Silk Investment in Gifts By Males of the Nuptial Feeding Spider Pisaura Mirabilis (Araneae: Pisauridae)

Abstract

SummaryAdult males of the hunting spider Pisaura mirabilis wrap up prey with silk and pass these nuptial gifts to females prior to copulation. The females digest the nuptial gifts, including the silk, during mating. Laboratory experiments were carried out to determine the amount of silk males of P. mirabilis invest in nuptial gifts, and its possible role in sexual reproduction. The amount of silk was always small, indicating that the silk of the nuptial gift has little nutritional value for females. Males that had more time to wrap up the prey produced a larger amount of silk. Starved males required more time than satiated males to produce a given amount of silk. A larger male body size had a positive effect on the amount of silk. In general, the size of the prey used for nuptial gifts had no influence on the amount of silk. However, due to handling problem, smaller males produced no silk for very large flies. Females took more time to digest a nuptial gift with a larger amount of silk than a nuptial gift with a smaller amount of silk. A possible interpretation of the adaptive significance of wrapping is that males use silk to prolong the copulation time during mating.

Condition dependence of male nuptial gift construction in the spider Pisaura mirabilis (Pisauridae)

“…Nuptial gifts are presented in the form of captured prey, regurgitation, glandular or salivary fluids, or specialized male body parts, which are donated to the females during courtship and mating (Thornhill 1976;Boggs 1995;Sakaluk 2000;Vahed 1998Vahed , 2007. In spiders, the nuptial gift-giving trait of Pisaura mirabilis (Pisauridae) has been studied extensively (Bristowe 1968;Austad and Thornhill 1986;Lang 1996;Drengsgaard and Toft 1999;Stålhandske 2001Stålhandske , 2002Bruun et al 2003;Prokop 2006;Bilde et al 2006;2007;Andersen et al 2008;Hansen et al 2008;Prokop and Maxwell 2009), and a similar behaviour has been studied in Paratrechalea ornata (Trechaleidae) (Costa-Schmidt et al 2008;Albo et al 2009;Albo and Costa 2010). In P. mirabilis, females exert strong preference for a nuptial gift.…”

“…Stålhandske (2001) observed that, although males may acquire copulation without offering a gift, the presence of a gift greatly increases mating success and also facilitates male mating position, and importantly keeps the female occupied by feeding during the mating. The gift thus functions as a male mating effort, and larger gifts promote longer copulations and more fertilized eggs than small gifts (Austad and Thornhill 1986;Lang 1996;Stålhandske 2001;Bilde et al 2007;Andersen et al 2008).…”

“…Prey wrapping is elicited even in the absence of a female by sexual stimuli such as female silk (Nitzsche 1988), and courting males that are initially rejected by a female usually perform additional bouts of gift wrapping and are often eventually accepted (Bilde et al 2007). Copulation duration is positively correlated to the amount of silk applied to the gift (Lang 1996). Several hypotheses have been put forward to explain the function of silk wrapping; among these, it was suggested that silk functions to avoid prey disintegration during handling, or to allow the males to pack more than one prey within a gift and thus increase the gift size (Austad and Thornhill 1986;Lang 1996).…”

Cryptic Female Choice and Nuptial Prey Gifts in a Spider Model

“…So, the list of factors influencing mate choice in prey gift giving spiders would include not only the presence and the quality of a prey gift, but also additional courtship traits/units performed by the males (e.g., Costa-Schmidt et al 2008). There is a widespread correlation between mating success and male condition, which will reflect in the intensity of courtship and also in the degree of investment in prey gift quality (Lang 1996;Albo et al 2014b). As an emerging pattern from the available evidences, it is possible to set a hierarchy of the factors that influence mate choice in prey gift giving spiders, starting with the presence of a prey gift, followed by the male condition (independent of the prey gift), and ending with the quality of the prey gift.…”

“…This pattern of prey gifts being determinant traits for mating success goes along with the hypothesis that prey gifts exploit the female foraging motivation through chemical signals found within the external silk layer (Pi. mirabilis : Lang 1996;Bilde et al 2007;Pa. ornata: Brum et al 2012).…”