SEXUAL SELECTION FOR HOMOGAMY IN THE GERRIDAE: AN EXTENSION OF RIDLEY'S COMPARATIVE APPROACH

Area of Science:

• Evolutionary biology
• Behavioral ecology
• Population genetics

Background:

• Positive assortative mating, or homogamy, describes the tendency of individuals to mate with similar partners.
• Ridley's 1983 hypothesis posits three factors driving homogamy: male size-mating success correlation, female size-fecundity correlation, and prolonged pairing.
• Evidence for homogamy in insects is equivocal, necessitating further investigation.

Purpose of the Study:

• To test Ridley's hypothesis on the development of positive assortative mating in three waterstrider species (Gerridae; Hemiptera).
• To determine if the proposed factors for homogamy are present and lead to observed mating patterns in these insect species.

Main Methods:

• Measuring the three proposed factors (intrasexual selection, female fecundity correlation, prolonged pairing) and homogamy in Gerridae species.
• Comparing predicted homogamy based on the factors with observed mating patterns within populations.

Main Results:

• Homogamy was predicted and observed in Gerris remigis.
• Homogamy was neither predicted nor observed in Gerris comatus and Gerris buenoi.
• The findings support Ridley's hypothesis, indicating similar homogamy mechanisms in insects and other taxa.

Conclusions:

• Ridley's hypothesis for positive assortative mating is supported in the studied waterstrider species.
• The processes driving homogamy in insects appear consistent with those in other animal groups.
• The study highlights the importance of assessing homogamy levels and their impact on genetic variance.