The seemingly ordinary East Lawn Cemetery in Ithaca, New York, has emerged as the unexpected sanctuary for one of the largest and oldest known aggregations of ground-nesting wild bees ever documented, a discovery that is reshaping scientific understanding of insect biodiversity and the crucial role of overlooked urban habitats. What began as a simple observation by a Cornell University entomology lab employee has led to a groundbreaking study, revealing a subterranean metropolis teeming with an estimated 5.5 million individual bees, primarily the solitary mining bee species Andrena regularis. This astonishing density, concentrated within a mere 1.5 acres, surpasses the population of Manhattan by more than threefold and is equivalent to over 200 commercial honeybee hives, underscoring the profound ecological significance of this tranquil resting place.
The Serendipitous Discovery of an Insect Supercolony
The remarkable finding traces back to Rachel Fordyce, an employee at Cornell University’s entomology lab. In the spring of 2022, while seeking to economize by parking at Ithaca’s East Hill Plaza and traversing East Lawn Cemetery en route to her workplace, Fordyce noticed an unusual abundance of bees. Her curiosity piqued, she collected several specimens in a jar and presented them to her supervisor, Bryan Danforth, a professor of entomology in Cornell’s College of Agriculture and Life Sciences. "These are all over the cemetery," she reportedly informed him, her words initiating a chain of events that would unveil a hidden ecological marvel.
The collected insects were identified as Andrena regularis, commonly known as the "regular mining bee." This species is characterized by its solitary nesting habits, excavating burrows underground and playing a vital role in the pollination of both agricultural crops and native wild flora. The sheer volume of these bees in the cemetery, however, was far beyond anything previously recorded in scientific literature for this species.
Unveiling the Scale: A Subterranean Bee City
The subsequent research, spearheaded by then-undergraduate researcher Steve Hoge ’24 and published on April 13 in the esteemed journal Apidologie, confirmed the extraordinary nature of the East Lawn Cemetery site. Scientists meticulously analyzed the bee population, estimating it to house approximately 5.5 million individual Andrena regularis bees within a confined 1.5-acre area. This density is not only statistically significant but also offers a compelling perspective on the scale of the aggregation: it dwarfs Manhattan’s human population and represents a concentration of pollinator biomass previously unimagined in such an urban setting.
"I’m sure there are other large bee aggregations that exist around the world that we just haven’t identified, but in terms of what is in the literature, this is one of the largest," stated Hoge, the lead author of the study, highlighting the novelty of their findings. His undergraduate research in Danforth’s lab provided the crucial impetus for this extensive investigation into the biology and ecological importance of these often-underappreciated solitary bees.
The Cemetery: A Haven for Biodiversity
The study aimed to illuminate the biology of these poorly understood wild bees while simultaneously emphasizing their indispensable role as pollinators for economically significant crops. In New York State, apples are a signature commodity, and Andrena regularis contributes significantly to their successful fruit set.
Professor Danforth elaborated on the research’s implications: "The research elevates the value of solitary ground-nesting bees and shows just how abundant these bees are, how important they are as crop pollinators, and that we need to be aware of these nest sites and preserve them." The historical presence of A. regularis at East Lawn Cemetery dates back at least to the early 1900s, with the cemetery itself established in 1878, suggesting a long-standing ecological relationship.
This discovery adds substantial weight to the growing body of evidence suggesting that older cemeteries can serve as vital refuges for urban biodiversity. These often-peaceful, infrequently disturbed landscapes, particularly those in urban environments, are increasingly recognized for their capacity to support a diverse array of plant and animal life, including rare insects, birds, and mammals.
Keven Morse, the superintendent of East Lawn Cemetery, has personally witnessed this rich biodiversity during his family’s 46 years of managing the nonprofit grounds. He has observed deer, geese, hawks, foxes, coyotes, and, of course, countless bees. Morse noted his long-standing awareness of the bee activity, stating, "I just felt bad having to mow in certain areas. There’s probably three or four sections where they really migrate heavy, there’s a lot of them." He also shared an interesting anecdote: "And of course, bees, which he said have never stung him," underscoring the generally docile nature of these solitary pollinators.
The research team posits that cemeteries provide exceptionally favorable habitats due to their tranquility, infrequent human intervention, and, crucially, their general lack of pesticide application. These factors create an environment where ground-nesting bees can thrive undisturbed.
