uet to identify both rewarding and unrewarding flowers. In addition, bumblebees rely on this chemical bouquet more when the flower has a high handling time (i.e. it takes a longer time for the bee to find the nectar).
Once they have collected nectar and pollen, bumblebees return to the nest and deposit the harvested nectar and pollen into brood cells, or into wax cells for storage. Unlike honey bees, bumblebees only store a few days' worth of food and so are much more vulnerable to food shortages.
Providing Nest Locations for Bumble Bees. Unlike solitary bees, which can be very particular about tunnel diameters, bumble bees are flexible in their nesting needs. All they want is a warm, dry cavity, roughly the size of a shoebox (Figure 44). Artificial nests can be constructed to attract bumble bees, but occupancy is typically extremely low – often far less than 25 percent.
A simple wooden bumble bee box can be made from preservative-free lumber. An appropriate size will have internal dimensions of about 7 inches high by 7 inches wide and 7 inches long. Drill a few ventilation holes on the upper sides of the box (near the roof) and cover with window screen to deter ants. Also drill some drainage holes in the bottom. Make an entrance tunnel from 3/4-inch diameter plastic pipe and fill the box with soft bedding material, such as short lengths of soft unraveled string, dry straw or upholsterer's cotton (do not use cotton balls, as the fibers become tangled in the bees' legs). The box must be weather tight; if the nest gets damp, the larvae may become too cold and mold and fungus will grow.
Bumble Bee Box.
Place the nest in a dry, undisturbed area that has some obvious landmarks (a fence post, rock or building) to aid bee navigation; these landmarks are important to bees returning from foraging. Nesting boxes that are at ground level or slightly buried (either with soil or straw) are the most attractive to queens of many species. Boxes placed on the surface should be level and stable. If you are burying your box, extend