Where Have All The Insects Gone?

In the past month, I’ve seen two articles on a topic I’ve been worrying (along with a lot of other people) about some time: the decline in insect populations. The articles are different, although one was triggered by the other, and both have the same title as this blog post:

To quote from the science article:

Entomologists call it the windshield phenomenon. “If you talk to people, they have a gut feeling. They remember how insects used to smash on your windscreen,” says Wolfgang Wägele, director of the Leibniz Institute for Animal Biodiversity in Bonn, Germany. Today, drivers spend less time scraping and scrubbing.

But in 2013 they spotted something alarming. When they returned to one of their earliest trapping sites from 1989, the total mass of their catch had fallen by nearly 80%. Perhaps it was a particularly bad year, they thought, so they set up the traps again in 2014. The numbers were just as low. Through more direct comparisons, the group—which had preserved thousands of samples over 3 decades—found dramatic declines across more than a dozen other sites.

Now, I’m a child of the early eighties, but even I remember bug splats on the windscreen, and I know that now that’s basically not an issue for me as a driver. Bird droppings and mud splatter can make the windscreen dirty, but not insects. This means that either the insects have learned how to avoid cars in a few short decades, or there are much fewer of them around to get splatted in the first place. Which seems more likely?

The big cause, of course, is intensification of agriculture, reduction in the wild gaps and hedgerows, and more spraying of chemicals. Even chemicals which were believed to be safe for “good” insects, like neonicotinoids, have now been shown to have serious if sub-lethal effects on pollinators. And the reduction of insect populations has effects right up the food chain, as insects are populous and right there at the bottom. Reduce their numbers and birds struggle to feed their young, for example.

Having said that, I think the mild spring has made 2017 a good year for insects. I’ve seen many more butterflies for the time of year than normal, and even some new insects. Have you ever seen one of these in Midlands garden before? They’re impressive things, so if you’ve seen one you probably know it.

Hummingbird hawk-moth, source: Wikipedia, by IronChris

Well, I hadn’t until this year. I’ve lived in Nottinghamshire my entire life and never seen them except on holiday in Brittany, but this spring I’ve seen three flitting around our garden and feeding on the flowers of the Aubrietas. Supposedly they sometimes make it over here in the summer, but if so they must prefer warmer parts of the country.

I like to think we’re doing our part to boost the good insect year too. Our garden is full of the flowers of fruit, herbs and groundcover plants and almost entirely chemical free, to the occasional frustration of my wife when I leave the aphids in hope of the arrival of red-spotted saviours. The bees have been going crazy the last few weeks over the bugle, lungwort and comfrey, and just this evening I noticed a hum coming from the corner of the garage roof. Some careful observation revealed the odd bee flying in and out of a small ventilation grill high on the garage wall, so I’m pretty sure we have our very own nest up there. Again, I suspect I’m much happier than my wife at hosting them, but they shouldn’t do any harm.

It might be that the cities are the last refuge of the insects after the countryside has been completely sterilised.