Table 3.

Response of fruit and seed set to experimental exclusion or enrichment of bumble-bee queens in caged groups of plants, late 1991. (Fruit set did not differ between the control and bees-added treatments (2 × 2 contingency χ² = 0.36, p = 0.55), although both differed sharply from the bees-excluded treatment. Control and bees-added produced equivalent numbers of seeds per fruit (two-tailed t-test, p = 0.34).)

	control	bees added	bees excluded
flowers that successfully fruited	31	30	0
flowers that aborted	23	28	27
seeds per successful fruit (mean, s.d.)	23.7, 11.2	26.9, 13.8	undefined