Meeting Abstract
Animal life histories are dependent on animals’ ability to acquire resources and to invest those resources into fitness-related traits, such as growth, reproduction, and self-maintenance. Yet, animals may struggle to invest resources into several traits simultaneously due to variation in resource availability. For example, food serves as a currency for most biological processes (e.g., locomotion, reproduction, and somatic growth), and its availability exhibits spatiotemporal variation. Water is also critical to maintaining cellular homeostasis, and its availability can covary with food availability in nature (e.g., a drought can lead to a famine). The acquisition of these two resources may also be linked because water is needed to digest food. Thus, we used a 2 x 2 factorial design to investigate the independent and interactive effects of water and food limitation on life history traits using the wing-dimorphic sand field cricket Gryllus firmus. We placed newly molted females into two water treatment groups (water access or no access) at a constant temperature, while controlling access to dry food (food access or no access). After 5 days, we determined food consumption and survival, as well as investment into somatic and reproductive tissues. Water limitation reduced survival, investment into ovary and body mass, and food consumption. Also, food availability had a much greater effect on ovary and body mass when water was available. However, neither resource influenced investment into flight musculature, which is important for dispersal from low quality environments. Our results indicate that traits vary in their sensitivities to important resources and resource-resource interactions, and they generally demonstrate that water limitation can modulate and overwhelm the effects of food availability on investment into key life history traits.
