Entomology Section

The Scaly Cricket Pseudomogoplistes vicentae (Gorochov) in the Channel Islands.

Introduction
Scaly Crickets, a drawing by Roselyn Coulomb
Photo of Scaly Cricket

Scaly Crickets are small, brown, wingless crickets that live on the seashore. Before 1998 they were only known from one place in N.W. Europe, but since then they have been found in several other places.

Discovery
The Scaly Cricket was first discovered in the Channel Islands by Eileen & Peter Brown at Dixcart Bay in Sark in 1998. Before this it was only known in N.W. Europe from Chesil Bank in Dorset, England, where it had been since at least the 1940s, and from one record from Granville in France in 1950. (Sutton 1999, Beaufils 1999). Also in 1998, it was found near Carolles on the Normandy coast by M. Beaufils and at Branscombe in S. Devon.

Since then it has been found at several more sites on the coasts of Normandy and Brittany, in Wales, and at several beaches in Guernsey. It was realised that the scaly cricket from the beaches of the English Channel was a native species, and not as had been previously thought, an introduction from the Mediterranean. It is a subspecies (septentrionalis) of a species known from Portugal and Morocco, and is not the Mediterranean P. squamiger (Gorochov 1996, Morère & Livory 1999).

Habitats in the Channel Islands
As in the rest of its range the cricket is found near the high tide mark of pebbly beaches and on pebble banks. It can sometimes be found by turning over larger stones, and the nymphs are occasionally seen hopping around on the beach like sand-hoppers. Other animals found in the same area of the beach include the woodlice Ligia oceanica, Porcellio scaber and Halophiloscia couchi, many amphipods, the centipede Strigamia maritima, Lycosid spiders, the Carabid beetle Agonum albipes, Staphylinid beetles of the genus Cafius and large numbers of Coelopid, Sphaerocerid, Sepsid and Anthomyid flies whose larvae feed on decaying seaweed.

Distribution in the Channel Islands
In Sark there are several stony beaches apparently suitable for the cricket, but it has not yet been found there apart from at the west end of Dixcart Bay. In Guernsey a long length of the coast at the N. and W. of the island has pebble banks or stony beaches at the high tide mark interspersed with sand dunes or rocky headlands. The cricket has so far been found in three areas - on stony beaches N. and S. of Spur Point in St Sampsons on the east coast, further north at a large pebble bank opposite Hoummet Paradis island and on pebble banks along the northwest coast between Port Soif and Pecqueries Bays. It is likely that the cricket occurs on most of this coast, but is hard to find where it has a low population. The cricket is probably mostly nocturnal, so it might be found more easily by searching at night with a torch, or by using pitfall traps. There are stony beaches in Alderney, Herm, Jethou and Jersey, and on several of the small islands round Guernsey, but the cricket has not yet been found in those islands.

Habitats of the scaly cricket in the Channel Islands


Distribution of stony beaches and the Scaly Cricket in the Bailiwick of Guernsey.

Pebble bank between Portinfer and Pecqueries bays on the W. coast of Guernsey.
Pebble bank at Portinfer Bay on the W. coast of Guernsey.
Stony beach N. of Spur Point on the E. coast of Guernsey.
Pebble bank opposite Hommet Paradis island on the N.E. coast of Guernsey.
Dixcart Bay in Sark
 



Biology
Little is known about the biology of the cricket. We do not know what it eats - the only field observation is of one eating a bird dropping (Livory et al. 2000) - or where it lays it eggs, but there is some information on its life-cycle. In Guernsey and Sark small nymphs have been found in spring and summer, and adults from late summer to winter. This seems consistent with studies in England & France (Timmins 1994, Livory et al. 2000). It appears that the insects can live for up to three years, and can overwinter as eggs, nymphs or as adults. Apparently most eggs laid one summer or autumn hatch the next summer. The resulting nymphs overwinter and mature the following summer. These adults may in turn overwinter. The insects are wingless and so, presumably, make no sound as crickets use their wings to stridulate. Most other species of cricket use sound for mate-finding and courtship.

References

Beaufils, M. 1999. Un heureux concours de circonstances. Argiope 23, 26-27.

Gorochov, A.V. 1996. A new species of Pseudomogoplistes from Morocco and Portugal (Orthoptera:Mogoplistidae). Zoosystematica Rossica 4(2), 292.

Livory, A., Coulomb, R., & Morère, J-J. 2000. Nouvelles observations sur le Grillon Maritime Pseudomogoplistes vicentae septentrionalis. Argiope 28, 47-63.

Morère, J-J. & Livory, A. 1999. Le grillon maritime de la Manche: une espèce nouvelle pour la France. Argiope 23, 29-37.

Sutton, P. 1999. The Scaly Cricket in Britain: A complete history from discovery to citizenship. British Wildlife 11, 145-151.

Timmins, C.J. 1994. The life cycle of Pseudomogoplistes squamiger Fischer (Orthopt. Gryllidae). Entomol. Month. Mag. 130, 218.



 
   
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