New 'Pied' Shieldbug species: Tritomegas sexmaculatus

[tristanba]

This is a plea for people (particularly those in the south-east) to look out for a shieldbug which has recently been found in Britain for the first time, Tritomegas sexmaculatus. It is very similar to the Pied Shieldbug (Tritomegas bicolor), the main difference being the larger area of white on the margins of the pronotum, just behind the eyes. The bug has recently been expanding its range on the continent and was put forward as a candidate for arrival in Britain only last year. Please see this short article in Het News (p7) for further details:
http://www.hetnews.org.uk/pdfs/Issue...010_1170kb.pdf

All credit for the discovery must go to Ashley Wood (asheleaf), whose suspicions were aroused by a photo of an unusually dark Tritomegas nymph, photographed recently on black horehound (Ballota nigra) near Maidstone by Jason Elmore. The nymphs are typically much darker than T. bicolor:
EDIT~Tritomegas sexmaculatus. A new find for the UK !! | Flickr - Photo Sharing!

On checking through Jason's photos, she then discovered a picture of an adult taken earlier this year in April:
Tritomegas sexmaculatus. | Flickr - Photo Sharing!

The bug apparently prefers black horehound to white dead-nettle (the commonest foodplant for T. bicolor in Britain), so any Tritomegas nymphs found on horehound are well worth checking. At the moment it is very unlikely to be present outside the south-east, but it's worth keeping an eye out for it wherever you live so we can track the colonisation and get some idea of how fast its spreading. I have been looking in the London area without success. Even if you don't find it, you could well record other interesting insects on horehound such as woundwort shieldbug (Eysarcoris venustissimus) and the plant bug Macrotylus horvathi.

The new generation of adults is maturing now and these will soon go to ground and be much more difficult to find, so time is of the essence here!

Many thanks
Tristan

[Wild-Woman]

Thanks for this tristan, as living in the SE I shall certainly be on the lookout. I've seen Pied Shieldbugs locally so I'll take a second look.

[htcdude]

This is great news! Any ideas whether it'll have any major impact on anything?

I'm in Greater London, but will keep a lookout too

nige

[tristanba]

T. sexmaculatus should slot in perfectly well here and since it is entirely herbivorous I doubt it will have much impact on 'native' species.

It does however mean that identification of any 'pied' shieldbug now needs to be supported by a good photo showing the extent of white on the pronotum. It also has implications for the common names of Tritomegas species - what should we call it? Clearly the name 'Pied Shieldbug' is now ambiguous. This is one reason why I am not a great advocate of vernacular names for insects, despite their usefulness in improving their accessibility to the wider public.

[Jason Claxton]

Thanks for that Tristan

T.sexmaculatus looks very distinctive too from T.bicolor,I kind of assumed they would all be T.bicolor that I was seeing,lets hope that I haven't overlooked the newbie,anyway I shall start searching now.

[asheleaf]

the nymphs are easier to seperate than the adults (for a change). I'm hoping host plant will help.

I've been looking and have scouts out, no sightings in Sussex yet

Ashe

[tristanba]

I have just received reports of nymphs from the Benenden area, also in Kent, so keep looking on any stands of black horehound!

[tristanba]

For info, further publicity on the arrival of this (and other recently arrived) insect species:
BBC News - New species of bug found at Kent nature park
Kent Bug is First in UK!xe-xeKent Wildlife Trust

[Acutipuerilis]

Wow - a bit of BBC I can actually watch from China.
Good to see them getting a bit of publicity - well done, if it was you who sorted that out (although you seem to have missed out on your potential five minutes of fame)...

[Wild-Woman]

Interesting articles there. The bee is quite distinctive too. Thanks for posting.