Where are all the insects in our garden?

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Burnished Brass attracted to light

In over 50 years of recording and photographing wildlife I can’t recall there ever being such a dearth of insects. And apparently I’m not alone in finding this. From across the country and highlighted in the recent Springwatch series insect numbers appear to be desperately low.

Many insect species are known for their numbers being volatile, booming one year, collapsing the next, before recovering.

However, this year numbers seem drastically low across many different insect orders.

This poses the question – following years of steady decline, are ecosystems now nearing the tipping point that some have been predicting.

Only a single Comma Butterfly in the garden so far this year

This year our garden in Cornwall had never been better prepared for nurturing the various life cycle stages of a broad diversity of insects. Yet despite this the increased wild areas with their diversity of larval foodplants and nectaring flowers for all seasons have attracted exceptionally low insect numbers. The swathes of ox eye daises, the uncut grass studded with flowering wild plants and the set aside nettle beds look inviting enough, yet few nectaring and pollinating insects have been drawn to them.

Butterfly numbers have been pitifully low. Small numbers of Holly Blues and Orange-Tips outnumbering the normally more common overwintering butterflies in the Spring such as Small Tortoiseshell, The Comma and Peacock. The numbers of every species are dramatically down.

Green Oak Tortrix , Tortrix viridana. over 20 attracted to light in Cornish garden.

Numbers and species of moths attracted to light are a tiny fraction of previous years. With the 20 plus nightly records of Green Oak Leaf Tortrix the only species seemingly to have bucked the dismal trend. The next few months will be critical to see if some of the gardens most notable resident species such as the Portland Ribbon Wave, Idaea degeneraria and the recently established Jersey Tiger, Euplagia quadripunctaria have also succumbed to the general decline.

Sloe Bug in Cornish garden - photo Steve Ogden

Parts of the lawn and weedy, rough areas are now receiving a second cut. Several species of butterfly and moth lay eggs on the resulting fresh growth this cut generates in preference to older growth. It also gives wild plants a chance to push through that would otherwise have been smothered by long grass.

The only insects that seem to be thriving in the garden this Spring are several species of Shieldbug – particularly The Sloe Bug, Dolycoris baccarum and The Green Shield Bug, Palomena praasina and also the Squashbug, Coreus marginatus. Unfortunately the only Ladybird doing well is the adventive Harlequin Ladybird, Harmonia axyridis.

Harlequin Ladybird larva, Harmonia axyridis.

The likely reasons for the large percentage fall in insect number over the last few decades is thought to be a mix of increased pesticides, loss of habitat, land management changes and climate change.

However, the suddenness and almost universal severity in the UK of this Springs decline suggests its been triggered largely by the last 12 months weather. We can only hope later broods bounce back and, of course, climate changes slow. If not we are in serious trouble as every species depends on another – including us.

On a brighter note if the winds eventually shift around to the South/ South East, coming off the continent, at least some interesting migrants may arrive.