Due to the nitrogen deficiency on Kangaroo Island, local ants arrange "quarries" and "mines" and extract urea from the sand soaked in large animals for weeks.
We are used to imagining distant exotic islands full of amazing and varied life. However, in fact, their inhabitants are often few in number and are forced to constantly struggle with a shortage of certain resources. This is also the case on the small arid island of Kangaroo off the southern coast of Australia: the lack of key nutrients forced local ants to even master the "extraction" of animal urine. This unusual adaptation is highlighted in a new article published in the journal Austral Ecology.
A few years ago, University of South Australia biologist Sophie Petit, working on Kangaroo Island, noticed that crowds of "sugar ants" Camponotus terebrans quickly gather in the place where the urine got, and then regularly visit him. This unusual behavior attracted the attention of the scientist, and now, after a few years, she has found a complete explanation for it.
Kangaroo Island is marginal and arid. Local vegetation is forced to live on sandy soil, extremely poor in nutrients. Only flocks of kangaroos eating these thorns will diversify the landscape. Apparently, it was their urine that the ants learned to collect. But why did the workers gather in the same place later, when all the moisture had already dried up?
Aside from water, urea is a key component of this excretion, which can be an excellent source of nitrogen. This element accounts for the lion's share of the earth's atmosphere, but only a few nitrogen-fixing bacteria are capable of breaking the super-strong bonds of molecular nitrogen and turning it into biochemical circulation. It is on them that most of the biosphere relies on obtaining vital nitrogen, which, among other things, is part of both DNA and proteins.
Perhaps it is urea - and the invaluable nitrogen, which is practically nonexistent in easily washed sandy soils - that ants are interested in. To test this idea, Sophie Petit and her colleagues prepared several solutions containing urea in about the same amounts as it is in the urine of kangaroos and humans (2.5 percent), as well as in increased amounts (10 percent). Sweet water was used as a control: it should attract these ants especially, and it is not without reason that they received the name "sugar".
Having poured equal amounts of liquids into the sand, the scientists set up cameras to observe Camponotus terebrans. Of course, the ants were attracted by all three food sources: they “developed” these resources long after the water evaporated. However, biologists noticed that most of all they were attracted by the area with the maximum urea content, and least of all - by ordinary sweetened water: apparently, nitrogen on the island is much more valuable than high-calorie sugars.
The ants worked actively in the "urea quarry" for many weeks and even dug "mines" under the surface, getting to the urea carried to the depths. “If the colony is lucky, the nearby urea deposits could become a valuable resource for the colony,” American ecologist Walter Kaspari commented on the work. "Urea is essentially a natural sports drink."