Nature Conservation Lewisham

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Nice weather for water beetles — not (with thanks to R.Jones)

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Reposted here, with kind permission from Bugman Jones

One of the delights of entomology is that you can always find insects — any place, any time of day, any time of year. They are so many and so diverse that you can find them everywhere. On Monday 20 June 2016 my thesis, however, was about to be sorely tested. At the height of the British summer (quite literally, since this was the day of the summer solstice this year), it was tanking down. And insects really don’t like the rain.

When I started the ‘Curious Entomologist‘ workshops my title was partly inspired by Simon Barnes’s book How to be a bad birdwatcher. His credo was similarly based on the notion that if you look out of the kitchen window on a winter’s day you will see no mammals, reptiles or amphibians — but you will see birds. You can always find birds; and you can always find pleasure in them. This is even more true of insects. You might have to look a bit harder, a little closer perhaps, but they are always there, and they can always be found.

This, then, was to be my pompously grand claim when offering a two-day class to some London Wildlife trainees; “Let’s go and find some insects” I said, as we peered through the rain splattered classroom windows, off into the sodden undergrowth of Devonshire Road Nature Reserve. No-one seemed very enthusiastic. Nevertheless, we trudged off into the deluge.

I hate to tell you, but you're holding that beating tray upside down.

I hate to tell you, but you’re holding that beating tray upside down.

The plan behind the workshop was to introduce the environmental management trainees to some of the basics of entomology — how to use nets, beating trays, collecting tubes, hand lenses and microscope. How to find insects, if necessary how to deal with sample specimens collected for identification, and how to mount, label and store them for later examination, or for forwarding to someone else to look at. We were struggling at the ‘find’ stage, though.

We caught one butterfly; sort of.

We caught one butterfly; sort of.

Previous LWT events at the reserve were alive with insects — butterflies and bees flying past our ears, and the sweep nets thronging with small fry to look at back in the make-shift laboratory. Today I was going to be happy finding a few watery woodlice and some damp springtails. If this were an environmental survey, I’d have taken one look out of the kitchen window and immediately rescheduled. Insects really, really, do not like rain — even water beetles. Entomologists aren’t that fond of it either really.

Despite our meagre findings, microscope work is still very rewarding — everything, but everything is revealed as a miniature marvel of colour or form.

Despite our meagre findings, microscope work is still very rewarding — everything, but everything is revealed as a miniature marvel of colour or form.

We’d found a few waterlogged grass bugs, a couple of speckled bush-cricket nymphs, bedraggled dung flies, some centipedes, and those woodlice. OK that was enough to be getting on with I suppose, and there was a fair bit of interest as we examined them under the stereoscopes. Then there was this.

Gymnosoma rotundatum, nationally rare (red data book) shield-bug parasitoid.

Gymnosoma rotundatum, nationally rare (red data book) shield-bug parasitoid

This scarce southern fly had occurred on the site before (2007), but to have one turn up in the net of the proverbial tyro was a gift. It proved there was an ongoing colony here, in what is one of its most northerly and most urban localities. This is exactly the thing to demonstrate how beginners can find unusual and scarce things, but that they are usually small, need to be collected and need to be preserved so that an expert can spot them. A very positive end to the day.

Thankfully day two was brighter and, more importantly, drier. Now we could get stuck in.

Two more unusual finds confirmed that you do not need the accustomed eye of the hardened bugman to find scarce insects:

Female of Eucera longicornis. A more obviously long-horned male turned up further down the railway line, at Hither Green, in 2008. Good to know there are established colonies in this area.

Female of Eucera longicornis. A more obviously long-horned male turned up further down the railway line, at Hither Green, in 2008. Good to know there are established colonies in this area.

 

A tiny weevil, Acalles misellus; not necessarily scarce, but secretive, and new to me. A 'dead hedge' species, declining in an age when dead hedges are

A tiny weevil, Acalles misellus; not necessarily scarce, but secretive, and new to me. A ‘dead hedge’ species, declining in an era when dead hedges are no longer a common boundary construction.

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