Reproductive tactics of sexes and fitness in the dragonfly, Diastatops obscuraJorge Bañuelos Irusta and Arrilton Ara¨˛joSector of Psychobiology, Department of Physiology, Federal University of Rio Grande do Norte (UFRN), Caixa Postal 1511 ¨C Campus Universit¨˘rio, 59072-970, Natal-RN, Brazil
AbstractThe sexual selection strategies of territorial Odonata that do not present courtship behavior is still not completely understood, especially the role of the females. Diastatops obscura Fabricius (Odonata: Libellulidae) females participate in mate selection in a passive manner, allowing copulation with the first male that captures them and afterwards choosing whether to oviposit or not. This study introduces the idea of female passive choice as an adaptative tactic in intersexual selection. Also discussed is the adaptative value of this tactic and its flexibility according to environmental conditions and reproductive strategies adopted by the males. A natural population of Diastatops obscura was observed in the Pitimbu River of northeast Brazil. Focal continuous and ad libitum techniques were used to record attempted copulation, copulation, and oviposition behavior, in addition to registering male territoriality. An estimate of individual reproductive success (IRS) was obtained by recording 187 reproductive events. Territorial males, mainly occupying areas near the river margin, achieved greater copulation and oviposition success (IRS = 0.371) than did satellite males (IRS = 0.028). Females that copulated with territorial males experienced, for the most part, only one copulation and oviposition event, while those that copulated with satellite males fled or performed a second copulation with a territorial male. Thus, the best tactic adopted by the D. obscura males was to occupy a territory providing the greatest access to females, while the females used passive choice for fitness optimization. Keywords: sexual selection, female choice, dragonfly, Pitimbu River
Abbreviations: IRS: individual reproductive success
Correspondence: banuelos@ufrnet.br, arrilton@cb.ufrn.br Received: 7 October 2005 | Accepted: 25 October 2006 | Published: 16 April 2007 Copyright: This is an open access paper. We use the Creative Commons Attribution 2.5 license that permits unrestricted use, provided that the paper is properly attributed. ISSN: 1536-2442 | Volume 7, Number 24
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