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 the 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 Piel 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 claims that chemical composition pollen of flowers pollinated by bats, mice, is adapted for use by these animals and differs from the composition of 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 evidence 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 points to common features in the physiology of all considered bats. 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 appearance similar 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.
Pollination is the transfer of pollen from the stamen to the stigma of the pistil. Precedes fertilization. Distinguish cross pollination and self-pollination. Cross-pollination can be carried out by wind, insects, water, birds, bats.
When it rains during flowering orchards, conditions are created for a poor harvest. This is due to the fact that the conditions for pollination are not created, the bees did not fly in the rain. The formation of fruits in flowering plants is preceded by pollination - the transfer of pollen grains (pollen) from the stamens to the stigmas of the pistils.
Christian Sprengel, rector of the gymnasium in the German city of Spandau, devoted every free minute to the study of plant life. For about a year, he observed the “live communication” of flowers and insects in the fields and meadows and came to the conclusion that insects carry pollen and pollinate plants. In 1793, Sprengel published the book “ open secret nature in the structure and fertilization of flowers”, in which he convincingly proved that pollination is an obligatory process in plant reproduction.
There are self-pollination and cross-pollination.
self pollination
During self-pollination, pollen from the anthers falls on the stigma of the pistil of the same flower (Fig. 157). Self-pollination often occurs even in a closed flower - a bud. Self-pollination is characteristic of peanuts, peas, nectarines, wheat, rice, beans, cotton and other plants.
Biologically, self-pollination is less “profitable” than cross-pollination, since the future plant, which develops after the fusion of gametes, repeats the mother plant. At the same time, the possibility of the emergence of new devices is reduced. At the same time, the process of self-pollination does not depend on weather conditions and intermediaries, and, therefore, is carried out under any conditions, often even in unblown flowers, and ensures the emergence of new offspring.
cross pollination
In cross-pollination, pollen from one flower is transferred to the stigma of another flower. Pollen carriers during cross-pollination can be insects, wind, water (Fig. 158). Insects pollinate flowers of apple, plum, cherry, poppy, tulip and other plants.
Wind pollinated are sedge, couch grass, ryegrass, alder, hazel, oak, birch. In aquatic plants (elodea, vallisneria), pollination is carried out with the help of water (see Fig. 158).
In tropical latitudes, small birds (hummingbirds) and bats can carry pollen from flower to flower (Fig. 159, p. 178). Birds, for example, pollinate eucalyptus, acacia, fuchsia, aloe and other plants.
Cross-pollination is biologically more valuable. Male gametes are formed in the pollen grain, and female gametes are formed in the ovary. When they merge, a zygote is formed, from which a new organism develops. During cross-pollination, the zygote is formed from gametes belonging to different plants, so the new organism will have the characteristics of two plants, and hence a wider set of adaptive characteristics.
artificial pollination
When breeding new varieties of plants to increase productivity, a person carries out artificial pollination - he himself transfers pollen from the stamens to the stigma of the flower. In calm weather, a person pollinates wind-pollinated crops (corn, rye), and in cold or wet weather- insect pollinated plants (sunflower).
Pollen
Plants have certain adaptations for pollination by different pollinators. Insect pollinated plants produce a lot of pollen - it serves as food for insects. The surface of pollen grains is sticky or rough, so it attaches well to insects.
bright flower
Many plants have brightly colored flowers that are clearly visible against the background of green leaves. Single-night flowers are usually large. Small flowers, as a rule, are collected in inflorescences.
Nectar
The flowers of many plants secrete a sugary liquid - nectar, which also attracts pollinators. Nectar is formed in nectaries - special glands that are located deep in the flowers. Nectar is consumed by butterflies, bees, bumblebees, hummingbirds, some species of parrots and bats.
