Essex bumblebee report 2002
On 3lst July, a dark male B. ruderarius was noted near Dedham, and the first males of B. pascuorum
were seen at Flatford. Finally, a trip with John Dobson to Foulness on 24th August yielded two
further observations of interest. The first was a fine, freshly-emerged queen B. muscorum between
Church End and Naze Wick. The presence of this species at Foulness is of interest, since this corner
of Essex appears to mark the boundary between the distributions of B. muscorum (east coast) and
B. humilis (Thames Estuary). After leaving Foulness, we visited the area around Barling, where we
found a single worker of B. sylvarum near the seawall in TQ9389.This is considerably further east
than any previous Essex record for this rare species, and extends our knowledge of its range in the
county.
2002 update on Odynerus simillimus in north-east Essex
DAVID SCOTT
Ford Farm, Brightlingsea, Colchester, Essex C07 OSA
The rediscovery of the RDB1 Eumenine wasp Odynerus simillimus in August 2000, some 100
years after its initial UK discovery in the Colchester area by Harwood, was reported by Harvey &
Scott (2001). Finding a nesting aggregation at Alresford meant that there was an opportunity to
discover something of the autecology of a wasp about which 'Nothing seems to be known of its
life history' (Shirt 1987).
Observation at the nesting sites has at last started to fill in some of these details. O. simillimus, in
north-east Essex at least, has a liking for a sea view, some of the Alresford nests being within yards
of the high tide mark. The female wasp excavates holes about 5mm diameter in bare or lightly
vegetated ground either on flat or sloping surfaces, seeming to prefer clay or clay/sand mixtures.
The holes are topped with a short (1 cm or less) chimney made of excavated soil, handled by the
wasp in small pellets, water being carried to soften the soil if conditions are dry. Below the surface
nest chambers are excavated off the main shaft and stocked with weevil larvae, genus Hypera, as
food for the larval wasp. The chimneys are in loose aggregations, some centimetres apart, although
solitary chimneys have also been found.
A section of bank that had a number of chimneys in 2000 had hardly any in 2001 (although that
may have been the result of a large travellers' van permanently parked against the bank), and
though the other site on a nearby sea wall was up to strength in 2001, by 2002 activity seemed
much reduced. I was much relieved, therefore, arriving at a pre-arranged site inspection on 15th
July, to see Peter Harvey, Peter Hodge and Mike Edwards, undertaking work on behalf of the
Aculeate Conservation Group, heads down in a corner of the field adjacent to the original bank.
They had discovered chimneys on the ploughed, but undrilled, corner of the field, with good wasp
activity. The interesting point is that the wasp is willing to nest in recently disturbed soil. This was
confirmed when the ACG party discovered two nesting aggregations in two areas on old ditch
dredgings, totalling 57 chimneys, at Hickling Broad (Norfolk) on 17th July, and I discovered a
further north-east Essex site at Brightlingsea, about 15 nests in the side of a new borrowdyke dug
four or five years ago as part of new sea defences.
A major remaining problem is the exact identification of the prey larvae. Returning female wasps
usually drop the captured larva in the net when caught, but these cannot be reared on to the adult
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Essex Naturalist (New Series) 20 (2003)