The evolutionary trajectories of trade-offs are ultimately governed by the evolution of the underlying physiological processes of the acquisition and subsequent allocation of resources. In this study, we focused directly on acquisition and allocation as traits and estimated their genetic architecture in the trade-off between flight capability and reproduction in the cricket, Gryllus firmus. To determine the evolutionary genetics of acquisition and allocation both within and between resource environments we performed a large-scale quantitative genetic breeding experiment in which families were split over several resource levels. Our findings were fourfold: 1) there was substantial genetic variance in acquisition and allocation; 2) contrary to the assumption of independence between acquisition and allocation, there was a significant genetic correlation between them; 3) the genetic covariance between acquisition and allocation was significantly different in the different food environments, 4) the trade-off, as measured by the genetic correlation between flight muscle mass and ovary mass, was only significant in the food restriction environments. However, when measured directly as the genetic correlation between reproductive allocation and flight allocation, we found a consistent strong negative genetic correlation, demonstrating that when allocation is measured independently of acquisition we find evidence for the trade-off.

Half-Sib DataThis data is from a half-sibling breeding experiment done in the lab using Gryllus firmus females at 7 days of age. All masses are dry masses. Energy values were calculated as described in King et al. 2010. Column headings are: Animal: individual number, Sire: male parent number, Dam: female parent number, Bucket: cage number, Wing Morph: long-wing (L), short wing (S), Food: Low, Medium (Med), Ad libitum (AD), State of DLM (0=histolyzed, 1=partially histolyzed, 2=intact), DLM Mass (mg), Ovary Mass (mg), Remaining Mass (Body mass-DLM and Ovary Mass), Acquisition (total energy content, J), DLM Energy (J), Ovary Energy (J).Kingetal2011.xls