Small World Discoveries
by Tony Enticknap - tickspics
Taking a close look at insects and other small species that can be found in and around East Dorset and the New Forest ...
HYMENOPTERA | Stinging Wasps
Chrysididae (Cuckoo Wasps)
Although the members of this family are also known as ruby-tailed or jewel wasps, the common descriptive name of cuckoo wasps is the one that's usually applied to the 35 species on the British List. It's an appropriate name as the most of the British species are cleptoparasites that lay their eggs in the nests of other unrelated solitary wasps or bees who inadvertently act as the host species by feeding the chrysidid wasp larvae.
All the wasps in this family are colourful and distinctive in their own way, which would lead you to think that they must be relatively easy to identify but, typically, that’s not always the case as many species are so superficially similar that it can be a challenge even under a microscope.
​
Hedychrum nobile
Noble Cuckoo Wasp
HYMENOPTERA > APOCRITA | Aculeata > Chrysididae > Elampinae
​
Fortunately, Hedychrum nobile is one of the species that can be identified, and can be separated from the similar, but smaller, Hedychrum niemelai species with which it was formally associated.
Hedychrum nobile is described as a medium-sized (6-10mm body length), robust cuckoo wasp with a green, bluish hue coloured head and thorax, and reddish abdomen and, in the case of the female, a wide reddish band across the front of the thorax and, importantly, feint reddish markings between the eyes.
It was only recognised as a British species in 1998 when a specimen found in Surrey was examined. Since then, it has been recorded from various locations across south-east England and at a few sites further west and north. It can be found in areas with dry sandy soils, such as on heathland or dry grassland, where its host species Cerceris arenaria (Sand Tailed Digger Wasp) has her nest. It is thought that Cerceris arenaria is the sole host and looking at the distribution map of that species, which covers much of southern Britain, it is likely that Hedychrum nobile will continue to be recorded from new sites other than the Norfolk Brecks, New Forest and Dorset heaths, where it is already starting to establish itself. At the time of writing, the furthest westerly point it’s been recorded is Wareham.
​
​
Hedychrum nobile
Hengistbury Head, Christchurch, East Dorset | Sept.21