Non-Conceptive Sexual Behavior in Spiders: A Form of Play Associated with Body Condition, Personality Type, and Male Intrasexual Selection


Jonathan N. Pruitt, Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.


In the socially polymorphic spider Anelosimus studiosus, males mature early in the reproductive season and recruit to the webs of juvenile females and guard them until they mature. During the period before females mature, males and females engage in repeated bouts of non-conceptive (play) sexual behavior, where the pair courts and engages in mock copulation; both males and females gain performance-enhancing experience via these encounters. In this study, we examined the factors that underlie individual variation in the tendency to engage in non-conceptive mating and determine whether it impacts male–male competition for females. We found that docile females, being less resistant to mating in general, are more likely to accept male courtship and non-conceptive copulation as juveniles. Personality type influenced the exhibition of non-conceptive sexual behavior in males as well. High body condition males of the aggressive phenotype were more likely to engage in non-conceptive sexual behavior than males with lower body condition. Body condition did not influence docile males’ propensity to engage in non-conceptive sexual behavior, but female size did. Docile males engaged in more non-conceptive sexual displays with larger females. Engaging in non-conceptive sexual displays negatively impacted male performance in staged male–male contests for access to females. This cost was greatest for males of the aggressive phenotype, which are otherwise favored in male–male contests. Our findings indicate expression of non-conceptive sexual displays is linked to personality and results in reproductive performance trade-offs for male A. studiosus.