Sudden declines of frequent and effective pollinators are often assumed to reduce pollination success. Yet this assumption has rarely been tested experimentally and may depend upon responses of other pollinators in the community. Hallett et al. temporarily excluded bumble bees in populations of the milkweed Asclepias verticillata, and quantified pollinator visitation rates and pollen receipt in both control and bumble bee exclusion plots. Asclepias pollination success did not decline following bee exclusion due to a nearly three-fold increase in wasp visitation. This highlights the importance of studies that explore the effectiveness and compensatory responses of other pollinator species in the community.
Here is a link to the paper: https://doi.org/10.1093/aobpla/plx020
Pollination success following loss of a frequent pollinator: the role of compensatory visitation by other effective pollinators
Allysa C. Hallett, Randall J. Mitchell, Evan R. Chamberlain, and Jeffrey D. Karron