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Heat waves seem to sterilize male insects, a discovery that has serious consequences in a world characterized by rising temperatures and the massive extinction of populations.
A new study found that heatwaves reduced sperm production in beetles by three-quarters and halved the number of offspring they could produce.
German scientists have already recorded massive declines of insects, which is another source of considerable concern for scientists.
Heat waves such as those that hit much of the northern hemisphere this summer are thought to be rising and intensifying as the world's average temperature rises.
Scientists have suggested that their discoveries may even impact humans, as previous work has suggested that thermal shocks also have the potential to induce infertility in mammals.
"We know that biodiversity suffers from climate change, but the causes and specific sensitivities are hard to pin down," said Professor Matt Gage of the University of East Anglia, who led the research.
1/11
Mammal Society's assessment of mammal populations in Great Britain is the first study of its kind in over 20 years. The results reveal winners and losers, as well as some of the main threats to the country's wildlife, such as habitat loss, invasive species and the spread of disease.
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The populations of the beloved insectivore could have decreased up to 73%
Richard Bowler
3/11 Big bats
Only one of these flying mammals has been recorded throughout the country, in a West Sussex railway tunnel
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4/11 rabbits
Although it is common to see through the countryside, the number of rabbits has decreased by almost 10%.
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5/11 Black rats
Although they are generally not considered endangered animals, the number of black rats has collapsed in recent years, largely because of pest control measures. However, their much more common cousins, the brown rats, are in full swing.
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6/11 Red squirrels
Although it is difficult to measure changes in the number of squirrels, their range has been significantly reduced, largely because of the spread of squirrel pox virus by an invasive gray squirrel.
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7/11 Wild cats
There has been a marked decline in wildcat populations, leaving only about 200 people in Scotland.
Rachel Profit
8/11 badgers
Thanks to legal protections, badgers have recovered from past persecution and the density of their niches has increased by more than 100% in recent decades.
Phil Mumby
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Prohibition of persistent organic pesticides has had a positive effect on otters
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10/11 Suede
The 2018 review estimated that deer population size is nearly three times that estimated in the 1995 examination – a positive trend observed in other deer species.
James Shooter
11/11 Beavers of Eurasia
These aquatic mammals were almost extinct in Europe at the beginning of the 20th century, but their reintroduction to the United Kingdom was largely successful.
Paul Scott
1/11
Mammal Society's assessment of mammal populations in Great Britain is the first study of its kind in over 20 years. The results reveal winners and losers, as well as some of the main threats to the country's wildlife, such as habitat loss, invasive species and the spread of disease.
2/11 hedgehogs
The populations of the beloved insectivore could have decreased up to 73%
Richard Bowler
3/11 Big bats
Only one of these flying mammals has been recorded throughout the country, in a West Sussex railway tunnel
Andrew Harrington
4/11 rabbits
Although it is common to see through the countryside, the number of rabbits has decreased by almost 10%.
Danni Thompson
5/11 Black rats
Although they are generally not considered endangered animals, the number of black rats has collapsed in recent years, largely because of pest control measures. However, their much more common cousins, the brown rats, are in full swing.
Tim Melling
6/11 Red squirrels
Although it is difficult to measure changes in the number of squirrels, their range has been significantly reduced, largely because of the spread of squirrel pox virus by an invasive gray squirrel.
Alistair Marsh
7/11 Wild cats
There has been a marked decline in wildcat populations, leaving only about 200 people in Scotland.
Rachel Profit
8/11 badgers
Thanks to legal protections, badgers have recovered from past persecution and the density of their niches has increased by more than 100% in recent decades.
Phil Mumby
9/11 otters
Prohibition of persistent organic pesticides has had a positive effect on otters
Allan Chard
10/11 Suede
The 2018 review estimated that deer population size is nearly three times that estimated in the 1995 examination – a positive trend observed in other deer species.
James Shooter
11/11 Beavers of Eurasia
These aquatic mammals were almost extinct in Europe at the beginning of the 20th century, but their reintroduction to the United Kingdom was largely successful.
Paul Scott
"We have shown in this work that sperm function is a particularly sensitive trait when the environment is warming up and in a model system representing a huge amount of global biodiversity."
Beetles such as the red flour beetle used in research represent a staggering quarter of all biodiversity on Earth, with about 400,000 species described to date.
In the team's study, published in the journal Nature Communications, beetles were exposed to simulated heat waves of 5 to 7 ° C above optimal conditions for five days.
They then followed this work with experiments to evaluate damage to reproductive success and sperm function, as well as long-term effects on offspring.
After the first exposure, the chances of reproduction were reduced, a second heat wave rendered them virtually sterile – producing only 1% of the offspring produced under normal conditions.
"Insects in the wild are likely to face multiple heat waves, which could become a problem for the productivity of the population if male breeding can not adapt or recover," said Kirs Sales. , a PhD student who led the research.
To make matters worse, the effects of heat stress seem to affect several generations. The offspring of fathers in shock of heat waves had a shorter life and the sons had fewer offspring.
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Recent studies have shown that the decline of insects can reach 75% in some areas, an effect that has been linked to everything from the excessive use of pesticides to the destruction of the habitat.
Insects playing a vital role in global biodiversity and pollinators, scientists have warned that their disappearance would trigger an "ecological Armageddon".
"Given that sperm function is essential for the reproduction and viability of the population, these results could provide an explanation of why biodiversity suffers from climate change," said Professor Gage.
"Heat waves are extreme weather events that are particularly damaging. Local extinctions are known to occur when temperature changes become too intense.
"We wanted to know why this is happening. And an answer could be related to sperm. "
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