They are tiny. They fly and squirm, skitter and crawl. They are so humble that they easily escape notice. But ask a Clark scientist about the insects and worms at the center of their research and they’ll let you know that these creatures are also endlessly fascinating—the stories they tell, the secrets they reveal, and their role in responding to pressing challenges with climate change, food insecurity, and the prevention and treatment of disease. In these pages, University photographer Steven King introduces us to some of these mini-warriors at the frontiers of important research. Humble no more, they are ready for their close-up.
Sex and death
In a tiny tunnel snaking through the soil, a dramatic courtship plays out.
Armed with a pair of devil-like horns, a male dung beetle guards the female with whom he’s just mated. Bowing his horned head like a shield, he drives away other males.
Via a side tunnel, a smaller, sneakier Onthophagus taurus—hornless but horny, with big testes full of sperm—meets up with the female. In a blues song, he would be the “Back Door Man.”
For Erin McCullough, professor of biology, the mating rituals of dung beetles are not only fascinating, but their courtships can also provide a window into understanding how climate change affects biodiversity.
Native to the Mediterranean but accidentally introduced to Florida in the 1970s, the range of Onthophagus taurus has expanded steadily northward.
“Because of climate change, we have species expansion,” McCullough says. “But there’s still a lot to learn about why some species are expanding, and why some species are not. Understanding how sexual selection plays a role in all of this is not well documented.”
Dung beetles are important for maintaining healthy soil and ecosystems, McCullough says. “They’re burying animal waste, they’re restoring nutrients to the soil, and they’re promoting plant growth by aerating the soil and allowing rainwater to penetrate deeper.”
She and her students are studying Onthophagus taurus collected from Florida, North Carolina, and Virginia, measuring and comparing the horn sizes of “major males,” who use their horns to fight each other for access to the tunnels housing females. “Minor males” have tiny horns—or none at all—so they sneak.
“We’re interested in how sexual selection differs across the range and how many major males versus minor males there are,” McCullough says.
In controlled lab experiments, they are exploring whether more diverse beetle communities bury waste faster, which could benefit farmers and the environment even more. The researchers have discovered that there are more major males starting at the end of summer. “One strategy for the little guys might be to come out earlier in the season so they don’t have a fight with the big guys,” she says.
Ultimately, McCullough notes, “a lot of biology is about sex and death. That’s what really matters.”
The bees’ needs
It’s all about the bees. What they give. What they mean. What we lose if they one day go away.
Dana Bauer, research scientist in conservation and sustainability with the George Perkins Marsh Institute at Clark, has spent much of her career studying the impact of pollinators on everything from ecosystems to the economy. In her research, she gathers farmers’ insights and gauges their perceptions on many topics, like the decline in bee colonies, the use of pesticides, and their willingness to set aside some farmland to preserve natural habitat for pollinating creatures.
Bauer is currently in the early stages of a research project whose main focus is to better understand farmers’ views on how they deploy pollinators to help them raise robust crops and determine if there are more efficient and enviro-friendly methods to get the job done. She is conducting a nationwide survey of farmers, many of whom employ “managed pollinators” that are raised and used specifically to pollinate crops, as opposed to “wild pollinators” that exist naturally without any human oversight or intervention.
Large industrialized farms—think almond farming in California—typically use managed pollinators. Smaller operations, such as apple orchards in upstate New York, rely more heavily on wild pollinators, which include not only bees but also other insects, birds, and small rodents. Whether farmers are willing to voluntarily carve out small tracts from their property to promote the health of wild-pollinator populations is particularly intriguing, she says.
In addition to the survey, Bauer has conducted focus groups with farmers, and many have expressed comfort with the managed-pollinator system as a reliable component of their operations. Small-farm operators are more likely to rely on wild pollinators, she says, but may also lease honeybees as insurance. (Climate change, she notes, has made conditions for the pollination ritual less predictable, including knowing when flowers will open.)
“We go to the grocery store, to the coffee shop, and we don’t even think about the contributions that bees play in what we ultimately eat and drink,” Bauer says. “Without them, we’d lose so much.”
Squirmy medicine
Some people look at worms and see fish bait. Others see the future.
Working in the laboratory of Arshad Kudrolli, professor and chair of the Physics Department, Ph.D. candidate Sohum Kapadia conducts experiments detailing how California blackworms (Lumbriculus variegatus) move through water-filled spaces of various shapes and strictures.
The research is expected to one day inform the development of “soft robots” that could worm their way through digestive tracts and other complex “terrains” within the human body. They might assist with the diagnoses of illnesses, the delivery of medicines and other treatments, and the development of more efficient surgical techniques.
“We are trying to understand the mechanisms,” says Kapadia. “This is very root-level research, but the robotics are the ultimate goal.”
