The rooms that make up the Bloomington Drosophila Stock Center at Indiana University are lined from wall to wall with identical shelves. Each shelf is filled with uniform racks and each rack with indistinguishable glass vials.
The tens of thousands of types of fruit flies in the vials, however, are each beautifully different. Some have fluorescent pink eyes. Some jump when you turn on a red light on them. Some have short bodies and curly iridescent wings, and look like “little ballerinas,” said Carol Sylvester, who helps care for them. Each strain doubles as a unique research tool, and it has taken decades to introduce the traits that make them useful. If left unattended, the flies would die off within weeks, blocking entire scientific disciplines.
Throughout the Covid-19 pandemic, workers in all sectors have held the world together, taking great personal risks to care for sick patients, maintain supply chains and feed people. But other essential jobs are less well known. At the Stock Center, dozens of employees came to work every day, through a lockdown and afterwards, to deal with the flies that underpin scientific research.
Small bug, huge impact
For most casual observers, fruit flies are tiny dots with wings that hang around old bananas. But over the past century, researchers have turned the insect – known to science as Drosophila melanogaster – into something of a genetic standard. Biologists regularly develop new “strains” of flies, in which certain genes are turned on or off.
Studying these slight mutants can reveal how these genes work – including in humans, as we share more than half of our genes with Drosophila. For example, researchers discovered what is now known as the hippo gene – which helps regulate organ size in fruit flies and vertebrates – after flies with a defect grew to become unusually large. and wrinkled. Further work on the gene has indicated that such defects can contribute to the uncontrolled cell growth that leads to cancer in people.
Other work on flies shed light on diseases ranging from Alzheimer’s to Zika, taught scientists about decision-making and circadian rhythms, and helped researchers who used them win six Nobel Prizes. Over a century of fine-tuning fruit flies and cataloging the results has made Drosophila the best characterized animal model we have.
This is a great role for an unpretentious bug. “When I try to tell people what I’m doing, the first thing they usually say is, ‘Why would you keep fruit flies alive? I’m trying to kill them! Said Ms Sylvester, who has been a storeroom at Bloomington since 2014.
If a few hitchhiking from the grocery store at her house her kids screw her up, she added, “Mom, you brought your co-workers home.” “
The Bloomington Drosophila Stock Center is the only institution of its kind in the United States and the largest in the world. It is currently home to over 77,000 different fruit fly strains, most of which are in high demand. In 2019, the center shipped 204,672 vials of flies to laboratories in 49 states and 54 countries, said Annette Parks, one of the centre’s five principal investigators.
It’s “one of the gems we have in the community,” said Pamela Geyer, a stem cell biologist at the University of Iowa who has been ordering flies at the storage facility for 30 years.
Other model organisms can be frozen at particular life stages for long term storage; Laboratory freezers around the world contain mouse embryos and cultures of E. coli. But fruit flies cannot go on ice. Caring for the creatures means “turning” them regularly: transferring them from an old vial to a clean one that has been supplied with a spoonful of food. Quarantined with other members of their strain, the flies mate and lay eggs, which hatch, pupate and reproduce, continuing the cycle.
“We have strains in our collection that have been continuously propagated like this since about 1909,” across generations and institutions, said Cale Whitworth, another senior researcher at the repository. To keep their millions of fruit flies returned and happy, the center employs 64 stockists, as well as a media preparer – think fly cook – as well as a kitchen assistant and five dishwashers.
At the storage center, as everywhere, the first eddies of the pandemic seemed worrying. “I remember joking with people, ‘We’re the people at the start of the dystopian novel, and we don’t know what’s going to happen yet,” ”Ms. Sylvester said.
As the number of cases increased, Dr Whitworth packed a backpack with a pillow and a toothbrush, imagining the worst. “I was right in the middle of the ‘Everybody’s sick, last man on earth’ kind of thing,” he said. “For example,” How many flies can I return in 20 hours, sleep for four hours, and continue to return the next day? “
Instead, when Indiana University closed on March 15, the storage facility remained open.
Kevin Gabbard, the fly boss, made an emergency store. Although they eat the same thing every day – a yeast puree made mostly from corn products – flies can be picky. Mr. Gabbard, without risking anything, ordered two months of their favorite brands. “You think of cornmeal from cornmeal,” he says. “But it isn’t if it isn’t fair.”
The co-directors devised a more robust Hail Mary plan that, if absolutely necessary, would allow them to “keep most of the flies alive with just eight people,” Dr Whitworth said. They also decided to stop all expeditions, focusing their energy on caring for the flies.
On March 26, the flies stopped leaving the building – and almost immediately messages of support began to arrive. “You are all wonderful,” read one email. “The fly community is strong because of the phenomenal work you do.”
At about the same time, employees had a choice to make. Deemed to be essential workers, they were allowed to come to campus. The university guaranteed them a full salary even if they decided to stay home, or an hour and a half to enter. (The center covers its costs through a combination of federal grants from the National Institutes of Health and its own income from fly sales.)
The vast majority chose to continue working, Dr Whitworth said – even though the work was suddenly quite different. The center is generally a very social place to work, with birthdays and group lunches. Hours are normally flexible, which is a big selling point for employees, many of whom are parents or students, or have retired from full-time work.
Now people work in masks, often in separate rooms. Changes in one of the buildings in the center have become strictly scheduled to avoid overlaps. “You can work alone for a while, maybe all day,” said Roxy Bertsch, who has been a stockist since 2018.
And for the first few weeks, stockists – many of whom do additional tasks, such as packaging, shipping, and training – spent all of their time turning flies, which is monotonous and hard on the hands. “All we did was come in, feed the flies and leave,” Ms. Bertsch said.
But she kept coming back. After her son was potentially exposed to the coronavirus and had to self-quarantine, she counted the 14 days until she could return.
“There is no way you could stop me from working if I could be here,” she said.
Ms. Sylvester specializes in caring for flies whose mutations mean they need more TLC. She also worked full time throughout the shutdown, fueled by concern for her charges. “I especially love flies and I don’t want them to die,” she says. “I never thought I would love the larvae so much.”
In mid-May, the center resumed shipping inventory. Dr Parks delivered another batch of messages, many of which are now tinged with relief.
“It feels like Christmas,” tweeted a lab at Aarhus University in Denmark, with a photo of a box of vials.
A post earlier in the spring from Tony Parkes, a biologist at Nipissing University in Ontario, praised all those who “do their jobs with little distinction, but whom everyone relies on as a fundamental backbone.”
When Dr. Parkes’ lab shut down, he spent some of his unexpected downtime thinking about the storage facility. It’s an equalizer, he said, allowing even small labs to tackle big issues “without requiring massive resources.”
It also allows researchers to literally share their findings with each other. “You don’t have to run your own library to have access to all this information,” he said, because the repository is “there when you want it”.
The people who run the center also think about it. “It means a lot to know that you are a part of it,” Ms. Bertsch said.
But it adds some pressure. “We all feel that great weight in making sure the storage facility is there for everyone,” Dr Whitworth said.
The pandemic continues, of course, and other obstacles are emerging. Although the fall semester went off without incident, cases are increasing in the region, increasing the potential for another shutdown. Mail delays, both at home and abroad, have prompted the center to suggest that its customers turn to private carriers – the flies perish if they are in transit for too long.
Although they are no longer paid extra, everyone continues to come to work. And even if things change, Dr. Whitworth is ready. “I never unpacked my bag,” he says. “He’s still sitting in the closet.”