Tuesday, December 12, 2006 - 7:30 PM

The peculiar design of insect societies

David C. Queller, queller@rice.edu, Rice University, Ecology and Evolutionary Biology, 133E Anderson Biology Lab, Houston, TX

Social insects provide some special advantages in studying evolutionary adaptation and these can be used to counter views that organisms are designed according to some kind of intelligent engineering criteria. Social insects expose issues of the level of selection better than any other group. What exactly is adapted? The answer turns out to be a very odd one from any standpoint other than evolution by natural selection. The behavior of social insect societies shows that they have been molded by the replication strategies of individual genes. As is well known to social insect biologists, kin selection is predicted to produce, and does produce, some startling inefficiencies at the individual level and at the group level. On the one hand, worker individuals, under a set of conditions defined by Hamilton's rule, become withered ghosts of their former selves, unable to reproduce. But this does not lead to pure efficiency at the colony level. For example, there is great inefficiency in the production and subsequent killing of males due to sex ratio conflict, and the in production and murder of young queens in conflict over queenship. Hamilton's rule successfully predicts these conflicts. Science can never rule out the possibility of a designer because one can posit an infinite number of different kinds of designers to match any observed world. But we can reduce the set of possible designers to a very small and odd set that seem to have had Hamilton's rule hardwired into their brains.

Species 1: Hymenoptera Apidae Apis mellifera (honey bee)