Successive Olfactory Reversal Learning in Honeybees

Abstract

Honeybees Apis mellifera can associate an originally neutral odor with a reinforcement of sucrose solution. Forward pairings of odor and reinforcement enable the odor to release the proboscis extension reflex in consecutive tests. Bees can also be conditioned differentially: They learn to respond to a reinforced odor and not to a nonreinforced one. They can also learn to reverse their choice. Here we ask whether honeybees can learn successive olfactory differential conditioning tasks involving different overlapping pairs of odors. The conditioning schedules were established in order to train the animals with 3, 2, 1, or 0 reversals previous to a last differential conditioning phase in which two additional reversals were present. We studied whether or not successive reversal learning is possible and whether or not learning olfactory discrimination reversals affects the solving of subsequent discrimination reversals. Therefore we compared the responses of bees that had experienced reversals with those of bees that had not experienced such reversals when both are confronted with a new reversal situation. In experiment 1 we showed that bees that had experienced three previous reversals were better in solving the final reversal task than bees with no previous reversal experience. In experiment 2, we showed that one reversal learning is enough for bees to perform better in the final reversal task. The successive different reversals trained in our experiments resemble the natural foraging situation in which a honeybee forager has to switch successively from an initial floral species to different ones. The fact that experiencing such changes seems to improve a bee's performance in dealing with further new exploited food sources has therefore an adaptive impact for the individual and for the colony as a whole.

The Memory Trace Supporting Lose-Shift Responding Decays Rapidly after Reward Omission and Is Distinct from Other Learning Mechanisms in Rats

“…In particular, animals performing operant tasks for appetitive outcomes tend to repeat responses that were rewarded in immediately preceding trials (win-stay), whereas they tend to shift to alternative choices if preceding responses were not rewarded (lose-shift). These choice strategies have been reported in many studies spanning a wide array of tasks and species, including humans (Frank et al, 2007; Wang et al, 2014), nonhuman primates (Mishkin et al, 1962; Schusterman, 1962; Lee et al, 2004), rats (Evenden and Robbins, 1984; Skelin et al, 2014), mice (Means and Fernandez, 1992; Amodeo et al, 2012), pigeons (Rayburn-Reeves et al, 2013), and honeybees (Komischke et al, 2002). It is important to identify the neural mechanisms of these ubiquitous strategies to improve neurobiologically grounded theories of choice behavior.…”

Sleep deprivation affects extinction but not acquisition memory in honeybees

“…One of three odors-2-octanol, limonene, and peppermint-was used as a CS, and 30% sucrose solution was used as the unconditioned appetitive stimulus (US). The odors were delivered by an olfactometer (Galizia et al 1997;Komischke et al 2002). A continuous stream of air was blown over the bee's antennae, which was switched to a cartridge containing 4 mL of odor pipetted onto a half square inch filter paper, inside a 1-mL syringe.…”

Forward and backward second-order Pavlovian conditioning in honeybees

“…Citral, geraniol, 2-hexanal, nonanone, 2-octanol, and limonene were used as odor CSs, referred to as A, B, and C in later sections. A computer-driven odor device, blowing a continuous stream of air over the antennae, was used to deliver the odors to the bees (Galizia et al 1997;Komischke et al 2002). Four 1-mL syringes, each containing 4 µL of the desired odor on a half square inch of filter paper, were fitted into the holes of the odor-delivering device (Galizia et al 1997).…”