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SOURCE: The Guardian

DATE: November 13, 2018

SNIP: Heatwaves severely damage the fertility of male beetles and consecutive hot spells leave them virtually sterilised, according to research.

Global warming is making heatwaves more common and wildlife is being annihilated, and the study may reveal a way in which these two trends are linked. The scientists behind the findings said there could also be some relevance for humans: the sperm counts of western men have halved in the last 40 years.

Insects are such an integral part of life, as pollinators and prey, that scientists say their decline could lead to “ecological Armageddon”. Little is known about the precise causes of the decline, though climate change, habitat destruction and global use of pesticides are considered probable factors.

The research, published in the Nature Communications journal, found that exposing beetles to a five-day heatwave in the laboratory reduced sperm production by three-quarters; females were unaffected.

After being exposed to a heatwave, the number of offspring produced by males fell by half. Even more worryingly, harmful effects were inherited by the males they produced – their lives were 20% shorter and they in turn produced fewer offspring.

The most extreme impact was in male beetles exposed to two heatwaves 10 days apart – their offspring production fell by 99%.