This surprising study from Germany raises the possibility that a catastrophic loss of insects is occurring and that it could lead to ecological collapse.
Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxonomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape.
I knew about the frogs, elephants, tigers, bees, and loss of larger animal species and biomass in general, but I hadn’t really heard this idea that insects are disappearing. I can see a silver lining to this – I can’t really create elephant or tiger habitat around my house, and frog habitat is a little tough, but insects – I can actually help the little guys. On a larger scale, there is the question of green infrastructure – can we deliberately design habitats in cities, larger reserves, and corridors connecting them to support as much ecological function as we can? I think so, but I don’t think our public officials, engineers, urban planners, scientists, and others in a position to do this are tuned into the issue or even very open to hearing about it.