I really enjoying learning how to identify wildlife, so not only do I spend time identifying soil invertebrates as part of my PhD project but I like to attend identification workshops and courses in my leisure time. On Saturday I was at a workshop organised by the British Entomological and Natural History Society (BENHS) learning how to identify land Heteroptera with Tristan Bantock and Jim Flanagan. Many people use the term ‘bug’ to refer to any invertebrate but in strict entomologist sense a bug is a member of the order Hemiptera. These are characterised by having a straw-like mouthparts (a rostrum) which they feed on fluids of various kinds, often plant sap but some on other insects and even blood. They include familiar insects such as aphids, bed-bugs and shield (stink) bugs. UK bugs species are split into three major groups and today I was looking at the Heteroptera which include shieldbugs/stinkbugs and assassin bugs. There are some bugs that live in water, such as the pondskaters and water boatmen, but this workshop was just to identify species which live on land.
Like most insects bugs are identified using keys, which provide a set of questions about features of the insects, progressively narrowing down possibilities until (hopefully!) the correct species is arrived at. There are several types of identification keys but the most commonly used is a dichotomous key which offers two options at each step (called a couplet). Unfortunately keys can be problematic, firstly they rely on knowing what you are looking for, which in some cases can be straightforward e.g. leg black or yellow but in others subtle or open to interpretation e.g. leg thickened towards base or leg equal width. With small species you will need a microscope to see the differences! Keys also have problems that new species may have be found since the key was published, sometimes a very variable species will not fit the description, your specimen may not be an adult, missing the part that you need to look at, or even deformed or unusual in some way. On occasion the keys can just have errors!
Identifying using keys can be frustrating, but I rather despite this I rather enjoy it, it’s like a puzzle. It helps enormously to have someone who knows the group and a reference collection to refer to, and that is where BENHS is very useful, their headquarters at Dinton Pastures Country Park has a library and labelled specimens which can be used to compare against your specimen to check if your identification is feasible.
During the workshop I identified a few bugs which I found in leaf litter during my MSc Taxonomy and Biodiversity project, I didn’t have very many but it is particularly satisfying to work on your own specimens, and I can add to the species list for the site. The first bug I identified was a small brown specimen which I found in leaf litter from a rotting tree stump}, I got stuck keying this specimen as the couplet asked if the head was heavily punctured (lots of small round dents) or less heavily punctured. Mine seemed to have a lot of punctures but I soon came to a dead end following that route. After asking one of the tutors for advice it transpired this was one of the less punctured species, but of course without the contrasting one to check against how would I have known that!
I finally successfully identified the bug as Drymus brunneus, a common bug in leaf litter. Next I identified some even smaller bugs which I sieved from moss during my MSc. These were only 2-3mm in length, but under high magnification were immediately identifiable as a species of lacebugs (Tingidae), which as the name suggests have lace-like wings. These keyed much more easily to Acalypta carinata, which was then confirmed by Jim. The rest of the afternoon was spent practising using the keys on specimens in the BENHS collection, I will have to find time to go through more of my insect collections to see if there are more to identify!