There are many important pollinating insect species in the orders:
- Hymenoptera (bees, wasps, and ants)
- Lepidoptera (butterflies and moths)
- Diptera (flies)
- Coleoptera (beetles)
As adults these insects feed on pollen and/or nectar from flowers. They forage from plant to plant and may initiate pollination
by transferring pollen from an anther
to a stigma
. Female bees (Apoidea) and pollen wasps (Masarinae) provision their nests with pollen and/or nectar that they actively collect onto their bodies. Their larvae then feed on the collected pollen and nectar. Yucca moth (Prodoxidae) larvae do not feed on pollen or nectar but on the seeds of yucca plants
. The adults pollinate the yucca plant by actively collecting pollen onto their palps and then placing the collected pollen on a receptive stigma to ensure proper seed set for their offspring.
Pollinators are usually multi-habitat insects, requiring resources found in different habitats at different times. For instance most pollinating insects require:
- Nest sites (many bees and wasps)
- Larval feeding sites (beetles, butterflies, moths, flies, and some wasps)
- Hunting sites (some wasps and flies)
- Over-wintering sites
Furthermore, all of these sites must occur in areas with optimal (or at least tolerable) light, temperature, and humidity levels, and perhaps have relatively low densities of natural enemies. The dependence of native pollinators on the appropriate habitats must be recognized . Populations will not persist in a habitat if all life stage requirements are not met. A bumble bee species might require abandoned rodent burrows for nest sites and a particular range of flower types as pollen and nectar sources. Many solitary bees and wasps require specific nesting substrates (e.g., soil banks, decaying wood), as well as a variety of materials for nest construction such as mud, resin, leaves, plant hairs, or pebbles. These resources support the pollinator populations, and in return, the pollinators aid in the reproduction and maintenance of genetic diversity of the plant community and interact with other organisms as prey or host items.