Millions of Bees Discovered in Unlikely Urban Habitat
A study by Cornell University researchers has documented a massive aggregation of solitary, ground-nesting bees at East Lawn Cemetery in Ithaca, New York. The research, published in the journal Apidologie, estimates that between 3.1 million and 8 million bees emerged from the site in one season, with activity levels equivalent to more than 200 honey bee hives in a small area.
The findings highlight the abundance of these pollinators and the potential role of cemeteries as stable, low-disturbance habitats.
Study Overview and Methodology
The research focused on the bee species Andrena regularis, which was the dominant species at the site. Over several weeks, researchers collected over 3,000 insects from 16 different species using emergence traps. The project began after Cornell researcher Rachel Fordyce brought bees collected from the cemetery into the lab of Professor Bryan Danforth, the study's corresponding author.
Key Findings
Population Size and Significance: Lead author Steve Hoge stated that, based on existing scientific literature, the aggregation is one of the largest ever recorded.
Pollination Activity: The researchers calculated that the bees' activity at the cemetery provided pollination services equivalent to the output of more than 200 managed honey bee hives.
Emergence Patterns: The study tracked the timing of bee emergence. Male Andrena regularis bees emerged from their ground nests before females. Parasitic insects, including the bee species Nomada imbricata as well as some flies and beetles, emerged later and more slowly than the host bees.
Population Health Indicators: Researchers noted that while more male bees emerged by number, the overall energy investment in offspring favored female production. They cited this, along with a low measured parasitism rate of approximately 1.4%, as indicators of a healthy, stable population with sufficient resources.
Context and Ecological Role
Bee Biology: The study notes that most bee species are solitary and nest in the ground, unlike social honey bees that live in hives.
Agricultural Importance: Solitary ground-nesting bees are pollinators for crops including apples, cherries, strawberries, and blueberries. The East Lawn Cemetery is located near Cornell University apple orchards, and researchers stated the bee population may support pollination in those areas.
Habitat Value: The researchers suggested that cemeteries can provide stable habitats for such bee populations due to factors like infrequent soil disruption and typically low pesticide use.
Researcher Statements
The study's authors provided statements on the implications of their work:
Corresponding author Bryan Danforth said 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."
Danforth also noted, "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."
Lead author Steve Hoge commented on the emergence timing, stating, "The males come out first and wait for the females, so that they have the best opportunities to mate and pass on their genes."
A staff member at the cemetery was quoted in some reports as saying, "I just felt bad having to mow in certain areas... there's a lot of them."