Chronobiology of seasonal reproduction: Neuroendocrine mechanisms and geographic variation

Abstract

Event Abstract Back to Event Chronobiology of seasonal reproduction: Neuroendocrine mechanisms and geographic variation Deborah I. Lutterschmidt1* 1 Portland State University, Department of Biology, United States The ability to integrate and respond to changing environmental cues with appropriate physiology and behavior is crucial to the survival and reproductive fitness of all organisms. One of the most critical life history traits subject to environmental control is reproduction. However, the upstream mechanisms governing how the reproductive axis receives and integrates environmental cues are poorly understood. Moreover, temperature may be the primary environmental cue regulating reproduction in ectotherms, yet we know very little about the neuroendocrine mechanisms mediating temperature-induced reproduction. We recently demonstrated that melatonin concentrations of common garter snakes (Thamnophis sirtalis) hibernated at 5°C were significantly lower than those of snakes maintained at 10°C. These temperature-induced differences in melatonin rhythms between treatment groups persisted even after both groups were again acclimated to 10°C, indicating that low temperature exposure has a lasting influence on melatonin rhythms. We further examined whether melatonin rhythms may mediate differences in reproductive timing both between sexes and among populations. Critically, we observed sex differences in melatonin cycles of T. sirtalis during the spring mating season, and these sex differences were present in each of the 3 garter snake populations studied. Whether sexually dimorphic melatonin cycles are related to the expression of male courtship behavior requires further study. We also observed population differences in melatonin cycles across a wide range of acclimatization conditions, and these differences were themselves plastic. Changes in male courtship behavior and androgen concentrations during spring emergence also varied significantly among these populations, despite acclimatization to identical environmental conditions. These data provide support for the hypothesis that melatonin-mediated responses to environmental cues govern differences in reproductive timing. Keywords: courtship behavior, geographic variation, melatonin rhythm, Reproduction, reptile, sex steroid hormones, temperature, winter dormancy Conference: ISAREN 2011: 7th International Symposium on Amphibian and Reptilian Endocrinology and Neurobiology, Ann Arbor, United States, 11 Jul - 13 Jul, 2011. Presentation Type: Invited Symposium Topic: Reproduction Citation: Lutterschmidt DI (2011). Chronobiology of seasonal reproduction: Neuroendocrine mechanisms and geographic variation. Front. Endocrinol. Conference Abstract: ISAREN 2011: 7th International Symposium on Amphibian and Reptilian Endocrinology and Neurobiology. doi: 10.3389/conf.fendo.2011.03.00028 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 20 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Dr. Deborah I Lutterschmidt, Portland State University, Department of Biology, Portland, OR, 97207, United States, dil@uci.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Deborah I Lutterschmidt Google Deborah I Lutterschmidt Google Scholar Deborah I Lutterschmidt PubMed Deborah I Lutterschmidt Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.