By Published: Dec. 1, 2014

Closeup of bee

Colorado has one of the nation's most diverse bee fauna. An army of volunteers is helping CU scientists track hundreds of front range species.

When a phenomenon called colony collapse disorder began ravaging honey bee populations in the mid-2000s, the world took notice: Flowers, food crops and ecosystems depend on bee pollination.

Of late, mass colony collapse has moderated in the United States, but honey bees鈥 long-term population trend is still sharply downward. And there are thousands of other bee species about which little is known because they get less attention. Colorado alone is home to 946 species, more than all but four other states.

Their circumstances are not assumed to be good, based on existing surveys.

鈥淚n general, bee populations are considered to be in decline everywhere,鈥 says Virginia Scott, entomology collections manager at the University of Colorado Museum of Natural History in Boulder.

To learn more about Colorado鈥檚 abundant solitary wood nesting bees, which make up about 25 percent of all Front Range species 鈥 and to lay a foundation for scientific assessments of population changes 鈥 Scott and colleague Alexandra Rose in 2013 established The Bees鈥 Needs, a research project involving hundreds of volunteer 鈥渃itizen scientists.鈥

鈥淲e want to understand the 鈥榦ther鈥 bee mystery,鈥 says Rose, a bird biologist who is the museum鈥檚 program manager for citizen science.

Counting bees isn鈥檛 easy: Small and spry, they can live throughout a vast area.

鈥淪ome are the size of gnats,鈥 says Rose.

鈥淵ou鈥檇 think they were fruit flies.鈥

Also, the Front Range is home to a great diversity of bees, about 650 species, or more than two-thirds of all Colorado species. (Only the desert states of California, Arizona, New Mexico and Utah have more.) Learning something about them all requires a small army.

The Bees鈥 Needs鈥 volunteers 鈥 528 in 2014, up from 337 a year earlier 鈥 don鈥檛 need advanced science training. Mainly, Scott says, they need to be diligent observers and recorders.

鈥淚 suppose patience helps, too,鈥 she says.

A goal of The Bees鈥 Needs is establishing baseline populations for as many species as possible.

These will provide a basis for comparison in the future.

To make data collection convenient, the museum provides volunteers with nesting boxes similar to birdhouses 鈥 stationary attractions where bees (and wasps) take shelter and deposit identifying traces.

The first year of the program, Rose, Scott and friends drilled 10,000 holes of varying sizes into each of 250 wooden boxes.

Volunteers install the boxes in sunny spots (shady ones attract earwigs) and track nests bees build there, noting the plugs mother bees put into the holes to protect their larvae. Different species use different plug materials 鈥 resin, for example, or chewed leaves, grass, mud or silk. Volunteers check the nests every two weeks from April to October, taking pictures and reporting on nest materials.

Adult bees die after the first hard frost. In the spring, offspring chew through the plugs to enter the world outside.

鈥淚t鈥檚 fun, especially as you get others involved,鈥 says volunteer Sandra Laursen, a researcher in CU鈥檚 ethnography & evaluation research unit.

Last year Laursen hung her nesting box on the fence of her Boulder condominium complex and found that the box鈥檚 鈥渁partments鈥 especially appealed to children.

鈥淥ne ten-year-old boy quite liked it when he had spotted something I hadn鈥檛,鈥 she says.

So far, nobody鈥檚 been stung (or said so, anyway), according to Rose 鈥 not even by the wasps that also take advantage of the boxes for nesting.

Wasps engender less fondness than bees 鈥 鈥淲e discovered early on that wasp is a four-letter word,鈥 says Scott 鈥 but they too are important pollinators. Solitary wasps harvest aphids, caterpillars and other garden pests. Rose calls them 鈥渢he unsung heroes of the gardening world,鈥 noting they pollinate flowers along the way: 鈥淭alk about organic gardening!鈥

Rose soon expects to finish analyzing the citizen scientists鈥 2013 data sets. This will yield initial baseline populations for many Colorado bee and wasp species. Data sets collected in the years ahead will help reveal population changes.

鈥淭his is a long-term project,鈥 Scott says. 鈥淭he more cumulative data we can collect, the more we鈥檒l understand the mysteries of these solitary insects.鈥

To volunteer for the 2015 Bees鈥 Needs project, visit聽.

Photo courtesy CU Museum of Natural HIstory (bee); Diane Wilson (bees on flowers)

Colorado Bees: A Sampler

Common name:聽Cuckoo leaf-cutting bee
Scientific name:聽Coelioxys sp.
Looks like:聽White stripes, pointy abdomen
厂颈锄别:听1/2鈥

Common name:聽Mason bee
Scientific name:聽Hoplitis albifrons
Looks like:聽Jet black, elongate, patches of pale hairs
Size:听5/8鈥

Common name:聽Green mason bee
Scientific name:聽Hoplitis fulgida
Looks like:聽Bright metallic green or blue-green, elongate
Size:听1/2鈥

Common name:聽Masked bee
Scientific name:聽Hylaeus leptochepalus
Looks like:聽Shiny, black, nearly hairless with ivory marking on face, legs
Size:听1/4鈥

Common name:聽Leaf-cutting bee
Scientific name:聽Megachile sp.
Looks like:听贵耻锄锄测
Size:听5/8鈥

Common name:聽Pugnacious leaf-cutting bee
Scientific name:聽Megachile Pugnata
Looks like:聽Gray, large-head, white stripes on elongate abdomen
Size:听3/4鈥

Common name:聽Mason bee
Scientific name:聽Osmia sp.
Looks like:聽A fly; rotund, metallic blue
Size:听3/8鈥

Common name:聽Cuckoo bee
Scientific name:聽Stelis rudbeckiarum
Looks like:聽A stocky wasp, bald, black with yellow stripes
厂颈锄别:听5/16鈥