Observing the biolocomotion patterns of worms is central to Kudrolli’s research, which lies at the nexus of biology, physics, and technology. With a core of student researchers, “we are trying to understand how organisms and robots move through media which are not quite liquid or solid,” Kudrolli said when the experimentation began several years ago. In his lab, conditions are created to approximate sand and water, clay, sludge, and even fluids in the human body, which he describes as “a giant hydrogel.”
Also in Kudrolli’s lab, students experiment with magneto-elastic robots that are made to emulate worm-movement patterns. An oscillating magnetic field generated by a Helmholtz coil—a device that creates a nearly uniform magnetic field—allows the robots to burrow, swim, or crawl through polystyrene beads. The students record the variables that contribute to the worms’ forward propulsion.
Kudrolli received a grant from the National Science Foundation for the development of soft robots that could one day revolutionize the ways that emerging technologies influence biomedical science.
His worm work is expected to “result in a deep understanding of biolocomotion and soft robot design in sediment beds,” he notes, and perhaps, someday, within the landscape of the human body.
Our genetic cousin
You might call it the noble—or nobel—fruit fly.
In 1933, Thomas Hunt Morgan won the Nobel Prize for uncovering the role that chromosomes play in heredity. His discovery arose from his experiments with Drosophila melanogaster in “The Fly Room,” his Columbia University lab now considered the birthplace of modern genetics research.
It wasn’t until 2000 that the Drosophila melanogaster genome sequence was published. Subsequent research clarified that fruit flies share over 60 percent of genes with humans, making them ideal model organisms for studying ge- netic mutations that can contribute to cancer, diabetes, Alzheimer’s, Parkinson’s, and other diseases. It’s easy, quick, and inexpensive to breed multiple generations of fruit flies in the lab—10 days from egg to larvae to adult.
“The function of the majority of genes has been conserved for some 250 million years since the last common ancestor of flies and humans. You might not think it, but their genomes are quite similar,” geneticist Justin Thackeray says.
“One of the great things about fruit flies is that over the last century, we have isolated a slew of important new genetic tools to study how their genes work.”
The biology professor and his students are researching a mutation in the PLCG1 and PLCG2 genes that encode, or “instruct,” the PLC-gamma enzyme, a protein catalyst that speeds up chemical reactions in the cell. Overactivity in PLC-gamma, he explains, contributes to about “50 percent of breast and prostate cancers, each of which is the No. 1 cancer type in females and males.”
Because of this connection, Thackeray and his students seek to identify an inhibitor drug that can successfully block overactive PLC-gamma. They are now using CRISPR-Cas9, a technology allowing them to “edit” the DNA sequence of Drosophila melanogaster and recreate activating mutations found in human tumors.
Several years ago, Mariah Torcivia ’20, M.A. ’21, was working in Thackeray’s lab and made an important discovery: A few flies with CRISPR edit had “a weird defect in the vein of their wings,” he recalls. Because the wing defect—an incomplete posterior cross vein—is easy to observe, the researchers plan to use it to identify a novel PLC-gamma inhibitor drug.
Most scientific discoveries happen in fits and starts, Thackeray notes.
“You feel like you’re making absolutely no progress at all for long periods, and in some cases, you aren’t,” he says. “But then suddenly, you’ve figured it out.”
Warriors and builders
“Ants are more complicated than people think,” says Mathis, who has studied the behaviors of social insects for almost two decades. “I love how ants are this incredibly simple organism, but they can come together cooperatively in groups and do really complex things.”
Ants are farmers—some turn grass and leaves into fungi, which they store to eat later. Others “herd aphids like cattle,” she says. Honeypot ant workers collect liquid in their abdomens to feed the rest of the colony, including the queen.
Ants are warriors and builders. “They wage these complicated wars between themselves and other competitors,” Mathis says. “And they build all kinds of elaborate nest structures—in the ground, within hollowed-out acorns, or high up in the tree canopy.”
By studying ants living in areas modified by human agriculture or urbanization, Mathis unpacks how these undersized creatures can have oversized impacts on the food we grow and the places we call home, including the roles they may play in efforts to increase biodiversity and reduce pesticide usage. In her lab, she and her students seek to understand how New England farmers might leverage the insects’ activities to grow food more sustainably and how various habitats influence the dynamics of some ant colonies.
The researchers are also investigating how destructive ants introduced by humans—such as the Argentine ant (Linepithema humile) and the European fire ant (Myrmica rubra)—can drive out native, beneficial insects, upsetting the ecological balance. The spread of these interlopers can lead to negative effects, from potential citrus crop losses in Southern California to declining biodiversity in New England forests.
As Mathis and her students have found, climate change can upset the biodiversity of ant populations. They’ve investigated how higher temperatures have affected three types of cavity-dwelling ants that live in fallen acorns and galls (wasp-made abnormal growths) in oak twigs.
Researching how the ants adapt to such stressors “can provide insight into the future of biodiversity and the ways in which conservation efforts should be applied to these areas of change,” they write in the Ecology and Evolution journal.
“Different species are evolving at different paces with different behaviors,” Mathis says, “so it’s a complicated web to untangle.” □
