Flies مگس ها

Flies are one of the major success's of the insect world, and the 120,000+ species are divided into three sub-orders:

The Nematocera, (larva with complete head and horizontally biting mandibles).

The Brachycera, (larva with incomplete head and vertically biting mandibles).

The Cyclorrhapha, (larva with vestigial head).

These in turn are divided into about 100 families.

Flies can be found in most places in the world, and the common house fly Musca domestica has followed mankind to every corner of the earth.

Flies have a holometabolous life cycle meaning that the egg hatches into a small grub like creature which don't look anything like a fly at all. The larvae eats and grows and occasionally sheds its skin until it is big enough to make an adult fly, then it pupates.

Flies are great opportunists and as adults they also eat a great variety of foods. The mouth parts of adult flies are all designed either for sucking and sponging, or piercing and sucking. No adult fly can chew its food. Biting flies actually should be called stabbing flies.

Flies have been of incredible importance to mankind all over the world, and it is possible to say that on many occasions it has been a fly which has changed history. This is because many of the primary diseases of man are transmitted by flies. (This means the disease is actually caused by a bacterial, viral or protozoan agent which spends part of its life in a fly and gets into the person when a fly pierces that persons skin).

2 examples are:

1. Malaria (believed to have killed more human beings than any other known disease and is still a major cause of illness in many countries).

2. Yellow Fever.

Spiders and Flies

Though everyone thinks of spiders feeding primarily on flies, the spiders don't always get it all their own way. A Dance Fly Microphorus crassipes (Empididae) steals much of its food from the spiders own web. Robber Flies (Asillidae) have been observed catching and eating spiders which were sitting on a blade of grass. A whole family of flies, the Cyrtidae (about 250 species) are all internal parasite of spiders during their larval life. The eggs are laid on the ground and the first instar larva wait on damp vegetation for a passing spider. They leap up and attach themselves to the spiders body where they slowly eat their way through its cuticle before eating the spider from the inside out.

Crane-flies (Tipulidae)

These are one of the most easily recognized groups in the nematocera and are commonly called Daddy-Long-Legs or Mosquito Hawks (where they are often erroneously believed to feed on mosquitoes). They are a diverse group of flies characterized by their long legs and thin bodies and long thin wings. A bit like larger mosquitoes except that the adults are flower feeders and not blood suckers. Larval crane flies are commonly called 'leather jackets' and live in the soil where they feed on plant material, particularly grass roots which tends to make them unpopular with gardeners.

Land Midges (Mycetophilidae, Sciaridae, Bibionidae and others)

Over 2,300 species Worldwide

The Mycetophilidae and Sciaridae are small inoffensive and delicate little flies which, though found all over the world in basically terrestrial habitats, have mostly been recorded from temperate zones. The larva feed predominantly on dead and rotting vegetation though some prefer fresh fungi, hence the Mycete in Mycetophilidae and are often called Fungus gnats.

The larvae of many species are capable of spinning a delicate web of silk from special labial glands in their heads, which generally are used to help them move about. The best known and most unusual of these are the 'Glow Worms' of the famous 'Glow Worm Cave' at Waitomo in New Zealand. These are really the larvae of Arachnocampa luminosa which hang from the ceiling of the cave and use their light to attract the Chironomids which breed in the caves. They then become tangled in the pendulous sticky threads of silk let down by the larvae.

Water Midges (Chironomidae and others)

Over 2,000 species Worldwide.

You have probably seen these little flies in the late spring and early summer swarming in the evening over the edges of ponds and streams. The males gather in these swarms where they fly round and around for hours waiting for a female to arrive. When a female arrives she flies in with the males until she finds one she likes and the pair then the pair go off to the bushes to mate.

Black-Flies (Simulidae)

Many of these are small compact flies with a bad name for biting "stabbing and sucking" commonly known as buffalo-gnats and turkey-gnats as well as black-flies. Many of them transmit diseases to the animals they feed on. The females bite to suck blood to mature their eggs. Sometimes this can be serious or even lead to death. In 1923 20,000 domestic cases of diphtheria were reported (horses, cattle, goats and sheep) in Rumania, Bulgaria and Yugoslavia by the Golubatz fly.

The larvae are filter feeders living generally in fast flowing streams where they hang onto the rocks and stones on the stream bed filtering out small particles of food with a set of bristles around their mouths. Not all live on rocks though. Some live on other animals treating them as a substrate. Simulium reavei live on the crab Potamen niloticus. The larva of simulids are amazing in that they each manufacture a safety line of silk and attach it to the rock they are standing on before they start feeding. Then if they get washed off, all they have to do is to climb back up their safety line to get home safely.

The Brachycera

These are the second main stem in the evolution of flies. Many of them are stockier and more solid than the nematocera and some of them are exceptionally good fliers. The first major group are the Horse- flies.

Horse-flies (Tabanidae)

3,500 species Worldwide.

Small horseflies, 6-10mm, are generally of 2 genus's Haemotopa which has banded eyes and spotted wings and Chrysops which spotted eyes and banded wings. Larger Horseflies, 10-25 mm, are generally of the genus Tabanus.

