Winning in a changing climate: a jewel wasp new to Britain found in Kent

Monday 20th February 2017

Hedycrum nobile by Grant HazelhurstHedycrum nobile by Grant Hazelhurst

This jewel wasp is a species new to Britain and new to Kent, found on our reserves and most likely enabled by a changing climate – we always think of climate change as bad, but as species are pushed out of their continental range and expand north, they have to find stepping stones of habitat further north or go extinct. We are going to lose species to climate change, but also gain them.

Hedychrum nobile is a jewel wasp, a large one at that and a truly stunning little beast. Jewel wasps are members of the cuckoo wasp family Chrysididae, and are generally parasites or cleptoparasites (parasitism by theft). They lay their eggs in the nests of other insects, where their larvae consume the host egg or larvae alive. They are aptly named, generally being vibrant shades of bright metallic colours, and with minutely detailed and sculptured bodies. Most species in the family are found in desert regions of the world, as they are typically associated with solitary bee and wasp species, which are also most diverse in such places. This particular jewel wasp is a parasite of another wasp, the weevil hunting wasp Cerceris arenaria. The jewel wasp sneaks into the burrow of the weevil hunting wasp while she is away hunting weevils and lays her eggs. The weevil hunting wasp larvae consume the provisioned weevils, only to then be consumed themselves, a grim but exquisite intricacy of the struggle for life in the natural world.

It is a species more commonly found in Europe (Austria, France, Germany, Greece, Italy, Poland, Portugal, Spain, Switzerland) and in the East Palearctic ecozone and in North Africa, however it is a recent arrival to Britain. First found in Surrey in 1998, and in the High Weald around Tunbridge Wells, for example, it first appeared in 2007 at Hargate Forest just over the Sussex border. It was first recognised in Kent in 2014, and subsequent re-examination of old records confirmed that it had been in Kent as early as 2010 and very likely before. It can be found at Sevenoaks KWT reserve and has been seen fairly regularly at a number of heathland sites in Tunbridge Wells and Pembury and RSPB Dungeness. Perhaps the best place to see it in Kent though is Hothfield Common KWT reserve where it is relatively abundant and can be seen inspecting the wasp holes along the sandy paths and visiting flowers such as ragwort, yarrow and members of the Apiaceae (cow parsley and related species). The best time to see it is in July and August.

So how did it arrive in Britain? Well, this northward range expansion is likely to have been enabled by our changing climate. As average temperatures creep up in more northerly latitudes, so too do the species adapted to a particular suite of conditions, including climate. A degree or so increase could mean the difference between life and death for some of the multitude of tiny mobile insects that must blow into our airspace on a daily basis. While some more northerly species may be pushed off the northern coast of Scotland as the climate becomes too warm, others moving up from the continent will find Britain if they are lucky, and the stepping stones of suitable habitat the enable them to expand their range northward as they are pushed out of it from the south.

Conservation is not only about protecting the species and habitats we have, but also about providing these stepping stones and connected landscapes to enable species to move and adapt. Species are not only arriving from abroad, they are also moving within the UK, in both instances enabled by climate change. Species with southerly distributions now may well find themselves moving up north. It's our job as conservationists to ensure that the infrastructure and network are there to allow them to do so, so the arrival of a jewel wasp is both a harbinger of our changing climate and a welcome addition to our fauna. Our knowledge of this new arrival is thanks to dedicated recorders Grant Hazelhurst, Geoff Allan, David Baldock and Ian Beavis.

 

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