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Hemiptera; the true bugs
Although the word 'bug' is commonly used for almost any insect, the Hemiptera are the true bugs.
The order Hemiptera consists of three main suborders; Heteroptera, Sternorrhyncha and Auchenorrhyncha, with around 80,000 species worldwide and over 1,700 having been recorded in Britain. They are variable in form, but nearly all have piercing mouthparts, known as the rostrum, for sucking the juices from either plants or animals (depending on the species of bug). The adults usually have two pairs of wings, with the forewings in many cases hardened, although some species have reduced wings or no wings at all.
The Heteroptera number over 500 species in Britain. They have hardened bases to the forewings with membranous tips, while the hindwings are membranous throughout. The wings are folded flat over the abdomen and the antennae have up to five segments. The rostrum appears to arise from the front of the head, as there is cuticle behind it known as the gula.
Amongst others, this suborder contains the Pentatomidae (shieldbugs), Tingidae (lace bugs), Miridae (capsid bugs), Nabidae (damsel bugs), Anthocoridae (flower bugs), Lygaeidae (ground bugs) and the aquatic bugs such as the Notonectidae (water boatmen).
The Sternorrhyncha and Auchenorrhyncha may have hardened or membranous forewings, but they are usually uniform throughout. The hind wings are membranous. The wings are folded over the abdomen in a tent-like manner and the antennae are variable in the number of segments. The Sternorrhyncha and Auchenorrhyncha do not have a gula so the rostrum is set back underneath the head.
The Sternorrhyncha have the rostrum set far back (appearing to originate between the front legs) and have no more than two segments to the tarsi (feet) in adults. The Sternorrhyncha contains the Aleyrodidae (whiteflies), Aphidoidea (aphids), Coccoidea (scale insects and mealybugs etc) and similar species.
The Auchenorrhyncha have the rostrum below the head and have three segments to the tarsi of the adults. This suborder includes the Delphacidae (planthoppers), Cercopidae (froghoppers or spittlebugs), Cicadidae (cicadas), Cicadellidae (leafhoppers) and Membracidae (treehoppers).
The Hemiptera have a large economic effect on man. The planthoppers, aphids, scale insects and others are major pests of horticulture, agriculture and forestry and are the main vectors of plant pathogenic viruses. Some species are even human parasites (such as the blood sucking Common Bed Bug Cimex lectularius).
This is not the whole picture, as the Hemiptera are not all bad. Most bugs, because of their choice of food plants are not pests. Many of the predacious species have a positive effect on man, as they eat the larva and adults of invertebrates that are themselves agricultural pests.
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Bibliography
Chinery, Michael, Collins guide to the Insects of Britain and Western Europe, William Collins Sons & Co. Ltd. [HarperCollinsPublishers] 1986
Chinery, Michael, A field guide to the Insects of Britain and Northern Europe, William Collins Sons & Co. Ltd. [HarperCollinsPublishers] 1972
Dolling, W.R., The Hemiptera, Natural History Museum Publications, Oxford University Press 1991
Southwood, T.R.E. and Leston, D., Land and Water Bugs of the British Isles, (The Wayside and Woodland Series), Frederick Warne & Co.Ltd. 1959
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