True Bugs (Hemiptera)

For the many farmland birds that thrive on the Weald Moors, insects are a vital protein-rich source of chick food. In spring, the hatching of young is often timed to coincide with their availability, and one of the largest and most important groups is the vast order of ‘true bugs’ … 

A Cast of (Many) Thousands: there are over 80 000 species of True Bug around the world, although only around 1,700 occur in Britain. While you won’t find all of them on the Weald Moors, it may prove helpful to know they are broadly divided into three major suborders, each with their own barely pronounceable scientific name! The Heteroptera include a wide variety of terrestrial, aquatic and water surface bugs many of which (but not all) feed on plant matter. Auchenorrhyncha are exclusively land-dwelling and typically active insects that feed on plant sap, some of the best known of which are the froghoppers (they are responsible for the countless secretions of ‘cuckoo-spit’ found in our wayside verges each summer). Many insects belonging to the sub-order Sternorrhyncha, on the other hand, are characterised by their inactivity — a large number are wingless, while some also lack legs — and include aphids and whiteflies among their massed ranks.

While there are clearly many differences in the physical appearance and lives of True Bugs, they are all unified by one thing — an inability to chew food! To get around this potentially fatal flaw, they are endowed with a piercing rostrum (a snout-like projection centrally located on the head) and sucking mouthparts that enable them to feed on liquids in a manner akin to drinking through a straw! Many Heteropteran members of the True Bug order also have forewings that are hardened at the base and translucent at the tip, which is where the scientific name Hemiptera (meaning ‘half wing’) originates.

Hawthorn Shieldbugs (Acanthosoma haemorrhoidale) also feed on Birch, Rowan, Hazel and Oak besides the shrub from which they take their name (Nigel Jones)

The Great Stink: with a name that serves as a very accurate description of their appearance, shield bugs, of which there are around thirty British species, are among the most common and easily identifiable of all the Hemiptera on the Weald Moors. Woodland edges and hedgerows with plenty of native trees and shrubs are a good place to start looking for common species such as the Green Shieldbug (Palomena prasina) and Hawthorn Shieldbug (Acanthosoma haemorrhoidale) which, despite a predilection for haws, also feeds on birch, rowan, hazel and oak. If you happen to find a Field or Dog Rose on your moorland travels, keep an eye out, too, for the distinctive purple and brown scutellum (a.k.a the aforementioned shield!) and black and white banded antennae of the Hairy Shieldbug (Dolycoris baccarum), an insect truly covetous of rosaceous plants! With a predilection for the sap of oaks and alders, the Red-legged Shieldbug (Pentatoma rufipes) is another colourful character you may encounter, although its legs can appear decidedly more orange than red. While you may be pleased to see it, a less auspicious welcome is almost certainly assured among the caterpillars to which this partly predatory insect is also partial!

Unlike dragonflies and craneflies, shieldbugs do not begin life’s journey in larval form but, instead, as wingless nymphs that hatch from clusters of eggs laid on the undersides of leaves. While they resemble adult insects from birth, each must go through a series of moults (known as instars) before reaching maturity. In common with a number of Heteropteran species, shieldbugs are known to exhibit parental care and can remain in familial groups for life. However, do be careful not to attribute every massed sighting of shieldbugs as some kind of family outing because these insects also mate (which typically occurs back-to-back) en masse, too! While shieldbugs are capable of overwintering in nymph and adult form they are, as outlined at the beginning of this article, an important source of chick food. Many Hemipteran species have developed lurid colouration to warn passing predators of their unpalatable taste but shieldbugs are also capable of secreting a foul smelling substance from glands on their thorax. Not only has it earned them the nickname of ‘stink bugs’ but the malodorous concoction is also endowed with the ability, it is said, to turn fruit sour!

Well, hello there! A group of Green Shieldbugs (Palomena prasena) caught in the act of mating (Nigel Jones)
In the Land of Giants? If you decide to take a late season walk on the Weald Moors, keep an eye on any willows and sallows you pass during your journey. Should you notice any dark patches on the undersides of the branches take a closer look, as you may have discovered a colony of Giant Willow Aphids (Tuberolachnus salignus). During winter, no other insects appear in patch-forming groups on willow species, where they feed on the sap contained in older stems and twigs (which are reached by gnawing the bark). Growing to a length of five to six millimetres, this insect’s name is well-earned as it is indeed, by aphid standards at least, very large — and quite unique. Dark brown, with a peppering of black spots, individuals are also endowed with a very distinctive tubercle that protrudes from the back like a tiny shark-fin or thorn. Autumn and winter find Giant Willow Aphids at their most active but a great deal of mystery surrounds what happens in early spring, when they disappear for several months only to return again in late summer. Currently, the whereabouts of these all-female colonies (which reproduce asexually) are unknown to science, so if you do happen to see where they go, pass it on… enquiring minds need to know!
Where do they come from, where do they go? The springtime whereabouts of the mysterious Giant Willow Aphid (Tuberolachnus salignus) are not well-known to science (Harper Adams University)

On the Weald Moors: searching specific locations, such as the verdant lanes of Kynnersley and Donnington Drive, or the vibrant wildflower meadows of Wall Farm, will almost certainly deliver sightings of True Bugs. However, you could take a more abstract approach to finding insects by focussing on more elemental moorland landscape features, such as low vegetation, for example. Some of the largest families of insects within the Hemipteran order, such as Miridbugs (also known as capsids, or grassbugs), Leafhoppers (Cicadellidae) and Groundbugs (Lygaeidae) exploit a wide variety of ground level flora, including nettles, brambles and grasses.

In many instances, identifying individual species will probably require a field guide at the very least (and, in others, a skilled entomologist!) but the ability to recognise general features can prove helpful; many Mirids, for instance, possess long slender bodies and wings that fold over the abdomen, creating a translucent diamond-shaped effect at the insect’s rear. Conversely, some True Bugs, such as the Creeping Thistle Lace Bug (Tingis ampliata), have specific host plants, while many others are associated with deciduous trees. So while the hedgerows, woodlands and pastures of the Weald Moors may not be part of the area’s ancient peat fenland heritage, they are certainly among the most varied and nuanced habitats on our modern day safari.

The Red-Legged Shieldbug (Pentatoma rufipes) is partially predatory and feeds on caterpillars (Nigel Jones)