Find out about ants, why they are a pest, and how to get rid of them
Insects are thought to represent around 90% of the diversity of animal life on earth. There are over a million currently described species and an estimated 10 million species in total.
The majority of insects have wings in the adult stage and move around mainly by flying. Some insects, such as cockroaches, have wings but are reluctant flyers, preferring to crawl to find food and shelter. Termites and ants are mainly wingless, so most of their behaviour involves crawling, and produce ‘reproductives’ that are temporarily winged during a short breeding season.
Other insects, such as the flea and louse, are wingless and can only crawl or jump to move around. Crawling insects here refers to insects that are perceived as pests mainly due to their crawling behaviour.
Insects are distinguished by having an exoskeleton with a three-part body, consisting of: a head with compound eyes, a pair of antennae and very variable mouthparts; a thorax with six legs and often one or two pairs of wings; and an abdomen.
Most insects go through a life cycle starting with eggs and a series of developmental stages or moults, before they reach their adult stage. This is typically egg, larva (eg caterpillar, maggot), pupa (often sealed in a cocoon) and adult, which often has wings.
Other arthropods, the arachnids (spiders, ticks, mites, scorpions) and the Myriapods (centipedes) are all wingless so only move around by crawling. They are characterised by having two body sections, the cephalothorax (fused head and thorax) and abdomen with eight legs. Ticks and mites have a similar life cycle to insects, with egg, larva, nymph and adult stages. Spiders and scorpions produce eggs and progress through larval stages in the egg, hatching as small immature adults that have to go through several moults to grow to the adult size. These are included with the crawling insects for convenience.
Crawling insects and arachnids are regarded as pests for a number of reasons:
Ants are generally more of a nuisance than a danger, though they can sting and a can few bite. Different species of ant sting with a range of chemicals, including formic acid, alkaloids and piperidines.
Ants can invade homes, other buildings, and gardens to forage for food and build nests. They are not known to transmit diseases. Out of the thousands of species of ant worldwide, there are only a few ant species that are regarded as pests in each country.
Bed bugs bite to feed on blood, often producing an itchy bump on the skin. They tend to form colonies in small hidden places in bedrooms and furniture where humans are still for long periods. These include bed frames, carpets and underlay, drawers and cupboards. You are most likely to pick up bedbugs from a hotel where they can crawl into your luggage or clothing. However, they are not known to transmit diseases.
Cockroaches carry a large number of disease-causing organisms that can contaminate food and surfaces, including Salmonella. They also produce particles that produce allergic reactions, causing asthma. They are one of the most serious pests of homes, food processing factories, restaurants, and healthcare facilities worldwide.
Textile pests can be found in products of animal origin including wool, silk, animal hair, leather and feathers. They can damage products such as clothing, carpets, upholstered furniture and tapestries. The pests include moths and many beetle species that feed on the protein keratin that is found in animal products.
Mites are a highly diverse group with many species that are parasites of plants and animals. A relatively small number are regarded as pests for causing diseases in humans and domestic animals — including bees — and for infesting food products.
Grain or flour mites are important pests of cereals, and dried fruits and vegetables [Link to food product pests]. Diseases caused by mites include scabies and asthma — which is caused by particles produced by dust mites.
Of the many thousands of spider species worldwide very few cause problems for humans. The main problem is unsightly cobwebs that are considered unacceptable around homes and businesses, as well as people’s fear of spiders. In temperate countries they may seek shelter in houses in autumn as the temperature drops.
Businesses, organisations and homeowners need to control insect pests to: