Allochronic separation versus mate choice: nonrandom patterns of mating between fall armyworm host strains

Area of Science:

• Behavioral Ecology
• Animal Behavior
• Genetics

Background:

• Assortative mating, where individuals mate with similar partners, can arise from mating preferences or assortment traits.
• In Spodoptera frugiperda moths, temporal differences in mating activity (temporal assortment) have been proposed as a cause for nonrandom mating between host strains.

Purpose of the Study:

• To investigate the relative contributions of temporal assortment and intrinsic mating preferences to assortative mating in Spodoptera frugiperda.
• To determine if mating preferences are time-dependent and if there are sex-specific differences in mating behavior.

Main Methods:

• Controlled mate-choice experiments were conducted with Spodoptera frugiperda.
• Experimental manipulation of the temporal trait (mating activity timing) was performed.
• Mating patterns were analyzed across multiple nights to assess changes in preferences.

Main Results:

• Nonrandom mating in Spodoptera frugiperda is influenced by an interaction between temporal assortment and mating preferences.
• Mating preferences dominate assortative mating, particularly on the first night of encounters, and diminish over subsequent nights.
• Males exhibited less restriction in mating activity timing and mate preferences compared to females.

Conclusions:

• Assortative mating in Spodoptera frugiperda results from a dynamic interplay between temporal traits and evolving mating preferences.
• Female mating preferences are a key driver of assortative mating, with a potential role for male-produced pheromones.
• The findings highlight the complexity of mating systems and the influence of both extrinsic and intrinsic factors on mate choice.