Sexual size dimorphism, mating system and seasonality of a Neotropical damselfly, Telebasis carmesina (Coenagrionidae)

Abstract

Our understanding of mating systems is highly skewed toward temperate examples. This study investigated the mating system, sexual size dimorphism and seasonal variation in local distribution and abundance of male and female Telebasis carmesina, a common damselfly in Brazilian tropical savanna. In a natural reserve, daily census and behavioral observations were made throughout 1 year at the edges of a permanent pond. Males were more abundant during the rainy season, when mating and oviposition by females occurred. The operational sex ratio at the pond was heavily male biased, c. 1\female: 19\male. Males were smaller than females but were larger in the dry season than in the wet season, when they were more abundant at the pond. Females were larger in the dry months of July to September than in the rainy season. Both males and females principally used the macrophyte Eleocharis sp. as perches and for oviposition. Males exhibited polygynous, scramble mate competition, as in most coenagrionids that have been studied.

Keywords: Odonata, population dynamics, habitat requirements, scramble competition, male-biased sex ratio

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