Meeting Abstract
Primary productivity and thus food quality are predicted to fluctuate along with changing global climates. Organismal performance and life history investments are limited by suboptimal diets, unless feeding behavior is altered to compensate. Further, nutritional demands of life history traits differ. We hypothesized that optimal diets should shift through ontogeny along with investment in life history and predicted that behavioral responses and performance consequences of imbalanced diets will change concordant with life history demands. Within populations of the wing polymorphic cricket Gryllus lineaticeps, alternative development trajectories produce adult morphs that specialize in either dispersal or reproduction. We characterized dietary preferences and compensatory feeding strategies on imbalanced diets, by feeding last instar and adult crickets one of three isocaloric diet treatments: 1) protein-biased diet (2P:1C), 2) carb-biased diet (1P:4C), or 3) both diets (choice). As last instars, dispersal morphs needed to consume more food to support muscle development, and met this higher caloric requirement irrespective of diet macronutrient content. Males did not alter their feeding behavior across life stages. In contrast, females selected a more protein-biased diet and shifted their regulatory strategy to avoid overconsuming excess macronutrients on imbalanced diets as adults. Consequently, adult females incurred large caloric and protein deficits on the carb-biased diet, which in turn constrained reproductive investment and resulted in a reduction of ovary size and energy provisioning. These findings suggest that when physiological demands are high, behavioral adjustments do not fully offset costs of imbalanced diets, leaving specific individuals more sensitive to fluctuations in food quality.
