Bees are flying insects closely related to wasps and ants. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila. There are slightly fewer than 20,000 known species of bee, in nine recognized families,though many are undescribed and the actual number is probably higher. They are found on every continent except Antarctica, in every habitat on the planet that contains flowering dicotyledons.
Honey bees (or honeybees) are a subset of bees which represent a far smaller fraction of bee diversity than most people suspect; of the approximately 20,000 known species of bees, there are only seven presently-recognized species with a total of 44 subspecies (Engel, 1999; historically, anywhere from six to eleven species have been recognized). These bees are the only living members of the tribe Apini, all in the genus Apis, and all of which produce and store liquefied sugar ("honey") to some degree, and construct colonial nests out of wax secreted by the workers in the colony. Other types of related bees produce and store honey, but only members of the genus Apis are considered true honey bees.
An insecticide is a pesticide used against insects in all developmental forms. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind the increase in agricultural productivity in the 20th century. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans; and others are concentrated in the food chain. It is necessary to balance agricultural needs with environmental and health issues when using insecticides.