Invertebrate survey at Gunpowder Park, the former Royal Ordnance Site in the Lee Valley
Hydraenidae Hydraena testacea Notable/Nb, Essex Red Data species
This small water beetle was found in Area D. It is found in stagnant water and muddy streams.
Hydrophilidae Helochares lividus Notable/Nb, Essex Red Data species
This is a widely distributed water beetle in England and Wales, most frequent in the south. It occurs
in ponds inland as well as in dykes on the coastal levels.
Mordellidae Mordellochroa abdominalis a scarce species
This very local tumbling flower beetle was found in Area B, swept off herbaceous vegetation at the side
of the ditch underneath the dead and diseased trees before they were removed. The beetle is included as
a saproxylic (dead wood) indicator species for use in evaluating wooded habitats for the conservation of
dead-wood Coleoptera (Fowles, Alexander & Key 1999). It is assigned a rarity score of 4 out of a
maximum of 32 for use in calculating Saproxylic Quality Indices. In Area B, the beetle probably developed
in the standing dead timber that has now been removed.
DIPTERA-flies
Acroceridae Paracrocera orbiculus Local, Essex Red Data species
This hunchback fly was swept in Area C. It is mainly a southern species but records extend more
sparsely into East Anglia, Wales and central and northern England, as well as near Glasgow and in
West Perthshire (Stubbs & Drake 2001). It is not a common species, with a very few scattered
Essex records. Many old localities contained heathland, but it has since been recorded from fens,
bogs and even Saltmarsh, although it is particularly associated with dry grassland (Stubbs & Drake,
op. cit.). The species is a parasitoid of spiders, recorded from hosts in the lycosidae and gnaphosidae.
Agromyzidae Agromyza ferruginosa Unknown NCR
The local species was recorded in Areas C and D. The larvae of the fly mines Comfrey Symphytum,
and this is the first Essex record of the species.
Chloropidae Aphanotrigonum trilineatum NCR
The species was recorded in Area C. This small fly is nationally widespread amongst grasses,
especially in damper areas. Although the first Essex record it is supposed to be a common species.
Chloropidae Oscinomorpha arcuata Notable/N, Essex Red Data species
The species was recorded in Area B. Oscinomorpha arcuata is a small fly, whose biology is uncertain,
though larvae are probably leaf miners in monocotyledons. It has been recorded from Hants, to
Suffolk, and although Nationally Scarce, this species appears to be widespread and reasonably
frequent in suitable habitat in South Essex and the East Thames Corridor.
Dolichopodidae Hercostomus celer Local, second Essex record
The species was recorded in Area D. This shining metallic fly is found in damp places. Larvae of
this genus are almost completely unknown. It is not uncommon in the north, becoming scarcer
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Essex Naturalist (New Series) 21 (2004)