A pest is any organism harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environment for their own purposes and are intolerant of other creatures occupying the same space when their activities impact adversely on human objectives. Thus, an elephant is unobjectionable in its natural habitat but a pest when it tramples crops.
Carpet beetle larvae damaging a specimen of Sceliphron destillatorius in an entomological collection
Pests, such as these termites, often occur in high densities, making the damage they do even more detrimental.
Feral pigeons can become very numerous in cities.
Caltrop, Tribulus terrestris, is sometimes considered a pest plant because of its sharp spiny burrs, shown here in a person's foot.
A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. The wasps do not constitute a clade, a complete natural group with a single ancestor, as bees and ants are deeply nested within the wasps, having evolved from wasp ancestors. Wasps that are members of the clade Aculeata can sting their prey.
Wasp
Polistes sp., India
Megascolia procer, a giant solitary species from Java in the Scoliidae. This specimen's length is 77 mm (3.0 in) and its wingspan is 115 mm (4.5 in).
Megarhyssa macrurus, a parasitoid. The body of a female is 50 mm (2.0 in) long, with a c. 100 mm (3.9 in) ovipositor
