Dr Drosophila

Kelly’s Field Notes

Common Name: Fruit Flies, Vinegar Flies, Pomace Flies, Banana Flies

Order: Diptera

Family: Drosophilidae

Genus: Drosophila

Species: melanogaster

A few species near you (There are about 4,000 species of flies in family Drosophilidae):

• Drosophila melanogaster - if someone says “fruit fly” this is the fly you are likely thinking of! Common in biology and genetic research, they are found on every continent except Antarctica.

•  Drosophila subobscura - originally discovered in the Mediterranean, but has since spread to North America, Europe, and parts of South America. It is a common model organism in evolutionary biology research.

• Scaptomyza flava - commonly found across Europe, North America, and Asia, it is a common model organism for research on the evolution of herbivory in insects.

• Drosophila suzukii - originally discovered in southeast Asia, it has since become a pest species in North America and parts of Europe. 

• Drosophila hydei - like melanogaster, this species is commonly used as food for reptiles and other small insectivores kept as pets. A flightless mutation is popular!

Description: 

Fruit flies are small, usually around 3 mm (⅛ in) in length. They have yellow-orange, yellow-brown, or brown-black bodies and usually red eyes. Some species have orange eyes. There are also mutant species, usually lab reared, with sepia or white eyes or even eyeless. Adults are sexually dimorphic. The larvae are cylindrical maggots and slightly smaller than adults. Pupae look similar to the larvae, but a darker color and immobile. 

Life Cycle: 

Fruit fly females lay their eggs on rotting fruits and vegetables after being attracted by the smell of fermentation, as many as 500 eggs at a time. The larvae will hatch in about 24 hours then begin feeding on fungi and bacteria found on the rotten fruit. They are very sloppy eaters! By the time they are ready to pupate (after 4 to 5 days) the fruit is mushy and wet. The larvae head to dry ground before pupation. Pupation takes place for another 3 to 4 days before they emerge as adults. The average lifespan of a fruit fly adult is about 50 days. Once the flies emerge as adults they can mate within a few hours and females can lay eggs within 24 hours! As with some other insects we’ve covered, fruit flies have elaborate courtship rituals. If you have struggled with fruit flies in your home, the best way to control them is to eliminate the breeding areas – usually old fruit or organic particles in a drain. Many fruit fly traps use vinegar, a product of fermentation, to lure in the adult flies and reduce reproductive success.

Fruit Flies and Science:

Fruit flies are very commonly used in research! We have been using them as model organisms for over 100 years. The first famous fruit fly study was done by Thomas Hunt Morgan at Columbia University in 1910. He was interested in how traits are inherited from parents to offspring. Using Drosophila melanogaster as a model, he bred thousands of fruit flies looking for mutations. When he found a white-eyed male, he bred him with red-eyed females. In the first generation there were no white-eyed offspring, but in the second generation it was a 3:1 ratio of red eyes and white eyes with the only white-eyed offspring being a male. This not only correlated with Mendel’s recessive trait theory, Morgan proposed some traits are sex-linked, as only males moving forward were white-eyed. This also led to the discovery of chromosomes. Morgan won the Nobel Prize in 1933.

Speaking of chromosomes, we often use fruit flies in research because they have very few chromosomes. They have five chromosomes (X, 2L, 2R, 3L, 3R, and 4). They also have a fairly small genome, containing 14,000 genes. For comparison, humans have about 25,000 genes and 46 chromosomes. The genes of fruit flies are easy for scientists to manipulate, giving them insight into how traits are inherited and how specific mutations affect how a fly might look or behave. Their small genome also allows for the tagging of proteins and understanding what happens when a gene is turned on or off. The fruit fly genome was one of the first to be sequenced. The short turn over between generations, easy matchmaking, and ease of care make them ideal laboratory animals.

