THE EVOLUTION OF ALTERNATE MORPHOLOGIES: FITNESS AND WING MORPHOLOGY IN MALE SAND CRICKETS

Area of Science:

• Evolutionary biology
• Animal behavior
• Genetics

Background:

• Organisms exhibit diverse morphological types, influencing evolutionary trajectories.
• Wing dimorphism, characterized by winged (macropterous) and wingless (micropterous) forms, is common in insects.
• Female trade-offs between macroptery and reproduction are known, but male costs are less understood.

Purpose of the Study:

• To investigate life-history trade-offs associated with macroptery in male sand crickets (Gryllus firmus).
• To estimate the genetic correlation of wing dimorphism between sexes.
• To explore the evolutionary implications of these factors on alternate morphology.

Main Methods:

• Examined trade-offs between macroptery and life-history traits in male Gryllus firmus.
• Assessed development time, size, testis size, and reproductive success in relation to wing morph.
• Estimated genetic correlation of wing dimorphism between male and female crickets.

Main Results:

• Macropterous males exhibited faster development than micropterous males.
• No significant differences were found in testis size or reproductive success between wing morphs.
• A high genetic correlation (r=0.86) was observed for wing dimorphism between sexes.

Conclusions:

• Wing macroptery in male Gryllus firmus does not incur significant life-history costs related to size or reproductive success.
• The high genetic correlation suggests that selection on females strongly influences the frequency of macroptery in males.
• This highlights the importance of intersexual genetic correlations in shaping the evolution of alternate morphologies.