A person sows rye and corn on hundreds of hectares, and sometimes thousands of hectares of land.

In summer, flower pollen rises above the rye field in a cloud. Wind pollinated plants produce a lot of pollen. Part of the dry and light pollen necessarily falls on the stigmas. But most of the pollen is wasted without pollinating the flowers. The same can be seen in spring when hazel, birch and other wind-pollinated trees and shrubs bloom. Poplar, alder, rye, corn and other plants with inconspicuous flowers are pollinated by the wind.

Most wind-pollinated trees bloom in early spring, before the leaves appear. This ensures that the pollen gets to the stigma better.

Plants pollinated by the wind do not have bright and fragrant flowers. Inconspicuous, usually small flowers, anthers on long hanging threads, very small, light, dry pollen - all these are adaptations for wind pollination.

2.2 Hydrophilia or water pollination

Hydrophilia is of more ancient origin, since it is believed that the first higher plants appeared in water. However, most aquatic plants are air-pollinated, just like their terrestrial relatives. Plants such as Nymphaea, Alisma and Hottonia are entomophilous, Potamogeton or Myriophyllum anemophilous, and Lobelia dortman self-pollinating. But for pollination of some aquatic plants, an aquatic environment is necessary.

Hydrophilia can occur both on the surface of the water (ephidrophilia) and in the water (hyphydrophilia). These two types of pollination represent a further development of anemophily or entomophily. Many small, self-pollinating land plants can flower while submerged in water; at the same time, the self-pollination mechanism functions, usually enclosed in an air sac inside the flower. Cleistogamous flowers represent the highest stage of such development.

Ephydrophily is a unique type of abiotic pollination, since in this case pollination occurs in a two-dimensional environment. Compared to the three-dimensional environment in which anemophily or hyphydrophilia occurs, this type of pollination provides a greater economy of pollen. In epihydrophilia, pollen is released from the anthers in the water and floats to the surface where the stigmas (Ruppia, Callitriche autumnalis) are found. Pollen grains quickly spread over the surface film of water. This is easy to see when watching Ruppia bloom: small yellow drops appear on the surface of the water and spread quickly, like drops of fat; this is facilitated by an oily layer covering the shell of the pollen grain.

An interesting case of pollination in Vallisneria is widely known, in which, instead of individual pollen grains, the entire male flower comes to the surface of the water; therefore, the pollen does not even touch the surface of the water. Small funnels form around the emerging female flowers; male flowers floating nearby slide from the edge of such a funnel to its center; while the anthers touch the stigmas. Due to this efficient method of pollination, the number of pollen grains in male flowers is greatly reduced. Vallisneria-type mechanisms are also found in various representatives of the Hydrocharitaceae, sometimes, as in Hydrilla, along with exploding anthers. A similar mechanism of pollination is also observed in Lemna trisulca, only the entire plant rises to the surface of the water; and in Elodea, with a similar mechanism of pollination, staminate flowers are brought to the surface of the water, which are partly attached and partly free-floating.

Hyphydrophilia has been described in a very few plants, such as Najas, Halophila, Callitriche hamulata and Ceratophyllum. So far, they are treated simply as separate cases, since there is probably little in common between them, except for the extreme reduction of the exine. In Najas, the slowly descending pollen grains are "caught" by the stigma.

The dispersing pollen unit in Zostera is 2500 µm long and much more like a pollen tube than a pollen grain. Being very mobile, it quickly wraps itself around any object encountered on the way, for example, around a stigma. However, this reaction is completely passive. The pollen grain morphology of Zostera can be seen as an extreme case of a trend that seems to be shared by other hyphydrophilic plants: a rapidly growing pollen tube ensures that the pollen grains spread rapidly. In Cymodoceae, even more elongated pollen grains (5000-6000 µm) have been described.

2.3 Ornithophily or bird pollination

Since the birds fly well and the surface of their body is not smooth, they have good external conditions for pollination. No one is surprised that insects get food from flowers, but the corresponding actions of birds cause great surprise and reflection on how they got the “idea” to use the nectar of flowers. One of the ideas put forward was the idea that pollination arose as a result of the eating of flowers by birds, and that food may have been primarily fruits. It has also been suggested that woodpeckers or sap-eating woodpeckers (Sphyrapicus) sometimes change their diet and switch to juices flowing from hollows (some of them also peck fruits; Dendrocopus analis - fruits of Cassia grandis). A third group of "explanations" suggests that the birds pursued insects in flowers and happened to find nectar or pierce succulent tissues; or at first they drank water collected in flowers to quench their thirst, since in tropical forests water is difficult to access for animals living in the crowns of trees. The fact that hummingbirds originally pursued insects in flowers can be seen even today. The rapid absorption of nectar makes it difficult to identify it in the stomach of birds, while indigestible remains of insects are easily recognized. However, in the ornithological literature there is a large amount of data indicating that the digestive systems of birds are filled with nectar. Extraction of nectar by piercing the base of the corolla is further evidence that all this is done for the sake of extracting nectar. Insects cannot obtain nectar in this way. Some hummingbirds are addicted to piercing flowers, like some hymenoptera. None of the insects get nectar from the closed flowers of the Loranthaceae from Java, which open only when struck by nectar-seeking birds. The fact that birds visit flowers can be confirmed even on very old museum preparations by the presence of pollen grains in feathers or on the beak.

Hummingbirds need a large amount of energy, especially when hovering. It is precisely such a large expenditure of energy for soaring and flying that can explain the small size of these birds. After a period of fasting, nutrient stores can be severely reduced despite low metabolic rates during sleep.

In pollinators with different energy budgets, the efficiency of nectar uptake and its metabolism are different. The presence of flowers with a large amount of nectar is a signal forcing hummingbirds to seize and defend territories. One could refer to the migration of hummingbirds to those places where these flowers are numerous, especially during the breeding season.

From a pollination point of view, it didn't really matter whether the birds visited the flowers for nectar or to catch insects, until these visits became regular. Whether nectar or insect is the reason for the visit is a problem of adaptation, not function. In Java, Zosterops visits the non-ornithophilous Elaeocarpus ganitrus to collect mites, which are in abundance in the flowers.

