Table Of ContentBR. J. ENT. NAT. HIST.,4: 1991 123
INVREIA SUBARMATA FORESTER (HYMENOPTERA:
CHALCIDIDAE) AT DUNGENESS, KENT
R. K. A. Morris and M. S. Parsons
TheNature Conservancy Council, NorthminsterHouse, Peterborough PE1 1UA*.
Boucek(1972)reportedthecaptureoffourspecimensofInvreiasubarmatawhich
wereswept fromshortgrassatDungenessin 1971. Thecaptureofthisspeciesin 1988
and again in 1989, in pitfall and water traps during a Nature Conservancy Council
surveyofDungeness, is therefore not entirely surprising. The samplegenerated was
substantial however, and provides an indication of the ecology of this species at
Dungeness. Priorto 1988, publishedrecordsof/. subarmatawerelimitedtoasingle
19thcenturyrecordfromPortland(misidentifiedas/. subaeneainFerriere&Kerrich
1958) and the four individuals taken in 1971 at Dungeness.
In 1988, the NCC undertook a survey ofthe invertebrate fauna ofDungeness as
part ofwork commissioned by the then Central Electricity Generating Board (now
Nuclear Electric). Twenty trapping stations were established in 1988 and were
maintainedbetweenMayandOctober. DataonthetrappingstationsisgiveninMorris
&Parsons(1991b). In 1989, thestudywasextendedtocoverthewholeoftheshingle
system at Dungeness and others elsewhere in south-east England. As a result, 37
trapping stations were established at Dungeness with a further 10 at Rye Harbour,
EastSussex. Eachtrappingstationcomprisedalinearrunoffivepitfalltraps(plastic
vending cups) spaced at approximately two metre intervals, and two white water
pitfall traps
water traps
Trapping Period
23.5-6.6-1989
1
2 06-20.6 -1989
3 20.6-57-1989
4 29.8-12.9-1989
5 12-279-1989
Break
trapinping Fig. 1. Numbers ofindividuals of
Invreiasubarmata taken in pitfall
and water traps during 1989.
2 3
Trapping Period
*Presentaddress:TheJointNatureConservationCommittee,MonkstoneHouse,CityRoad,Peterborough
PE1 1UA.
124 BR. J. ENT.NAT. HIST.,4: 1991
traps(whiteplasticbowls20cmindiameterand9cmdeep). Boththepitfallandwater
traps were partially filled with a mixture of 10% ethylene glycol in water and were
emptiedevery2weeksduringtwotrappingperiods;23Mayto5 Julyand29Augustto
27 September. ThelocationsofthesetrapsaredescribedinMorris&Parsons(1991a).
During the survey in 1988, parasitic Hymenoptera were not a target group and
only a limited sample of material was retained. As a result, data for this period is
onlyavailablefromtrappinginAugustandSeptember. In 1989, aninterestinasmall
group ofparasitic Hymenoptera led to recording of Chalcididae. For the purposes
of this article, the comments are therefore confined to the results of work in 1989
whenitwaspossibletoextractallrelevantmaterial. In 1989, atotalof380individuals
of/, subarmatawererecorded. Figure 1 showsthenumberscapturedineachtrapping
period and from the available data, the peak frequency of/. subarmata appears to
be August but, as there was a gap between trapping periods, this is not certain.
Thereis adistinct succession ofvegetation types at Dungeness which is described
by Ferry and Barlow (in Ferry&Walters 1985). Further studies and a classification
ofshinglevegetationaredescribedbyFerryetal. (1990)and, asaresultofthiswork,
the vegetation is mapped by Fuller (1989). The trapping stations were arranged so
that they remained within a distinct vegetation type and therefore, it is possible to
compare the results ofpitfall and water trapping against vegetation type (see Ferry
et al., 1990, page 94). Comparing the average number of individuals per trap run
Keyto
VegetationTypes
Crambe
1
2 Arrhenatherum B3
3 Acid heath A1
4 Acid heath A2
5 Acid heath A2S
6 Acid heath A2
7 Acid heath A3f
8 Mesotrophic B1
9 Wetland B2
Wetland with Salix B2S
Bareshingle
Alluvial soil
Sand
== Vegetation type
Fig. 2. Average numbers ofInvreiasubarmata related to trapping effort and habitat type.
