The Characteristics of Insect Order Diptera

The insect order Diptera consists of the insects commonly known as true flies, mosquitoes, midges and gnats.  This order is made up of 130 families that contain over 98,000 species.  Although it is not the largest order of insects, Diptera is definitely the most infamous thanks in part to the mosquito and fly species that it contains. 

The Greek words di and ptera traslate to “two wings” which describes the number of wings found on species belonging to the order Diptera.  Unlike other insects like bees and wasps which have four wings, flies, mosquitoes, gnats and midges only have two wings that they are able to use for flight.  Their remaining two wings have been reduced to club-like appendages, which are known as halteres, are useless for flight but instead are used to maintain balance while the insect is flying.  It is the presence of two wings, rather than four, that define a fly or other insect belonging to this order from other winged insects.

Common characteristics that all members of Diptera share besides having two wings is that they all go through complete metamorphosis (egg, larva, pupa, adult).  The larva of Diptera differs from other insects as that they are legless and will either have a head with chewing mouth parts (culiciform) or no head with only rudimentary mouth hooks for feeding (veriform).  Culiciform-type larvae are typical in mosquitoes while veriform-type larvae are typical in true flies and are commonly referred to as maggots.  All Diptera larva live in aquatic or moist environments where they feed on plant and animal material. 

The order Diptera is split into two suborders which are Nematocera and Brachycera.  Nematocera includes the fine-bodied flies with long antennae such as mosquitoes, crane flies, and midges.  Brachycera includes the flies that are thicker in body size and have shorter antennae such as house flies, horse flies and robber flies. 

Families of Diptera can also be categorized into groups based on their behavior and/or lifestyle.  There are five main categories which include biting flies, the herbivores, scavengers, predators, and parasites.    

The biting fly group consists of all of the flies that are able to pierce and bite using mouth parts that are adapted to do so.  This group includes mosquitoes, horse flies, black flies, moth flies, no-see-ums, and the common house flies. 

The herbivorous group is made up of the flies whos larva eat plant material.  Fruit flies and gall midges are representatives of this group.

The scavenger group includes species that feed off of rotting and decomposing waste or other organic matter found in soil or dung during their larval stage.  Crane flies, blow flies, pomace flies and flesh flies are all part of this group.

The predatory species prey on other insects as either adults or larva.  Flies belonging to this group include robber flies, dance flies, bee flies and flower flies.

The parasitic group parasatize other organisms internally or externally as larva or adults.  This group includes marsh flies, bot flies and louse flies. 

All of these groups share the common characteristics of the order Diptera with their similar body and wing structure and complete cycle of metamorphosis.  Because of the many similarities that the members of this order share, many species of flies are extremely adaptable and can be found globally in every corner of the earth.  As long as they are able to find a suitable food source for the larva to feed from, flies will be able to survive and thrive just about anywhere.  Although many species are regarded as pests and disease carriers, there are flies that serve as important pollinators for many crops.  These beneficial flies too often take the backseat while their aggressive, disease spreading relatives are in the spotlight.