34 The Essex Naturalist
Several uncommon Arachnospila species have recently been recorded in new
localities in the county. One female of the Nationally Scarce (Notable B)
Arachnospila minutula was taken in July 1996 near the Thames at Barking Levels.
Of interest is a male taken this year in June 1997 at Thamesmead on the Kent side
of the Thames. These two sites are geographically close and have proved to be rich
in scarce and rare insects, showing a remarkable biodiversity typical of the good
sites that still remain in the East Thames Corridor. Unfortunately both localities
are almost certainly soon to disappear under retail and housing development. The
very local Arachnospila spissa was found to be quite common by Colin Plant and
myself at Alsa Sand Pit in June 1996. This appears to be first record for North
Essex since Harwood's time (Harwood, 1884). The only other modern county
record is for Mucking Heath (Orsett Golf Course) in Thurrock. Arachnospila
trivialis has previously only been recorded in the county at Mill Wood Pit in the
Chafford Hundred development area in Thurrock. In August 1996 one male was
taken at Alphamstone in North Essex and one female at West Thurrock PFA
lagoons. I recorded one female of the Nationally rare (RDB3) Arachnospila
consobrina at Aubrey Buxton N.R. on 7th June 1997. This record needs
confirmation, especially since Day (1988) and Falk (1991) give the habitat as
coastal dunes and other sandy spots on the coast. However the ecology of the
species states that the wasp is recorded as taking a Segestria in Turkey and these are
typically spiders found under bark or in cracks in walls, not in sandy habitats.
Mason wasps (Family Eumenidae)
Two males of the Nationally Scarce (Notable A) Odynerus melanocephalus were
taken on 1 3th June 1996 at Alphamstone, the first records for North Essex since
Harwood's time. The species is otherwise only to be found in Essex in the East
Thames Corridor at several sites in Thurrock. Modern strongholds are said to be
the coasts of the Isle of Wight, Dorset and Kent, with sparse post-1970 records
from other areas suggesting a substantial decline (Falk, 1991). The combination
of scarce species found at Alphamstone suggest this is an important area for
aculeates in north Essex. One male and one female of the Notable B
Microdynerus exilis were also found at Alphamstone in July and August 1996, the
first records for North Essex.
One male was found again in the Thurrock area on the 25th July 1996 at
Gravelpit Farm Pits and a female was taken at Warren Pit near Woodham
Walter on 3rd August 1996. The species may turn out to be present in widely
scattered localities across the county.
Social wasps (Family Vespidae)
The tree wasp Dolichovespula norwegica is rare in the county but there have been a
number of recent records (Harvey & Plant, 1996). A male was taken at Broaks
Wood in North Essex on 17th August 1996. The Hornet Vespa crabro continues
to be reported in the county and has clearly become much more common again