Losses in behavioural plasticity and the evolution of altruism

DSC_0105A trade-mark of sociality is the evolution of specialist task-performers, who show life-time commitment to a specific role. Social insects are great study organisms for understanding how and why this happens. The prime example is the highly eusocial species, the honeybee, where each individual larvae retains the ability to develop as a queen or a worker up until a certain point in development, after which it is committed to one or the other for the rest of its life.  Conversely, in simpler societies of insects, each individual retains the plasticity to change caste/phenotype throughout life. This means a female can start life off as a worker, but end up as a queen if the right opportunity arises. Loss of caste plasticity is an important way to view the mechanisms of social evolution.

We have been studying the limitations of plasticity and its implications on social evolution and behaviour in paper wasps from around the world. We are interested in determining to what extend all females are equal in their capacity to switch castes and become egg layers or foragers; are males really limited to being packages or flying sperm, or are they able to express some behavioural plasticity to improve their personal fitness; how and why do seemingly paradoxical behaviours such as nest-drifting behaviours evolve, and how does the environment influence the evolution of altruism?