HYMENOPTERA REPORT 2023
187
Pemphredon austriaca (Kohl, 1888) (Hymenoptera, Crabronidae) new to Suffolk
Jeremy Early
Early in 2022, this small solitary wasp was added to the British list as the result of rearing adults from Oak Marble galls, collected by Rosie Bleet in West Kent (Bleet & Early, 2022). Hymenopterists in mainland Europe have long known about this wasp’s use of these galls as nest locations, utilising the hollow within the woody gall once the original nest occupants (the cynipid wasp Andricus kollari) have vacated the gall. It is possible that this is the only nest location used by this Pemphredon, which immediately entangles its life history with that of the gall wasp and its dependence upon Turkey Oak (Quercus cerris) to complete its lifecycle. Despite this long-known association, it would appear that British entomologists have not been able to record this Pemphredon in Britain previously, suggesting that this might herald a new colonisation event rather than it being a long-overlooked native. Having read about this discovery in Kent, the author resolved to try and find P. austriaca in Suffolk. To that end, on 10 February 2023, about 20 galls were collected from field hedgerows and young planted woodland north of Capel St Mary, south of Ipswich (Ordnance Survey grid reference TM0938). Having heard about this, David Basham also collected some galls, from Christchurch Park and Purdis Heath in Ipswich. Whilst David kept his galls in the cooler conditions of a garden shed, the author kept his indoors in a heated room. On 17 March, a male and female Pemphredon emerged from one of the author’s galls. Pemphredon species are not easy to identify,
Crabronid wasp Pemphredon austriaca female. Trans. Suffolk Nat. Soc. 59 (2023)