Variability in Precipitation Weakens Sexual Selection for Nuptial Gifts in Spiders

Area of Science:

• Evolutionary biology
• Behavioral ecology
• Sexual selection

Background:

• Environmental conditions significantly impact reproductive traits and sexual selection.
• The effect of environmental variability on sexual selection remains debated, with some evidence suggesting it relaxes selection.
• Nuptial gifts in species like Paratrechalea ornata offer a model to study the interplay between environment and sexual selection.

Purpose of the Study:

• To test the hypothesis that variable environmental conditions relax sexual selection.
• To investigate how climatic variation influences female choice and male mating strategies in Paratrechalea ornata.
• To determine if deceptive mating strategies are favored in unpredictable environments.

Main Methods:

• Studied six populations of Paratrechalea ornata across diverse climatic conditions.
• Assessed variations in male sexual traits and female choice.
• Quantified the frequency of nutritive versus worthless nuptial gifts and correlated with mating duration.

Main Results:

• High precipitation variability was found to limit female choice.
• Populations with high environmental variability showed a higher frequency of worthless gifts (70%).
• In variable conditions, males with worthless gifts achieved longer mating durations, unlike in stable conditions where females shortened mating.

Conclusions:

• Findings support the hypothesis that variable environmental conditions relax sexual selection.
• Limited female choice in unpredictable environments can favor the evolution of deceptive male strategies.
• Climatic variation plays a crucial role in shaping the dynamics of sexual selection and mating behaviors.