Meeting Abstract

P2-21  Friday, Jan. 5 15:30 – 17:30  Toxicity Assesment of Glyphosate on Honey Bee (Apis Meliffera) Spermatozoa HOOPMAN, AR; NORTH, HA*; RAJAMOHAN, A; BOWSHER, JH; North Dakota State University, Fargo; North Dakota State University, Fargo; USDA-ARS, Fargo; North Dakota State University, Fargo Heather.ann@ndsu.edu

In 2016-2017, 33.2% of managed honey bee colonies in the U.S. were lost due to Colony Collapse Disorder (CCD). Commonly used pesticides are among the suspected reasons for bee mortality. N-(phosphonomethyl)glycine (glyphosate) is a widely used herbicide in the U.S. and has previously been shown to have behavioral effects on worker honey bees. However, effects of pesticides on honey bee reproductive physiology is understudied, especially with respect to the drone (male) bee. The queen bee receives semen from multiple drones just once during her life and stores the spermatozoa for 2-7 years. Even small amounts of pesticide tainted spermatozoa has the potential to affect the queen’s fertility for the duration of her life. The purpose of this study was to assess toxicity of glyphosate to honey bee spermatozoa by determining the lethal dose (LD₅₀) and lethal time (LT₅₀). Previous studies elsewhere report that the nectar in a plant sprayed with glyphosate can contain between 0.002-0.0032 mg/ml of the herbicide. Sperm samples were collected from drones returning from the mating flight and treated with glyphosate dissolved in dimethyl sulfoxide (DMSO) to determine the lethal dose and time (LD₅₀ and LT₅₀), respectively. After exposure, sperm samples were subjected to motility and live/dead assays. Preliminary results of this study support the hypothesis that glyphosate negatively affects honey bee spermatozoa. At 40 minutes of exposure time, the LD₅₀ concentration was found to be 0.31mg/mL (p<0.0001). At 0.05mg/mL concentration of glyphosate in the semen, the LT₅₀ was found to be 468 minutes (p=0.009).