Some Unresolved Issues of Measuring the Efficiency of Pollinators: Experimentally Testing and Assessing the Predictive Power of Different Methods

Table 5

Foraging modes, number of foragers, foraging rates, and pollen transfer efficiency of different flower visitors of alfalfa (Medicago sativa).

Parameter	Foraging mode	Visitor species
		Apis dorsata	Apis florea	Chalicodoma cephalotes	Chalicodoma rubripes	Megachile nana
No. of foragers /m^2; (a)	N	1.87±0.09	5.81±0.8	0	0	0 (b)
	P	0.50±0.001	0	0	0	0
	NP	0.25±0.01	0	0.23±0.04	3.6±0.4	2.70±0.2(c)
	N+P+NP	1.89±0.09	5.81±0.8	0.23±0.04	3.6±0.4	2.70±0.2(c)
Foraging rate (per minute); (a)	N	7.6±0.42	4.9±0.31	0	0	0
	P	7.2±0.47	0	0	0	0
	NP	5.8±0.34	0	11.5±0.52	15.3±0.43	18.4±0.3(c)
PTE (per minute)		0.65	0.0	11.5	15.3	18.4

a: mean ± SD of 125 observations; N: only nectar gathering; P: only pollen gathering; NP: nectar as well as pollen gathering; PTE: Pollen transfer efficiency; b: t (p < 0.05) = significant (values tested on the basis of paired t-test); c: F (P< 0.05) = significant (values tested for the visitors of a row); zero values indicate that pollinator behavior was absent.