Flies

"Flies are so mighty that they win battles, paralyse our minds, eat up our bodies."
- Blaise Pascal

introduction

The blanket moniker 'flies' refers to insects in the order Diptera, which includes true flies, mosquitoes, gnats, leafminers, and midges. The order name is derived from the Greek words for two (di) and wing (pteron), referring to these insects having two sets of wings, though on most species today, the second pair have evolved into smaller, club-like appendages that assist with rotational movements, allowing these insects to perform advanced aerobatics.

Flies have mobile heads, equipped with a pair of large compound eyes and mouthparts designed for sucking or lapping. They have claws and pads on their feet, allowing them to cling to and climb smooth vertical surfaces with ease. These insects undergo complete metamorphosis, and typically have very short lives as adults. They are important insects to human civilization, both economically and ecologically. Flies are second only to bees in the list of major pollinators, and help us to grow most of the crop species we cultivate. They are also used in medicine in their larval stage to clean out wounds. While they can be helpful, other genera of flies can harm humans, such as horseflies, bot flies and mosquitoes, who also are vectors for disease.

Fly Behavior

Flies are found in almost all terrestrial habitats worldwide apart from Antarctica. Their vision allows them to see 360 degrees around their bodies all at once, and they can sense movement and make a decision to move within 100 milliseconds. This makes them very hard to swat, as many of us know. Flies typically feed on organic decaying material, including fruit, vegetables, meat, and excreta. Both male and female flies suck nectar from flowers, as well.

Flies will eat any decaying material.

Flies are some of the most important pollinators on the planet, and are attracted to flowers with nectar.

The larvae of some flies, such as bot flies, are carnivorous.

Although most species of flies are harmless to humans, there are some that can do physical damage. Mosquitoes, for example, are well-known for their proclivity for 'biting' humans and extracting blood. Deer flies and horse flies can also pierce skin to drink blood, and do so in a much more painful manner than mosquitoes. Other fly species that can pierce human skin and extract blood include yellow flies, biting midges, sand flies, snipe flies and stable flies.

Diptera Species

The order Diptera includes over 150,000 species, over 61,000 of which are common in North America north of Mexico. Flies represent the most diverse insect group in North America, and the various families are listed and described below, along with lists of representative species.

Asilidae (Robber Flies, Assassin Flies)
This group of flies are large insects. Most have a long, tapered abdomen with strong legs and a stout thorax. They have hairy faces, almost appearing bearded. These are highly predaceous flies, and often attack other insects, including bees, dragonflies, grasshoppers, and wasps while they are in flight. They capture their prey while flying, and then bring them to the ground for consumption.

Efferia pogonias
Yellow-Bearded Hammertail

Mallophora bomboides
Florida Bee Killer

Mallophora leschenaultia
Belzebul Bee-Eater, Black Bee Killer

Nemochtherus pallipes
Devon-Legged Robber Fly

Calliphoridae (Blow Flies, Carrion Flies)
Most of the organisms in this grouping are about the size of a housefly and are predominately metallic blue or green. They are commonly referred to as 'Blue Bottle' or 'Green Bottle' flies, and many are scavengers in the landscape. Their larvae live inside of carrion, excrement, and other similar materials. They perform an invaluable service to ecosystems, breaking down dead animals and other debris in landscapes. Their larvae are also farmed for use as a fishing bait, called gentles.

Calliphora livida
Blue Bottle Fly

Calliphora vomitoria
Bottlebee, Orange-Bearded Blue Bottle

Chrysomya megacephala
Oriental Latrine Fly

Chrysomya rufifacies
Old World Blowfly

Cochliomyia macellaria
Secondary Screwworm

Lucilia coeruleiviridis
Green Bottle Fly

Lucilia mexicana
Green Bottle Fly

Lucilia silvarum
Common Toad Fly

Lucilia thatuna
Green Bottle Fly

Phormia regina
Black Blow Fly

Protophormia terraenovae
Northern Blow Fly, Blue-Bottle Fly, Blue-Assed Fly

Culicidae (Mosquitoes)
These flies are known for their proclivity for sucking blood and transmitting diseases such as malaria, yellow fever, West Nile virus, and encephalitis. Females are the blood-suckers, male mosquitoes feed on nectar and other plant juices. Mosquito larvae are called wrigglers, and develop in stagnant water wherever it sits. There can be mosquito larvae in water-filled containers as small as the cap of a water bottle, where they feed on algae and other small aquatic plant life.

Aedes aegypti
Yellow Fever Mosquito

Aedes atropalpus
American Rock Pool Mosquito

Aedes canadensis
Woodland Pool Mosquito

Aedes communis
Woodland Snow Pool Mosquito

Aedes infirmatus
Silverback Mosquito

Aedes japonicus
Asian Bush Mosquito

Aedes notoscriptus
Australian Backyard Mosquito

Aedes sierrensis
Western Tree Hole Mosquito

Aedes taeniorhynchus
Black Salt Marsh Mosquito

Aedes vexans
Tomguito

Anopheles freeborni
Western Malaria Mosquito

Anopheles punctipennis
Woodland Malaria Mosquito

Culex erythrothorax
Tule Mosquito

Culex pipiens
Common House Mosquito

Culex quinquefasciatus
Southern House Mosquito, Quinx

Culex tarsalis
Western Encephalitis Mosquito

Culiseta incidens
Cool Weather Mosquito

Psorophora columbiae
Dark Ricefield Mosquito

Wyeomyia smithii
Pitcher Plant Mosquito

Drosophilidae and Tephridae (Fruit Flies, Peacock Flies)
These small flies don't usually exceed 3/16-inch long, and are yellow-tan in color with darker markings on their bodies and wings. They are typically found around decaying fruit and vegetation. Larvae will feed on yeasts that grow on decayed fruits.

