Virgins are necessary for crosses, because you need to be certain that the sperm they carry are from the specific males you use to mate them. The heterozygotes are produced by crossing an all-homozygous dominant to an all-homozygous recessive.

d) Use the dissecting microscope to view the flies. Why was it necessary for the females of the parental generation to be virgins? To ensure controlled mating. Females store sperm in their receptacles and if they were not virgins, then we would not be able to tell who the fathers were.

Virgin flies are needed to make sure that that the crosses are being appropriately made with the females using the desired sperms to fertilize their eggs. Female Drosophila are considered virgin eight to ten hours after they hatch from their pupa because during that time they are not receptive to male companionship and …

Note that virgin females are much larger than older females and do not have the dark coloration of mature females. In addition, in the early hours after eclosure, there will be visible a dark greenish spot (the meconium, the remains of their last meal before pupating) on the underside of the abdomen.

about 25 days

Health Risks of Fruit Flies Some of the bacteria they may carry include salmonella, E. coli, and listeria. These three germs each cause food poisoning. Severe cases may put you in the hospital and can even be life-threatening.

Fruit flies are primarily nuisance pests. The longer a fly is on your food, the higher the chance of harmful bacteria, viruses and parasites being transferred to it. If a fly lands on your food and you swat it right away, the food will likely be safe to eat.

There’s a couple of things going on. First, flies, like all arthropods, have exoskeletons which protect them. If you aren’t “squishing” them, crushing the exoskeleton, you aren’t going to kill them. In other words, you need to hit them harder.

Fruit flies have no problem surviving in a fridge. One way to prevent infestation is to just wash your fruits before storing them in your fridge. However, if there are already swarms of the little insects in the fridge, then you can try trapping them with jar filled with vinegar or a mix of wine, soap and water.

Look first for fruit fly sources in areas where vegetables or fruits are stored outside refrigeration. Also look for fruit fly sources in garbage cans, under appliances, and recycling bins. Even a little-spilled juice behind an appliance can contribute to their breeding.

Infestations have to start somewhere. Fruit flies move into kitchens, bathrooms, and basements if they sense a food source. Overripe fruit on the counter or any fermenting matter in drains, mops, and trash bins appeals to them. Unsuspecting homeowners may also bring these pests inside on garden crops.

Fruit flies are especially attracted to ripened fruits and vegetables in the kitchen. But they also will breed in drains, garbage disposals, empty bottles and cans, trash containers, mops and cleaning rags. All that is needed for development is a moist film of fermenting material.

Clean the drains in your kitchen Do not use bleach. Since bleach does not coat the pipes, it will not kill the flies. It’s the bio-buildup that attracts fruit flies to your drains. It also gives them another place to lay their 500 plus eggs, other than on your fruit and in your plants.

Take the cap off the bleach bottle and pour bleach into the cap. Then pour the capful of bleach into the drain. That’s more than enough bleach to kill insects and their larvae inside the pipe. This will sanitize the drain and kill the flies and their eggs.

Scientists have found that at 60°F, the lifespan of fruit flies decreases. When the temperatures fall below 53°F, these flies stop developing entirely.