St Petersburg University biologist talks about how ants build communism on a Heinrich Terahertz podcast
Dmitry Dubovikoff, Associate Professor in the Department of Applied Ecology at St Petersburg University and an expert in social insects, is the guest of the 12th episode of the popular scientific podcast "Heinrich Terahertz". He talked about the social structure of ant colonies, what kind of ‘societies’ these insects have, and where zombie ants come from.
For scientists, it still remains a mystery when ants became social animals. What they are certain about is that this definitely happened no later than the Cretaceous period, i.e. 66,140 million years ago. This is much earlier than people built their society. According to Dmitry Dubovikoff, both ants and their society have gone through a significant evolutionary path.
It is generally accepted that the nest of ants, or an anthill, is a small hummock. In fact, weaver ants, for example, make intricate nests from leaves fastened with silk in trees. The nests of other ants, on the contrary, can be found underground or under stones, without visually standing out from the external environment. What is more, there are ant nomads that constantly move from place to place, carrying their larvae with them. The largest ant nests can look like entire cities, containing several smaller nests at some distance. Such a "city" can have more than 12 million inhabitants.
No less diversity can be seen in the society in which ants live. Dmitry Dubovikoff talks about one of the species of Japanese ants. In their hierarchy, all ants are workers and equal. Blood ants, in their turn, which live in the north of Eurasia and North America, are essentially slave owners.
St Petersburg University scientists, under the leadership of Dmitry Dubovikoff, made a number of important discoveries in the field of palaeomyrmecology. For the first time since the 19th century, they discovered the proventriculus in Baltic amber, i.e. an additional section of the stomach of ants which was used to accumulate and transport food to the nest. Earlier, they refuted the discovery by American scientists of the oldest nomadic ant, which was supposed to be 40 million years old.
"These ants tend to have powerful mandibles and are generally quite large compared to other ants. When an ant sees a nest of ants of another species, it runs to its nest, takes its relative in its teeth and carries it to show what it has found. Then, they return to the nest together, take one more relative in their teeth and again carry it to the discovered nest. They do it until there are enough of them to attack the anthill and carry away the larvae," said Dmitry Dubovikoff.
As a result, slave ants emerge from the larvae, which are forced to care for the offspring of slave owners, get them food and guard the nest.
Another fascinating phenomenon in the social life of ants is infection with spores of parasitic fungi. Fungal spores, once in the body of an insect, affect its brain, disrupting how the circadian rhythms influence the smell sensitivity and neurotransmission. Thus, the fungus begins to control and parasitise the insect. As a result, the ant leaves its nest, finds a long blade of grass or branch, climbs and freezes there to die.