5.5 million subterranean bees thrive under Ithaca cemetery

A Cornell University research team has documented an immense colony of about 5.5 million Andrena regularis—subterranean mining bees—under East Lawn Cemetery in Ithaca, New York. The colony spans roughly 1.25 acres, helped by conditions that make the cemetery a

On a morning walk through East Lawn Cemetery in Ithaca, New York, the ground looked ordinary—until it didn’t. What was uncovered was an immense colony of subterranean bees, numbering about 5.5 million, living under the cemetery for more than a century.

The discovery was published in April by a Cornell University research team in the journal Apidologie. The scale is striking: it documents one of the largest aggregations of these insects ever recorded in the world. The bees belong to the species Andrena regularis, often called mining or miner bees. They occupy an area of about 1.25 acres and play a crucial role in pollinating the region’s orchards. including nearby apple trees.

The story began in spring 2022. when Rachel Fordyce—then a laboratory technician in Cornell University’s entomology department—noticed an anomalous presence of insects during her usual walk to work. After collecting some specimens, she showed them to Bryan Danforth, an entomologist at Cornell. The analysis identified them as Andrena regularis.

What made the find feel bigger than a single patch of bees was what older records suggested: the species has been present in the cemetery, established in 1878, since at least the early 1900s.

To understand how large the colony really was, the scientists carried out a field census in the cemetery. They placed 10 traps there between late March and mid-May 2023. Each trap used small net curtains covering less than one square meter of soil. channeling insects coming out of the ground into a glass container.

In total, more than 3,000 insects belonging to 16 different species were sampled, including bees, beetles, and flies. Andrena regularis dominated the results. Using extrapolation based on the average density found in the traps. the researchers estimated a total population between 3 and 8 million. with an average value of 5.5 million—roughly equivalent to more than 200 domestic bee hives.

The traps didn’t just count bees. They also captured details about a species that, for all its importance as a pollinator, has remained little studied. During the first warm days of April. males emerge from the ground a few days earlier than females. a timing strategy that maximizes mating opportunities. Afterward, females dig nests and lay eggs in cells filled with pollen and nectar.

One of the most important biological traits—and one that helps explain why activity can begin so early—is how the species winters. Andrena regularis winter underground at the adult stage. allowing it to become active very early in spring. synced with the flowering of apple trees in Cornell University’s orchards.

Even under the cemetery’s quiet surface, the research also found complex ecological dynamics. Among them is parasitism by bees of the Nomada imbricata species, which lay their eggs in the nests of the host species at the expense of the original larvae.

The discovery lands on a broader point that’s hard to ignore: most wild bees are not social colonies like honey bees. The study notes that 75 percent of solitary wild bees live underground, which means their nesting sites can be invisible—until something disrupts them.

Old city cemeteries, the researchers say, can offer unusually suitable conditions: sandy soils that are easy to dig, no pesticides, and an environment not shaped by the major changes seen in intensive agriculture or housing development.

But even refuges have risks. The study’s authors warn that populations of this magnitude could be accidentally destroyed by concrete pours or road work. To prevent that, they have launched a global citizen science initiative. The project asks citizens to report the presence of underground bee aggregations. so these pollinators can be surveyed and protected before habitat fragmentation jeopardizes their survival.

The finding has the texture of a small miracle—something thriving where people rarely look. And yet it’s also a reminder that protecting biodiversity isn’t only about protecting forests and fields. Sometimes it begins beneath the paths we’ve walked for decades.

East Lawn Cemetery Ithaca Cornell University Apidologie Andrena regularis miner bees subterranean bees solitary bees pollination citizen science Nomada imbricata biodiversity