BR. J. ENT. NAT. HIST.,4: 1991
126 BR. J.ENT. NAT. HIST.,4: 1991
attention to the more recent record of /. subarmata. We also thank Dr R. S. Key
for help and advice during the preparation of this note.
References
Boucek, Z. 1952. The first revision of the European species of the family Chalcididae
(Hymenoptera). Sborn. Nas. Mus. Praze 27: (Suppl. 1): 1-108+17 pi.
Boucek, Z. 1972.OnsomeEuropeanChalcididae(Hymenoptera), withadescriptionofanew
Euchalis Dufour. Ent. Gaz. 23: 237-242.
Ferry, B. W. & Walters, S. 1985. Dungeness, ecology and conservation. Focus on Nature
Conservation 12. The Nature Conservancy Council, Peterborough PE1 1UA.
Ferry,B.W.,Lodge,N.&Walters,S. 1990.Dungeness:avegetationsurveyofashinglebeach.
Research and Survey in Nature Conservation 26. The Nature Conservancy Council,
Peterborough PE1 1UA.
Fuller, R. 1989.Dungenessvegetationsurvey—mapping. TheInstituteofTerrestrialEcology,
Monks Wood. Report to the NCC.
Ferriere, C. & Kerrich, G. J. 1958. Hymenoptera: Chalcidoidea. HandbkIdent. Br. Insects
8(3b). Royal Entomological Society, London.
Morris,R.K.A.&Parsons,M.S. 1991a.A Surveyofinvertebratecommunitiesontheshingle
ofDungeness, Rye Harbour and Orford Ness. Contract Survey 120 (in prep.). Joint
Conservation Committee, Peterborough PE1 1UA.
Morris, R. K. A. & Parsons, M. S. 1991b. An invertebratesurvey ofaproposedDungeness
'Cstationstudyarea.ContractSurvey 133.TheNatureConservancyCouncil,Peterborough
PE1 1UA.
BENHS FIELD MEETINGS
Shortheath and Slab Commons, East Hampshire, 24 June 1990
Leader: S.R. Miles. Sixmembersattendedthisdaytimemeeting. Fortunatelyearly
sunshinehadbroughtoutvariousinsects, howeveruntypicallyfor 1990therainclouds
were gathering. The party admired the large amounts of cranberry (Vaccinium
oxycoccus L.) in the bog at Shortheath Common, some still in flower. Some large
horseflies Tabanus autumnalis L. were seen at rest on dead birch tree boles, as by
this time it had become overcast. Andrew Halstead took a single specimen of the
local flyAcrocera orbicula F. swept from long grass adjacent to the bog. As larvae
theseareobligateparasitesofspiders. Thehoverfly Trichopsomyiaflavitarsis(Meig.)
whichislocalinsouthernEnglandduetoitsrequirement forwetheathlandwasfairly
frequent withintheconfines ofthe bog. Andrew was also fortunate to take a single
specimenofthehoverflyHeringiaheringi(Zett.) and anexampleofthelocal sawfly
Aneugmenus temporalis Thorn. Peter Chandler found two local fly species, the
scathophagid, Pogonota barbata (Zett.), which he informs me also occurs on the
nearby Surreybogs and theMycetophilid, RymosiaarmataLac, whichis a fen and
lakeside inhabitant.
AfterlunchthepartywalkedtothenearbysiteofSlabCommon, whichisanarmy
tracked-vehicletraining and recovery area. This is what I term degraded heathland,
however because ofthe army use it retains considerable open bare sandy areas. At
the margins of these many small flowering plants occur, including various small
Compositaewhichwouldprobablybeout-competed bymore rankgrowth ifit were
not for the continued erosion. Some local solitary bees occur here, however as the
weather was most unfavourable, by now windy as well as verycloudy, few aculeata
were seen. Frances Murphytook aninteresting linyphiid spider, Erigonepromiscua
(O.P.-C.)andPeterChandlerwasalsopleasedtocapturetwofliesofdampwoodland,
