Meeting Abstract

83-7   15:00 - 15:15  Vegan or not: diet influences latitudinal gradients in life-history traits, but not reproductive output, in lizards Bansal, U*; Thaker, M; Washington University in St. Louis, St. Louis, MO, USA; Indian Institute of Science, Bengaluru, India; Indian Institute of Science, Bengaluru, India b.udita@wustl.edu

Latitudinal gradients in life-history traits are apparent in many taxa and are expected to be strong for ectotherms that have temperature-driven constraints on performance and fitness. The strength of these gradients, however, should also be affected by diet because diet type influences accessibility to nutrition and assimilation efficiency. We studied how diet affects latitudinal gradients in lifetime reproductive output and the underlying life-history traits in ectotherms. We used empirical (352 species) and phylogenetically imputed data (563 species) to analyze the interactive effects of latitude and diet on life-history traits (longevity, age at maturity, reproductive lifespan, hatchling mass, clutch/brood size, clutch/brood frequency, female mass) and lifetime reproductive output of lizards. Lifetime reproductive output does not significantly differ in lizards across diet types, and only carnivores exhibit a small increase at higher latitudes. Diet type, however, influences latitudinal patterns of individual life-history traits. Carnivores exhibit a shift towards “slower-paced” life-histories at higher latitudes for most traits. By contrast, herbivores either display “faster-paced” life-histories or no change at higher latitudes. We suggest that the nutritional challenges of herbivory, compounded by thermal constraints at higher latitudes, may explain differences in life-history characteristics of herbivorous ectotherms. Intermediate and muted patterns exhibited by omnivores highlight how flexibility in diet can buffer environmental challenges at higher latitudes. Our results indicate that lizards with different diet types display various trends in their life-histories across latitudes, which eventually balance out to result in similar reproductive outputs throughout their lifetime, with little benefits to carnivory.