The number of terrestrial insects is gradually decreasing worldwide by an average of 0.92% per year, or 9% per decade. This has resulted in the death of about 27% of insects – at least one in four – in just the last 30 years. This is reported by AMNA citing a new international study, the most comprehensive to date.
The study was conducted by German scientists, it considered data from 1676 districts around the world for the period 1925-2018. The results are published in the journal “Science” and show the main differences in insect populations from district to district.
Researchers estimate that the number of terrestrial insects (butterflies, locusts, ants, etc.) has decreased by 50% over the past 75 years. In Europe in particular, the downward trend in their population is becoming more pronounced after 2005. Reductions occur “quietly” and are usually invisible to people. Some people realize this when they realize that fewer and fewer insects die on their car windshields over the years.
On the other hand, studies show that freshwater insects living in lakes and rivers are in a better position as their numbers grow internationally at an average annual rate of 1.08% or almost 11% over a decade.