Heat waves damage serious fertility of male shoulders and subsequent hot spells allow them to almost sterilize, according to research.
Global warming makes heat waves more common and wildlife eradicated, and the study can reveal a way in which these two trends are linked. The researchers behind the results found that it could also be of significance to humans: The sperms of Western men have been halved over the past 40 years.
Researchers studied beetles because their 400,000 species represent about a quarter of all known species. Insect populations are disturbed throughout the world as temperatures rise, decreases by about 80% in 30 years in Puerto Rico rainforest and with 75% in German nature reserves.
Insects are an integral part of life, such as pollinators and replacements, as scientists say their decline can lead to "organic armageddon". Little is known about the exact causes of the decline, but climate change, habitat destruction and global use of pesticides are considered likely factors.
The research, published in the Nature Communications Journal, found that exposure of beetles to a five-day heat wave in the laboratory reduced sperm production by three quarters; Honors were unaffected.
"Beers are considered a quarter of biodiversity, so these results are very important in understanding how the species reacts to climate change," said Kris Sales, at the University of East Anglia, who led the work.
Other research has shown that heat can damage male reproduction in humans as well as cows, sheep and other mammals.
"It may be relevant to human fertility," says Prof Matt Gage, co-leader of the UEA research group. "The paradox is that one of the reasons why the climate is warming up and we have more heat waves is that there are too many people. So maybe this is a level."
Stuart Wigby, from Oxford University, who was not involved in the study, said: "Given what we already know about the generosity of the sensitivity of sperm to heat, there is every reason to expect similar effects to be seen in other insects and also at mammals including humans. "
The red flour bag used in the experiments is a tropical species that thrives at 35C. When exposed to temperatures of 5C and 7C, male fertility increased. While these were high temperatures, 90 countries had experienced them in recent years, Gage said.
After being exposed to a heat wave, the number of offspring that the men produced by half decreased. Even more worrying, the harmful effects of the men they produced were damaged – their lives were 20% shorter and, in turn, resulted in fewer offspring.
The most extreme impact was in male bins exposed to two heat waves 10 days apart – their decommissioning decreased by 99%. "It can handle them," said Gage.
The sale is added: "Bugs in nature are likely to experience several heat wave events, which could be a problem for population productivity if manual reproduction can not adapt or recover."
Further experiments are ongoing to find out if the beers can adapt to heat shocks and investigate how other species, such as butterflies, can withstand elevated temperatures.
Research is among the first in its kind of cold-blooded creatures. "There is a big gap, because most of life on earth is cold blooded and it is much more directly affected by temperature variations," said Gage. "We have shown that sperm function is a particularly sensitive move when the environment warms up and in [species] represents a large amount of global biodiversity. "
How the heat damages the sperm is not fully understood, but the researchers observed damage to sperm membranes. It is likely that DNA in the sperms is also damaged, which means that damage can be transmitted to offspring. Most warm-blooded male animals protect sperm from excessive heat by testing outside the body and leaving them several degrees cooler.
Wigby said that understanding of factors such as decreased male fertility was poor. "So, some studies that add to our understanding of the basic mechanisms underlying the variation in male fertility are valuable. To show that the damage can occur in a heat-curve scenario is new and important, as is the demonstration of transgenerational effects. But the applicability of The real world is always a problem for lab studies. "