Meeting Abstract
Variation in food resources during early life stages (e.g., embryo, juvenile) can generate variation in future body composition and reproductive output, and hence has critical consequences for fitness. In this study, we evaluate spatial variation in food resources and body composition in the brown anole lizard (Anolis sagrei) across different habitat types on an island in Florida. Body composition was determined with quantitative magnetic resonance (QMR), and compared between lizards collected from the interior (forested) and perimeter (shoreline) of the island. After validating that QMR provides accurate estimates of fat mass, lean mass and water mass for A. sagrei, we show that lizards that occupy territories in the interior of the island have more fat mass and less lean mass than individuals that occupy the shoreline of the island. Habitat differences in prey type and/or composition might provide an explanation for this pattern. Indeed, preliminary invertebrate surveys indicate that more marine-based prey (isopods, amphipods) are found in shoreline habitats than in the interior of the island. We have recently initiated detailed studies of the invertebrate community across the study island and will assess energetic and nutrient contents of different prey types found in different habitats. These data will form a foundation for future studies focused on understanding (1) the fitness consequences of early life nutrition, and (2) how organisms distribute themselves across nutritionally-variable landscapes relative to nutrients or energy available during early life stages.
