Theoretical and experimental studies on behavioral syndromes in aphids

Individuals’ behaviors can be correlated across time and contexts, in a phenomenon now known as behavioral syndromes. Using an experimental approach, I demonstrate that genetically identical pea aphids are highly repeatable in multiple behavioral traits, however these behaviors are uncorrelated. Then using a state variable model I show that asymmetries in size can maintain a hierarchy between least and most bold individuals in foraging intensity across development. However, individuals that complete compensatory growth show an inversion in the rank-order of foraging activity between early and late development (ie individuals that are the boldest early in life are less bold than their “timid” counterparts late in life). In conclusion, I demonstrate both theoretically and empirically that non-genetic differences are capable of explaining repeatability in the expression of a single behavior; however I found no evidence that non-genetic mechanisms can correlations between multiple behaviors.