Multiple paternity in wild-caught Drosophila mojavensis

Area of Science:

• Evolutionary biology
• Behavioral ecology
• Genetics

Background:

• Female remating frequency and sperm allocation significantly impact sperm competition and reproductive success.
• Laboratory studies on Drosophila mojavensis indicate males transfer few sperm per mating, and females remate frequently, suggesting common multiple paternity in natural settings.

Purpose of the Study:

• To investigate female sperm loads, the incidence of multiple paternity, and sperm utilization in wild Drosophila mojavensis.
• To assess the relationship between female remating behavior and reproductive outcomes in a natural population.

Main Methods:

• Genotyping of progeny from 20 wild-caught females at four highly polymorphic microsatellite loci.
• Indirect paternity analyses were performed on 814 offspring to determine paternity and assess sperm utilization patterns.

Main Results:

• Evidence of high levels of multiple paternity was found in wild Drosophila mojavensis.
• Reproductive output was relatively low, aligning with predictions for a sperm-limited species with high female remating rates.
• Little evidence for last-male sperm precedence was observed, although some temporal variation in sperm utilization occurred.

Conclusions:

• High female remating in Drosophila mojavensis contributes to frequent multiple paternity.
• Sperm utilization patterns in nature are complex and may vary over time, with limited evidence for strong last-male precedence.