TCV - Introduction to Invertebrate Survey Techniques

Hello!
Last Friday I took part in a free training course offered by The Conservation Volunteers (TCV) at their office in Stirling which was handy as it's not far on the train.

The workshop offered a general introduction to invertebrates and the groups and orders within. I learned there are 26 species of Harvestmen in the UK, 17 of which are present in Scotland - who knew! I also discovered that species which undergo an incomplete metamorphosis from larvae to adult (that is to say they go, egg - nymph - moultmoultmoultmoult - adult) are Hemimetabolous, which includes cockroaches, dragonflies, earwigs and the like. Those which do a full on complete metamorphosis (egg - larvae - pupae- adult), for instance ladybirds and butterflies, are Holometabolous.

After lunch we moved on to actual survey techniques which you'll need if you want to study these wonderful creatures at close range. The various types of moth traps were explained, and which ones were best for portability and effectiveness. Next were pitfall traps, where you dig a small container like a plastic cup into the ground with the lip flush with the ground level, leave it overnight and see what unsuspecting beasties have fallen in the next day. Also water traps which are brightly coloured bowls filled with some water with a dash of washing up liquid to break the surface tension, unfortunately these result in a watery death for the insects that are attracted to them. Apparently wasps are attracted to white most of all, so bear that in mine when you're picnicking next summer. Simple methods like beating trays, where you have a large white sheet stretched over a wooden frame and then hold it under bushes while you shake the foliage to see what falls out, and sweep netting which involves vigorously swishing a sturdy fabric net to and fro among plantlife, are basic but very effective ways of surveying.
We also discussed walking transects and the best times of year to carrying them out (May to September if anyone is interested) and then turned to aquatic techniques including kick sampling (disturbing the sediment and then sweeping your net to catch anything) and water sweeping (similar to terrestrial sweep netting).

After some pointers on the best places to submit any data you collect (irecord - www.brc.ac.uk.irecord) we headed out to the TCV garden for a pond sweep. I've done a few kick samples and pond sweeps myself however I was surprised at the density and diversity of this one! Check out all the goodies - Newt larvae, ramshorn snails, great pond snail, lesser and greater water boatmen, non-biting midge larvae, caddisfly, hoglouse, waterfleas and tons of tiny zooplankton.

Newt nymph and Great Pond Snail

Caddisfly larvae (centre) and Lesser Water Boatman

Ramshorn snail

Backswimmer (Greater Water Boatman)

We then had a look at a couple of pitfall traps which had been put out the night before and were bustling with rove and ground beetles. A quick look around the rest of the garden found 7-spot ladybirds huddling together in dried out knapweed flower heads.

We then walked along near Stirling castle and caught a few different types of hoverflies, including the Marmalade and the Sunfly, as well as several types of tree and frog hoppers, money spiders, common flower bugs, woodlice, earwigs and millipedes. Certainly a fruitful day for inverts and free too!

Tasty brambles

 

 

 

 

 

I bagged this gorgeous orb weaver spider..and put it back obviously

Raspberry Pipistrelles

On the evening of the 4th September we went out to Loch Ardinning, near Milngavie for a Bat walk and moth trapping night organised by Mugdock Country park and the Scottish Wildlife Trust.

It was the perfect weather for it, even down to the midges providing snackettes for the bats we were hoping to spot and hear. The two species we were listening out for with the bat detectors were soprano pipistrelles (it was only relatively recently discovered that there were two separate species of pipistrelle) and Daubenton's bats (who tend to hunt over and near water).

With the detectors turned to 55Hz we found a clearing in the trees and everyone was soon ping-ponging their heads back and forth tracking the feeding bats flying above. Their high-frequency echolocation clicks are translated to a wet slapping sound through the bat detectors, which quickens and ends up sounding like someone blowing a raspberry when they home in on a midge!
Listen to the video and you'll see what I mean -

No signs of Daubenton's were found at the loch unfortunately so we wandered along to where the first moth trap was set up, a Robinson with a terribly high UV light which was attracting all sorts of night flying insects. Of the species I can recall there were July High Flyers, Square Spot Rustic, Yellow Underwing, Garden Carpet and Common Wainscot among many other pedestrian looking micromoths (of which there are approximately a bajillion species in the UK alone).

There was (half of) a Skinner moth trap set up in the bushes nearer the loch not far away so it could be seen if there were any difference in the species caught. There were some new faces as well as a lovely chunky carrion beetle which Richard Sutcliffe of the Butterfly Conservation Society spotted just shortly after starting to talk about the trap. The guys had also tubed some moths they caught earlier and so those were passed around with everyone trying to remember the names and identify them on their own with varying degrees of success.

If you are interesting in more fun and frolicks involving bats and moths, then why don't you check out these websites?

http://www.bats.org.uk/
http://butterfly-conservation.org/
http://www.buglife.org.uk/local/buglife-scotland