Smell
Many flowers emit a pleasant aroma that also attracts insects (white acacia, rose, some types of lilies, lily of the valley, bird cherry, etc.). The smell of flowers can be not only pleasant, like most ornamental plants, but also unpleasant (for humans) - like the smell of rotten meat, manure. Such smells attract beetles, flies. material from the site
Some plants are pollinated only by certain types of insects. For example, clover flowers, which are characterized by a tubular structure, are pollinated only by bumblebees with a long proboscis. Bumblebees also pollinate sage flowers. As soon as the bumblebee climbs inside the flower for nectar, immediately two stamens on long stamen filaments protrude from under the upper petal and touch the back of the bumblebee, sprinkling it with pollen. Then the bumblebee flies to another flower, climbs inside, and pollen from its back falls on the stigma of the pistil.
The special structure of the inflorescence
In wind-pollinated plants, the flowers are numerous, small and inconspicuous, collected in small inconspicuous inflorescences. The perianth is absent or poorly developed and does not obstruct the movement of air. The stamens have long filaments on which anthers hang, as, for example, in rye flowers (Fig. 160).
Pollination
What is pollination? Bloom- this is the state of plants from the beginning of the opening of flowers to the drying of their stamens and petals . During flowering, pollination of plants occurs.
Pollinationcalled the transfer of pollen from the stamens to the stigma of the pistil. If pollen is transferred from the stamens of one flower to the stigma of the pistil of another flower, then cross pollination . If pollen falls on the stigma of the pistil of the same flower, this is self-pollination .
Cross pollination. With cross-pollination, two options are possible: pollen is transferred to flowers located on the same plant, pollen is transferred to flowers of another plant. In the latter case, it must be borne in mind that pollination occurs only between individuals of the same species!
Cross-pollination can be carried out by wind, water (these plants grow in water or near water: hornwort, naiad, vallisneria, elodea ), insects, and in tropical countries also birds and bats.
Cross-pollination is biologically more appropriate, because the offspring, combining the characteristics of both parents, can better adapt to the environment. Self-pollination has its advantages: it does not depend on external conditions, and the offspring stably retains parental characteristics. For example, if yellow tomatoes are grown, then next year, using their seeds, you can again get the same yellow tomatoes ( tomatoes are usually self-pollinators). Most plants cross-pollinate, although there are few strictly cross-pollinated plants (e.g., rye), more often cross-pollination is combined with self-pollination, which further increases the fitness of plants for survival.
Flower pollination types: self-pollination, cross-pollination
Wind pollinated plants. Plants whose flowers are pollinated by the wind are called wind pollinated . Usually their inconspicuous flowers are collected in compact inflorescences, for example, in a complex spike, or in panicles. They produce a huge amount of small, light pollen. Wind pollinated plants often grow in large groups. Among them are herbs. (timothy grass, bluegrass, sedge) and shrubs and trees (hazel, alder, oak, poplar, birch) . Moreover, these trees and shrubs bloom at the same time as the leaves bloom (or even earlier).
In wind-pollinated plants, the stamens usually have a long filament and carry the anther outside the flower. The stigmas of the pistils are also long, "shaggy" - to catch dust particles flying in the air. These plants also have certain adaptations to ensure that pollen is not wasted, but rather falls on the stigmas of flowers of its own species. Many of them bloom by the hour: some bloom early in the morning, others in the afternoon.
Insect pollinated plants. Insects (bees, bumblebees, flies, butterflies, beetles) are attracted by sweet juice - nectar, which is secreted by special glands - nectaries. Moreover, they are located in such a way that the insect, getting to the nectaries, must touch the anthers and stigma of the pistil. Insects feed on nectar and pollen. And some (bees) even store them for the winter.
Therefore, the presence of nectaries is an important feature of an insect pollinated plant. In addition, their flowers are usually bisexual, their pollen is sticky with outgrowths on the shell to cling to the insect's body. Insects find flowers by a strong smell, by bright colors, by large flowers or inflorescences.
In a number of plants, nectar, which attracts insects, is available to many of them. So on blooming poppies, jasmine, buzulnik, nivyanika you can see bees, and bumblebees, and butterflies, and beetles.
But there are plants that have adapted to a particular pollinator. However, they may have a special structure of the flower. Carnation, with its long corolla, is pollinated only by butterflies, whose long proboscis can reach the nectar. Only bumblebees can pollinate flaxseed, snapdragon : under their weight, the lower petals of the flowers are bent and the insect, reaching the nectar, collects pollen with its shaggy body. The stigma of the pistil is located so that the pollen brought by the bumblebee from another flower must remain on it.
