title: Behavioural assessment of visual acuity in bumblebees (Bombus impatiens).
abstract: The present study used previously developed techniques to measure resolution acuity in bumblebees (Bombus impatiens). Bees were required to discriminate between horizontal and vertical gratings in a Y-maze apparatus. The gratings had a mean luminance of 9 cd m(-)(2) and a Michelson contrast of 84 %. For different bees, either the horizontal or vertical grating was rewarded. Rewarded gratings were associated with a sucrose and water solution (30 % sucrose by volume) and unrewarded gratings with plain water. Acuity estimates were established at several different viewing distances over several sessions using a method of constant stimuli. Visual acuity functions were generated from the performance data, and acuity thresholds were interpolated at a performance level of 65 % correct. When corrected for viewing distance, best angular acuity obtained for horizontal and vertical gratings was 0.35 and 0.36 cycles degree(-)(1), respectively. These results are compared with those of the honeybee and discussed in the context of the bumblebee's foraging behaviour.
authors.affiliation: Department of Psychology and Department of Zoology, University of Western Ontario, London, Ontario, Canada N6A 5C2.
authors.forename: T
authors.initials: T
authors.lastname: Macuda
authors.forename: R J
authors.initials: RJ
authors.lastname: Gegear
authors.forename: T M
authors.initials: TM
authors.lastname: Laverty
authors.forename: B
authors.initials: B
authors.lastname: Timney
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*