All around the world there are entomologists, people who study insects. We should be very proud of these fine folk for without their understanding it would be harder to manage many diseases transmitted by insects, resolve many pathogens, figure out how to assist insects pollinate crops and, most importantly, support insects and their invertebrate cousins maintain soil fertility.

Then there are insect people you might know about. The pest control folk who make sure the fly spray kills the flies and not us.

Sounding a bit posh and, dare we say a little ivory tower, ‘entomologist’ usually refers to the researchers who gather the data and sift through it to find evidence for the good, bad and ugly on the insects that share our spaces. So we can listen to them with some confidence. Not only are they spending their days with ‘bugs’, yuck, they are also the right kind of skeptic using the numbers to find inference.

Lately the number of insects observed by entomologists are in decline. This is not because the entomologists are getting lazy, spending more time watching TV than setting malaise traps or peering down microscopes, but because there are fewer insects around to be studied.

A recent publication confirmed from long-term trapping data in 63 German nature reserves, what many have casually observed in many parts of the world. Insect numbers are going down. And not just by a little bit, they are plummeting.

Hallmann C.A., Sorg M., Jongejans E., Siepel H., Hofland N., Schwan H., Stenmans W., Müller A., Sumser H., Hörren T., Goulson D., de Kroon H. (2017) More than 75% decline over 27 years in total flying insect biomass in protected areas. PLoS ONE, 12(10), eo185809

Three quarters in a generation.

If such a collapse had happened to the Dow Jones the sky would have fallen in. Imagine trying to survive on a quarter of your wages you earned when you started out. Heaven forbid if the defence budget from the 1990s was reduced by all those billions, how scared and vulnerable would we feel?

“Not a problem” the observant reader cries out. “The crawling insects will simply fill the space left by the loss of the flying ones, that’s what you ecology types tell us all the time.”

Perhaps.

Equally a loss in numbers does not necessarily mean a loss of function. Pollination only needs one bee to transfer pollen from stamen to stigma. Fewer mosquitos has to be a good thing and those beetle larvae can’t be doing that much to soil when we have fertilisers.

It is always very easy to play the ostrich. Only they are remarkable and very dumb birds.

When an observation so dramatic and material to so many key ecological processes becomes known we dismiss it at our peril. If we ignore these numbers just because we like the idea of fewer midges at summer evening picnics without looking deeper to find out what is going on, we increase risk to our already precarious food security.

We need to enable our entomologists to find out why the numbers went down and if the decline is going to affect the key ecosystem services we rely on.

Or, of course, we could ignore them and buy more submarines.