SHIELDBUG SUCCESS

They’re colourful, accessible and popular, and many are expanding their ranges into and across the British Isles. We uncover more about the changing fortunes of some of Britain’s favourite insects.

- Richard Jones

Everyone loves shieldbugs – why else would we have given them such a heroic and heraldic name? These distinctive bugs are relatively large, stout and brightly coloured – and robust enough that they can be picked up with impunity. They walk across the hand with a friendly clockwork gait and take to the wing from the end of a finger with an assured model-aeroplane whirr. They are highly photogenic, and there are just enough of them (about 70 British species) to pique the interest of non-specialists.

‘Bug’ (also bugg or bugge) is an old word. Though it is often used nowadays to refer to almost any small, mean creepy-crawly, for the strict entomologist it means a member of the insect order Hemiptera. Characterised by long piercing and sucking mouthparts and an incomplete metamorphosis (see page 61), this large group includes about 100,000 species worldwide, with cicadas, spittlebugs, leaf-hoppers, aphids, scale insects, water boatmen, back-swimmers, bedbugs, capsids and shieldbugs among their number.

Traditionally, ‘shieldbug’ meant a member of the family Pentatomidae, named for their five antennal segments (most other bugs have four) – but this rather unfairly excludes many four-segmented species (family Coreidae) that are still very shield-shaped. Shieldbugs are, in fact, a slightly arbitrary grouping of several related bug families lumped together.