The evolution of sociality in subsocial animals

Associations with family members, namely the mother and siblings from the same brood, is one of the most common forms of social living, and is thought to be key for the transition from solitary living to sociality. Whether or not juveniles remain with their mother and siblings, and so form social groups, or leave to live a solitary lifestyle, is determined by many factors.

The ecological costs and benefits of these different choices will strongly determine whether more social living will evolve or not.

However, this decision will also be influenced by other individuals. A mother's influence on the traits of her offspring, beyond those due to directly inherited genetic effects, are known as maternal effects, while other individuals, such as siblings, can also influence the traits of a focal individual through indirect effects. Both maternal and indirect effects are very important for trait evolution and could be fundamental in determining the evolvability of traits that facilitate group living to evolve, such as sociality and aggression.

However, how important maternal and indirect effects are for the transition from simple to more complex forms of sociality is not well known.

I will use the group-living cockroach Blaptica dubia to study how the mother and other individuals influences social behaviour, the decision to stay or leave a family group, and therefore the evolution of more or less social lifestyles. I will conduct experiments in a laboratory population at the University of Aberdeen to determine what drives individuals to stay or leave groups, and how this impacts the evolvability of sociality.

Little is known about dubia ecology in the wild, so I will also conduct field work in South America on natural populations to determine their social structure in the wild, how it varies with environmental gradients, and collect diverse specimens to estimate the degree of genetic variation in traits of interest.