Spider-man riding an ant: 100 million years of myrmecophilia
A friend in need will not give up, he will not ask too much, this is what a true loyal friend means. The concept of friendship between us, humans, and animals is slightly different. After all, if a friend uses you, then it's hard to call him a friend. In the world of wildlife there is no place for moral and ethical principles, there is only one rule – to survive in any available way. Therefore, some creatures of one species begin to cooperate with creatures of another species. Such relationships are both mutually beneficial and beneficial only to one individual from a duet. Interspecific "friendship" is called symbiosis, examples of which in the modern world are mass, but how long has such a non-standard survival mechanism originated? If the calculations of scientists are correct, then not less than 100 million years ago.
Today we will get acquainted with a study in which a group of scientists examined a fossil beetle, once stuck in tree sap and preserved to this day in very good condition. Observations have shown symbiotic relationships between this insect and the forefathers of modern ants. What exactly did the scientists find, how did the findings from the past explain the present and what is so unusual about this beetle? The answers are waiting for us in the report of the research group. Go.
The main character
One hundred million years ago, one little bug was crawling on a tree, thinking about its own and did not bother anyone. He was so excited that he did not notice how he got into the viscous woody sap. Who knows, maybe he would be calmer if he knew that after millions of years would become the hero of scientific research. This ill-fated tree sap later became an amber prison, and more specifically, the Burmese amber.
Insect in amber.
Burmese amber is amber, which can be found in northeastern Burma (now Myanmar). Another name for this fossil resin is burmit.
Description of burmit was first seen in 1893, when the German researcher Otto Helm described in his work an unusual substance, which he received from the German geologist Fritz Nötling.
Burmit, as is customary among people, began to be massively mined, but the mass scale was not so great – only 40 tons from 1897 to 1930. Then in 1936, mining was stopped and resumed only in 1999. Since then, only 10–500 kg per year have been mined. By the way, the largest natural piece of amber weighing 15 kg is stored in the London Museum of Natural History.
Amber Market in Kachin, Myanmar.
Scientists are not so much interested in amber itself, but in what can be found in it, namely, the remains of various creatures that inhabited our planet millions of years ago. This also applies to the main character of the study.
Promyrmister kistneri This is a fossil species of beetles from the insect family with a very cute name – the little cub. This family currently has about 3,500 species, and they received their name due to their small size – from 1 to 25 mm.
The beetle-beetle, which in English is for some reason called clowns (Clown beetle), possibly due to the appearance. Second name Hister beetle (from Latin “hister” is an actor) perhaps given for the ability to depict the dead in case of danger.
The main feature of these insects is their symbiosis with ants, although ants are not very aware of this. The fact is that some species of mummers, like Stirlitz, penetrate into the camp of the enemy, that is, a colony of ants, and enjoy their benefits. But the bug cannot just enter the colony and say: “Hi, I’m a bigo, let's be friends, don’t grieve and live together”. In this case, the ants would quickly deal with the stranger. However, the Karapuzik is cunning and ready for much to enjoy the free food and the shelter of ants. It adapts to ants, while changing its anatomy, behavior, and even chemical trail. After that, the ants consider him one of them.
Such adaptation processes associated with symbiotic bonds are not so often found in nature. As a rule, creatures in symbiosis either do not change, or they do not change so radically, adapting to their partner.
The fossil parasitus beetle from amber, judging by the data of researchers, also adapted and took root in colonies of ants.
So, we proceed to a more detailed description of the beetle under study.
Image # 1: Promyrmister kistneri.
The size of the amber prison, in which the beetle is sharpened, is 5.5 mm long and 3.5 mm wide. As can be seen from the photo 1A, the beetle is well preserved, except for the fact that part of the left side is covered with exudate leaving the ventral side of the pronotum edge (arrows on 1A and 1G).
Scientists were able to determine the appearance of this beetle on certain distinctive external features:
- large recess behind the middle and hind basal limb segments (1C, 1H);
- metaventral postcoxal line, curved and extending laterally to metaneesternum (1B, 1C);
- three distinct strips (grooves) on each elytra (1A);
- absence of dorsal furrows on pronotum (1A, 1B);
- strongly developed apical spur on the limbs (1D, 1E);
- furrow between the combined platband and forehead (1B, 1C);
- triangular cavities at the antenna connection point;
- glandular hole in the postcoxal cavity behind the metacox (1H).
