7 Sep 2014

7 Sep 14 - A Stunning Bush Cricket

One of the interesting thing about some of the Bush Crickets in Dorset is the significant changes to some of their populations in Dorset. One of the most interesting is Roesel's Bush Cricket. For many years, this species was restricted to the the South East with isolated colonies at Needs Ore in Hampshire & the Dovey Estuary in Cardiganshire. Then for some reason in the 1990s, it suddenly started to expand its range in the Thames Estuary & started moving West. The Dorset range extension is well documented in the excellent Grasshoppers, Bush Crickets and Allies book which was recently published in 2011. The first Dorset record was in 2005. Since then it has steadily moved West through the Bournemouth & Poole conurbations and carried along some of the river valleys, especially the Avon, Stour & Piddle valleys. I thought I had photographed one at Alner's Gorse last Autumn, but thanks to Michael Skelton this has now been re-identified as a Dark Bush Cricket. They have been found this Autumn around Portesham, which is only about 20 miles from the Devon border: another impressive range extension.
Dark Bush Cricket: Female. I had through this was a Roesel's Bush Cricket, but thanks to Michael Skelton (see Comments), I've been corrected. It does explain why it wasn't well marked for a Roesel's Bush Cricket. I had assumed that was down to it being the equivalent of the teneral phase similar to the teneral phase seen in Dragonflies, where the freshly emerged adults are dull compared to the mature adults. Clearly, an identification error was a better explanation. Alner's Gorse (Aug 13)
I've been trying to photograph some more & have been out looking at a few sites in the Poole area as well as along the Jurassic Coastline. But the weather wasn't ideal on the days I was out looking for them. What has been slightly frustrating is despite listening to recordings of the call, I've not managed to hear any. But my mate, Kevin Lane, has been hearing them at various places in the Purbeck area recently. Although I'm able to pick out other calling species, I'm just wondering if I'm starting to struggle at the frequency that they call. Anyway, I ran into Kevin at Middlebere today as I found a good bird there today. But that will have to be the subject of tomorrow's post as I will have more time to look at the photos tomorrow. But to return the favour, Kevin asked if I had see any Roesel's Bush Crickets yet, as he had heard some nearby.  As I hadn't, I joined him on a quick look & he quickly found a calling individual, which I could just about hear. It didn't take him long to find it & it was a really well marked individual.
Roesel's Bush Cricket: Male. Note, the broad yellow edge to the side plate of the black pronotum and the 3 yellow spots to the side of the abdomen. Turns out this was a Tick for me

2 comments :

  1. Steve, I was interested to see your blog on Roesel's Bush-cricket: I'm glad someone else is taking an interest. I'm afraid I think your Alners Gorse specimen is a Dark Bush-cricket. Unfortunately the wings are concealed by the hind leg. The species has been slow to colonise Purbeck, but in the last couple of years it has made many gains, and is now common around Wareham, Arne, and on the Purbeck Hills at least as far west as Nine Barrow Down. Numbers are probably beginning to fall now, as it is an early species.

    Michael Skelton

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  2. Hi Michael,
    thanks very much for your feedback. I'm still trying to get into Bush Crickets & Grasshoppers, so any other mistakes you spot on the blog, I will be keen to hear.

    The photo was taken at Alner's Gorse, the Butterfly Conservation reserve near Hazelbury Bryan (ST736100) so well outside of the Purbeck area. I'll correct it.

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