The larvae of some tropical Horse-flies create little cylinders of mud by descending in a spiral 2-5 cm wide and 5-13 cm deep. They then crawl into the cylinders and eventually pupate. As the mud finally dries and cracks across the whole pond the pupae are protected from desiccation because the smallness of the cylinders prevents them from cracking open in a large way and exposing the pupae buried with the soil.

Robber-Flies (Asilidae)

Over 4,000 species Worldwide.

The larva of Robber-flies are believed to be mostly herbivorous (vegetarian) but the adult flies are highly active carnivores. They specialize in hunting down other insects, usually in flight. They have long spiny legs in which they hold their prey as they pierce it with their powerful proboscis in order to suck it dry on the wing.

Both sex's look exactly alike in most species having huge bulbous eyes separated by a trough at the top of the head. They also have a special collection of outwardly projecting hairs between their eyes and the proboscis to protect their eyes from the struggles of their victims. Robber-flies are not fussy about what they eat - Moths, ants, ichneumon-flies, wasps, bees, beetles, dragonflies, termites, horse-flies and smaller robber-flies.

Soldier Flies (Stratiomyidae)

1,500 species Worldwide.

These are generally rather pretty flies which can often be seen sitting on flowers during the summer. The adults are pollen or nectar feeders. The larva which eat a mixture of rotting vegetable and animal matter are unusual in having their skin thickened with calcium carbonate.

Dance Flies (Empididae)

3,000 species Worldwide.

Dance flies look and act like Robber-flies. They can be distinguished by their less bulging eyes and the lack of the trough between their eyes, and the fact that their larva are carnivorous as well as the adults. They are called Dance flies because they can often be seen flying low over the water in a twisting spiraling manner that to our eyes looks much like a dance.

Dance flies are also of interest because of their courtship. Because of their predatory nature the males often feel it is advisable to offer the female a gift of food to keep her occupied while the mating is occurring. In the least complicated species the male simply offers the female an insect he has caught.

In more advanced species the male wraps the gift in a ball of cotton spun from special glands in his front legs, and in some decadent species the male offers the female an empty ball of silk safe in knowledge he will have done the deed and escaped before she catches on to his deception.

The Cyclorrhapha

These are the most evolutionarily advanced flies with mostly maggot like larva. They are generally short and stocky and covered in short hairs.

Coffin-Flies (Phoridae)

These are remarkable ugly little flies (between 6mm and 0.5mm long). Renowned for the fact that some species of them can live for a year or more and produce numerous generations inside fully interred coffins where they feed on the dead bodies within.

Within the family Phoridae is the tribe Termitoxeniinae which live in Termite nests and are amazing in how short their larval life is. The first stage instar's molt immediately after hatching, the second stage does not eat and molts shortly after this and the third stage has been completely suppressed, thus the whole larval life lasts less than one hour and in some species only a few minutes.

Hover-Flies (Syrphidae)

Hover-flies are some of the most attractive and noticeable flies around. They are also as their name implies incredibly good at flying and hovering. Many Hover-flies are clever mimics of Bees and Wasps.

Volucella bombylans which exists in two forms, a yellow tailed form which looks like Bombus terrestris and a red tailed form which looks like Bombus lapidarius , though they themselves cannot bite or sting.

As larva, Hover-flies feed on a great variety of substances, from cow dung to living plant material to aphids. In fact so many Hover-fly larva eat aphids that, like the lady-beetles they are well known as a gardeners friend. Not only are Hover-flies useful because they eat aphids but they are also the second most important group of insect pollinators, after the Bees and Wasps.

Fruit-flies (Drosophilidae)

These are the small flies with light red eyes that you find in the kitchen in Summer when ever some fruit has become over ripe. Once you get some in your house they tend to fall into your drinks especially beer, wines and fruit juices. The genus Drosophila contains more than 1,000 species some of which have a two week life cycle and are commonly found in Universities and Colleges around the world where they are used for experiments in the study of genetics and in Pet Shops where they are sold as food for baby Spiders and Preying Mantids.

House-flies (Muscidae)

The Common House-fly Musca domestica has two large orange spots on its abdomen, and it's larva lives in rotting vegetable matter and dung.

The Lesser House-fly Fannia canicularis has four small orange spots on its abdomen and tends to fly around and around in circles in your living room.

Louse-Flies (Hippoboscidae, Streblidae and Nycteribiidae)

674 species Worldwide

The Hippoboscidae (197 species) are all parasites of mammals and birds. The adults all feed on fresh blood and after their initial dispersal seldom leave their host or its nest/lair though most of them are winged and can fly quite well.

The larva live their entire life inside the adult female who 'lays' pupa which in some bird parasites lies in the nest over winter, hatching in time to crawl onto the returning adults as they reoccupy the nest. The adults are nearly all flattened ugly looking things with strong clasping legs and a crab like gait.

The Streblidae (256 species) are much the same as the Hippoboscidae except that they only live on bats, and then only where the winter temperature remains above 10C and most stick their mature larva onto the walls of the caves where they live to pupate rather than dropping them to the ground.

The Nycteribiidae (221 species) are the worlds ugliest flies and look more like spiders. Like the Streblidae they are confined to bats as hosts and they stick their larva to the surroundings, however they are completely wingless and are totally dependent on their hosts for transport as well as for food