Floral reward production is timed by an insect pollinator

Area of Science:

• Animal Behavior
• Cognitive Ecology
• Insect Neuroscience

Background:

• Interval timing, the ability to perceive elapsed durations, is crucial for many animal behaviors.
• While studied in vertebrates, interval timing capabilities in invertebrates, particularly pollinators like bumble-bees, are less understood.

Purpose of the Study:

• To investigate interval timing and reward learning in bumble-bees (Bombus impatiens).
• To determine if bumble-bees can associate specific time intervals with distinct reward qualities.

Main Methods:

• Bumble-bees were trained to forage on artificial flowers with varying delays between low- and high-quality sucrose rewards.
• The delay intervals (30s, 150s) were systematically altered, and bee visitation times to the high-quality flower (HQF) were recorded.
• A reward-replacement test assessed bees' ability to distinguish reward content based on learned timing.

Main Results:

• Bumble-bees adjusted their foraging behavior based on the delay interval, visiting the HQF sooner after shorter delays.
• Bees' visits to the HQF peaked near the end of both delay intervals, indicating temporal anticipation.
• In a reward-replacement test, bumble-bees rejected the HQF when its reward quality was unexpectedly reduced, demonstrating memory of reward content.

Conclusions:

• Bumble-bees exhibit sophisticated interval timing abilities, adjusting foraging based on learned durations.
• These insects demonstrate associative learning, remembering both the timing and the quality of rewards.
• The findings highlight complex cognitive processes in bumble-bees, crucial for their ecological role as pollinators.