Small World Discoveries

HEMIPTERA > HETEROPTERA > PENTATOMORPHA > PENTATOMOIDEA > Cydnidae

As their colloquial name suggests, these ground-dwelling shieldbugs can often be found burrowing into loose substrate around the base of their respective food plants, as well as being seen feeding higher on the plant.  

Eight species occur in Britain, although only three are regarded as common and, even then, are mainly local across central and southern regions, rather than widespread. The remainder are all categorised as nationally scarce or rare.

They are generally quite small, ranging from 3-4mm up to the largest species that may reach 8mm or even 9mm. They are predominantly black with few markings and have a somewhat beetle-like appearance. Their legs are stout and spiny, good for digging, and their tarsi are three-segmented.

Their small size, colour and behavioural habits makes them very unobtrusive and easily overlooked. To date, I've only photographed one, the Bordered Shieldbug [Legnotus limbosus]. This species is around 4mm long and is very similar to the much rarer Heath Shieldbug [Legnotus picipes], but is easily distinguished by having a pale edge to the corium that extends almost to the brown wing membrane, whereas with the Heath Shieldbug it is confined to the front third. Both species are associated with Bedstraws, but in very different habitats. I would have thought that the Heath Shieldbug could have been found locally but, according to the NBN Atlas, they haven't yet been recorded from Dorset. The not dissimilar Down Shieldbug [Canthophorus impressus] has though, only a handful of times as it's another nationally scarce species, but it is one to look out for on chalk grassland.

The Forget-me-not Shieldbug [Sehirus luctuosus] is again very similar, but is much more common, particularly in May when they're at their most active. The distinctive Pied Shieldbug [Tritomegas bicolor] is the most attractive because of its white markings. It's probably the most common species in this group and used to be the easiest to distinguish, but now has to be looked at carefully as a recent colonist, the Rambur's Pied Shieldbug [Tritomegas sexmaculatus], first recorded in Kent in 2011, that is now slowly extending its range, has to be considered even though, at present, it hasn't been recorded further west than Surrey.