Anastrepha grandis
South American Cucurbit Fruit Fly

Anastrepha ludens
Mexican Fruit Fly, Mexfly

Bactrocera cucurbitae
Melon Fly

Bactrocera dorsalis
Oriental Fruit Fly

Bactrocera oleae
Olive Fruit Fly

Ceratitis capitata
Mediterranean Fruit Fly, Medfly

Chaetorellia acrolophi
Knapweed Peacock Fly

Chaetorellia australis
Yellow Starthistle Peackock Fly

Drosophila melanogaster
Lesser Fruit Fly

Drosophila suzukii
Spotted-Wing Drosophila

Euphranta canadensis
Currant Fruit Fly

Eurosta solidaginis
Goldenrod Gall Fly

Leucophenga varia
Fruit Fly

Rhagoletis cerasi
Cherry Fruit Fly, European Cherry Fruit Fly

Rhagoletis cingulata
Eastern Chery Fruit Fly

Rhagoletis indifferens
Western Cherry Fruit Fly

Rhagoletis juglandis
Walnut Husk Fly

Rhagoletis mendax
Blueberry Maggot

Rhagoletis pomonella
Apple Maggot, Railroad Worm

Strauzia longipennis
Sunflower Maggot

Terellia fuscicornis
Artichoke Fly

Zaprionus indianus
African Fig Fly

Zeugodacus tau
Pumpkin Fruit Fly, Tau Fruit Fly

Muscidae (House, Stable and Muscid Flies)
This group of flies are injurious to humans and animals, and include a number of recognizable species, including the common house fly, stable fly, horn fly, and tsetse fly. Most flies in this insect family breed in excreta, decaying vegetation, or garbage.

Atherigona reversura Bermudagrass Stem Maggot

Coenosia attenuata
Hunter Fly, Killer Fly

Fannia benjamini
Canyon Fly

Fannia canicularis
Little House Fly

Haematobia irritans
Horn Fly

Haematobosca alcis
Moose Fly

Musca autumnalis
Face Fly

Musca domestica
Common Housefly

Stomoxys calcitrans
Stable Fly, Barn Fly, Biting House Fly, Dog Fly, Power Mower Fly

Syrphidae (Syrphid, Hover Fly, Flower Fly)
These flies closely resemble bees and wasps and are often mistaken for them.

Anasimyia chrysotoma
Lump-Legged Swamp Fly

Brachyopa caesariata
Plain-Winged Sapeater

Brachyopa cinereovittata
Grey-Striped Sapeater

Brachyopa daeckei
Black-Tailed Sapeater

Brachyopa flavescens
Yellow Sapeater

Brachyopa gigas
Giant Sapeater

Brachyopa notata
Black-Banded Sapeater

Ceriana abbreviata
Northern Wasp Fly

Chalcosyrphus curvaria
Yellow-Haltered Leafwalker

Cheilosia latrans
Steely Blacklet

Chrysogaster antitheus
Short-Haired Wrinkle Fly

Copestylum vesicularium
Irridescent Bromeliad Fly

Copestylum vittatum
Striped Bromeliad Fly

Eumerus strigatus
Onion Bulb Fly

Eristalinus aeneus
Common Lagoon Fly

Eristalinus taeniops
Band-Eyed Drone Fly

Eristalis bellardii
Mexican Mountain Drone Fly

Eristalis stipator
Yellow-Shouldered Drone Fly

Neoascia globosa
Black-Margined Fen

Neoasicia metallica
Double-Banded Fen Fly

Orthonevra nitida
Wavy Mucksucker

Parhelophilus laetus
Common Bog Fly

Sphiximorpha willistoni
Williston’s Wasp Fly

Syritta pipiens
Thick-Legged Hoverfly

Temnostoma alternans
Wasp-Like Falsehorn

Tabanidae (Horse Fly, Deer Fly)
This group of flies contains flies that suck blood. As in mosquito species, only the females have this appetite; males are only interested in pollen and nectar. These insects are frequently found around lakes, streams, and ponds, and buzz around people's heads.

Brennania belkini
Belkin’s Due Tabanid Fly

Diachlorus ferrugatus
Yellow Fly, Doctor Fly

Stonemyia tranquilla
Peaceful Stonian Horsefly

Stonemyia velutina
Velvety Stonian Horsefly

Tabanus americanus
American Horse Fly

Tabanus fairchildi
Fairchild’s Horse Fly

Tabanus nigrovittatus
Greenhead Horse Fly, Greenhead Fly, Greenfly

Tabanus punctifer
Western Horse Fly

Tachinidae (Tachinid Fly)
These hairy flies are typically as large or somewhat larger than house flies, and are parasites of other insects, mainly of Lepidoptera (Butterfly), Sawfly, and Beetle species. Females lay eggs directly on the body of their host on the body of their host, and when the eggs hatch, larvae burrow into the host and eat the internal organs. Parasitized insects typically die as a result.

Ormia depleta
Brazilian Red-Eyed Fly

Paradejeania rutilioides
Spiny Tachina Fly, Hedgehog Fly

Trichopoda subdivisa
Fringe-Legged Tachinid Fly

Tipulidae (Crane Fly)
These flies have long legs and look like overgrown mosquitoes, though they do not bite. They reach an inch or more at maturity, and are mostly found flying around ponds and streams bordered by tall grasses. Larvae live in aquatic environments, and some feed on plant roots, especially in lawn areas. Adult crane flies typically feed on flowers.