Scientists reveal why male fertility is severely threatened in years to come

New research suggests that male fertility could be threatened in the years to come by the onset of climate change.

The potential threats to our very future posed by climate change are numerous, but the latest research from the University of East Anglia believes it even poses a threat to our ability to procreate.

In a paper published to Nature Communications, the research team found evidence that heatwaves have damaged sperm in insects, explaining why climate change is having such an impact on species populations, including climate-related extinctions in recent years.

“We’ve shown in this work that sperm function is an especially sensitive trait when the environment heats up, and in a model system representing a huge amount of global biodiversity,” said the research group’s leader, Prof Matt Gage.

“Since sperm function is essential for reproduction and population viability, these findings could provide one explanation for why biodiversity is suffering under climate change.”

As part of the study, the team collected a number of red flour beetles and exposed them to either standard control conditions or five-day heatwave temperatures up to seven degrees Celsius hotter than normal. The team found that heatwaves halved the amount of offspring males could produce, and a second heatwave almost sterilised them.

By contrast, the females were unaffected by changing temperatures. However, female reproduction was affected indirectly because experiments showed that heatwaves damaged inseminated sperm within female reproductive tracts.

Male sperm production was also shown to have reduced by as much as 75pc. Any sperm that was produced struggled to migrate into the female tract and was more likely to die before being fertilised.

‘These results are very important’

Attempting to find the underlying causes of male vulnerability to climate change, the researchers found that the male beetles were mating half as frequently as the control subjects. Even when offspring were sired by heatwave dads, they lived shorter lives than the control subjects.

Kris Sales, who led the research, said the implications for these discoveries are crucial in our understanding of biodiversity in a changed world. “Beetles are thought to constitute a quarter of biodiversity, so these results are very important for understanding how species react to climate change,” he said.

“Research has also shown that heat shock can damage male reproduction in warm-blooded animals, too, and past work has shown that this leads to infertility in mammals.”

The researchers hope that the effects can be incorporated into models predicting species vulnerability and, ultimately, could help inform societal understanding and conservation actions.