Lonchaeid fly

Distribution

Canada

Micro-habitat(s)

Insect

Damage, symptoms and biology

This saprophagous insect, is a major facultative predator of the white pine weevil (Pissodes strobi (Peck)), found in the terminal shoot of certain conifers. It often occurs along with another trunk pest, the northern pine weevil (Pissodes nemorensis Germar). The lonchaeid fly generally lives in association with phloeophagous insects of the order Coleoptera (beetles).

The young larvae are saprophagous, feeding on the dead or dying larvae (weakened by disease or parasites), as well as on frass. As they, however, the larvae become predators, feeding on healthy prepupae and pupae on the host trees. Since the species has difficulty on its prey, it feeds on the immobile stages. A diet of live individuals allows the insect to grow faster.

One predator larva consumes more than three weevil pupae during its development. At high larval densities, this insect is one of the most effective natural enemies of the white pine weevil. However, the lonchacid fly may also feed on the larvae of other species of insects that parasitize weevil larvae.

This species has one generation per year; it overwinters under the bark in the larval stage and completes its development the following spring. The adults emerge beginning in late May and the females lay their eggs under bark already infested by other insect pests.

Life cycle (East of the Rockies)

Other information

Well established in North America, this species has a distribution that coincides with that of the white pine weevil and the northern pine weevil. This beneficial insect is closely associated with its prey and is found mainly in white pine, jack pine, red pine and Norway spruce plantations.

Our knowledge of the species comes mainly from research on the white pine weevil. At high population densities, the lonchaeid fly can eliminate up to 85% of the larval population of the white pine weevil.

Main host(s)

Conifer