There is no doubt that birds perched on flowers for all the reasons mentioned above. Even if, from the gardener's point of view, the flowers were damaged, they were successfully pollinated. Damage to the flower itself is of little consequence as long as the pistil is not damaged. After all, explosive flowers are also destroyed themselves.

Other similar occasional flower visits by dystrophic birds have recently been recorded in birds migrating to England from more southerly areas. Campbell observed various birds in England chasing insects in flowers while landing very small amounts of pollen.

From these examples of dystropic visits to flowers, it appears that there is a gradual transition through certain allotropic birds with a mixed diet, in which nectar is one of the ingredients, to eutropic ones, as a result of which true ornithophily is established.

For a long time, observations were made of visits to hummingbird flowers. Ornithophilia as a scientifically recognized phenomenon was established by Treleese at the end of the last century, and Johaw, Freese, and chiefly Werth studied it in more detail. However, it was only when Porsche in the 1920s collected a huge amount of data and made convincing conclusions about the now well-known phenomena that ornithophilia was unanimously recognized, even if its origin is still a matter of controversy.

The habit of collecting nectar is obviously polyphyletic, having arisen in different groups of birds in different regions. The best-known example of high adaptation are the hummingbirds (Trochilidae) of North and South America. Hummingbirds were probably originally insectivorous, but later switched to nectar; their chicks still eat insects in addition to nectar. The same is observed in insects.

Another American group of more or less eutropic flower-eating birds are the much less important sugar-eating birds (Coerebidae). In the Old World, other families have developed the same characteristics as hummingbirds, even if their adaptations are usually less significant. In Africa and Asia live nectaries (Nectarinidae), in Hawaii - Hawaiian flower girls (Drepanididae), closely related to local lobelia, in the Indo-Australian region - honey badgers (Meliphagidae) and brush-tongued honey parrots or small loris parrots (Trichoglossidaei).

Less specialized pollinators of flowers with a mixed diet (allotropic pollinators) are also active, but as pollinators to a much lesser extent, especially in simpler bird-pollinated flowers (Bombax, Spathodea); this shows that flowers and their birds may have evolved in parallel, influencing each other. Pollinators are found in many other families, such as some tropical nightingales (Pycnonotidae), starlings (Sturnidae), orioles (Oriolidae), and even among tropical woodpeckers (Picidae), where the fringe at the tip of the tongue is the first sign of morphological adaptation.

The flower-suckers (Dicaeidae) visit a variety of flowers, while showing a curious "specialization" to one group of plants, namely the tropical Loranthoideae, in which they not only visit ornithophilous flowers, but also adapt to the digestion of fruits and the dispersal of seeds. The oldest observations of bird pollination in the New World were made by Catesby and Ramphius in the Old World.

The areas in which any type of ornithophilia is found practically cover the American continent and Australia and further tropical Asia and the deserts of South Africa. According to Werth, Israel is the northern limit of this area, with Cinnyris visiting the flowers of the red Loranthus as well. Galil recently reported on the abundance of these birds on plants growing in gardens.

In the mountains of Central and South America, the number of ornithophilous species is unusually large. If bees are present in the high elevations of Mexico, they are just as effective as pollinators as birds, except that birds are more effective under adverse conditions. However, Bombus species are not very sensitive to climate. Their presence can completely change the picture, as shown by van Leeuwen. Stevens points out similar results of Rhododendron pollination in the mountains of Papua.

Obviously, in Australia and New Zealand, the number of eutropic pollinating insects is also low, and the function of higher bees, performed by them on other continents, is taken over by birds.

Individual cases of feeding on flowers in various groups of birds, their geographical distribution and single cases of ornithophilous types of flowers in many groups of plants - all this indicates that ornithophily arose relatively recently.

The ability to soar, well developed in hummingbirds, is rare in other groups of birds; it is observed, for example, in the honey-eating Acanthorhynchus, and is poorly developed in the Asiatic Arachnothera. Some birds can soar in strong headwinds.

The brightness of the plumage, leading to a significant similarity in the color of birds and flowers, may seem rather strange. We have reason to consider this fact from the point of view of protective coloration. Van der Pale observed that a highly visible flock of red-green Loriculus (brightly colored hanging parrots) becomes invisible when landing on a flowering Erythrina. Obviously, these animals are largely vulnerable when they are immobile while eating.

Grant argued that "persistence" to flowers is poorly developed in birds and that their feeding habits are too complex. Information about the evolution of constancy to flowers is different for different authors. Snow and Snow suggest a very close relationship - monotropic, in our current terminology - between Passijloramixta and Ensiferaensifera. Obviously, the relationship between different species of hummingbirds and the plants that provide them with food varies greatly, ranging from strict territoriality to a highly inefficient strategy of successive visits, when birds use any available source of nectar. It is also necessary to take into account the possibility of learning in birds. If diversity is allowed, then impermanence may be due to the lack of a proper distinction between deceit and preferred constancy. Birds feed on any kind of food, so it is natural that if there is a profuse bloom and a large amount of nectar is available, the apparent preference of the birds in this case will simply be a matter of statistics and will not depend on the food itself. If there is no such flowering, then they can fly from one species to another or even use other food. Any observed consistency will be impressive even though flower tube length, beak length, nectar composition, etc. may play a role in flower selection. In emergencies, birds eat flowers. Johow noticed in Chile that hummingbirds can even switch to European fruit trees or Citrus species. Hemitropic birds switch to fruits more frequently. In the tropics, birds especially prefer fresh flowering trees. The ecological significance of this, of course, is not absolute, but relative and can be of selective significance.

The phylogenetic development of tropical plant species and the most highly developed groups of pollinators has led to a distinct and easily recognizable bird pollination syndrome that excludes other pollinators. Any random combinations in this case are impossible. The mutual dependence is well seen in the example of the Hawaiian flower girls Drepanididae and the flowers pollinated by them, which, when the birds were exterminated, became autogamous.

For the differential diagnosis of classes of ornithophilous flowers and flowers pollinated by diurnal Lepidoptera. The differences are rather indistinct, especially in American plants.

