Multidimensional plasticity in the Glanville fritillary butterfly: larval performance curves are temperature, host and family specific.

Abstract

Variation in environmental conditions during development can lead to changes in life-history traits with long-lasting effects. Here, we study environmentally induced variation, i.e. the consequences of potential maternal oviposition choices, in a suite of life-history traits in pre-diapause larvae of the Glanville fritillary butterfly. We focus on offspring survival, early growth rates and relative fat reserves, and pay specific attention to intraspecific variation in the responses (GxExE). Globally, we found that thermal performance and survival curves varied between diets of two host plants, suggesting that host modifies the temperature impact, or vice versa. Additionally, we show that the relative fat content has a host-dependent, discontinuous response to developmental temperature. This implies that a potential switch in resource allocation, from more investment in growth at lower temperatures to storage at higher temperatures, is dependent on other environmental variables. Interestingly, we find that a large proportion of the variance in larval performance is explained by differences among families, or interactions with this variable. Finally, we demonstrate that these family-specific responses to the host plant remain largely consistent across thermal environments. Altogether, the results of our study underscore the importance of paying attention to intraspecific trait variation in the field of evolutionary ecology.