Cohabitation of males and juvenile females: a prevalent mating tactic of spiders

Abstract

Cohabitation, a mating tactic in which males remain with juvenile females until they moult and mature, is shown to be common among spiders. Records are given for 161 species in 74 genera and 15 families. Records were obtained for 100 species of cursorial spiders (45 genera, eight families) and 71 species of web-builders (33 genera, 11 families). Cursorial species cohabit in nests, whereas web-builders cohabit either in the open on their webs or in nests in or near their webs. Duration of cohabitation in nature and in the laboratory was recorded for 12 species. An apparent tendency for web-builders to cohabit longer than cursorial species is discussed. The longest cohabitation occurred in three web-building species (Inola amicabilis, Inola subtilis: Pisauridae; Portia fimbriata: Salticidae) in which males remained with females two moults from maturity, and juvenile, as well as adult, males cohabited with juvenile females. The prevalence of cohabitation in the Salticidae, the family that provided the largest number of examples (72 species: 33 genera), is discussed in relation to current hypotheses about salticid phylogeny.