Figure 1.
Relationship between sucrose and shock responsiveness in honeybees.
a) Sucrose responsiveness. Black circles, % of PER to a series of sucrose solutions of increasing concentration (n = 198); white circles, % of PER of the same bees to the presentation of water (control). Bees increased their response to sucrose solution of increasing concentrations. b) Shock responsiveness of the same bees. Black circles, % of SER to a series of shocks of increasing voltage; white circles, % of SER of the same bees to placements in the same setup without shock delivery (control). Bees increased their response to shocks of increasing voltage. c A 7×7 matrix of correlation between sucrose and shock responsiveness scores in the same bees. Scores varied from 0 (no response to any stimulus tested in the series) to 6 (responses to all six stimuli of the series). Colors assigned to each box represent the percentage of bees exhibiting a particular combination of sucrose and shock responsiveness scores. No significant correlation exists between sucrose and shock responsiveness scores (R = −0.03; t (N-2) = −0.42; NS).
Figure 2.
Learning and retention performances in olfactory conditioning of SER as depending on shock responsiveness.
a) Black symbols: % of SER in differential conditioning of a low-responsiveness group (scores 1–3; n = 80); white symbols: % of SER in differential conditioning of a high-responsiveness group (scores 4–6; n = 67). Circles: responses to the CS+; squares: responses to the CS−. Both groups learned the differentiation between punished and non-punished odors but bees of the high-responsiveness group achieved better performances than bees of the low-responsive group and remembered better one hour after conditioning (white vs. black bars). b) Delta value (Δ) resulting from the difference between the response to the CS+ and to the CS−, for high-responsiveness bees (white circles) and low-responsiveness bees (black circles). High-responsiveness bees learned and remembered better (white vs. black bars) the discrimination between CS+ and CS−. *: p<0.05.
Figure 3.
Shock responsiveness and learning and retention performances of guard and nectar forager bees.
a) Guard bees (black circles; n = 151) were less responsive to a series of shocks of increasing voltage than forager bees (white circles; n = 205). Black and white squares represent the SER responses to the placements in the same setup without shock (control) of guard and forager bees respectively. b) % of SER responses of guard (black symbols; n = 105) and nectar forager bees (white symbols; n = 102) during differential SER conditioning. Circles: SER to CS+; Squares: SER to CS−. Both groups learned the discrimination between punished and non-punished odors but nectar forager bees responded more to and remembered better the CS+ one hour after conditioning (white vs. black bars) than guard bees. c) Delta value (Δ) resulting from the difference between the response to the CS+ and to the CS− along conditioning of nectar foragers (white circles) and guard bees (black circles). Foragers learned better to differentiate between CS+ and CS− and remembered better the difference (white vs. black bars). *: p<0.05.