Variação nos padrões de acasalamento da aranha Leucauge Volupis (Tetragnathidae) ao longo da estação reprodutiva: relações complexas entre o sucesso de acasalamento e o pareamento reprodutivo

Abstract

When individuals find mates and copulate, certain mating patterns may emerge in the population, influencing the effects of natural selection on a particular trait. Mating success by size occurs when individuals of a given size monopolize most copulation opportunities. After this stage, pairings can result in homotypic or heterotypic size pairings. This can affect genetic variation and has the potential to drive sympatric speciation, though the relationship between these mating patterns and their tendency to change over the reproductive season is rarely investigated. In this study, we describe the sexual size dimorphism and reproductive behaviors of the spider Leucauge volupis. We also assess temporal variations in the size of individuals of this species over a reproductive season and the relationship between mating success and size-based reproductive pairings. Our hypotheses were that (1) size-based pairings are homotypic and (2) larger individuals have greater mating success than smaller ones. We also explored the alternative hypothesis that (3) pairings are random when the size variation of paired individuals from one or both sexes is low due to the mating success of a particular size category. There was sexual size dimorphism, with females being larger than males in most body measurements. Pairings by body mass were homotypic, regardless of variations in mating success and individual size. Pairings by carapace width were homotypic only during the period of the reproductive season when larger males had greater mating success. We demonstrate the importance of investigating the relationships between mating patterns and their temporal variations to understand the effects of selection on size.