East Head Case

Posted by Graeme Lyons , Wednesday 11 September 2019 12:16

My first season as an almost full time entomologist is drawing to a close. It's been an incredible summer and one of the most exciting surveys has been the East Head survey I carried out for the National Trust in West Sussex. On Saturday I finished the sixth and final visit. It was one of those visits where you don't really feel like you've found very much, until you get home!

First off I thought I had found a new spider for me, being Agroeca inopina. After I got this male home, it was evident that this was actually the much more widespread Agroeca proxima. I did take the time to get some photos though. These late summers spiders look quite like small skinny wolf spiders with slightly wrong proportions. I took a female from a few metres away too. And I was really surprised that that one turned to be Agroeca inopina. This spider was new to me but known from the site. That makes 306 spiders for me this year. I am still way behind Matt. The spiders are done for the site with 13 of the 61 species recorded having conservation status! A whopping 21.3%. Here are the rare and scarce spiders for the site.

Alopecosa cuneata (NS)
Araneus angulatus (NS)
Argenna patula (NS)
Ceratinopsis ramosa (NR)
Crustulina sticta (NS)
Enoplognatha mordax (NS)
Nigma puella (NS)
Pardosa proxima (NS)
Phlegra fasciata (NR)
Sibianor aurocinctus (NS)
Sitticus saltator (NS)
Thanatus striatus (NS)
Zelotes electus (NS)

I could not find Marpissa nivoyii at this site but a more striking absence is that of the wolf spider Xerolycosa miniata which is usually common in sand dunes. This spider remains absent from West Sussex.

I still have 30 tubes of invertebrates to identify over the winter but this survey is definitely one of the most distinctive in terms of its statistics. It's by far the lowest in terms of overall diversity (I'm currently on 298 species) but the proportion of species with conservation status continues to be the highest I have ever surveyed. It's currently at 49 species, that's 16.4%! It was 17.4% after July, 16.2% after August so feels like it's oscillating around this area and won't change massively with the addition of the microscope work.

Under some tidal debris I found this this lively noctuid larva, which I believe to be Sand Dart. A Nb coastal specialist.

Other new species with status for the survey included Protapion difforme, Orthotylus rubidus and Sibinia arenariae. However, the highlight of the day and possibly the whole survey came in the last hour when I ran the suction sampler through some short sandy turf at the end of the dune slack. A funny orange carabid which turned out to be Bradycellus distinctus. This is Nationally Rare and Endangered and Mark Telfer says he can't recall hearing of any records  since he wrote the carabid review in 2016! Last recorded in Sussex was in 2000 at Rye Harbour and only known from there and Camber Sands in Sussex. Here it is!

The next day I was at the Secrets of the Heath event and the first family that came up to look at the inverts in the tray asked "were you at East Head yesterday hoovering up the dunes?"

1 Response to "East Head Case"

Guillermo García-Saúco Sánchez Says:

Interesting findings! Congratulations.
PS I love your blog

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