The flowers may have a smell attractive to different insects or smell especially strong in different time days. Many white or light flowers smell especially strongly in the evening and at night - they are pollinated by moths. Bees are attracted to sweet, “honey” smells, and flies are often not very pleasant smells for us: many umbrella plants smell like this. (snyt, cow parsnip, kupyr) .
Scientists have conducted studies that have shown that insects see colors in a special way and each species has its own preferences. It is not for nothing that in nature all shades of red reign among daytime flowers (but in the dark red is almost indistinguishable), and blue and white are much less.
Why so many devices? In order to have a better chance that pollen will not be wasted, but will fall on the pistil of a flower of a plant of the same species.
Having studied the structure and features of the flower, we can assume which animals will pollinate it. So, fragrant tobacco flowers have a very long tube of fused petals. Therefore, only insects with a long proboscis can reach the nectar. The flowers are white, well visible in the dark. They smell especially strong in the evening and at night. Pollinators - hawk moths, night butterflies, which have a proboscis up to 25 cm long.
The largest flower in the world - rafflesia - painted red with dark spots. It smells like rotten meat. But for flies there is no smell more pleasant. They pollinate this wonderful, rare flower.
Self-pollination. Majority self-pollinating plants are crops (peas, flax, oats, wheat, tomato) , although there are self-pollinating plants among the wild ones.
Some of the flowers are already pollinated in bud. If you open a pea bud, you can see that the pistil is covered with orange pollen. In flax, pollination takes place in an open flower. The flower blooms early in the morning and after a few hours the petals fall off. During the day, the air temperature rises and the filaments twist, the anthers touch the stigma, burst, and the pollen spills out on the stigma. Self-pollinating plants, including linen, can be pollinated and cross-pollinated. Conversely, under unfavorable conditions, self-pollination can occur in cross-pollinated plants.
Cross-pollinated plants in the flower have devices that prevent self-pollination: the anthers mature and shed pollen before the pistil develops; the stigma is located above the anthers; pistils and stamens can develop in different flowers and even on different plants (dioecious).
artificial pollination. In certain cases, a person carries out artificial pollination, that is, he himself transfers pollen from the stamens to the stigma of the pistils. Artificial pollination is carried out for different purposes: to breed new varieties, to increase the yield of some plants. In calm weather, a person pollinates wind-pollinated crops. (corn), and in cold or wet weather - insect pollinated plants (sunflower) . Both wind- and insect-pollinated plants are artificially pollinated; both cross- and self-pollinated.
Interactive lesson simulator. (Complete all the tasks of the lesson)
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 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 their 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 ...
Examination 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.
V tropical forests everywhere there are innumerable 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 choose a variety of flora certain types. 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 will not touch here on the part played by ants in the pollination of some flowers or in the dispersal of seeds, nor on the ways in which some 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, tubular 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 in general all year round do not leave the trees. 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. Cecropia (Cecropia peltata) belongs to the most famous 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 waxy 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 two of them - D. petiolaris and D. hlrsuta - have swollen stems directly under the inflorescence, and ants can enter the cavity through the cracks that appear. 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).
Korner describes various types of macaranga ( locals call them "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 noted, 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.
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, and a few weeks later, pepper trees begin to sprout everywhere—and especially in the flowerbeds where the thrushes were looking 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 extermination of all big trees, and had to look for another source of wood.
It is true that a few surviving young junipers reached maturity and began to bear seeds, but under these trees, which in America are called "pencil cedars" to this day, 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. Rossler has 40.025 seeds different plants fed to Californian oatmeal, only 7 sprouted.
In the Galapagos Islands off the west coast South America grows a large long-lived perennial tomato of particular interest, as 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 University of California, Berkeley Botanical Gardens, has experimented in Ghana with the germination of baobab seeds and sausage tree. 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 their origin is 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 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 their 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.
Examination 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 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 - there you have a nest.
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.
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 habitats.
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 example 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 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 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.
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.
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