Alarm over decline in flying insects

It’s known as the windscreen phenomenon. When you stop your car after a drive, there seem to be far fewer squashed insects than there used to be.

Scientists have long suspected that insects are in dramatic decline, but new evidence confirms this.

Research at more than 60 protected areas in Germany suggests flying insects have declined by more than 75% over almost 30 years.

And the causes are unknown.

“This confirms what everybody’s been having as a gut feeling – the windscreen phenomenon where you squash fewer bugs as the decades go by,” said Caspar Hallmann of Radboud University in The Netherlands.

“This is the first study that looked into the total biomass of flying insects and it confirms our worries.”

The study is based on measurements of the biomass of all insects trapped at 63 nature protection areas in Germany over 27 years since 1989.

The data includes thousands of different insects, such as bees, butterflies and moths.

Scientists say the dramatic decline was seen regardless of habitat, land use and the weather, leaving them at a loss to explain what was behind it.

They stressed the importance of adopting measures known to be beneficial for insects, including strips of flowers around farmland and minimising the effects of intensive agriculture.

And they said there was an urgent need to uncover the causes and extent of the decline in all airborne insects.

“We don’t know exactly what the causes are,” said Hans de Kroon, also of Radboud University, who supervised the research.

”This study shows how important it is to have good monitoring programmes and we need more research right now to look into those causes – so, that has really high priority.”

The finding was even more worrying given that it was happening in nature reserves, which are meant to protect insects and other living species, the researchers said.

”In the modern agricultural landscape, for insects it’s a hostile environment, it’s a desert, if not worse,” said Dr de Kroon.

”And the decline there has been well documented. The big surprise is that it is also happening in adjacent nature reserves.”

The loss of insects has far-reaching consequences for entire ecosystems.

Insects provide a food source for many birds, amphibians, bats and reptiles, while plants rely on insects for pollination.

The decline is more severe than found in previous studies.

A survey of insects at four sites in the UK between 1973 and 2002 found losses at one of the four sites only.

The research is published in the journal Plos One.

Andrena scotica – out of season

Today I found this spring bee in the garden, there are a few reasons that bees emerge earlier than they should. The first thing I checked is whether it had a stylops this parasite feeds of the developing bee so the bee doesn’t have enough fat to keep it going through to spring so emerges early but as you can see by the abdomen it doesnt have a stylops. Bees can become confused as in a long spell of cold followed by a warm period can trick them into thinking it’s spring, again this isnt the case.

So while I cant be 100% sure I would say this bee was disturbed from its slumber by a gardener who has dug its cell up forcing the bee to emerge early.

Most bees overwinter as fully formed adults that stay in their cell till spring.

Lasioglossum lativentre- female- Sandy

Another new bee it’s been a bumper year this year for new finds

Widespread in southern Britain, being found from the Isles of Scilly to East Kent and north to Yorkshire and in Wales but not in Scotland or the Isle of Man. It is known from the Channel Islands but only from Jersey. Recorded from Ireland in O’Connor et al. (2009).
Abroad, a western Palaearctic species, found from Western Europe east to Iran, north to southern Sweden and south to Iberia and Crete; accidentally introduced into the Azores (A W Ebmer, pers. comm.).
Status (in Britain only)
This species is not regarded as scarce or threatened.
A woodland edge species, sometimes found in gardens in southern Britain, also from grasslands, ruderal habitats and orchards.
Flight period
Probably univoltine. The female flies from early March to late October; the male, from mid July to mid October.
Nesting biology
Believed to be a solitary mining bee but the nesting behaviour is apparently unrecorded.
Flowers visited
Flower visits are mainly to Asteraceae, including dandelions, but other families are also used, including Rosaceae, Ranunculaceae, Salicaceae and Ericaceae.
The cleptoparasitic bees Sphecodes ephippius (Linnaeus) and Sphecodes puncticeps Thomson are reputed to parasitise this bee.