Density-dependent mating behaviors reduce male mating harassment in locusts

Area of Science:

• Animal Behavior
• Ecology
• Evolutionary Biology

Background:

• Male mating harassment can arise from differing mating objectives between sexes.
• Communal animals must develop strategies to mitigate the costs associated with male mating harassment.

Purpose of the Study:

• To investigate how desert locusts manage conflicts arising from male mating harassment in dense populations.
• To understand the role of density-dependent behaviors in mediating mating conflicts.

Main Methods:

• Observational study of desert locust mating behaviors in transient (dense) and solitarious (low-density) populations.
• Analysis of female ovarian status, spatial distribution of males and females, and mating interactions.

Main Results:

• In dense populations, nongravid females avoided males, while males aggregated at lekking sites awaiting gravid females.
• Mating pairs in dense populations were protected from harassment, particularly during oviposition.
• In low-density populations, solitarious locusts exhibited balanced sex ratios and females mated regardless of ovarian status.

Conclusions:

• Desert locust mating behaviors are significantly influenced by population density.
• Sex-biased behavioral group separation is a key strategy employed by desert locusts to minimize male mating harassment and competition.
• These behavioral adaptations are crucial for successful reproduction in varying population densities.