Forward and backward second-order Pavlovian conditioning in honeybees

Area of Science:

• Behavioral neuroscience
• Animal cognition
• Insect learning

Background:

• Second-order conditioning (SOC) involves associating a neutral stimulus with a previously conditioned stimulus.
• Previous SOC studies in honeybees yielded inconclusive results.
• Understanding SOC mechanisms in insects offers insights into associative learning.

Purpose of the Study:

• To investigate and demonstrate second-order conditioning (SOC) in honeybees (Apis mellifera).
• To delineate critical conditions for excitatory SOC using olfactory cues and gustatory reinforcement.
• To compare the effectiveness of forward- versus backward-pairing in SOC.

Main Methods:

• Classical conditioning of the proboscis extension response (PER) in honeybees.
• Differential conditioning using odor A (CS) and sugar (US), and odor B (non-reinforced).
• Three experiments tested SOC with partially overlapping odors (C-A, C-B) and varying temporal sequences (C-A vs. A-C).

Main Results:

• Forward-pairing of a novel odor (C) with a previously reinforced odor (A) elicited a 40% PER (Experiment 1 & 2).
• Forward-pairing with a non-reinforced odor (B) or backward-pairing (A-C) resulted in lower PER (20% and 15-25%, respectively).
• Excitatory SOC in bees requires forward-pairing, with backward-pairing being less effective.

Conclusions:

• Honeybees exhibit second-order conditioning (SOC) under specific forward-pairing conditions.
• Odor A acts as a secondary reinforcer for excitatory SOC when presented after odor C.
• Forward-pairing is crucial for effective SOC in honeybees, highlighting temporal dynamics in associative learning.