Behaviour 2019
Female emancipation from male sensory exploitation and the loss of the nuptial gift in spiders
Mauro Martínez VIllar1, Mariana Germil1, Camila Pavón-Peláez1, Ivanna H. Tomasco1, Søren Toft2, Trine Bilde2, Maria J. Albo1. 1Facultad de Ciencias, Montevideo, Montevideo, Uruguay; 2Aarhus University, Aarhus, Aarhus, Denmark

Sensory exploitation hypothesis has been proposed for the origin of nuptial gifts in spiders. Males exploit female preferences by luring them with food during courtship, which may lead females to suboptimal mating rates. Information on females’ emancipation from exploitation is limited, but recently suggested for a species from the genus Trechaleoides. It is composed by two species, T. keyserlingi in which males offer nuptial gifts but without mating advantages, and the unknown T. biocellata. We study the reproductive strategies of both species by exposing 15 times males to females (11 males in T. biocellata and 14 males in T. keyserlingi). During the experiments all males have the opportunity to grab and wrap a prey, but none did it in T. biocellata. Further, females showed to be extremely cannibals. In 53% of the cases T. keyserlingi males produced a gift but they acquired significant less mating number than males without gifts and obtained similar mating durations. Overall, the results suggest that T. keyserlingi females have changed their gift preferences and the gift is a non-functional remnant trait, while its absence in T. biocellata may represent a loss of the sexual trait.