The current special issue of the journal PNAS dedicates 11 studies to the global phenomenon of insect decline. Important results include the following:
The decline also concerns insect species that were previously abundant. The general insect decline puts whole ecosystems at risk, since insects are an important food source for other animals. Also resource cycles in soil and water and pollination are affected. While individual insect species profit from global warming, many others, in particular in tropical areas, suffer from rising temperatures. Likewise, species that are adapted to colder areas, are on decline. One of the main reasons for the insect decline is seen in the spread and intensivation of agriculture after the second world war. It seems, however, that not one single cause is responsible, instead, it is the sum of many negative factors on the insect world, which researchers call “death by a thousand cuts”. All these negative factors are realted to human doings, such as the use of pesticides, herbicides and light pollution. Although may questions remain unanswered, researchers are calling for imminent action to stop the species decline.