Intersexual cooperation during male clasping of external female genitalia in the spider Physocyclus dugesi (Araneae, Pholcidae)

RÓDRIGUEZ-MÁRQUEZ, I. A.; PERETTI, A. V.

JOURNAL OF ETHOLOGY

SPRINGER TOKYO

Lugar: Berlin; Año: 2010 vol. 28 p. 153 - 163

0289-0771

Sexual conflict may influence the shape and evolution of body structures that males use to grasp females during mating. Not only sexual coercion but also intersexual cooperation may be involved during clasping behavior. Among pholcid spiders, secondary sexual modifications of the male chelicerae, like apophyses with spines or tooth-like processes, function to grasp the female by specific parts of her external genitalia such as grooves or apophyses of the epigynum. We analyzed how the female and the male respond when their structures for clasping are experimentally modified in the tropical pholcid Physocyclus dugesi. We used three treatment groups for females that differed in the manipulation of the epigynum apophyses (uncovered, partially covered and fully covered by a plaster) and two groups of males (uncovered and fully covered cheliceral apophyses). We found that females are mainly cooperative to courting males not only when the female genital apophyses were experimentally covered but also when the male cheliceral apophyses were covered. The current data also indicate behavioral flexibility in males during courtship, especially when they had difficulty in genital intromission. Our experimental results, together with previous observational studies, confirm the presence of a modulated-cooperative scenario between the sexes for cheliceral clasping and genital intromission in pholcid spiders.