Challenging monogamy in a spider with nontraditional sexual behavior

Abstract

Each species and sex can develop different reproductive strategies to optimize their fitness while assigning reproductive effort. Allocosasenex is a sex-role reversed spider whose males construct long burrows in the sand. They wait for wandering females to approach, assess their sexual partners and donate their constructions to females after copulation. Females stay in the burrow and lay their egg-sac. When offspring are ready for dispersion, females leave the burrow and gain access to new mating opportunities. Males are choosy during mate courtship, preferring to mate with virgin females over copulated ones, which can even be cannibalized if males reject them. This situation turns new mating opportunities dangerous for copulated females. We wondered whether a copulated female inside the previous mate's burrow responds to courtship from a new male and if this new male can copulate, avoiding burrow construction costs. We also explored whether courtship and copulation behaviors during the first sexual encounter affected the probability of occurrence of a second copulation. For that purposes we exposed copulated females inside male burrows to new males (non-donor males). Males could locate and court females inside the previous male's burrow, and females accepted a second copulation. Hence, A.senex females are not monogamous as was expected but increase their reproductive success by copulating with non-donor males. Also, males can develop opportunistic tactics, suggesting a more dynamic mating system for this sex-role reversed spider than assumed.

Updates and perspectives on reproductive behavior of South American wolf spiders

“…Furthermore, De Simone et al (2019) reported that the construction of a burrow has negative repercussions on the weight of males; therefore, the donation of the burrow is an energy-costly investment. It has been reported that males from central Argentina may vary their reproductive tactics depending on the context; they are able to locate, court and copulate with females that are still housed within the burrows of their previous sexual partners (Bollatti et al 2022). These observations suggest that males could evade the costs of building and donating their burrow, revealing, in turn, that females from the same locality remate with males that do not offer burrows (Bollatti et al 2022).…”