The true bugs are insects belonging to a large order known as Hemiptera. I prefer to use the scientific name because many insects belonging to other orders are called bugs and also because for many people the word ‘bug’ has many negative connotations.
Entomologists do not fully agree about which insects can be classified as hemipterans. In the past two decades or so, their classification has changed and will probably change again as DNA studies reveal connections between different groups of insects that require their reclassification. In the latest classification, the Hemiptera consists of, among others, the cicadas, aphids, scale insects, assassin bugs and shield bugs.
In fact, the order Hemiptera consists of a wide diversity of insects that can range in size from one to 150 millimetres. Their only common features are their piercing and sucking mouthparts which most use to suck plant sap. A relatively small number of hemipterans are predators or parasites that feed on other small invertebrates.
Most hemipterans live on land although some have adapted themselves to live in or on fresh water. Hemipterans have an incomplete life cycle. Their nymphs resemble small wingless adults that grow in stages with every moult. The wings appear with the final moult.
Hemipterans can be both harmful and useful to humans. Some are important agricultural pests as they damage crops by sucking their sap or infecting them with viruses which they transmit while feeding. This happens because hemipterans inject a digestive enzyme in which there could be viruses into the plant to start digestion before they suck in the plant fluid.
On the other hand, some predatory or parasitic species are used in biological pest control as they destroy pests without farmers having to use harmful chemicals.
The cochineal, a scale insect native to parts of South America, is grown in large numbers as it produces a red dye known as carmine.
In the past there were attempts to cultivate this insect in the Maltese islands to start a new industry but none of them was successful.
This large group of insects is represented in the Maltese islands by several species, including the soldier bug which, for large parts of the year, can be seen walking on the ground in the vicinity of plants or walking on their leaves and flowers.