insects

A meta-analysis published today in PNAS shows that, globally, the loss of agricultural production due to insufficient pollination has declined since the 1980s, primarily thanks to the use of honeybees. The research includes 165 studies published between 1950 and 2019, the results of which showed that fields without managed pollinators did not exhibit a clear reduction in this loss of productivity. According to the authors, this type of pollination has mitigated yield losses, but the heavy reliance on a single pollinator species—the common honeybee—poses risks to agriculture. 

Decades ago, concerns began to be raised about the decline in honeybee populations. Although their situation has improved, the same cannot be said for other pollinating insects. Together, they enable the reproduction of nearly 90% of flowering plants and directly contribute to three out of every four crops that feed the world. We examine the causes of this decline, their current situation, and the measures being taken to protect them.

Exposure to agrochemicals, even in doses too low to kill insects, causes significant damage to their behavior, development and reproduction, which is aggravated when the temperature rises, according to a study published in Science. The research analyzes the effects of 1,024 molecules - insecticides, herbicides, fungicides, plant growth inhibitors - on the fruit fly Drosophila melanogaster and on other insects.

The decline of insects in Central and Western Europe in recent years is mainly due to human activities and the intensification of agriculture, according to a study funded by three companies (Bayer, BASF and Syngenta) that manufacture pesticides. The paper, published in PLoS ONE, summarises an analysis of 82 other published studies and explains the causes of population declines in two groups of insects: carabids (ground beetles) and lepidopterans (including moths and butterflies). The authors estimate that "anthropogenic activities in general" are most responsible for this decline, followed by agricultural intensification (including pesticides) and climate change in third place.