Courtship and copula duration influence paternity success in a spider
We tested whether in the cannibalistic spider Argiope keyserlingi courtship performance influences paternity shares in double-mated females. We quantified courtship perfromance in two contexts (during mating trials on the female's web and in the thread assay, simulating male courtship in a standardised test). Courtship comprises several different elements: shuddering (a series of antero-posterior rocks), abdominal wags (a series of dorso-ventral abdominal pumps) and mating thread dances (including plucks and bounces on the mating thread). We sterilised half of the males by irradiating them. We ran mating trials (each female copulated with two males, one irradiated and one control male) and we assigned paternity based on the sterile male technique. We validated the use of the thread assay by testing the correlation between courtship performances in the two contexts. We then used a Bayesian generalised linear mixed model to test the effect of irradiation, copulation duration and shudder number on paternity shares.