Colletes inaequalis Say 1837

N. S. to Ga., west to Sask., Kans., Tex., Idaho and Wash. (Man., N.S., Ont., Que., Sask., Ark., Conn., Del., D.C., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., N.H., N.J., N.Y., N.C., N. Dak., Ohio, Okla., Pa., R.I., S.C., S. Dak., Tenn., Tex., Vt., Va., Wash., W. Va., Wis., and Wyo.).

Main flight occurs from spring into summer, but occasional adults emerge in the fall (October and November). Nests have been found in a sand pit.

N. S. to Ga., west to Sask., Kans., Tex., Idaho and Wash. (Man., N.S., Ont., Que., Sask., Ark., Conn., Del., D.C., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., N.H., N.J., N.Y., N.C., N. Dak., Ohio, Okla., Pa., R.I., S.C., S. Dak., Tenn., Tex., Vt., Va., Wash., W. Va., Wis., and Wyo.).

Main flight occurs from spring into summer, but occasional adults emerge in the fall (October and November). Nests have been found in a sand pit.

Colletes inaequalis is a common vernal bee in the earliest days of spring. Females construct nests in grassy areas such as lawns, cemeteries, and gardens. Nesting aggregations can be huge (with several thousand nests) and dense (with over 100 nests in a square meter). If you are lucky enough to find these bees nesting in your yard, don't try to kill them; they won't sting, and they are probably good for soil aeration. They are also fun to watch! (New York State Biodiversity Research Institute)

Seasonal temperature changes are an important factor in determining when plants come into bloom. If there are significant changes in annual temperature cycles over time, the blooming schedule can be altered worldwide. This begs an important question for plant pollination. Have the insects and other animals that service animal-pollinated plants altered their behavioral calendar in a similar way?

Using historical museum datasets and recent bee-monitoring data, North American researchers have examined this question in ten species of wild bees: Colletes inaequalis, Andrena crataegi, Andrena carlini, Andrena miserabilis, Osmia pumila, Osmia bucephala, Osmia atriventris, Osmia lignaria, Bombus impatiens, and Bombus bimaculatus. Over the past 130 years, there has been a significant shift toward emergence earlier in the Spring among these bees, which average approximately ten days earlier now than in the late 1800s. This trend was most pronounced in the last forty years.(Bartomeus et al, 2011)

Does this shift resemble a shift in the bloom schedule of the plants these bees visit? Changes in plant bloom times in response to climate change have been a subject of intensive study recently and data is available through several studies of native plants in North America, from herbarium records and monitoring programs (Miller-Rushing et al, 2006; Primack et al, 2004; Bradley et al, 1999; Cook et al, 2008). Among 106 native plants that are visited by these ten bee species, there is also a significant trend toward earlier flowering. This trend also became more pronounced in the last forty years.(Bartomeus et al, 2011)

Do these two shifts mean that bees will continue to be active during appropriate periods to take advantage of the bloom calendar? That is difficult to say. Emergence and bloom dates are quite variable, and all ten of these bee species visit many different species of plant, which have different bloom calendars. Another important research question: do schedule shifts also correspond for specialist plant-pollinator pairs, where a single species of animal visits a single species of plant?

Colletes inaequalis is a common species of plasterer bee (family Colletidae), native to North America. Like other species in the genus, it builds cells in underground nests that are lined with a polyester secretion, earning the genus the nickname of polyester bees. C. inaequalis is a pollinator of red maple trees, willow trees, and apple trees.