Meeting Abstract

100.4  Saturday, Jan. 7  Do low energy systems practice state-dependent foraging strategies? WRIGHT, C.W.*; MOELLER, K.M; DENARDO, D.F.; Arizona State Univ., Tempe; Arizona State Univ., Tempe; Arizona State Univ., Tempe

Much of the existing literature on the influence of physiological state on foraging decisions (e.g., state-dependent foraging) examines high energy systems (i.e., birds and mammals). Assessing such interactions in low energy systems (i.e., vertebrate ectotherms) that feed infrequently and thus are typically in negative energy balance can provide insight into the broad applicability of current theories on the mechanisms that drive foraging behavior, thus furthering our understanding of state-dependent foraging strategies. We conducted a supplemental feeding experiment to investigate how meal consumption alters acute behavioral responses as well as chronic (seasonal) physiological and behavioral responses of Gila monsters, Heloderma suspectum. Radiotelemetered, free-ranging Gila monsters were supplementally fed or sham-manipulated throughout their active season, and we serially assessed physiological stores (body mass, energy stores via tail volume, and hydration state via plasma osmolality), field metabolic rate (FMR) using doubly labeled water, and behavioral responses (proportion of time spent surface active). We present the results of the impact of meal consumption on short-term behavioral responses as well as seasonal variations in physiological stores, FMR, and activity levels, discussing these results within the context of state-dependent foraging strategies and mechanisms driving foraging decisions in organisms across taxa.