Caddisflies or Trichoptera, (meaning, from the Greek trichos a hair and pteron a wing; hairy-wings)

This is one of the few insect groups where, at least in so far as the British fauna is concerned, the majority of the larvae are known and both adults and larvae can be identified to species. Careful manipulation of both larval and adult specimens, under the microscope, is required in order to see characters clearly. In the larvae, some important characters are the form and position of gills, hairs on various parts of the body and legs and the shape, position and colour of sclerotized plates on body segments, along with head patterns. In the adults, examination of the wing venation (front and hind wings) and genitalia, as well as spur formula are among the characters used to determine a species identification. Though some characters can be difficult to assess, the identification of the order, in both its life stages is relatively straight forward, using the excellent keys (listed below). These volumes also provide much interesting information on their ecology as well as instructions on collection and preservation. The majority of the larvae make, and live in, portable cases, but a considerable number of them do not. All the species in any particular family are either case bearing or caseless. This is not; however; as straight forward a division as it might seem, as some case-bearing larvae wait until their final instar before constructing a case and some flowing water species are known to abandon their cases from time to time to drift with the current. Caseless larvae construct a fixed shelter when they are ready to pupate.

Limnephilus politus in its amazing case. (Photo Credit Sharon Flint)

Keys to adults:-

Macan T.T.(1973.) A Key to the Adults of the British Trichoptera. Scientific publications of the Freshwater Biological Association, No.28.

Barnard and Ross (2012). The Adult Trichoptera (caddisflies) of Britain and Ireland. Handbooks for the identification of British Insects. Vol.1 Part 17.

Keys to the larvae:-

Edington, J.M. and Hildrew, A.G.(1995). A revised key to the caseless caddis larvae of the British Isles with notes on their ecology. Scientific publications of the Freshwater Biological Association, No. 53.

Wallace, I.D., Wallace, B. and Philipson, G.N. (2003) Keys to the case-bearing Caddis larvae of Britain and Ireland. Scienfitic Publications of the Freshwater Biological Association, No.61.

You can send records to the Trichoptera Recording Scheme here.

Adult Caddisflies can be humanely euthanised by putting them into a domestic freezer for a few hours. Each sample can then be preserved in 70% alcohol in a specimen jar for later identification or, if assistance with identification is immediately available, put into an envelope and posted, if necessary. Some Caddisflies can be identified reliably from good quality photographs, but most are difficult to reliably identify this way unless a high quality image of the genilalia and wing venation is provided. Please make sure the following data are recorded with any specimens: date of capture, six figure grid reference, catch method, habitat, name of collector. Please write this in pencil on a piece of paper; this is especially important if you are putting the label into a specimen jar containing alcohol. Records can also be put into https://www.brc.ac.uk/irecord/

Thankyou

The Review of the Status of British Caddisflies Report can be down loaded from this link: