Revisiting absent trails: Spatial memory of trail pheromones in termites

Area of Science:

• Animal Behavior
• Chemical Ecology
• Neuroethology

Background:

• Termites utilize pheromones for social coordination, particularly trail pheromones in foraging and recruitment.
• Current models often view termite navigation as a direct response to pheromone gradients, lacking spatial memory.
• The capacity for termites to form and use spatial information about chemical cues remains largely unexplored.

Purpose of the Study:

• To investigate if prior exposure to trail pheromones influences termite movement after the pheromone source is removed.
• To determine if termites can retain and utilize spatial information from past pheromone encounters.
• To explore the potential for coarse spatial bias in termite navigation.

Main Methods:

• Termites were exposed to artificial trail pheromones on a substrate.
• Movement patterns were analyzed after the pheromone-marked substrate was removed.
• Entries into target zones and inward excursions were quantified in immediate and extended tests.

Main Results:

• No significant immediate return to the precise pheromone location was observed.
• Termites showed increased entries and inward movement towards the previously marked area in extended tests.
• A broad spatial bias, rather than precise point revisitation, was evident in pheromone-exposed termites.

Conclusions:

• Termites can retain and utilize coarse spatial information about previously encountered trail pheromones.
• Pheromone experience can influence termite movement even after the chemical cue is removed.
• Findings suggest a role for spatial memory in termite navigation, extending beyond immediate stimulus-response models.