Bermuda grass (Cynodon dactylon) as a pollen resource for honey bee colonies in the Lower Colorado River agroecosystem

Abstract

Beekeepers in southwestern Arizona and southeastern California frequently report the poisoning of numerous honey bee colonies following the application of insecticides to blooming bermuda grass grown for seed. This study was undertaken to characterize the relative frequency, intensity, and seasonality of honey bee foraging for bermuda grass pollen. The results show that bermuda grass pollen was gathered only intermittently at both of two study sites throughout the 54 week study period. Moreover, only a small fraction of all pollen gathered, 1.2% at site A and 1.5% at site B, was from bermuda grass. Bermuda grass does not appear to be a preferred pollen resource for honey bees, and it may be foraged only in response to the relative unavailability of other more acceptable sources. Honey bee losses due to insecticides applied to bermuda grass may be driven by these foraging dynamics and/or other factors.