Insects on the Up?

The progress of the season has been rather erratic this year, with spells of very warm or even hot weather interspersed with much colder days. Overall I think that we are still a little behind the average of recent years, but it is a very mixed picture.

Sunday was a fine, warm, sunny day with little wind, ideal for insects and I saw my first beautiful demoiselle, broad-bodied chaser, four-spotted chaser and emperor dragonfly of the year. The four-spotted chaser had emerged from the Centre pond, I think th efirst time I have proved that they have done so there, although I have seen individuals there a number of times. Numbers of large red, common blue, azure and blue-tailed damselfly are also continuing to build.

I am trying to look more closely at the bees on the reserve this year, Blashford has a lot of dry ground with sandy slopes, ideal for solitary bees. In fact “brownfield sites” such as Blashford are particularly good for bees as they often have variations in soil type, slopes and banks ideal for nesting.

Andrena bicolor

Andrena bicolor

Gwynne’s mining bee, Andrena bicolor is one of our commonest spring mining bees and also has a summer brood, it is a close relative of the much rarer grey -backed mining bee, Andrena vaga which was found on the reserve for the first time a couple of weeks ago. The rarer species is still around, but not in the same numbers as a fortnight ago, some of them are getting worn now and so look rather like the much commoner ashy mining bee Andrena cineraria.

ashy mining bee excavating

ashy mining bee Andrena cineraria excavating a nest tunnel.

For several years now there has been increasing evidence of an overall decline in total insect abundance, it is very hard to prove absolutely but accounts of declining moth trap catches and a general scarcity of many insects is attested by many. Older people will remember that when travelling any distance by car in the summer it was necessary to clean many squashed insects off the windscreen. Of course more aerodynamic cars may be a factor too. Whatever the reason it has become much harder to find many insect species in the average summer these days. It was pleasing to see a fair few hoverflies out yesterday including a number of Cheilosia species, a rather difficult genus of mainly black species, the identification of the images below maybe open to revision!

Cheilosia bergenstammi male

Cheilosia bergenstammi (male)

Cheilosia impressa

Cheilosia impressa (female)

Despite the warmer days the nights are still quiet cool and so the moth trap has remained quiet. The pick of the catch was a chocolate-tip moth, it is evidently quiet a good year for therm as this was the third we have caught recently.

chocolate-tip

chocolate-tip

The only grasshoppers and crickets about at present are a few tiny nymphs, but this is the time for finding adult groundhoppers, although the only one I saw was a common groundhopper, but at least it posed for a picture.

common groundhopper

common groundhopper

It would be good to think that we are turning a corner in the insect decline, unfortunately I doubt it, I suspect the wider environment is continuing to become less insect friendly. Although some of this is down to the use of very effective insecticides and industrial mono-culture farming, it is also our overall failure to leave any space for them, even where it would be easy to do so.

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