Meeting Abstract

81.2  Wednesday, Jan. 6  Dietary quality effects on resource allocation in lizards: A quantitative stable isotope analysis WARNE, R.W.*; GILMAN, C.A.; GARCIA, D.A.; WOLF, B.O.; Vassar College, NY; University of New Mexico rw.warne@gmail.com

The degree to which lizards can alter resource allocation to reproduction or growth in response to variation in environmental resource availability remains an open question. Using carbon stable isotopes and manipulation of the dietary resources available to experimental prairie lizards (Sceleporus undulatus consubrinus) we quantify the plasticity in their allocation of stored-endogenous resources versus recent dietary intake to the competing demands of growth and reproduction. We show that reproducing females can vary their use of stored resources for egg production by more than 60% in response to reduced resource availability prior to hibernation. When fed a high quality diet during the spring – after hibernation, however, these females showed rapid ‘catch-up’ growth and comparable reproductive effort to lizards fed an ad libitum diet both before hibernation and during vitellogenesis. These results show that dietary conditions have a strong affect on the trade-off between resource allocation to growth vs. reproduction. Furthermore, this study demonstrates that variation in resource quality during periods of resource accumulation (e.g. preparation for hibernation in the fall) can have strong delayed and long-term effects on subsequent life cycles events (e.g. reproduction and growth in the following spring). We also present similar isotope and reproductive data for eight species of wild caught lizards with diverse life histories to examine the interactions between environmental resource variation and evolved life history strategies.