Why Are Female Fruit Flies Bigger Than Male Fruit Flies?

Fruit flies are attracted to rotting fruit.

Fruit flies, or drosophila melanogaster, are tiny insects that are often used for scientific research. The name fruit fly came about because the insects are often found surrounding rotting fruit or vegetables left out in a kitchen. They may also be found in restaurants, grocery stores, drains, garbage disposals and anywhere else with decaying food products.

Diet and Life Cycle

Fruit flies prefer a diet of yeast, which develops in fruit when it begins to decompose. Fruit flies most likely are already on the fruit in microscopic eggs when it is first taken into the home or restaurant, where they hatch if undisturbed for approximately 30 hours. Fruit flies can live on a diet of just about anything edible once they hatch, including residue in a sink drain or on a mop. Fruit flies live for eight days and females can lay up to 1,000 eggs during that time.

Anatomy of Fruit Flies

Fruit flies are commonly around 2.5 mm to 3 mm long and are commonly yellow, brown or black in color. Most species have red eyes. Female fruit flies are usually slightly larger than male fruit flies. Fruit fly larvae are commonly around 1 mm long and white. Fruit flies have a banding color pattern. Male fruit flies are solid black at the end and females having banding all the way down their backs. Male fruit flies have a rounded abdomen, while females have an ovipositor that is slightly pointy and used to lay eggs.

Gender Differences in Fruit Flies

Larger female fruit flies have been found to be more attractive to male fruit flies than smaller females. This may be because the larger females carry more eggs and have the opportunity to have more offspring in their life cycle. Due to natural selection, larger females may have better reproductive opportunities and therefore continue bringing larger females into the gene pool. Female fruit flies may be larger than males because they are carrying eggs as well.

Mating

Male fruit flies may court female fruit flies by using a mating call or song. They then follow the female fruit flies, exhibit licking behaviors, before finally entering into the copulation phase. Females can reject males by moving away before copulation occurs if they are not attracted to the male. Females store sperm from many different males to use to fertilize their eggs after they lay them.

Eradication

Prevention is important to avoiding fruit fly infestations. Keeping fruits and vegetables in a refrigerator may help avoid food decomposition and keep fruit flies away from the food items. Washing fruits and vegetables soon after bringing them into the home can help avoid the hatching of fruit fly larvae. Once a fruit fly infestation has occurred, throwing away the affected items and making sure that the area is clean will help to get rid of the problem.

References

• The University of Kentucky College of Agriculture: Fruit Flies
• Discovery Online: The Skinny on Where Fruit Flies Come From
• Michigan State University: The Importance of Size in Dipteran Mating System