The evolution of transgenerational effects: when should offspring listen to their parents?

When?

Friday 16 March 2012, 16:00 to 17:00

Where?

22AA04

Open to:

Staff, Students

Speaker:

Bram Kuijper

Instead, phenotypic variation may be transmitted in other ways, for example, through placental hormones that are transmitted from parents to offspring, or through social learning and imitation. This prompts us to ask under which conditions such transgenerational effects evolve. Here, I focus on the evolution of a maternal hormone in a fluctuating environment, which induces offspring to either copy the maternal phenotype, or to attain a phenotype that is different from the mother. I use a set of differential equations to derive the population dynamics of the model (environmental fluctuations, births, deaths), which are assumed to occur at a much faster timescale than the evolutionary change of the genetic modifier coding for the maternal hormone. Solving numerically for the equilibrium values of the maternal hormone, I find that the short-term copying of a maternal phenotype occurs when different environments are roughly equally common, and when environments change relatively slowly. Next, I focus on a more explicit model in which mothers apply this hormone to forewarn offspring about the presence of predators or parasites. Interestingly, the actual use of the hormone strongly depends on the fecundity of the mother: mothers with a high fecundity are predicted to ignore the potential danger of predators and do not forewarn their offspring, whereas mothers with a low fecundity are selected to be highly sensitive to potential predation and always forewarn their offspring. To summarize,  transgenerational effects are the result of a complex interplay between environmental variation and variation among mothers in their condition.