High-Quality Sperm or Strong Immune System? This is the Painful Choice Crickets Face Daily.
Australian scientists have discovered that male crickets must trade off high-quality sperm for a robust immune system, and vice versa. This reflects a common trade-off rule in evolution, indicating that one cannot have everything at once.
Professor Leigh Simmons and Benjamin Roberts from the University of Western Australia bred healthy crickets with females and then examined the offspring for sperm quality and three traits that indicate their ability to resist disease.
In the first two traits, crickets with better sperm quality also exhibited better immune responses. However, in the third trait, crickets with relatively high sperm quality had a lower level of lysozyme enzyme—this enzyme is a primary tool used by crickets to combat bacterial infections.
The results support the hypothesis that this trade-off is a way for males to signal the quality of their offspring’s immune system through their sexual capabilities.
Evolutionary biologist Rob Brooks from the University of New South Wales commented, “Previous evolutionary hypotheses have long identified this form of trade-off, so it is fascinating to see it validated in an actual mechanism. But the true value of this research goes beyond crickets; it also enhances our understanding of the reproductive mechanisms in many other species.”
