Hopping Mad - An Identification Guide to the Orthoptera of Worcestershire

By Gary Farmer

Identifying Grasshoppers and their allies is relatively easy compared with other groups of Invertebrates. They are a small group and with a little practice all can be recognised in the field without the need for complicated keys. But the unique thing with Orthoptera is that all (except the Groundhoppers) can be identified by their songs. The problem with this is that the high frequencies used by these Insects becomes inaudible to us as our hearing deteriorates with age. The answer comes in the form of high frequency analysers (Bat Detectors). These have been used very successfully in other counties to increase the number of records for distribution maps. A book recently been produced by the Surrey Wildlife Trust (The Grasshoppers and Crickets of Surrey would you believe) deals with the use of Bat Detectors in some detail and is a very good read. There is also an audio tape of British Orthoptera song available from Harley Books. This is very useful for anyone wishing to learn the songs and if you have trouble hearing the high frequencies then just point your Bat Detector at the hi-fi speakers - apparently this really works. I should be interested to hear from anyone who has tried to identify Orthoptera using a Bat Detector or is willing to bring one along to a field meeting in the Summer.

Meanwhile I shall concentrate on identifying Grasshoppers and Crickets by sight.

Editor's update: Gary has recently bought a modified bat detector and has now discovered how much his hearing has lost its high frequency response, but he is also finding many more grasshoppers.

General Identification

(see figs 1 & 2)

All Orthopteroid Insects have well developed hind legs for jumping, long antennae (1) and a pronotum (a hard shell covering at least the thorax) (2). The length of the wings (5) is an important identification feature as is the shape of the ovipositor (4) of female Crickets and the shape and length of the Cerci (3) of males. Grasshoppers have short cerci (8), females have ovipositor valves (9) quite different to Crickets and males have sub-genital plates (7). The young or nymphs are miniature versions of the adults and Crickets in particular can be identified at any stage. Always take care when catching and handling specimens as they damage very easily. I find small, clear perspex boxes to be ideal as this avoids handling the Insect at all (make sure that the long antennae of the Crickets fit in). There follows a short description of each of the species. I have deliberately used common names to try to broaden the appeal of this fascinating group of Invertebrates, and make no apologies for doing so.

References

Crickets

Crickets have very long, fine antennae (much longer than body). They 'sing' by rubbing their wings together (except the Oak Bush-cricket which 'tap-dances' on a leaf). Crickets are omnivorous, feeding on small Invertebrates and herbage. Females have sword-like (fig. 1) or pin-like (fig. 8) ovipositors.

Of the eight species of Cricket recorded in Worcestershire, four are very unlikely to be found so I have left three outside of the key - Mole, Wood and House Crickets (the fourth - Great Green Bush-cricket - has been included). Two others included - Long-winged Conehead and Roesel’s Bush-cricket have not been recorded in Worcestershire but their ranges are expanding rapidly and will hopefully soon be with us.

Grasshoppers

Grasshoppers have shorter antennae (about half length of body). Their song is produced by rubbing their legs against their wings. Grasshoppers feed on grasses and other vegetation. Females are larger than males and can be separated by the features shown in fig. 2 of the rear of the abdomen. An important identification feature of Grasshoppers is the pronotum and its side keels (figs. 4 to 7). The shape of these side keels are referred to in keys in all publications, but care (and experience) is needed.

My Key includes the five species so far recorded in Worcestershire plus one extra - Stripe-winged Grasshopper (just in case). Colour variation within species is considerable, ranging from browns and greens to pink and purple. Some have very well defined pronotum side keels, others need to be viewed very closely. Confusion between species is most likely as follows :

Groundhoppers

Groundhoppers are smaller than Grasshoppers and are distinguished by their extended pronotum (as long as the body or longer). They have no song. Groundhoppers are associated with mosses and can be found through out the year.

Two species occur in the county and are both around 10mm in length :-

Common Groundhopper Tetrix undulata

This has a pronotum as long as the body and a ridge along the back giving an almost 'hunch back' look.

Slender Groundhopper T. subulata

This has a pronotum much longer than the body and a flatter back.

The Key

The following key has been kept as simple as possible. I have left out any identification points that require previous knowledge of the group or the need to kill an individual.

First decide whether you have caught a Cricket or Grasshopper by reading the above General Identification.

Then simply read the first question (top left) in the appropriate Key. Answer TRUE or FALSE and follow the arrow to the second question and so on.

I have not included a Key for the Groundhoppers as there are only two and they have been identified above.

I should appreciate any comments after you have tried this Key out so I can make amendments where appropriate.

Crickets

Grasshoppers