where do fruit flies come from ?

Question

My colleague left an apple on his desk before vacation and someone found it, there are hundreds of fruit flies around it ?

Answer 1

If you see more than a couple of fruit flies, that means they're being born nearby.

Your colleague left an apple on his desk. A lone fruit fly found it and laid eggs on it. The eggs hatched. Enough time has gone by for metamorphosis, and so you now have a cloud of fruit flies. They're sticking around because the apple still smells good to them -- smells like a good place to lay more eggs.

Answer 2

Educational genetics kits!

Answer 3

Fruit Fly Identification

Fruit flies are small flies measuring about 1/8 inch in length, including their wings. Click here to see image of Fruit Fly. The key identifying characteristic of the fruit fly is its eyes, which are red in color. The head and thorax are tan in color with the abdomen somewhat darker. This fly is easily mistaken for the Phorid fly which has very similar markings but lacks red eye color. The Phorid fly also has a "humped back" appearance. Without the aid of a microscope or a good field magnifying glass, fruit flies would merely fall into the category of Small Flies, with elimination methods being similar for all flies in this category.

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Fruit Fly Elimination

Fly Elimination Products

The key to controlling fruit fly infestations is to locate and eliminate their breeding sources. Although there are several sprays and traps used to kill flies in a home, restaurant or other structure, the infestation cannot be eliminated without eliminating their source. A space spray (Pyrethrin spray) can be used as a quick kill, reducing populations of flying insects. Pyrethrin spray is also a crack and crevice tool that is used by pest control operators to spray the tiny areas where fruit flies and other insect pests breed. To monitor the area, use a Gold Stick trap. These traps use a fly sex lure to attract flies to their doom. Every fruit fly caught is one less breeding adult!
Professional fly traps use pheromones in combination with powerful ultraviolet bulbs in lighted fly traps. There are several sizes with varying power to choose from. Different designs offer options for the proper trap to be used in public areas, commercial kitchens, hospitals, offices and homes. The use of ultraviolet bulbs increases the numbers of flying insects captured while drastically reducing the need for use of sprays and other pesticides.
Use the powerful Fly Trap Professional in commercial kitchens or other areas that are not usually accessed by the public or your customers. In high profile areas, the Cento Fly Traps and Luralite Fly Traps are much more discreet.

If you locate a drain that is a breeding ground for fruit flies, use Drain Gel (Fly Gel) to destroy the film in which the fly eggs and larvae are developing. A surface spray is not recommended in this situation, unless there are great numbers of flies resting on the surface of trash cans, dumpsters or exterior walls. Fruit Fly Traps are also an excellent tool for capturing fruit flies. Attach the trap to the inside lid of garbage cans, dumpsters or compost bins to capture adult flies before they breed. Dispose of traps when full of flies or after 3 months. Click here to see fly elimination products. Inspecting the area for possible breeding sources is the key for fruit fly elimination.
Inspecting for Fruit Flies

When searching for fruit fly breeding sources, remember that the larva can only survive in decaying organic matter that is moist. The first obvious place to check is where any fruits or vegetables or stored outside of refrigerators or coolers. Other areas to inspect would be recycling bins, seldom used (or cleaned) garbage cans, underneath and behind large appliances. Do not overlook drains where small flies are often found breeding in the super thin layer or film of debris that naturally accumulates in pipes, traps and drains.

In commercial and residential structures, tiny amounts of organic debris are often found where the legs or feet of appliances, tables or cabinets touch the floor. These tiny spaces can harbor thousands of fly larvae. All small cracks and crevices at floor level need to be inspected and thoroughly cleaned.

Once one source has been located, continue with your inspection. Fruit flies easily follow air currents and usually have several breeding places in any structure. Do not assume that all of your breeding sources are indoors; fruit flies will wander in from nearby dumpsters, outdoor garbage cans or even damp compost piles where fruits and vegetables are disposed.

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Fruit Fly Biology

The fruit flies comprise several different species belonging to the genus Drosophila. The most common species encountered in homes and other structures is D.melanogaster. Fruit flies are also known as pomace flies or vinegar flies. These pests can be found throughout the world, in homes, food processing plants, warehouses, grocery stores, wineries, restaurants and other structures.
Life History of the Fruit Fly

Fruit flies develop by complete metamorphosis. The eggs (which are difficult to see with the naked eye) are deposited near the surface of fermenting fruit or organic matter. A pair of filaments that are attached to the eggs protrude above the surface of the liquid. The female fruit fly will lay about 500 eggs. The larvae emerge about 30 hours after the eggs have been laid and feed near the surface of the fermenting material. The larvae feed for five to six days then crawl to drier areas of the food source or even out of the food source to pupate. The larva transforms into the pupa in the last larval skin, or puparium, which bears a conspicuous pair of filaments on the anterior end. The adult fruit fly emerges several days later. The newly emerged fruit flies are attracted to light and become sexually active in about two days. The adults mate more than once. Under ideal conditions, the life cycle from egg to adult can be completed in as little as eight days. The sudden appearance of large populations is not uncommon inside buildings.

The complete dependence of all stages of the fruit fly on moist, decaying (or fermenting) organic materials is a key point to remember in inspection and elimination of fruit fly infestations.

The fruit fly breeds in and feeds on ripened fruits and vegetables, as well as moist, decaying organic matter. Fruit fly larvae living in fruit which is eaten can cause intestinal discomfort and diarrhea. In vinegar-producing facilities, the fruit fly is responsible for infecting tanks of vinegar with a tiny nematode called the vinegar worm.

Answer 4

larvae