Understanding the Solitary Bee Lifestyle
While honeybees often capture public attention, the reality is that approximately 75% of all bee species worldwide are solitary ground nesters, a lifestyle shared by Andrena regularis. "It’s the most common lifestyle for bees," Professor Danforth emphasized, highlighting the vast, yet largely invisible, world of solitary pollinators.
Hoge’s initial exploration into the scientific literature revealed a surprising paucity of detailed information on A. regularis. One of the most comprehensive references dated back to 1978, presenting an opportune moment for the Cornell team to contribute significantly to the documentation of this species’ biology.
The life cycle of A. regularis involves females excavating individual underground nests. Within these subterranean chambers, they provision cells with pollen and nectar before laying their eggs. The developing larvae mature beneath the surface, eventually emerging as adult bees. A particularly noteworthy aspect of this species’ biology is its overwintering as adults, a relatively rare trait among bees. "This species overwinters as adults, which is relatively rare, and that’s part of the reason why they come up out of the ground so early in the spring, timed to the apple bloom," Hoge explained.
These early-emerging bees coincide with the blooming of fruit trees and wildflowers, providing them with essential floral resources. In the Ithaca region, their emergence typically occurs in April, coinciding with consistent daytime temperatures around 70 degrees Fahrenheit. The proximity of Cornell Orchards, located approximately one-third of a mile from the cemetery, is believed to provide a crucial supplementary food source for this massive bee population. Furthermore, the researchers identified the cemetery’s abundant sandy soil as a preferred nesting substrate for A. regularis, further contributing to its suitability as a habitat.
Innovative Methods for Counting Millions
To accurately estimate the bee population and meticulously study their emergence patterns, the researchers employed a novel monitoring technique: emergence traps. These compact mesh enclosures, each covering less than one square meter of ground, are designed to capture insects emerging from the soil. As bees emerge, they are funneled into glass jars attached to the traps. "You capture a whole community of animals coming out of the ground with this approach," Danforth remarked, illustrating the effectiveness of the method.
Between March 30 and May 16, 2023, the research team strategically placed 10 of these traps across the cemetery. The collected specimens comprised 3,251 insects, representing 16 distinct species of bees, beetles, and flies. Andrena regularis overwhelmingly dominated these samples, confirming their status as the primary inhabitants of the site.
By extrapolating the number of bees captured in each trap to the cemetery’s approximate 6,000 square meters, researchers calculated an average bee density. This calculation led to an estimated total population ranging from a conservative 3 million to an expansive 8 million bees, with a median estimate of 5.5 million individuals.
The emergence traps also provided valuable insights into the timing of male and female bee activity. Male bees, eager to mate, emerged first during warmer spells in April. Females followed several days later, ensuring optimal opportunities for reproduction. "The males come out first and wait for the females, so that they have the best opportunities to mate and pass on their genes," Hoge elaborated, shedding light on the intricate mating strategies of this species.
The Specter of Parasitism and the Imperative of Conservation
The study also documented the presence of brood parasitism by nomad bees, specifically Nomada imbricata, also known as "cuckoo" bees. These parasitic bees exhibit a sophisticated strategy: they observe when A. regularis females have completed their brood cells and are about to lay their eggs. At this opportune moment, the nomad bee lays its own egg within the prepared cell. Upon hatching, the nomad larva consumes the host bee larva and devours the vital pollen and nectar provisions intended for the mining bee’s offspring.
Recognizing the critical need to protect such invaluable nesting sites, Danforth and his colleagues have initiated a global citizen science initiative. This program encourages the public to report any ground-nesting bee aggregations they encounter, fostering a collaborative effort in identifying and safeguarding these essential habitats.
"These populations are huge, and they need protection," Danforth stated with urgency. "If we don’t preserve nest sites, and someone paves over them, we could lose in an instant 5.5 million bees that are important pollinators." The potential for rapid and irreversible loss of such significant pollinator populations underscores the importance of this conservation call to action.
The groundbreaking research was made possible through the collaborative efforts of several individuals. Key co-authors included postdoctoral researchers Jordan Kueneman and Katherine Odanaka, undergraduate students Steve Hoge ’24 and Cassidy Dobler ’26, and lab technician Rachel Fordyce, whose initial observation sparked the entire investigation. Funding for this vital research was generously provided by the Cornell Atkinson Center for Sustainability, the National Science Foundation, and the Federal Capacity Funds program. This multidisciplinary support highlights the broad recognition of the ecological and economic significance of this remarkable discovery.