Some bird-pollinated flowers are brush-like (Eucalyptus, heads of Proteaceae and Compositae), others are slanted-mouthed (Epiphyllum) or tubular (Fuchsiafulgens). Some moths are typically ornithophilous.

The fact that various types of flowers are ornithophilous indicates a recent development of ornithophily, which is on top of the previous ecomorphological organizations that determine the types of structure, etc., but leading to a secondary convergence of the style. Isolated instances of resemblance between unrelated flowers, regarded by some morphologists as a mysterious "repeated pair" and by others as orthogenetic, probably represent a parallel adaptation in the field of pollination.

The effectiveness of this syndrome is shown by the fact that typical bird-pollinated flowers growing in European gardens attract the attention of short-beaked, unadapted dystrophic birds, and also by the fact that flower-pollinating birds immediately recognize and then try to use the flowers of introduced bird-pollinated plants. Flower size is not included in the syndrome. Many flowers pollinated by birds are relatively small. The flowers pollinated by birds are usually deep, not belonging to any one particular class, but brush-like and tubular are the most characteristic among them.

Sensitivity to different regions of the spectrum in different species of birds varies. In one species of hummingbird (Huth), a shift to the short-wavelength region of the spectrum was found compared to the human visible spectrum.

In Columneaflorida birds are attracted by red spots on the leaves, while the flowers themselves are hidden. Since this spot does not reproduce the shape of the flower, a high degree of mental integration can be assumed in birds pollinating Columneaflorida.

Flowers with a bright, contrasting color should include flowers in the species Aloe, Strelitzia and many bromeliads.

The transition to ornithophily is mostly recent, but in some groups the ornithophily appears to be older. Porsche identified a suprageneric group in Cactaceae (Andine Loxantocerei), in which, apparently, ornithophily in the tribe was fixed. Snow and Snow give other examples of the coevolution of ornithophilous flowers and their pollinators.

Among Euphorbiaceae with dense cyathium, Poinsettia has large glands and red bracts that attract hummingbirds. The genus Pedilanthus is characterized by an even higher specialization, which appeared from the beginning of the Tertiary period, and in this genus the glands are in spurs, the flowers are erect and zygomorphic.

Even among orchids, which have excellent pollinators - bees, some species have switched to ornithophily in an endless search for new pollinators typical of this family. In the South African genus Disa, some species have probably become ornithophilous. Therefore, the flowers of this genus pollinated by butterflies are already red, with a spur and with a reduced upper lip. The same occurs in Cattleyaaurantiaca and in some species of Dendrobium in the mountains of New Guinea. Birds visiting the flowers of Elleanthuscapitatus and Masdevalliarosea were observed by Dodson.

2.4 Chiropterophilia or bat pollination

Hart's observations in Trinidad in 1897 on Bauhiniamegalandra and Eperuafalcata are often mentioned in the literature, confusingly with incorrect conclusions.

Relationships between fruit and flower feeding Megalochiroptera are still partly dystropic. In Java, Cynopterus has been found to eat Durio flowers and parts of Parkia inflorescences.

In eastern Indonesia and Australia, Cynopterus and Pteropus destroy many Eucalyptus flowers, indicating hitherto unbalanced pollination conditions.

The possibility of bat pollination of the white-flowered tree strelitzia (Strelitzianicolai) in the eastern region of Cape Cod needs to be investigated.

2.5 Entomophily or insect pollination

Insects in the flowers are attracted to pollen and the sweet juice of nectar. It is secreted by special glands - nectaries. They are located inside the flower, often at the base of the petals. Pollen and sweet nectar are the food of many insects.

Here a bee sat on the inflorescence. She quickly makes her way to the nectar stores hidden in the depths of the flower. Squeezing among the anthers and touching the stigma, the bee sucks nectar with its proboscis. Her furry body was covered with yellow pollen. In addition, the bee collected pollen in special baskets on its hind legs. A few seconds pass, and the bee leaves one flower, flies to another, third, etc.

Large single flowers, small flowers collected in inflorescences, bright color of petals or tepals, nectar and aroma are signs of insect pollinated plants. Fragrant tobacco flowers open only at dusk. They smell a lot. By night, the aroma intensifies, and white large flowers still attract night butterflies from afar.

Large, brightly colored poppy petals and an abundance of pollen in the flower are a good bait for beautiful golden-green bronze beetles. They feed on pollen. Smeared in pollen, bronzes fly from one plant to another and transfer the dust particles adhering to the body to the stigmas of the pistils of neighboring flowers.

There are plants whose flowers are pollinated only by certain insects. For example, snapdragons are pollinated by bumblebees. During flowering, hives with bees are brought to the gardens. Bees in search of food pollinate the flowers of fruit trees, and the yield of fruits increases.

The flowers, relying on insects for such an important matter, amaze with a variety of shapes and shades, and almost all of them are brightly colored. However, in all this diversity, one can trace the structure common to all. A typical flower is a receptacle surrounded by leaves that have taken the form of petals and stamens.

Some resemblance to the leaves was retained only by the calyx, formed from green sepals and forming the outer circle of the perianth. The sepals hiding the bud in poppies fall off when the flower blooms, while in tomatoes or strawberries they remain until the fruit is fully ripe.

Above the calyx are larger and brightly colored petals, although wind-pollinated flowers such as the single-flowered coastal (Littorella unijlora) do not have them at all. Hidden within some of the modified petals are nectaries, groups of cells that produce sweet nectar to attract insects. Nectaries may be pouches at the base of the petals, like buttercups, or long spurs, like violets. Spurs usually attract pollinators with long proboscises - hawks and butterflies.

The sepals and petals together form a perianth, although gardeners more often use this term to designate fused perianths, as in daffodils. The totality of all the petals is called the corolla. The reproductive organs of the flower are also located here. The female organ - pistil - consists of an ovary, a style and a stigma, on which pollen settles. The column is surrounded by male organs (stamens), each of which is a thin stalked filament with an anther at the top.

Depending on the position of the ovary, the upper one is distinguished when the petals and sepals are located below it, and the lower one, when parts of the flower are above the ovary. In some flowers - for example, in buttercups - several pistils are collected in one corolla, containing all the female organs; others may have fused pistils, sometimes with one style for all, sometimes with several.

