Diptera

The Diptera, or true flies, are a diverse order of insects that includes familiar species, such as house flies, mosquitoes, and fruit flies. The name “Diptera” refers to adults of this order of insects having only two wings (in Greek, di means “two” and ptera means “wings”).

Morphological characteristics of these insects:

• adults have a front pair of functional, membranous wings;
• the hindwings of adults are reduced and modified to a pair of balancing organs (halteres), which enable flies to be highly manoeuvrable in flight;
• larvae, sometimes called maggots, are conical in shape and usually legless, and have few distinguishing features;
• pupae are formed in a dark-coloured cocoon (puparium) formed by the larvae at the end of their feeding period; and
• the mouthparts of adult flies are adapted for sucking, piercing and sucking, or lapping, and dipteran larvae feed with piercing mandibles.

General biology and ecology

Flies develop by complete metamorphosis (holometabolous development). Their diet is highly varied. Those of interest in forestry and horticulture are defoliating leafminers (e.g., lilac leafminer), and various midges that form galls or other damage to needles (e.g., spruce gall midge and red pine needle midge) or to leaves (e.g., large oakapple gall). Perhaps more significant are flies that are predators and pollinators (syrphids) or form an important family (e.g., Tachinidae), which are very beneficial because they are parasitoids of many damaging insects.

Important families in the order Diptera that contain tree pests

Listed below are families from this order found in this database. Species listed within the families are linked to the site’s pest fact sheets.

Agromyzidae (leaf-miner flies)

• Lombardy leafminer
  Scientific name: Paraphytomyza populicola (Walker)

Cecidomyiidae (gall midges or gall gnats)

• Balsam gall midge
  Scientific name: Paradiplosis tumifex Gagné
• European pineneedle midge
  Scientific name: Contarinia baeri (Prell)
• Jack pine resin midge
  Scientific name: Cecidomyia resinicola (Osten Sacken)
• Ocellate gall midge
  Scientific name: Acericecis ocellaris (Osten Sacken)
• Red pine needle midge
  Scientific name: Thecodiplosis piniresinosae Kearby and Benjamin