An international group of scientists, including representatives of Russian and German research centers, analyzed the results of more than 160 studies of the land insect population. Data covers the whole world for the period 1925–2018.
A comprehensive comparison showed serious differences in the dynamics of the number of insects, even in neighboring areas. One way or another, the main trend is disappointing. The number of individuals that spend the entire life cycle in land conditions, on average, decreases by 0.92% per year. This means that in the next three decades they will be reduced by almost a third.
The number of insects is most significantly reduced in the western regions of the USA, as well as in European countries, mainly in Germany. Negative trends have been observed in Europe for 15 years.
Characteristically, flying insects, as well as those living in tree crowns and in the ground, lost more in numbers. Those who spend part of their lives in the aquatic environment (like mosquitoes and mayflies) even managed to increase the “population”. There are about a percent more each year.