Most flowering plants are bisexual, but some of them have chosen a different path of development. Almost all species of sedge (all wind-pollinated) have male and female flowers on the same plant, while the insect-pollinated holly has same-sex flowers on separate male and female plants.

If a tulip throws out only one flower, then, for example, lily of the valley flowers are collected in an inflorescence on one pedicel, attracting insects with their appearance and delicate fragrance. Some inconspicuous flowering plants lure pollinators by surrounding the flowers with brightly colored leaves. The fiery red "petals" of the poinsettia (Euphorbia pulcherti) are actually modified leaves, or bracts. No one, except for insects, usually notices real flowers.

Conclusion

Having done this work, we found out that pollination is the main method of reproduction of angiosperms, there are 2 types of pollination: autogamy (self-pollination) and cross-pollination.

In the work, morphological adaptations of flowering plants to cross-pollination, such as wind, water, bird, insect and bat pollination, have been considered and studied.

In this work, the goal was achieved and all tasks were disclosed.

pollination angiosperm plant morphological

Bibliography

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Birds, elephants and turtles

The relationship between trees and animals is most often expressed in the fact that birds, monkeys, deer, sheep, cattle, pigs, etc. contribute to the dispersal of seeds, but we will only consider the effect of animal digestive juices on ingested seeds.

Homeowners in Florida have a strong dislike for the Brazilian pepper tree (Schinus terebinthifolius), a beautiful evergreen that turns red berries in December, peeping from dark green scented leaves in such numbers that it resembles a holly. In this magnificent dress, the trees stand for several weeks. Seeds ripen, fall to the ground, but young shoots never appear under the tree.

Arriving in large flocks, the red-throated thrushes descend on pepper trees and fill full crops with tiny berries. Then they flit to the lawns and walk among the sprinklers there. In the spring, they fly north, leaving numerous business cards on Florida lawns, and a few weeks later, pepper trees begin to grow everywhere - and especially in flowerbeds where thrushes searched for worms. A weary gardener has to pull out thousands of sprouts so that the pepper trees do not take over the whole garden. The gastric juice of the red-throated thrush somehow affected the seeds.

Formerly in the United States, all pencils were made from juniper wood (Juniperus silicicola), which grew abundantly on the plains of the Atlantic coast from Virginia to Georgia. Soon, the insatiable demands of industry led to the extermination of all large trees and it was necessary to look for another source of wood. True, a few surviving young junipers reached maturity and began to bear seeds, but under these trees, which in America to this day are called "pencil cedars", not a single sprout appeared.

But driving along rural roads in South and North Carolina, you can see millions of "pencil cedars" growing in straight rows along wire fences, where their seeds have fallen in the excrement of tens of thousands of sparrows and meadow trupials. Without the help of feathered intermediaries, juniper forests would forever remain only a fragrant memory.

This service that birds have rendered to the juniper makes us wonder: to what extent do the digestive processes of animals affect the seeds of plants? A. Kerner found that most of the seeds, passing through the digestive tract of animals, lose their germination. In Rossler, out of 40,025 seeds of various plants fed to California oatmeal, only 7 germinated.

In the Galapagos Islands off the west coast of South America, a large, long-lived perennial tomato (Lycopersicum esculentum var. minor) grows, which is of particular interest because careful scientific experiments have shown that less than one percent of its seeds naturally germinate. But in the event that the ripe fruits were eaten by giant tortoises, which are found on the island, and remained in their digestive organs for two to three weeks or longer, 80% of the seeds germinated. Experiments have suggested that the giant tortoise is a very important natural mediator, not only because it stimulates the germination of seeds, but also because it ensures their efficient dispersal. The scientists also concluded that seed germination was due not to mechanical, but to enzymatic action on the seeds during their passage through the turtle's digestive tract.

In Ghana Baker ( Herbert J. Baker - Director of the Botanical Gardens of the University of California (Berkeley).) experimented with the germination of baobab and sausage tree seeds. He found that these seeds practically did not germinate without special treatment, while their numerous young shoots were found on stony slopes at a considerable distance from adult trees. These places served as a favorite habitat for baboons, and fruit cores indicated that they were included in the diet of monkeys. The strong jaws of baboons allow them to easily gnaw through the very hard fruits of these trees; since the fruits themselves do not open, without such assistance the seeds would not have the opportunity to disperse. The percentage of germination in seeds extracted from baboon dung was noticeably higher.

In Southern Rhodesia, there is a large, beautiful ricinodendron tree (Ricinodendron rautanenii), which is also called "Zambezian almond" and "Manketti's nut". It bears fruits the size of plums, with a thin layer of pulp surrounding very hard nuts - "edible if you can crack them open," as one forest ranger wrote. The wood of this tree is only slightly heavier than balsa (see ch. 15). The package of seeds that was sent to me said: "Collected from elephant droppings." Naturally, these seeds rarely germinate, but there are a lot of young shoots, since elephants are addicted to these fruits. Passing through the digestive tract of an elephant does not seem to have any mechanical effect on the nuts, although the surface of the samples sent to me was covered with grooves, as if made with the tip of a sharpened pencil. Perhaps these are traces of the action of the gastric juice of an elephant?

C. Taylor wrote to me that the ricinodendron growing in Ghana produces seeds that germinate very easily. However, he adds that musanga seeds may “need to pass through the digestive tract of some animal, as it is extremely difficult to germinate them in nurseries, and in natural conditions the tree reproduces very well.”

Although elephants in Southern Rhodesia cause great damage to the forests of the savannahs, they at the same time ensure the distribution of certain plants. Elephants love camelthorn beans and eat them in large quantities. The seeds come out undigested. During the rainy season, dung beetles bury elephant droppings. Thus, most of the seeds end up in an excellent bed. This is how thick-skinned giants at least partly compensate for the damage they cause to trees, tearing off the bark from them and causing all sorts of other damage to them.