Scientists use fruit flies as models for understanding how human genetics work, as we share 60% of our genes with them. This has led to breakthroughs in medical science, such as how tumors form and spread and how insulin signaling works (fruit flies have their own version of insulin). And despite having tiny tube-shaped hearts, fruit flies have also been incredibly helpful in understanding which genes control heart function. The brains are small enough that we have mapped them to better understand how neurons interlink to form complex behaviors. There are nearly endless studies all about how fruit flies have changed human lives!

Fun Fruit Fly Gene Names:

Cheap Date - flies are very attracted to alcohol

Clown - adult eyes are a mosaic of white and red (increased pigment cells)

Dachshund - adult flies have short legs

Halloween - a family of genes called spook, ghost, shadow, shade, shroud, disembodied, mummy, and phantom 

I’m Not Dead Yet - this gene supposedly doubles a fruit fly’s lifespan, though this is hotly debated

Ken and Barbie - adult flies have no external genitalia

Lush - flies are very attracted to ethanol, propanol, and butanol

Sonic Hedgehog - the gene is important in the shaping of the fly body. There is an inhibitor gene called Robotnikinin.

Swiss Cheese - the brains of adult flies are full of holes (vacuoles), used to study Alzheimer’s. 

Tinman - flies with this gene have no heart

Van Gogh - a swirl of hair on an adult’s wing, resembling Van Gogh’s style of painting.

Super Powers:

• Flight

• Cosmopolitan - they love both alcohol and traveling the world. Fruit flies can be found almost anywhere humans are present

• Clean up Crew - fruit flies help decomposition in rainforests

• Never Alone - quick propagation means fruit flies are always ready for a team up!

• Easy going - you may have kept fruit flies as pets by accident. Fruit flies are easy anesthetized for examination with products like FlyNap 

• Sense of humor - there is a long history of geneticists using fruit fly genes for jokes

• Mutations - honorary members of the X-men?

References:

British Heart Foundation. “Fruit Fly Helps Warwick Scientists Understand Human Heart.” Bhf.org.uk, British Heart Foundation, 17 Apr. 2023, www.bhf.org.uk/what-we-do/news-from-the-bhf/news-archive/2023/march/fruit-fly-helps-warwick-scientists-understand-human-heart. Accessed 26 Apr. 2025.

“Fruit Flies - Oklahoma State University.” Oklahoma State University Extension, Extension.okstate.edu, 26 Apr. 2021, extension.okstate.edu/programs/digital-diagnostics/insects-and-arthropods/fruit-flies-drosophila-sp./.

“Fruit Fly Research Solves Human Disease and Fuels New Cancer Immunotherapy Approach.” News-Medical, 5 Jan. 2024, www.news-medical.net/news/20240105/Fruit-fly-research-solves-human-disease-and-fuels-new-cancer-immunotherapy-approach.aspx.

Miko, Ilona . “Thomas Hunt Morgan and the Discovery of Sex Linkage | Learn Science at Scitable.” Nature, Nature.com, 2008, www.nature.com/scitable/topicpage/thomas-hunt-morgan-and-sex-linkage-452/.

“Researchers Use Fruit Flies to Unlock Mysteries of Human Diabetes.” News Center, 2025, med.stanford.edu/news/all-news/2014/08/researchers-use-fruit-flies-to-unlock-mysteries-of-human-diabete.html.

“Why Do Scientists Investigate Flies?” Max Planck Gesellschaft, www.mpg.de/10973625/why-do-scientists-investigate-fruit-flies.

Wikipedia Contributors. “Drosophila Subobscura.” Wikipedia, Wikimedia Foundation, 14 Aug. 2024.

Wikipedia Contributors. “Drosophila Suzukii.” Wikipedia, Wikimedia Foundation, 28 Apr. 2023, en.wikipedia.org/wiki/Drosophila_suzukii.

‌Wikipedia Contributors. “Scaptomyza Flava.” Wikipedia, Wikimedia Foundation, 30 July 2024.

Wolf, Matthew J, and Howard A Rockman. “Drosophila melanogaster as a model system for genetics of postnatal cardiac function.” Drug discovery today. Disease models vol. 5,3 (2008): 117-123. doi:10.1016/j.ddmod.2009.02.002