This Australian bee is one of a species that may be making the transition from solitary to insect colony life right now.
“The existence of life as we know it can be roughly broken down into the transitions between different levels of complexity,” says Lucas Hearn of Flinders University in Adelaide. “This includes, among other things, the development of multicellular organisms or the emergence of sophisticated communication, as is the case with human language. Understanding all of this can go a long way.”
In order to understand such a step in the complexity of evolution, Hearn and his team took a closer look at the world of insects. While some species, like many wild bees, still lead solitary lives, there are those that instead live in colonies, such as ants or honey bees do. How or why the transition to social behavior in a colony that is partly disadvantageous and partly advantageous for the individual organism takes place is only partially understood.
Studies of the bee species Amphylaeus morosus, which is native to Australia, could now provide a clue. These wild bees live in the montane forests of Australia’s east coast, where they build their nests in tree ferns. The species may be on the cusp of solitary to social living right now, according to Hearn’s team. In order to be able to assess this more precisely, the scientists examined just over 300 nests of the Australian bee species.
While most of the nests belonged to only a single female, the researchers also found those maintained by two female bees. The interesting thing here: The comparison of genetic material showed that on the one hand the two females are very closely related to one another and on the other hand only one was responsible for laying the eggs, while the other only guarded the nest. “This extreme reproductive skewness and close kinship was very unexpected and has challenged our theories of the evolution of social complexity,” says senior author Michael Schwarz, also of Flinders University.
The scientists were also able to determine that the bees, which act in pairs, could have an evolutionary advantage over the loners, since the size of their brood and their survival rate were above average in the nests examined. “We were able to find the first evidence here that kin selection can promote sterilization of worker animals and thus a transition from solitary to social life,” says Schwarz.