Native bee key to social evolution: Bridge between flying solo or as a colony

The unusual social behavior of an Australian native bee has allowed researchers to understand the earliest stages of social evolution.

Evidence of how individuals that live a solitary lifestyle can transition to colonial life involving sterile castes that seem to defy Darwin's natural selection theory unlocks a key biological question about evolution.

Evidence of early steps into sociality has been eroded over geological time scales, but organs living in highly complex and organized societies can explain how altruistic behavior is maintained.

A unique Australian native bee that only recently crossed the threshold from individual reproduction to selfless behavior within a colony has been studied to overcome this obstacle.

It is the only social species in its family that can be used to understand the transition from solitary to social living.

The existence of life can be separated into major transitions that define changes in complexity. The origin of human language and the evolution of multicellular life from single-celled organisms are included.

The ramifications of this understanding are far reaching.

In tall montane forests along the Australian Great Dividing Range, the Australian native bee species Amphylaeus morosus builds its nest. Its social nest is small, rarely containing more than two females, and females do not exhibit the types of queen-and-worker morphologies that are common in honeybees.

The study found that each social colony has a single female who lays all the eggs and another female who guards the nest but doesn't reproduce.

"This kind of extreme reproductive skew and high relatedness is very unexpected and undermines our theories about how social complexity evolved," says senior author, Michael Schwarz. The evolutionary social ladder seems to be able to be skipped by some species.

Some of the first evidence that kin selection can promote worker sterility is provided by this.

The paper "Extreme reproductive skew at the dawn of sociality is consistent with inclusive fitness theory but problematic for routes to eusociality" has been published.

More information: Extreme reproductive skew at the dawn of sociality is consistent with inclusive fitness theory but problematic for routes to eusociality, Proceedings of the Royal Society B: Biological Sciences (2022). DOI: 10.1098/rspb.2022.0652. rspb.royalsocietypublishing.or … .1098/rspb.2022.0652 Journal information: Proceedings of the Royal Society B