Ranking of sugar solutions by harnessed bees.

<p>The graph shows the percentage of proboscis extension responses (PER) upon antennal stimulation with fructose 1,66 M, glucose 1,66 M and sucrose 1 M. Each sugar was assayed with a different group of bees experiencing also a control stimulation with distilled water control (n = 30 each). Bees responded significantly more to the sugar than to the water. The preference ranking was fructose < glucose < sucrose. Different letters indicate significant between-group differences.</p

Devaluation of fructose 1.66 M.

<p>The graph shows the performance (percentage of proboscis extension responses or PER) during (<b>a</b>) an odor-fructose association in which the response to the odor (conditioned stimulus or CS) was quantified, and during (<b>b,c</b>) a test phase following a devaluation phase in which responses to the sugar (US; see <b>b</b>) and to the odor (CS see <b>c</b>) were quantified in paired and unpaired groups of bees experiencing or not an association between sugar and either distilled water, quinine 10 mM, LiCl 140 mM or amygdaline 1 mM (319 bees in total). (<b>a</b>) All bees learned the odor-fructose association. The graph shows the pooled acquisition performance of all eight groups of bees. (<b>b</b>) Ingestion of quinine, LiCl and amygdaline decreased US responsiveness with respect to a water control. Responses of paired and unpaired groups were similar. (<b>c</b>) Ingestion of quinine, LiCl and amygdaline decreased CS responsiveness with respect of a water control. Responses to a novel odor remained low and equivalent in all groups. Different letters indicate significant between-group differences.</p

Kaplan–Meier curves of survival for harnessed honeybees following feeding of aversive compounds.

<p>(<b>a</b>) <b><i>First series</i></b>. The probability of survival differed significantly between groups (long-rank test: <i>χ²</i> = 64.07, df:3, <i>p</i><0.0001). The group of honeybees having ingested NaCl 3 M (n = 30) and quinine 100 mM (n = 30) exhibited a significant decrease of their survival probability compared to the distilled water group (n = 30). The group having ingested salicine 100 mM (n = 30) had intermediate mortality levels and comparison to the distilled water group, which exhibited a low decrease of the probability of survival, was marginally non-significant (<i>Z</i> = 1.78, <i>p</i> = 0.07). (<b>b</b>) <b><i>Second series</i></b>. The probability of survival differed significantly between groups (long-rank test: <i>χ²</i> = 108.93, df:8, <i>p</i><0.0001). The group of bees having ingested sucrose 1 M group (n = 30) did not exhibit any variation of their probability of survival over time. The quinine 100 mM group (n = 30) experienced higher mortality than the distilled water group (n = 60). The quinine 10 mM (n = 60) and LiCl 140 mM (n = 60) groups experienced also induced higher mortality than the distilled water group. The amygdaline 1 mM group (n = 30) exhibited inetrmediate mortality compared to the the distilled water group. Mortality in the L-canavanine 40 mM (n = 30) and 100 mM (n = 30) groups was not significantly different from that of the distilled water group. The probability of survival from the groups having ingested mixtures of quinine 10 mM and sucrose 1 M (n = 30) and LiCL 140 mM and sucrose 1 M (n = 30) did not differ from that of the distilled water group.</p