Figure 7

Asclepias syriaca female function and male function pollinator effectiveness ( PE ), pollinator importance ( PI ), and self-incompatibility-controlled pollinator importance ( SICPI ) versus visitor taxon. A, measures of pollinator effectiveness for female function (calculated using pollinium insertions); B, measures of pollinator effectiveness for male function (calculated using pollinium removals). Black bars, Apis mellifera; gray bars, Bombus spp.; open bars, lepidopterans. The unit for PI and SICPI are the same as PE, insertions per flower on the focal inflorescence. The error bars for PE, PI, and SICPI are 95% confidence intervals (C.I.). Asterisks indicate P < 0.05 for comparisons between visitor taxa in PE, PI, or SICPI. Comparisons for PE were based on permutation tests generated from Monte Carlo re-sampling. Comparisons for PI and SICPI were based on mean and C.I. estimates. The mean male and female pollinator importance (PI) values in A. mellifera and Bombus spp. were not within the 95% C.I. of lepidopterans; therefore, pollinator importance in lepidopterans was significantly greater than pollinator importance in Bombus spp. or A. mellifera. This result is inconsistent with our pollinium-insertion data and may be due to the fact that lepidopterans had the smallest average inflorescence size (pollinator effectiveness is calculated as insertions or removals per focal-inflorescence flower) and that we controlled for sampling effort differences between diurnal and nocturnal visitors when calculating relative abundance (pollinator importance is pollinator effectiveness multiplied by relative abundance). In other words, we collected fewer nocturnal samples, and all nocturnal visitors were lepidopterans.