The size of the beetle itself is 3.2 mm in length and 2.3 in width (really karapuzik). A fossil beetle was found in an amber mine near Noah Bam, Tanaing city, Kachin state, Myanmar.
The uranium-lead method of dating fossils showed that this piece of amber (and hence the beetle in it) is about 98.79 ± 0.62 million years.
About friendship in nature
(in order not to stretch the story, a piece of one of the previous articles on symbiosis is hidden under the spoiler)
– Well, you yourself think, what is the use of this cat?
– Well, why is the benefit necessarily? What is the use of this picture on the wall, for example?
– From this picture on the wall is very big benefit – it blocks the hole on the wallpaper!
But back to the flora and fauna. In the wild (we will not consider symbiosis in controlled conditions) relations between representatives of different species are necessary for survival or for a more comfortable life.
Clownfish in anemone.
Vivid and one of the most famous examples are clown fish and sea anemones (sea anemones). The fishes, at the sight of which many exclaim something like “oh, Nemo!”, Living inside the anemone, are immune to their ciliary cells (stinging / stinging cells), but predators are very susceptible. In other words, clown fish live in a house with an electric fence. Sea anemones benefit from this neighborhood in the form of nutrients from fish waste products.
Another unusual symbiosis, some types of anemone form with hermit crabs.
From the depths of the sea move to a blooming meadow. Who do we always present next to the flower? Of course, the bees. These workaholics collect nectar from flowers, that is, they get food. At the same time, having flown from flower to flower, they carry out indirect pollination, so to speak, than they help plants in reproduction. In other words, the bee would answer yes to the question “what are you, holding a candle?”, After which it would sting you for such inappropriate questions.
Bees on a sunflower.
In addition to bees, other species of insects (ants, bumblebees, butterflies, etc.) as well as vertebrates (birds, bats, rodents, etc.) help plants in the pollination process.
As we have already understood, symbiotic relationships are not uncommon. We are rather surprised by the participants of these relations, rather than the fact of their existence.
Research results
Researchers point out that Myrmecophiles * existed in the period Eocene *, but eusociality * ants are twice as old. However, earlier there was no evidence that Mirmecophiles lived in ant colonies 100 million years ago.
Myrmekofil * – a creature that dwells with ants in or near one nest, and is also dependent on them.
Eocene* – one of the stages of the Paleogene period, began 56 and ended 33.9 million years ago.
Eusociality * – The highest level of social organization of animals.
The difficulty of determining the presence of ants at the time of the memekofilov ants is that ant fossils are not as common as one might think, and the number of possible myrmecophiles within one colony is very small, judging by modern observations.
The beetle found and studied in this work may be evidence that the coexistence of this species together with ants began as early as the Mesozoic (from 251 million to 0.024 million years ago).
The results of the analysis of morphology and phylogenetic position of the fossil Promyrmister indicate that before us is a new genus of an extinct branch obligate mirmekofilov * from taxon group Haeteriinae (2A, 2b).
Obligate Myrmecophiles * – organisms that cannot survive without myrmecophilia, that is, without ants.
Image number 2
It is worth noting that representatives of the haeteriine taxon feel more than comfortable among ants, as evidenced by the peculiarities of their behavior: stomodeal trophallaxis (regurgitation feeding), cleaning ants working, attaching to ants (Foresia *) and the transfer of workers on the territory of the nest.
Foresia * – the resettlement of one organism by transferring it to another organism.
To feel so free among the ants, the beetle beetle must adapt to its neighbors. And this happens not only at the level of behavioral characteristics, but also anatomical and chemical. First of all, the beetle mimics the cuticular hydrocarbons of the colony where it lives. In addition, the beetle uses a special substance secreted from the glands along the edges of the prothorax or the postcoxal region of the lower body, as a sedative for ants, that is, it is sedative.
At the moment there is a genus of karapuzik beetles Haeterius (2C), to which it will be logical to ascribe to the fossil beetle under investigation Promyrmister. Why is it important? Because this genus and taxons close to it (Eretmotus, Sternocoelis and Satrapes) together form a single group, which is found in Palearctic *. In the same region, we find Burmese amber.
Palaearctic * – biogeographical region (red color on the map).
