Over the last two decades, research has consistently shown a decline in both the biomass and diversity of insects worldwide. A significant body of evidence, including a 2020 study compiling 166 reports, points to an average annual decrease of 0.9% in insect populations globally. This decline, however, is not uniform across species or environments, with some insect populations decreasing, while others remain stable or even increase.

A recent study from the Chinese Academy of Agricultural Sciences, focusing on insect migrations in East Asia, supports the notion of a global insect decline. Between 2003 and 2020, nearly 12 million migrating insects were recorded, with an overall decrease of 7.6% across 98 species. This study is particularly revealing as it includes both pest species and their natural enemies, indicating that the decline is affecting a broad range of insects.

One alarming finding is that beneficial insects, which play crucial roles in ecosystems and agriculture, are declining at a faster rate than the pests they control. This imbalance could force farmers to rely more heavily on chemical insecticides, potentially exacerbating the problem.

The primary cause of this decline is believed to be agricultural intensification, which includes practices like mechanization, crop monocultures, and heavy use of chemical inputs. These practices have transformed large portions of land into environments hostile to most insects. With insects forming the foundation of many food chains, their decline has far-reaching consequences, including a negative impact on insect-eating bird populations in North America and Europe.

Insects, vital for pollination, pest control, nutrient recycling, and soil formation, are essential for the survival of ecosystems and the continuation of agriculture. The challenge now is to find ways to make our landscapes more insect-friendly.

To learn more, read this article by Stuart Reynolds.