Small World Discoveries

HEMIPTERA > HETEROPTERA > PENTATOMORPHA > PENTATOMOIDEA > Acanthosomatidae

The Pentatomoidea superfamily groups together five families of 'shieldbug', so named due to their general shape, but also because of their large scutellum that covers much or all of their wings. In some countries, such as the USA, they're called 'stinkbugs' as many species emit a pungent fluid when threatened. Apart from being characterised by the well-developed scutellum, these species have ocelli, five-segmented antennae and two or three-segmented tarsi.

The Acanthosomatidae family is represented in Britain by five species, although only four are normally considered as the Bilberry Shieldbug hasn't been seen for many years and is almost certainly extinct. They can be distinguished from the Pentatomidae 'typical shieldbugs' by having two-segmented tarsi.

Whilst all four are regarded as being common and widespread across much of the country, the Juniper Shieldbug [Cyphostethus tristriatus] is a more localised species within areas where Juniper is growing. It used to be pretty much confined to southern woodlands, but its range is now extending due to the planting of both Juniper and Cypress in parklands and gardens. It's an attractive species that I'd obviously like to see, although that may be quite difficult based on the current NBN Atlas records that only shows three sightings in Dorset over the past five years!

Fortunately, the superficially similar green species, the Birch Shieldbug [Elasmostethus grisea] and the Hawthorn Shieldbug [Acanthosoma haemorrhoidale] should be easier to find locally even though the recorded sightings lead you to think otherwise. In fact, I'm starting to think that the distribution maps for many insects are very misleading simply because so few people record so-called common species. That certainly applies to me, so I shouldn't complain when the information I'm looking for is so sparce! I've photographed the Hawthorn Shieldbug, which I believe is the more frequent of the two, and will now be looking out for the Birch Shieldbug. Although the common names relate to the main food plants, the Birch Shieldbug may also be found on Aspen or Hazel, and whilst the Hawthorn Shieldbug is primarily associated with Hawthorn it can also be seen on many other varieties of shrubs and trees.

The final species is the Parent Shieldbug [Elasmucha grisea], so named due to the female's habit of guarding her eggs until they hatch. This species lacks the green background colour of the others, being more reddish or grey/brown colour, with some darker markings. It is most likely to be found on Alder or Birches.