Females, however, were unaffected.
Climate change could pose a major threat to male fertility, scientists have warned, as heatwaves cause serious and long-lasting damage to sperm.
"We know that biodiversity is suffering under climate change, but the specific causes and sensitivities are hard to pin down", research group leader Professor Matt Gage, said in a statement.
Heatwaves halved the amount of offspring males could produce, and a second heatwave nearly sterilised males.
The team investigated the red flour beetle (Tribolium castaneum) to explore the effects of simulated heatwaves on male reproduction. With the insects that experienced the heatwave, fertility in male insects was reduced by three quarters, and any sperm that was produced couldn't migrate to the female insect, and ending up dying before fertilization took place.
"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", Gage said. The study also found that males sexual behavior was also affected by the heat with males mating half as frequently as controls.
"Two concerning results were the impact of successive heatwaves on males, and the impacts of heatwaves on future generations", said Sales.
'When males were exposed to two heatwave events 10 days apart, their offspring production was less than one per cent of the control group.
'Since sperm function is essential for reproduction and population viability, these findings could provide one explanation for why biodiversity is suffering under climate change.
'A warmer atmosphere will be more volatile and hazardous, with extreme events like heatwaves becoming increasingly frequent, intense and widespread.
Heatwaves can damage the sperm of insects and make them nearly sterile, according to new research.
Kirs Sales, a co-researcher on the study, said: "Our research shows that heatwaves halve male reproductive fitness, and it was surprising how consistent the effect was". Local extinctions are known to occur when temperature changes become too intense, they said.
"We'd really like to know what the mechanism of this trans-generational damage is", he said. "And one answer could be related to sperm", he outlined.
Regardless, the new study's findings "are very important for understanding how species react to climate change", he noted.
Sons were also less likely to produce offspring, with the scientists stating that it could add extra pressure to populations already struggling with the impact of climate change.
"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.