C. White reports that the seeds of the Australian quondong (Elaeocarpus grandis) germinate only after being in the stomach of emus, which love to feast on fleshy, plum-like pericarp.

wasp trees

One of the most misunderstood groups of tropical trees is the fig tree. Most of them come from Malaysia and Polynesia. Corner writes:

“All members of this family (Moraceae) have small flowers. In some, such as breadfruit, mulberries, and fig trees, the flowers are united in dense inflorescences that develop into fleshy buds. In breadfruit and mulberries, the flowers are placed outside the fleshy stem that supports them; the fig trees have them within it. The fig is formed as a result of the growth of the stem of the inflorescence, the edge of which then bends and contracts until a calyx or a jug with a narrow mouth is formed - something like a hollow pear, and the flowers are inside ... The pharynx of the fig is closed by many scales superimposed on each other ...

The flowers of these fig trees are of three types: male with stamens, female, which produce seeds, and gall flowers, so called because they develop larvae of small wasps that pollinate the fig tree. Gallic flowers are sterile female flowers; breaking a ripe fig, they are easy to recognize, as they look like tiny balloons on pedicels, and on the side you can see the hole through which the wasp got out. The female flowers are recognized by the small, flat, hard, yellowish seed they contain, and the male flowers by the stamens...

Pollination of fig blossoms is perhaps the most interesting form of interrelationship between plants and animals known so far. Only tiny insects called fig wasps (Blastophaga) can pollinate the flowers of the fig tree, so that the reproduction of fig trees depends entirely on them ... If such a fig tree grows in a place where these wasps are not found, the tree will not be able to reproduce with the help of seeds ... ( Recent studies have established that some fig trees, such as figs, are characterized by the phenomenon of apomixis (fetal development without fertilization). - Approx. ed. But fig wasps, in turn, are completely dependent on the fig tree, since their larvae develop inside gall flowers and the entire life of adults passes inside the fruit - excluding the flight of females from a ripening fig on one plant to a young fig on another. Males, almost or completely blind and wingless, live in the adult stage for only a few hours. If the female fails to find a suitable fig tree, she cannot lay her eggs and dies. There are many varieties of these wasps, each of which appears to serve one or more related species of the fig tree. These insects are called wasps because they are distantly related to true wasps, but they do not sting and their tiny black bodies are no more than a millimeter long...

When the figs on the gall plant ripen, adult wasps hatch from the ovaries of the gall flowers, gnawing through the wall of the ovary. The males fertilize the females inside the fetus and die soon after. The females get out between the scales covering the mouth of the fig. Male flowers are usually located near the throat and open by the time the fig ripens, so that their pollen falls on the female wasps. The wasps, showered with pollen, fly to the same tree, on which young figs begin to develop, and which they probably find with the help of smell. They penetrate into young figs, squeezing between the scales that cover the throat. This is a difficult process ... If a wasp climbs into a fig-gall, its ovipositor easily penetrates through a short column into the ovule, in which one egg is laid ... The wasp moves from flower to flower until its supply of eggs runs out; then she dies of exhaustion, because, having hatched, she does not eat anything ... "

Trees pollinated by bats

This phenomenon has been studied in detail in Trinidad, Java, India, Costa Rica, and many other places; observations revealed the following facts:

Rat "tree"

The method developed by the yeye to ensure cross-pollination is so unusual that it is worth talking about in more detail.

Ant trees

Some tropical trees are attacked by ants. This phenomenon is completely unknown in the temperate zone, where the ants are just harmless bugs that climb into the sugar bowl.

Regarding the latter, Darwin wrote:

“The protection of the foliage is provided ... by the presence of entire armies of painfully stinging ants, whose tiny size only makes them more formidable.

This union of trees and ants is carried out in three ways:

The second way of using leaves, which is observed much less often, is that ants bend the edges of the leaf, glue them together and settle inside.

Ants in the branches

Spruce detailed his introduction to ant trees in the Amazon:

All tree-like plants of the buckwheat family (Polygonaceae), Spruce continues, are affected by ants:

Corner describes the different types of macaranga (locally called mahang), the main ant tree of Malaya:

Ants inside leaves

Bag-like dwellings of ants also exist in the leaves of plants of other families.

Ant nests on epiphytes and vines

The most notable of the epiphytes that harbor ants high among the branches of tropical trees are the eighteen species of Myrmecodia, which are found everywhere from New Guinea to Malaya and the far north of Australia. They often coexist with another epiphyte, Hydnophytum, a genus of forty species. Both of these genera are included in the madder family. Merril reports that some of them are found in lowlands and even in mangroves, while others grow in primary forests at high altitudes. He continues:

“The bases of these trees, sometimes armed with short thorns, are very enlarged, and this enlarged part is penetrated by wide tunnels into which small holes lead; inside the strongly swollen bases of these plants myriads of small black ants find shelter. From the top of the tuberous, tunnelled base rises stems, sometimes thick and unbranched, sometimes thin and very branched; small white flowers and small fleshy fruits develop in the axils of the leaves.

“Perhaps the most peculiar adaptation of the leaves is noted in groups such as Hoya, Dlschidia and Conchophyllum. These are all creepers with abundant milky juice belonging to the family Asclepmdaceae. Some of them hang on trees as epiphytes or semi-epiphytes, but in Conchophyllum and some species of Noua, the thin stems lie close to the trunk or branches of the depewa, and the round leaves, arranged in two rows along the stem, are arched and their edges are closely pressed to the bark. Roots grow from their sinuses, often completely covering a piece of bark under the leaf - these roots hold the plant in place and, in addition, absorb the moisture and nutrients it needs; under each such leaf in a finished dwelling, colonies of small ants live.

Dischidia rafflesiana, a peculiar pitcher plant of Southeast Asia, provides shelter to ants. Some of its leaves are iloski, others are swollen and reminiscent of jugs. Willis describes them as follows:

“Each leaf is a jug with an edge turned inside, about 10 cm deep. An adventitious root grows into it, developing near on the stem or on the petiole. The jug ... usually contains various debris caused by ants nesting there. Rainwater accumulates in most pitchers ... The inner surface is covered with a wax coating, so that the pitcher itself cannot absorb water and it is sucked up by the roots.

