Introduction to bugs

What is a bug?

The word “bug” is commonly used as an umbrella term for all creeping insects (and sometimes non-insects too), but in its strict sense it refers to the order Hemiptera. This order is often called the “true bugs” to help make the distinction. Many of the true bugs might superficially look like beetles or other insects, but there are some important structural differences. The most reliable of these as a differentiator is the piercing tube-like sucking mouthparts of the bugs, which differ from the chewing mouthparts of the beetles, for instance. The tube-like construction of the bugs is known as the rostrum and can be seen in the image to the right being employed by a Common Green Shieldbug to suck out juices from a rose hip.

The Heteroptera are a suborder within the Hemiptera. Two other suborders are represented in the UK’s fauna: the Auchenorrhyncha, which include the froghoppers, leafhoppers and planthoppers; and the Sternorrhyncha, which include the aphids, scale insects, and whiteflies. The Heteroptera can be distinguished from the other two suborders by the position of the rostrum, which arises from the front of the head in the Heteroptera but further back underneath the body in the other suborders. The Heteroptera include both aquatic and land-based species. This page is concerned with the latter group.

How diverse are the terrestrial Heteroptera in Hertfordshire?

At the national recording level, the terrestrial Heteroptera are split across two schemes:

Shieldbugs and allies: These include shieldbugs and squashbugs, as well as some other closely related taxa, and in all there are approximately 60 species in the UK. Around 30 species are known to occur in Hertfordshire, with two of these pictured to the right: the Hairy Shieldbug (below, left), which is named on account of it being covered with long hairs; and  the Box Bug (below, right), which was historically very rare (RBD1) – being known only from Box Hill, in Surrey, where Box trees are its foodplant – but is expanding its range.






Plantbugs and allies: These include assassin bugs, damsel bugs, ground bugs, lacebugs, plant bugs and stilt bugs, as well as other closely related taxa. There are approximately 425 species in the UK, with around 240 known to occur in Hertfordshire. While herbivory is the norm in these species (as is also the case with the shieldbugs and allies), there are a small number of blood-sucking parasites and some predators too. One of the predatory species that occurs in Hertfordshire is the Tree Damsel Bug, which is pictured right.

Why might I want to record terrestrial Heteroptera?

Recording is at the heart of the society’s activities and its purpose includes tracking how wildlife is responding to the changing environment over time. It is important for as many taxa as possible to be covered in the recording efforts, and, for reasons presented below, the terrestrial Heteroptera may be a particularly good taxon both for existing recorders aiming to extend the breadth of their skills or for new recorders looking to find somewhere to gain a foothold.

1. Enjoyable to photograph: Many species are attractive and fairly easy to photograph, owing to stunning coloration and a restricted tendency to take to the wing. The Brassica Bug, shown below, is perhaps one of the most visually appealing species of all and occurs in several different colour forms.

The attractive patterns seen in many terrestrial Heteroptera species are not unique to the adult stage but often occur in the pre-adult stages too. Like dragonflies and a few of the other more primitive insect groups, the bugs are hemimetabolous, meaning that the transition from egg to adult occurs gradually through a series of moulting nymphal instars. The stunning final instar nymph of the Southern Green Shieldbug is shown to the right. This particular individual was part of a group of approximately 20 nymphs first identified by Paul Davis, in September 2014, and subsequently highlighted to the society by Martin Parr; along with another record from the same month, they are believed to constitute the first formal reports of the species in the county.

2. Relatively simple: As can be seen from the diversity of shieldbugs and allies in Hertfordshire described above, the challenge of getting to grips with this set of species is not as daunting as it might be for many other insect taxa. Moreover, reliable discrimination between species, at least for the adult stage, can in many cases be performed without the need to collect a specimen for microscopy or even to use a traditional key. This also applies to a certain extent for the plant bugs and allies (but it should be borne in mind that these species outnumber the shieldbugs and allies by an order of magnitude). High-quality close-up photographs with accompanying sighting notes are valuable as records, although, as is described here by Tristan Bantock (national recording scheme organizer for shieldbugs and allies), there is significant additional value in the collecting of specimens.

3. Understudied: While much is known about the terrestrial Heteroptera, compared with some of the other insect taxa they remain relatively understudied. This means that there are many discoveries waiting to be made, particularly concerning foodplants but also on their behavioural ecology. Among the evolutionary adaptations that have already been described within the terrestrial Heteroptera, there are a number of noteworthy examples for species known to occur in Hertfordshire. For instance, in the Parent Bug (Elasmucha grisea), the male dies shortly after mating but the female survives to brood the eggs in a remarkable demonstration of parental care. Another example is mimicry. In what is one such case, it is believed that the Blue Shieldbug (Zicrona caerulea) employs aggressive mimicry to help it prey on leaf beetles in the genus Altica.

This page has been written by Joe Gray, our new Hertfordshire recorder for terrestrial heteroptera. If you have any records to submit or any queries relating to terrestrial heteroptera in the county, please contact him by email.