Climate change could pose a major threat to male fertility, scientists have warned, as heatwaves cause serious and long-lasting damage to sperm.
Researchers found that fertility in male insects decreases significantly when temperatures rise above normal for short periods.
After exposing beetles to five-day heatwaves, with temperatures 5°C to 7°C higher, the amount of sperm produced was halved, while a second heatwave almost sterilised them. Females, however, were unaffected.
Group leader Professor Matt Gage of the University of East Anglia, Norwich, in the UK said: “We’ve shown that sperm function is especially sensitive when the environment heats up.”
The findings, published in the journal Nature Communications, also show that offspring sired during heatwaves were less fertile and have lives a couple of months shorter than normal.
Kris Sales, who led the study, said: “Insects in nature are likely to experience multiple heatwaves, which could become a problem for population productivity.”