The study of the development of the pitcher shows that it is a leaf, the lower part of which is invaginated.

Trees that cannot live without the help of animals

Relationship between trees and animals most often expressed in the fact that birds, monkeys, deer, sheep, cattle, pigs, etc. contribute to the dispersal of seeds, but it is not this obvious fact that is interesting, but the question of the effect of the digestive juices of animals on swallowed seeds.

Homeowners in Florida have a strong dislike of the Brazilian pepper tree, a beautiful evergreen that in December is covered with red berries that jut out from dark green scented leaves in such numbers that it resembles a holly (holly).

In this magnificent dress, the trees stand for several weeks. Seeds ripen, fall to the ground, but young shoots never appear under the tree.

Arriving in large flocks, wandering thrushes descend on pepper trees and stuff full crops with tiny berries. Then they flit to the lawns and walk among the sprinklers there.

In the spring, they fly north, leaving numerous business cards on Florida lawns, and a few weeks later, pepper trees begin to grow everywhere - and especially in flowerbeds where thrushes searched for worms. The unfortunate gardener is forced to pluck out thousands of sprouts so that the pepper trees do not take over the whole garden. The stomach juice of the thrushes somehow affected the seeds.

Previously in the United States, all pencils were made from the wood of the juniper, which grew abundantly on the plains of the Atlantic coast from Virginia to Georgia. Soon, the insatiable demands of industry led to the destruction of all large trees, and another source of wood had to be found.

True, a few surviving young junipers reached maturity and began to bear seeds, but under these trees, which in America to this day are called "pencil cedars", not a single sprout appeared.

This service that birds have rendered to the juniper makes us wonder: to what extent do the digestive processes of animals affect the seeds of plants? A. Kerner found that most of the seeds, passing through the digestive tract of animals, lose their germination. In Rossler, out of 40,025 seeds of different plants fed to California oatmeal, only 7 germinated.

In the Galapagos Islands off the west coast of South America, a large, long-lived perennial tomato is of particular interest because careful scientific experiments have shown that less than one percent of its seeds naturally germinate.

But in the event that the ripe fruits were eaten by the giant tortoises that are found on the island, and remained in their digestive organs for two to three weeks or longer, 80% of the seeds germinated.

Experiments have suggested that the giant tortoise is a very important natural mediator, not only because it stimulates the germination of seeds, but also because it ensures their efficient dispersal.

The scientists also concluded that seed germination was due not to mechanical, but to enzymatic action on the seeds during their passage through the turtle's digestive tract.

Baker, director of the Botanical Gardens at the University of California, Berkeley, experimented in Ghana with the germination of baobab and sausage tree seeds. He found that these seeds practically did not germinate without special treatment, while their numerous young shoots were found on stony slopes at a considerable distance from adult trees.

These places served as a favorite habitat for baboons, and fruit cores indicated that they were included in the diet of monkeys.

The strong jaws of baboons allow them to easily gnaw through the very hard fruits of these trees; since the fruits themselves do not open, without such assistance the seeds would not have the opportunity to disperse.

The percentage of germination in seeds extracted from baboon dung was noticeably higher.

In Zimbabwe, there is a large beautiful ricinodendron tree, which is also called the "Zambezian almond", mongongo or "Manketti nut".

The wood of this tree is only slightly heavier than balsa wood. It bears fruit the size of a plum, with a thin layer of pulp surrounding very hard nuts - "edible if you can crack them open," as one forest ranger wrote.

Naturally, these seeds rarely germinate, but there are a lot of young shoots, since elephants are addicted to these fruits. Passing through the digestive tract of an elephant does not seem to have any effect on the nuts, although their surface in this case is covered with grooves, as if made by a sharp object. Perhaps these are traces of the action of the gastric juice of an elephant?

Mongongo nuts after passage through elephant intestines

C. Taylor wrote that the ricinodendron growing in Ghana produces seeds that germinate very easily. However, he adds that musanga seeds may “need to pass through the digestive tract of some animal, as it is extremely difficult to germinate them in nurseries, and in natural conditions the tree reproduces very well.”

Although elephants in Zimbabwe cause great damage to the forests of the savannas, they also provide the distribution of some plants. Elephants love camelthorn beans and eat them in large quantities. The seeds come out undigested. During the rainy season, dung beetles bury elephant droppings.

Thus, most of the seeds end up in an excellent bed. This is how thick-skinned giants at least partly compensate for the damage they cause to trees, tearing off their bark and inflicting all sorts of other damage on them.

C. White reports that the seeds of the Australian quandong germinate only after being in the stomach of emus, which love to feast on fleshy, plum-like pericarp.

The cassowary, a relative of the emu, also enjoys eating kwandong fruit.

ASPEN TREES

One of the most obscure groups of tropical trees is the fig (fig, fig). Most of them come from Malaysia and Polynesia.

Korner writes: “All members of this family have small flowers. In some, such as breadfruit, mulberries, and fig trees, the flowers are connected in dense inflorescences that develop into fleshy buds. In breadfruit and mulberries, the flowers are placed outside the fleshy stem that supports them; the fig trees have them within it.

The fig is formed as a result of the growth of the stem of the inflorescence, the edge of which then bends and contracts until a calyx or a jug with a narrow mouth is formed - something like a hollow pear, and the flowers are inside ... The pharynx of the fig is closed by many scales superimposed on each other ...

The flowers of these fig trees are of three types: male with stamens, female, which produce seeds, and gall flowers, so called because they develop larvae of small wasps that pollinate the fig tree.

Gallic flowers are sterile female flowers; breaking a ripe fig, they are easy to recognize, as they look like tiny balloons on pedicels, and on the side you can see the hole through which the wasp got out. The female flowers are identified by the small, flat, hard, yellowish seed they contain, while the male flowers are identified by the stamens...

Pollination of fig blossoms is perhaps the most interesting form of interrelationship between plants and animals known so far. Only tiny insects called fig wasps can pollinate the flowers of the fig tree, so the reproduction of fig trees depends entirely on them ...

