The role of testosterone in development of sexual size dimorphism in the tropical lizardParoedura picta(Squamata: Gekkonidae)

Abstract

Event Abstract Back to Event The role of testosterone in development of sexual size dimorphism in the tropical lizard Paroedura picta (Squamata: Gekkonidae) Zuzana Starostova1, Lukas Kubicka2*, Alison Golinski3 and Lukas Kratochvil2 1 Charles University in Prague, Department of Zoology, Czechia 2 Charles University in Prague, Department of Ecology, Czechia 3 Rutgers, The State University of New Jersey, Graduate Program in Endocrinology and Animal Biosciences, United States Sexual size dimorphism (SSD) is a nearly ubiquitous phenomenon and has been extensively studied in animals, including lizards. However, the proximate mechanism responsible for development of SSD is still only poorly understood in this group. Currently the most pervasive candidates are (1) sex steroid effects, whereby elevated circulating levels of androgens in males (but not females) stimulates growth in male-larger species, or (2) sex differences in energy allocation, whereby females invest relatively greater amount of energy (compared to males) towards reproduction. We tested these alternative hypotheses in the tropical lizard Paroedura picta, in which hatchlings do not exhibit SSD and both sexes reach sexual maturity at a relatively small body size, but males attain much larger final body size than females. Individuals of P. picta were kept separately under the same conditions. When animals reached sexual maturity we established three groups of males (intact control, surgically castrated, castrated with testosterone replacement) and four groups of females (intact control, intact control allowed to mate regularly, testosterone supplemented, castrated). Body size was measured monthly until the lizards reached asymptotic body size. Neither of the hypotheses was supported by the results. Castrated males reached a final structural body size (i.e., snout-to-vent length) comparable to control males or castrated males with testosterone implants. Thus, testosterone had no significant effect on growth (i.e., final body size) in males. Control females maintained in social isolation to prevent reproduction reached the same final body size as mated females that produced eggs frequently. Interestingly, ovariectomized females and females with testosterone implants grew to larger body size than both groups of intact females. This finding suggests that not the cost of reproduction but gonadal hormones in females (estrogenes and/or gestagenes) may retard growth in P. picta. Acknowledgements The research was supported by the Czech Science Foundation, projects no. 206/09/0895 (LK and LK) and P505/10/P174 (ZS) and by the Fulbright Commission (AG). Keywords: gecko, Growth, sexual size dimorphism, Testosterone Conference: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology, Ann Arbor, United States, 13 Jul - 16 Jul, 2011. Presentation Type: Oral Presentation Topic: Growth and aging Citation: Starostova Z, Kubicka L, Golinski A and Kratochvil L (2011). The role of testosterone in development of sexual size dimorphism in the tropical lizard Paroedura picta (Squamata: Gekkonidae). Front. Endocrinol. Conference Abstract: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology. doi: 10.3389/conf.fendo.2011.04.00065 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: 22 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Dr. Lukas Kubicka, Charles University in Prague, Department of Ecology, Prague, Czechia, kubickalukas@gmail.com 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 Zuzana Starostova Lukas Kubicka Alison Golinski Lukas Kratochvil Google Zuzana Starostova Lukas Kubicka Alison Golinski Lukas Kratochvil Google Scholar Zuzana Starostova Lukas Kubicka Alison Golinski Lukas Kratochvil PubMed Zuzana Starostova Lukas Kubicka Alison Golinski Lukas Kratochvil 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.