The perks of being in good conditions: How does female parasitism affect male mate choice in an orb-web spider?

It is assumed that males increase their reproductive performance by mating with the highest number of females. However, in some species males are reproductively constrained, being able to mate only a few times. In these cases, it is expected that males choose the highest quality females available. One factor that can change female quality is parasitism, however, many empirical studies fail to find conclusive support for a non-parasitized female preference. This might be due to the fact that behavioral tests in many studies are made in a controlled environment or use indirect measures of mate choice. Using a natural-environment approach, we tested whether the mate choice of the golden orb-web spider Trichonephila clavipes male is affected by the presence of the parasite in the female. We hypothesize that males will prefer to establish on webs of non-parasitized females and will attempt to mate and copulate more with non-parasitized females over parasitized ones. For this, we conducted field observations for 76 h. We found that males prefer to establish on non-parasitized female webs than on parasitized ones. However, there was no difference between the number of attempts to mate and copulations of parasitized and non-parasitized females. It seems that males can distinguish between parasitized and non-parasitized females, but once they establish on a female web, they are resistant to leave. One possible explanation is that some males stay on a parasitized female web to avoid competition with other males. Therefore, it is possible that mating with parasitized females represents a “making the best of a bad job” mating tactic in T. clavipes.