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1Laboratory of Biological Invasion and Ecosecurity, Yunnan University, , Kunming 650091, People's Republic of China.
Biology Letters
|January 17, 2014
Summary
Male moths adjust sperm expenditure based on mating competition. Increased sperm use against rivals reduces lifespan and future reproduction, while mating with more females enhances fitness.
Area of Science:
- Evolutionary biology
- Animal behavior
- Reproductive strategies
Background:
- Spermatogenesis represents a significant energetic cost for males.
- Optimizing sperm allocation is crucial for maximizing lifetime reproductive success.
- Experimental data on male reproductive trade-offs remain limited.
Purpose of the Study:
- To investigate how male moths (Ephestia kuehniella) adjust their reproductive expenditure in response to the presence of rivals or additional mates.
- To determine the impact of these adjustments on lifetime reproductive fitness, including offspring production and longevity.
Main Methods:
- Observational studies on male Ephestia kuehniella under varying social conditions (rivals vs. additional females).
- Quantification of sperm ejaculation, female insemination, offspring sired, and male lifespan.
- Analysis of trade-offs between reproductive effort, sperm competition, and longevity.
Main Results:
- Males facing rival competition ejaculated more sperm but inseminated fewer females, sired fewer offspring, and had reduced lifespan.
- Males encountering additional females showed the opposite pattern, inseminating more females and potentially increasing future reproductive output.
- Reproductive expenditure under sperm competition intensity came at the cost of longevity and future reproductive opportunities.
Conclusions:
- Male reproductive strategies involve significant trade-offs between current mating opportunities, sperm competition, and long-term survival.
- Sperm competition intensity can directly impact male longevity and future reproductive potential.
- Findings highlight the complex interplay between mating systems, sperm allocation, and fitness in insects.
