Nonconceptive sexual experience diminishes individuals’ latency to mate and increases maternal investment

Although the evolution of sex has proven a perennial topic in evolutionary biology, the function of nonconceptive sexual behaviour in animal societies is more enigmatic. Here we consider the function of nonconceptive sexual displays in the comb-footed spider, Anelosimus studiosus. In this species, mature males and juvenile females engage in iterative displays of courtship behaviour and pseudocopulatory posturing. We tested whether individuals with nonconceptive sexual experience mated more rapidly with established versus sexually naïve partners, and whether the amount of individuals’ nonconceptive sexual experience was associated with pairs’ latency to engage in conceptive sexual encounters. We found that pairs with at least one sexually experienced individual mated more rapidly than pairs of purely inexperienced individuals. Furthermore, we found the more nonconceptive bouts experienced by an ‘experienced’ individual, the more rapidly the pair engaged in conceptive sex, regardless of partner fidelity. We also detected a positive association between the amount of nonconceptive sexual experience by females and their relative reproductive investment in their first egg cases. Our findings suggest nonconceptive sex serves both (1) as a kind of rehearsal behaviour, which helps hone individuals’ courtship and/or copulatory finesse, and (2) as a cue that affects females’ downstream reproductive decisions (i.e. maternal provisioning).