Palaearctic * – biogeographical region (red color on the map).Fossil Representatives Promyrmister (2C) judging by the research, they possess classical external signs of beetles from the genus Haeterius. Scientists believe that these signs are directly related to the insect's lifestyle, that is, with the need to live with ants, imitating them. The external features include: wide tibia with spikes on the outer edge, short legs on the legs, the space between the antennae of a triangular shape, pronounced antennal cavities on the ventrolateral part of the myotome, a wide provental lobe. Scientists believe that such anatomical features are due to the need to resist the mandibles (creeps) of ants.
Also curious is the fact of the behavioral peculiarities of the mummy beetle. The fact is that scientists previously investigated a different species of beetles (Staphylinidae) who live in symbiosis with termites. Despite the presence of protective morphology (features of the structure of the body), these beetles are considered invaders or “parasites” in the everyday sense of the word. But the beetles-cocks coexist with ants quite peacefully precisely due to the social integration into the life of the colony (2D, 2E).
In addition, the pied beetles use some pacifying substance supposedly secreted by the glands at the edges of the prothorax. It is quite problematic to investigate this aspect in detail in fossils, however, the presence of exudates on the studied specimen (1A and 1G) says that the substance was released in the area of the left margin of the protox.
If to sum up, it is possible to say with a certain degree of confidence that the fossil beetle Promyrmister, like his modern relatives, lived in ant colonies, taking advantage of all the attendant benefits. At the same time, there was a complete social and symbiotic integration into the society of ants, realized by means of anatomical mimicry, a soothing substance and an imitation of ant cuticular hydrocarbons.
The question remains – what exactly ants Promyrmister bugs lived with?
All ants that have ever been found in Burmese amber belong to the same branch. Formicidae: representatives of childbirth Gerontoformica, Myanmyrma and Camelomeciaas well as an extinct subfamily Sphecomyrminae. The listed ants do not have signs of a common crown group, but were nevertheless assigned to one group. Formicidae. However, as I said earlier, there are very few fossil ants in amber, therefore it is difficult to compare the beetles Promyrmister with a certain type of ant.
Crown group (crown group) * – a group of all descendants of a common ancestor of living species.
Stem group * – all extinct species minus included in the crown group.
Scientists assume that the beetle under study could live in symbiosis with representatives of the ant species belonging to the stem-group. But scientists do not discard the likelihood of finding in the future fossils of the very same ants that may be from a crown group.
Regardless of whether Promyrmister with ants from a crown group or not, one thing is clear – their original symbiont ants have long since died out.
Image number 3
Considering modern ants, it becomes clear that representatives of the karapuzik beetles are not tied to a specific species or genus of ants. They can be found in ant colonies of the genus Dolichoderinae, Dorylinae, Formicinae, Myrmicinae and Ponerinae (picture number 3). It is this "inconstancy" in the choice of a partner that explains the long history of the symbiosis between the goop and ants, as scientists say. Without being tied to one species or genus of ants, beetles were able to avoid extinction with them.
One gets the impression that in the process of evolution, the Karapuz beetles did not get rid of the symbiotic lifestyle, but perfected it by not only better adapting to a certain symbiont, but also by choosing the best symbiont.
Image number 4: examples of adaptation of beetles to symbiotic ants.
On the image 4A shows the migration of ants species Eciton burchellii, in the ranks of which there were a few karapuzik beetles. As you can see from the photo, beetles have a similar color, like their "brothers" ants. Picture 4B – Ant-worker species Eciton hamatum and the beetle, whose appearance clearly speaks of adaptation to this particular type of ant. Picture 4C This is a test of attentiveness. Pay attention to where the arrow points – this is not the Gaster ant, but a bug. By attaching to the ant's body, the beetle can migrate along with the colony. And its color and place of attachment help to mask in order to avoid hazards.
For more detailed acquaintance with the nuances of the study I strongly recommend to look into the report of scientists and additional materials to it.
Epilogue
Symbiosis is not something new, it is not a breath of wilderness fashion. This is a phenomenon that has evolved over millions of years along with those who used it. Of course, finding the original source of symbiosis is almost impossible, but thanks to this research it becomes clear that symbiotic relations between different species of living organisms exist for at least 100 million years.
Without knowing our history, we condemn ourselves to ignorance. This thesis is applicable not only to the history of our civilization, but also to the world around us. The flora and fauna of this world has been developing for a very long time, and we cannot reveal all its secrets at once. There is still much to discover, much to explore and much to understand, before we can say with confidence that we know the world in which we live.
A small video about the life of beetles in an ant colony.
