Sharon Flint is the Recorder for Mayflies (Ephemeroptera), Stoneflies (Plecoptera) and Trichoptera (Caddisflies). Sharon can be contacted via e-mail on http://This email address is being protected from spambots. You need JavaScript enabled to view it.

Dragonfly and damselfly records are collated by Mrs Jill Lucas, who verifies them and passes them on to the British Dragonfly Society.  Mrs Lucas can be contacted at 8 Cambourne Drive, Fixby, Huddersfield, HD2 2NF.

YNU members, Please note: I am looking to increase records of light trapped, adult Mayflies, Stoneflies and Caddisflies from VC61, 62 and 63. Please do get in touch if you would like to send me specimens from your vice county. Thankyou. Sharon.

Mayfly, Stonefly and Caddisfly records can also be put into: where the national recording scheme organisers can verify them.

YNU members light trapping in Dentdale. Credit Shraon Flint

Chinese Mitten Crab Sarflondondunc Flickr
The Chinese Mitten Crab (Eriocheir sinensis) - An exotic addition to Yorkshire’s aquatic fauna.

Chinese mitten crab


A native of China, this impressive beast, which spends much of its life in brackish and fresh water, is thought to have been transported to Europe in ballast tanks of shipping. It was first noticed in Germany in 1922 and is now well established in several of the continental river systems which discharge into the Baltic and southern North Sea (Fryer 1993).


In 1949 a young angler from Castleford caught a mitten crab in Southfield Reservoir, a compensation reservoir for the adjacent Aire/Calder Navigation nr. Thorne (SE/6518). The animal was trans-located to a ‘fenced off’ section of a stream near Hollywell Wood, Glasshoughton but disappeared a few days later (Limbert & Wall 1983).


In 1976 and 1979 specimens were found in eel nets on the south Humber shoreline near the River Ancholme outlet (SE/9721) and in 1984 one was actually located in the Ancholme itself (Clark 1984). In 1984 unconfirmed anecdotal evidence came from eel nets-men working the Blacktoft-Faxfleet area of the estuarine Ouse/Humber confluence (SE/82) (Mel. Todd pers. comm.1984). In 1986 one was found further up the tidal Ouse at Cawood (SE/5738) and in September 1991 ‘a colony’ was found in the River Wharfe (presumably the lower reaches) (Fryer 1993).

On 1st October 1995 one was caught on rod and line in the New Junction Canal, Kirk Bramwith, Doncaster (SE/6111). After being examined by Environment Agency biologists it was donated to Doncaster Museum by Chris Firth (EA Fisheries Officer) (Accession no. DONMG ZZ.267). This specimen was exhibited at the YNU Conference on the ‘Freshwater Ecology of Yorkshire’ (March 2001).


White Clawed Crayfish Jenny Wheeldon Flickr

In Britain the white-clawed crayfish is our only native crayfish and is our largest freshwater invertebrate. It lives in clean, relatively hard, mineral-rich waters with a pH of between 7 and 9 and calcium concentrations above 5mgL -1. It is widespread in clean, calcareous streams, rivers and lakes in England but many populations have been lost since the 1970s

The White-clawed Crayfish has now been identified as a priority species in the Biodiversity Action Plans of at least 12 planning authorities in the Yorkshire region.

As a result of legislative and conservation protocols the YNU has provided records and data on the former distribution of the White-clawed Crayfish in Yorkshire waters to a large number of planning authorities, statutory organisations, conservation bodies, academics and ecological consultancies.

Within the last decade the White-clawed Crayfish has been the subject of numerous site and river catchment surveys within the Yorkshire region, the results of which are being collated the Environment Agency.

Research paper: Gazetteer of White-clawed Crayfish in Yorkshire, by Colin Howes

Distribution map of White-clawed Crayfish from the NBN Gateway

Caddisfly Petros Pete Flickr

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 via:

I am happy to receive members specimens for identification and have been receiving specimens from members to identify,usually from moth trap catches. Members have also been very accomodating about me taking Caddisflies from their moths traps when we are out in the field recording moths. When the specimens are identified,  the records are submitted to Dr Ian Wallace or entered into the NBN database.

Adult Caddisflies can be humanely euthanised by putting them into a domestic freezer for a few hours. Each sample can then be put into an envelope and sent direct to me. I often receive specimens from members when they see me at field meetings, conference or other YNU meetings and events. I have received specimens that have been put into 70% alcohol in specimen jars. 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 provide the following data with your 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 alcoholed specimen jars.Records can also be put into


The Review of the Status of British Caddisflies Report can be down loaded from this link:
Orange-striped Stonefly Diggleken Flickr
Stoneflies, belonging to the Insect order Plecoptera, are so called because the adults of the larger species may often be encountered walking, and hiding, amongst the rocks on the shore after emerging from rivers and streams.   Many of the smaller species are active flyers and may also be found on tree trunks and amongst bankside vegetation.   The scientific name refers to the complex pattern of venation in the wings which, in some species, resembles braiding when the wings are folded along the back when at rest.   Adults may be fairly short lived as many of them are not known to feed; although they do drink; but there is evidence (shown by gut content analysis) that some species do feed on lichens and pollen.  The juvenile stages, at least of the larger species, may take up to three years to grow to maturity.   Both adults and mature juveniles can be identified to species using the keys in Hynes (1993).

Hynes, H.B.N. (1993). A key to the adults and nymphs of the British Stoneflies (Plecoptera) with notes on their Ecology and Distribution. Scientific Publications of the Freshwater Biological Association No. 17.

Stoneflies are occassionally found in light trap by-catches. Some can be identified from qood quality photographs, but, most require more detailed examination, usually on deceased specimens, in order to identify them reliably to species. Photographs of the relevent characters will be necessary if records are to be veritied on iRecord. You can upload Stonefly records into:

Freshwater Ecology ~ Contacts and Recorders


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Mayflies, Stone flies and Caddisflies and aquatic ecology: Sharon Flint  Email:


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