When Stella Cho ’19 (CLAS) puts the metal tip of the gas-filled tube into a foam-capped plastic vial filled with fruit flies, the tiny insects fall asleep almost instantly.

She carefully taps them out onto a white fly sorting plate. It’s also emitting carbon dioxide, keeping the flies in their state of peaceful slumber while she uses a tiny, soft-bristled paintbrush to sort them.

Examining the flies through a microscope, Cho’s trained eyes make quick work of her task. Male flies to one side, female flies to another – the males and females look completely different when you see them up close like this, once you know what to look for.

Once the flies are sorted, back into their separate, warm, cozy vials they go, where they pop back awake.

These laboratory-raised fruit flies, or Drosophila melanogaster, are both similar and dissimilar to the clusters of tiny, winged nuisances that populate our kitchens when a bunch of overripe bananas sits on the countertop just a little while too long.

They live about the same amount of time – about 70 days, at the longest. They all start as eggs laid by a female, who can produce up to 70 eggs a day during the first month of her life. They all progress through three instar stages, form pupae, and emerge as adult flies in an egg-to-adult process that takes about nine days.

“The fly actually has very high reproductive capacities,” says Jianjun Sun, Cho’s mentor and a professor of physiology and neurobiology at UConn.

“That’s why if you have one female in your kitchen, two weeks later, you have so many flies in your kitchen,” Sun explains. “They have really good, high capacity for reproduction.”

Unlike the flies in your kitchen, the thousands of winged wonders in Sun’s lab at UConn have been specially bred so that they have different mutations allowing for the study of individual attributes.

“We can manipulate those mutations in a very specific cell type or a very specific time point, so then you can study those processes, study those genes and their specific functions,” Sun says.

And those studies are important.

Because despite how tiny they are, despite the differences in how they are born and how they develop, fruit flies are strikingly similar to mammals – including human beings.

“About 70 % of Drosophila genes, or fruit fly genes, actually have human homologs,” says Sun. “So, we can study those genes in the flies, and we can find out what are the conserved functions between the fly and mammals.”

In Sun’s lab, the fruit fly functions that researchers care the most about center around that high-capacity female reproduction.

The way a fruit fly ovulates is similar to how a mammal ovulates – utilizing some of the same genes and the same processes – but the speed at which they do so allows researchers to analyze those processes, replicate them, and isolate the mechanisms at work in ways and at a pace that are impossible to study in humans.

A lot of what is known today about how ovulation and reproduction occur within a female organism started with what scientists have learned from studying fruit flies.

“Women’s reproduction – actually, it’s become a pretty important aspect right now. People are putting a lot of focus and emphasis on this area, because it’s a really neglected area,” says Sun. “In female reproduction, a lot of people focused on the ovaries – how the egg is developed, how the follicle develops – and there’s also people focused on the uterus, because the uterus is important for pregnancy.

“But a very big, neglected area is actually the oviduct.”

It’s only been within the last decade that researchers discovered that oviduct secretory cells are the cell-of-origin for ovarian cancers, Sun explains.

“So, that really ignited the whole field trying to get into this area to find out what’s going on,” he says.

That’s where the flies play an important role in his own research, but they’re critical in other areas of scientific study as well.

Research into central nervous system disorders, like Parkinson’s disease. Stem cell research. Questions about metabolic processes.

In almost every aspect of biological questions, Sun says, the flies can be used as a system to study, offering the opportunity to find causal relationships, identify gene systems, screen potential drugs and treatments, and identify genetic tools.

They’re even a great model organism for undergraduates to use to learn scientific methodologies and explore their own research questions – fast, inexpensive to maintain, and easy to learn how to work with.

“We have a lot of undergraduates in labs learning all the techniques, and they really enjoy it, because they can manipulate them and they can really see the experiment, the outcome, and they can also hypothesize ideas and test them,” Sun says. “And it’s also very short. The generation is only a little bit over a week. So, in one semester, they can test multiple hypotheses.”

With so many similarities, so much potential for learning, it’s almost enough to make you think a little bit differently about that swarm of tiny little fruit flies buzzing all around your kitchen.

Almost.