If such a fig tree grows in a place where these wasps are not found, the tree will not produce seeds ... But the fig wasps, in turn, are completely dependent on the fig tree, since their larvae develop inside the galls and the whole life of adults passes inside fetus - excluding the flight of females from a ripening fig on one plant to a young fig on another. Males, almost or completely blind and wingless, live in the adult stage for only a few hours.

If the female fails to find a suitable fig tree, she cannot lay her eggs and dies. There are many varieties of these wasps, each of which appears to serve one or more related species of the fig tree. These insects are called wasps because they are distantly related to true wasps, but they do not sting and their tiny black bodies are no more than a millimeter long...

When the figs on the gall plant ripen, adult wasps hatch from the ovaries of the gall flowers, gnawing through the wall of the ovary. The males fertilize the females inside the fetus and die soon after. The females get out between the scales covering the mouth of the fig.

Male flowers are usually located near the throat and open by the time the fig ripens, so that their pollen falls on the female wasps. The wasps, showered with pollen, fly to the same tree, on which young figs begin to develop, and which they probably find with the help of smell.

They penetrate into young figs, squeezing between the scales that cover the throat. This is a difficult process. If a wasp climbs into a fig gall, its ovipositor easily penetrates through a short column into the ovule, in which one egg is laid. The wasp moves from flower to flower until her supply of eggs runs out; then she dies of exhaustion, because, having hatched, she does not eat anything ... "

BAT POLLINATED

In the temperate zones, the pollination of flowers is in most cases done by insects, and it is believed that the lion's share of this work falls on the bee. However, in the tropics, many species of trees, especially those that bloom at night, rely on bats for pollination. Scientists have found that flower-eating bats seem to play the same ecological role as hummingbirds during the day.

This phenomenon has been studied in detail in Trinidad, Java, India, Costa Rica and many other places. Observations revealed the following facts.

1) The smell of most flowers pollinated by bats is very unpleasant for humans. This applies primarily to the flowers of Oroxylum indicum, baobab, as well as some types of kigelia, parkia, durian, etc.

2) Bats come in different sizes - from animals smaller than a human palm to giants with a wingspan of more than a meter. Babies, launching long red tongues into the nectar, either soar above the flower, or wrap their wings around it. Large bats put their muzzles into the flower and begin to quickly lick the juice, but the vegka falls under their weight, and they take off into the air.

3) Flowers that attract bats belong almost exclusively to three families: bignonia, mulberry cotton and mimosa. The exception is the Phagrea from the Loganiaceae family and the giant cereus.

RAT "TREE"

The climbing pandanus found in the Pacific Islands is not a tree, but a vine, although if its many trailing roots can find suitable support, it stands so straight that it looks like a tree.

Otto Degener wrote about him: “Freucinetia is quite widespread in the forests of the Hawaiian Islands, especially in the foothills. It is not found anywhere else, although more than thirty related species have been found on the islands located to the southwest and east.

The road from Hilo to Kilauea Crater is teeming with yeye (the Hawaiian name for the climbing pandanus), which are especially conspicuous in the summer when they bloom. Some of these plants climb the trees, reaching the very tops - the main stem wraps around the trunk with thin aerial roots, and the branches, bending, get out into the sun. Other individuals crawl along the ground, forming impenetrable plexuses.

The woody yellow stems of the yeye are 2-3 cm in diameter and are surrounded by scars left from fallen leaves. They produce many long adventitious aerial roots of almost the same thickness along the entire length, which not only supply the plant with nutrients, but also enable it to cling to a support.

The stems branch every meter and a half, ending in bunches of thin glossy green leaves. The leaves are pointed and covered with spines along the edges and along the underside of the main vein ...

The method developed by the yeye to ensure cross-pollination is so unusual that it is worth talking about in more detail.

During the flowering period, bracts consisting of a dozen orange-red leaves develop at the ends of some yeye branches. They are fleshy and sweet at the base. Three bright plumes stick out inside the bract.

Bracts are liked by field rats. Crawling along the branches of a plant, rats pollinate flowers. Each sultan consists of hundreds of small inflorescences, which are six combined flowers, of which only tightly fused pistils have survived.

On other individuals, the same bright stipules develop, also with sultans. But these plumes do not carry pistils, but stamens in which pollen develops. Thus, the yeye, having divided into male and female individuals, completely secured themselves from the possibility of self-pollination.

Inspection of the flowering branches of these individuals shows that they are most often damaged - most of the fragrant, brightly colored fleshy leaves of the bract disappear without a trace. They are eaten by rats, which, in search of food, move from one flowering branch to another.

Eating fleshy bracts, rodents stain their whiskers and hair with pollen, which then falls on the stigmas of females in the same way. Yeye is the only plant in the Hawaiian Islands (and one of the few in the world) that is pollinated by mammals. Some of its relatives are pollinated by flying foxes - fruit-eating bats, which find these fleshy bracts tasty enough.

ANT TREES

Some tropical trees are attacked by ants. This phenomenon is completely unknown in the temperate zone, where the ants are just harmless bugs that sometimes crawl into the sugar bowl.

Throughout the rainforests there are innumerable ants of the most varied sizes and with the most varied habits, ferocious and voracious, ready to bite, sting, or in some other way destroy their enemies. They prefer to settle in trees and for this purpose they choose certain species in the diverse plant world.

Almost all of their chosen ones are united by the common name "ant trees". A study of the relationship between tropical ants and trees has shown that their union is beneficial for both parties.

Trees shelter and often feed ants. In some cases, trees secrete lumps of nutrients, and ants eat them; in others, the ants feed on tiny insects, such as aphids, that live off the tree. In forests subject to periodic flooding, trees save their homes from flooding.

Trees undoubtedly extract some nutrients from the debris that accumulates in ant nests - very often an aerial root grows into such a nest. In addition, ants protect the tree from all sorts of enemies - caterpillars, larvae, grinder beetles, other ants (leaf cutters) and even from people.

Regarding the latter, Charles Darwin wrote: "The protection of foliage is provided by the presence of entire armies of painfully stinging ants, whose tiny size only makes them more formidable."

Belt, in his book The Naturalist in Nicaragua, gives a description and drawings of the leaves of one of the plants of the Melastoma family with swollen petioles and indicates that, in addition to small ants living on these plants in large numbers, he noticed dark-colored Aphids (aphids) several times.

