Mating duration and sperm precedence in the spider Linyphia triangularis

Abstract

In many animal species, mating behaviour is highly ritualised, which may allow us to relate some of its consequences, e.g. male paternity and female receptivity, to the progression of phases in the mating sequence; at the same time, ritualisation raises the question of to what extent the partners, especially the males, are able to influence the outcome of mating for their own benefit. We studied the linyphiid spider Linyphia triangularis in which mating follows a strict sequence during which the male inducts two droplets of sperm and transfers them to the female. We performed sperm competition experiments (sterile-male technique) including four treatments, in which the copulation of the first male was interrupted at prescribed phases of the mating sequence, while the second male was allowed a complete mating. Second males spent a shorter time than first males on the behaviours prior to sperm transfer, but the amount of sperm (2 droplets) and the time spent in sperm transfer were independent of the females' mating status. The proportion of females accepting the second male depended on the mating duration of the first male, i.e. whether the first male had transferred one or two sperm droplets. After a complete first mating, most females accepted no further males. A last-male sperm precedence was apparent if only half of the first sperm droplet had been transferred by the first male, but this switched to a first male precedence if one full sperm droplet had been transferred. Thus, even in the face of sperm competition, it is sufficient for the first male to transfer one sperm droplet. The second sperm droplet and the extended copulatory courtship associated with its transfer may serve to induce a lack of receptivity in the female, but the males seem unable to enhance their reproductive success through variable copulatory tactics.

Hogna radiatamales do not deplete their sperm in a single mating

“…In our experiment, most females followed this strategy, and only a tiny portion mated twice. In species in which polyandry is female-driven, multiple mating by females has been related either to sperm competition or to sperm supply, which is demonstrated by a negative relationship between multiple mating and first mating duration (Weldingh et al 2011). We found no relationship between number of matings and mating duration in H. radiata, though first mating duration by polyandrous females represented, on average, roughly half the mean mating duration by monandrous females.…”

Costs and benefits of multiple mating in a species with first‐male sperm precedence

“…Alternatively, the pattern of sperm precedence may be context‐dependent. Indeed, in several species, it has been shown to vary according to multiple factors, such as the number of matings (Zeh & Zeh, ), the interval between mating events (Bullini, Coluzzi, & Bianchi Bullini, ) or the effectiveness of the first mating (Weldingh, Toft, & Larsen, ). Finally, multiple mating, even without offspring fertilization, might be beneficial for one of the sexes.…”

Strategic mate‐guarding behaviour in ladybirds

“…Mate guarding is a process in which males spend an extended time with females after copulation or sperm transfer, beyond what is necessary for fertilization (Birkhead & Møller, 1998;Chaudhary et al, 2015). While this interaction may have other benefits to both sex (Alcock, 1994), the term mate guarding refers specifically to its role in reducing sperm competition (Calbacho-Rosa, Córdoba-Aguilar, & Peretti, 2010;Chaudhary et al, 2016;Harari, Landolt, O'Brien, & Brockmann, 2003;Parker & Vahed, 2010;Weldingh, Toft, & Larsen, 2011). Mate guarding is a widely occurring phenomenon in insects (Alcock, 1994), crustaceans (Sparkes, Keogh, & Pary, 1996), reptiles (Ancona, Drummond, & Zaldívar-Rae, 2010), birds (Low, 2006) and mammals (Schubert, Schradin, Rödel, Pillay, & Ribble, 2009).…”