Bee Diversity in New York

We estimate that there are a total of 416 bee species in New York state. Forty-two of the 425 genera of bees in the world (Michener 2007) occur in New York. Our most common (and speciose) genera are AndrenaLasioglossumNomadaSphecodesMegachileColletesOsmiaHylaeusMelissodesBombus, and Coelioxys. A survey of bee species in Pennsylvania (Donovall and vanEngelsdorp 2010) documented a total of 371 species, comparable to the number we report here for New York, but likely an underestimate given the size of Pennsylvania.

The majority (54%) of bees in New York State are digger bees (ground-nesting, solitary bees, such as AndrenaLasioglossumColletes, and Melissodes). Species of Andrena are typical of ground-nesting bees in their life history. At the start of the nesting season (in the spring, summer, or fall, depending on the species), female Andrena begin constructing burrows in the soil. At the end of these subterranean burrows they construct brood cells, which are lined with waterproof secretions from the Dufour’s gland. Once a brood cell has been constructed, a female provisions it with a mixture of pollen and nectar collected from flowering plants in the vicinity of the nest. Foraging ranges in these solitary bees are small – on the order of 500 m maximum – so nests are typically close the floral resources. Once the provisions have been collected, the pollen/nectar mixture is sculpted into a spherical pollen ball and an egg is laid on top. The brood cell is then closed and the female begins constructing a new brood cell. Brood cells range in depth from just a few inches to several feet. A typical solitary female might produce just 10–15 offspring over a period of two to three weeks of active foraging.

While the majority of bees in New York State are ground-nesting, several species also make nests in preexisting cavities, such as twigs, hollow stems, beetle burrows, or in sites above ground. These aboveground, cavity nesters include the mason bees, the wool carder bees and various resin bees. Mason bees in New York State include genera such as Osmia, HoplitisProchelostoma, and Heriades. Mason bees comprise roughly 7 percent of the species of bees in New York State. Other cavity- and stem-nesting bees include the leaf-cutter bees in the genus Megachile (Sheffield et al. 2011), carder bees in the genus AnthidiumPseudoanthidium, and Paranthidium, and the yellow-faced bees in the genus HylaeusMegachilefemales line their cells with circular pieces of leaf that they cut from rosebushes and other plants. Hylaeusfemales line their burrows (constructed in plant stems or other hollow tubes) with a cellophane-like material produced by the Dufour’s gland. Hylaeus are unusual bees because they carry pollen internally and not externally, as do most pollen-collecting bees.

Another important group of bees are the carpenter bees. In North America we have both small (Ceratina) and large (Xylocopa) carpenter bees. These bees construct nests in wood or preexisting cavities. Xylocopa virginica is a common bee in New York State. Nests are conspicuous because males hover in front of the nests (typically located in fence posts, wooden park benches, and houses) and engage in aggressive territorial battles.

Cleptoparasitic bees comprise 23 percent of the bee species in New York. The two largest genera of cleptoparasitic bees in New York are Sphecodes and Nomada. Parasitic bees are fascinating creatures. They have lost the morphological structures associated with nest construction and pollen collection in most other bees. Instead of constructing and provisioning their own brood cells, parasitic bees enter the nests of other bees (usually when the host female is away) and lay their eggs within the host nest. Once the host female has laid her egg and closed the cell, the parasitic larva hatches from its own egg and kills either the host egg or young larva, then feeds on the host’s pollen. Parasitic bees have devious methods for hiding their eggs from the host females. For example, Nomada and relatives (in the subfamily Nomadinae) put their eggs in the cell wall of the host bee’s nest. 

So far, the vast majority of bees we have mentioned are solitary (or parasitic). Important eusocial bees in New York State include both advanced eusocial taxa in which queens and workers are morphologically distinct (such as Apis mellifera, the introduced honey bee) and primitively eusocial taxa, in which queens and workers are distinguishable from each other based only on size or behavior. Important primitively eusocial taxa include Bombus (bumblebees; Apidae), as well as AugochlorellaHalictus, and some species of Lasioglossum (Halictidae). We estimate that approximately 19 percent of the bee species in New York State are eusocial.

References

  • Donovall, L. R., and D. vanEngelsdorp (2010). A checklist of the bees (Hymenoptera: Apoidea) of Pennsylvania. Journal of the Kansas Entomological Society 83: 7-24. 
  • Michener, C.D. (2007). The Bees of the World. Baltimore: Johns Hopkins University Press.
  • Sheffield, C.S., C. Ratti, L. Packer, and T. Griswold (2011). Leafcutter and mason bees of the genus MegachileLatreille (Hymenoptera: Megachilidae) in Canada and Alaska. Canadian Journal of Arthropod Identification 18: 1-107.