In his opinion, these small, painfully stinging ants bring great benefits to plants, as they protect them from enemies that eat leaves - from caterpillars, slugs and even herbivorous mammals, and most importantly, from the ubiquitous sauba, that is, leaf-cutting ants, which, according to in his words, "they are very afraid of their small relatives."

This union of trees and ants is carried out in three ways:

1. In some ant trees, the branches are hollow, or their core is so soft that the ants, arranging a nest, easily remove it. Ants look for a hole or a soft spot at the base of such a branch, if necessary, gnaw their way through and settle inside the branch, often expanding both the inlet and the branch itself. Some trees even seem to prepare entrances for ants in advance. On thorny trees, ants sometimes settle inside the thorns.

The second way of using leaves, which is observed much less often, is that ants bend the edges of the leaf, glue them together and settle inside.

3. And, finally, there are ant trees that do not themselves provide dwellings for ants, but ants, on the other hand, settle in those epiphytes and vines that they support. When you stumble upon an ant tree in the jungle, you usually don't waste time checking whether the leaves of the ants are erupting from the leaves of the tree itself or from its epiphyte.

Spruce described in detail his acquaintance with ant trees in the Amazon: “Ant nests in thickenings of branches are found in most cases on low trees with soft wood, especially at the base of the branches.

In these cases, you will almost certainly find ant nests either at each node or on the tops of the shoots. These anthills are an expanded cavity inside the branch, and communication between them is sometimes carried out along passages laid inside the branch, but in the overwhelming majority of cases - through covered passages built outside.

Cordia gerascantha almost always has bags at the branching point, in which very vicious ants live - tahi. C. nodosa is usually inhabited by small fire ants, but occasionally by tahis. Perhaps the fire ants were the first inhabitants in all cases, and the takhs are pushing them out.

All tree-like plants of the buckwheat family, according to Spruce, are affected by ants: “The entire core of each plant, from roots to the apical shoot, is almost completely scraped out by these insects. Ants settle in a young stem of a tree or shrub, and as it grows, releasing branch after branch, they make their moves through all its branches.

These ants all seem to belong to the same genus, and their bite is extremely painful. In Brazil, as we already know, it is “tahi” or “tasiba”, and in Peru it is “tangar-rana”, and in both these countries the same name is usually used for both ants and a tree, in which they live.

In Triplaris surinamensis, a fast-growing tree throughout the Amazon, and in T. schomburgkiana, a small tree in the upper Orinoco and Casiquiare, thin, long, tube-like branches are almost always perforated with many tiny holes that can be found in the stipule of almost every leaf.

This is the gate, from which, at a signal from the sentinels constantly walking along the trunk, a formidable garrison is ready to appear at any second - as a carefree traveler can easily see from his own experience, if, seduced by the smooth bark of a takhi tree, he decides to lean against it.

Ant trees exist throughout the tropics. Among the most famous is the cecropia of tropical America, which is called the "trumpet tree" because the Waupa Indians make their wind pipes from its hollow stems. Ferocious ants often live inside its stems, which, as soon as the tree is shaken, run out and pounce on the daredevil who disturbed their peace. These ants protect cecropia from leaf cutters. The internodes of the stem are hollow, but they do not communicate directly with the outside air.

However, near the apex of the internode, the wall becomes thinner. A fertilized female gnaws through it and hatches her offspring inside the stem. The base of the petiole is swollen, outgrowths are formed on its inner side, which the ants feed on. As the outgrowths are eaten, new ones appear. A similar phenomenon is observed in several related species.

Undoubtedly, this is a form of mutual adaptation, as evidenced by the following interesting fact: the stem of one species, which is never "ant-like", is covered with a wax coating that prevents leaf cutters from climbing it. In these plants, the walls of the internodes do not become thinner and edible outgrowths do not appear.

In some acacias, the stipules are replaced by large spines swollen at the base. In Acacia sphaerocephala in Central America, ants enter these spines, clean them of internal tissues and settle there. According to J. Willis, the tree provides them with food: “Additional nectaries are found on the petioles, and edible outgrowths are found on the tips of the leaves.”

Willis adds that any attempt to damage the tree in any way causes the ants to pour out in masses.

The old riddle of which came first, the chicken or the egg, is repeated in the case of the Kenyan black-knot locust, also known as the whistling thorn. The branches of this small shrub-like tree are covered with straight white thorns up to 8 cm long. Large galls form on these thorns. At first, they are soft and greenish-purple, and then harden, blacken, and ants settle in them.

Dale and Greenaway report: “The galls at the base of the thorns ... are said to be due to ants that gnaw them from the inside. When the wind hits the holes of the Gauls, a whistle is heard, which is why the name “whistling thorn” arose. J. Salt, who examined the galls on many acacias, found no evidence that their formation was stimulated by ants; the plant forms swollen bases, and the ants use them.

Ant tree in Sri Lanka and southern India is Humboldtia laurifolia from the legume family. In him, cavities appear only in flowering shoots, and ants settle in them; the structure of non-flowering shoots is normal.

Corner describes the different types of macaranga (locally called "mahang"), the main ant tree of Malaya:

“Their leaves are hollow, and ants live inside. They gnaw their way out in the shoot between the leaves, and in their dark galleries they keep a mass of aphids, like herds of blind cows. Aphids suck the sugary juice of the shoot, the bodies secrete a sweetish liquid that the ants eat.

In addition, the plant produces the so-called "edible outgrowths", which are tiny white balls with a diameter of 1 mm, which consist of oily tissue - it also serves as food for ants ...

In any case, the ants are protected from the rain... If you cut the shoot, they run out and bite... Ants penetrate young plants - winged females gnaw their way into the shoot. They settle in plants that have not reached even half a meter in height, while the internodes are swollen and look like sausages.

The voids in the shoots arise as a result of the drying of the wide core between the nodes, like in bamboos, and the ants turn individual voids into galleries, gnawing through the partitions in the nodes.

Which tree flowers are pollinated by bats. Bats pollinate durians. Pollination by bats. Chiropterophilia

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