The recessive mutant, diminutive-wing (di), discovered in 1966 at the University of California, Davis, has fore wings averaging 7.5 mm in length (79-4 percent of normal), wing area (right side) 17.3 mm² (62.9 percent of normal), and a normal venation pattern. The queens have slightly convex wings and do not fly; thus they must be artificially inseminated. Some di workers and a few di queens uncouple their fore and hind wings.

In this study, the wing-beat frequency of di workers averaged 251.8 beats/sec (22.2 percent more than normal). Flight time to a feeder 1 km distant averaged 3.9 min (5.4 percent longer than normal), and return flights averaged 6.1 min (35.6 percent longer than normal).

Departing di foragers had an average of 1.9 ?liters of nectar (57.6 percent of normal), and returned with an average of 7.8 ?liters (30.8 percent of normal). Pollen loads averaged 16.4 mg (88.2 percent of normal). When given a 76-mg metal weight, 50 percent of the normal bees returned from 100 m, but none of the di bees were recovered. Syrup loads of both normal and di bees became larger when gathered at increasing distances from the hive.

The ratio of diminutive-wing to normal bees at feeding stations diminished with increasing distance. When di and normal foragers were from different colonies, di successfully dominated feeders to 300 m.

There were no significant quantitative or qualitative differences between normal and di bees with respect to communication of the distance to feeders. However, among nectar carriers, significantly more di than normal bees performed “round” dances, signifying food at close range.

Successful return of foragers released 1 km from the hive was 28.9 and 10.0 percent, respectively, for normal and di workers. Colonies of diminutive-wing bees appeared to have a natural foraging range that was less than that of normal bees, but the difference was not great.