Male spiders use differential genitalic movements for sperm displacement and copulatory courtship

CALBACHO ROSA, LUCIA SOLEDAD; GALICIA MENDOZA, IVETTE; DUTTO,MARIA SOFIA; CORDOBA-AGUILAR, ALEJANDRO; PERETTI, ALFREDO VICENTE

NATURWISSENSCHAFTEN

SPRINGER

Lugar: Berlin; Año: 2013 p. 407 - 416

0028-1042

It is known that males perform differential genitalic movements during copulation in order to prevent sperm competition or influence female?s fertilization decisions. In some species one common fact is the ejection of sperm stored from the female genital tract. Here we investigated whether copulation duration and pedipalp movements that males of the pholcid spider Holocnemus pluchei, carry out during copulation can be used for sperm removal and/or copulatory courtship. In this species, there is last male sperm precedence but paternity values are highly influenced by how long males guard females after copulation. We compared copulation duration, pedipalp movement type, frequency and duration when males mate with virgin vs. nonvirgin females. We expected longer copulation duration, more complex and frequent pedipalp movements when males mate with non-virgin females compared to virgin females. Results corroborated these predictions. Furthermore, when mating with already mated females, sperm masses were observed to come out from the female gonopore. Measurements of stored sperm masses in females with one or two completed matings vs. females with interrupted matings indicated a significant reduction of stored sperm volume for the latter group. We suggest that males use the type I of pedipalp movements to remove almost all sperm of rival males from inseminated females prior to transfer their own sperm. In addition, copulation duration and the type II of male pedipalp movements can be ascribed as transfer sperm and a form of copulatory courtship.