Insect populations in regions hit by global warming and intensive agriculture are almost half those in the bestpreserved habitats, according to a study published on Wednesday (20), raising concerns about the impact on crop pollination .
The researchers measured both the number of insects and the number of different species found in different regions of the world.
The study, published in the journal Nature, concludes that the overall insect population has fallen by almost half. The number of species fell by 27%.
“The reductions are greater below the tropics,” lead author Charlie Outhwaite of University College London told AFP.
She believes these numbers may be understated due to a lack of data in tropical regions.
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Reducing the numbers of insects critical to the diet of many other species is having disastrous results.
About three quarters of the 115 most important food crops depend on pollination, such as cocoa, coffee and cherries.
Some insects such as ladybugs, praying mantis and wasps are also needed to control other insects that are detrimental to crops.
The study shows that the combined impacts of climate change and intensive farming, including widespread insecticide use, are worse than either of these factors when acting individually.
Even if there were no climate change, the conversion of a tropical forest to farmland heats the region through the loss of vegetation that provides shade and maintains air and soil moisture.
In a previous study, researchers estimated that the number of flying insects in Europe had fallen by an average of 80%, leading to a decline in bird populations.
The new research suggests ways for insects to survive, e.g. B. Extensive farming with fewer pesticides and surrounded by natural habitats.