Drosophila increase exploration after visually detecting predators.

Area of Science:

• Ethology
• Neuroethology
• Insect Behavior

Background:

• Novel stimuli trigger specific exploration behaviors for familiarization.
• Predator cues often suppress specific exploration through defensive reactions.
• Drosophila melanogaster cultured for decades lack recent predator threat exposure.

Purpose of the Study:

• To investigate if Drosophila melanogaster exhibit suppressed specific exploration in response to predator cues.
• To determine the sensory modalities Drosophila melanogaster use to detect predators.
• To examine the behavioral responses, including exploratory activity and habituation, to predator stimuli.

Main Methods:

• Experimental setup in a circular arena with centrally-caged wild-harvested predators (Plexippus paykulli, Phyllovates chlorophaena) and mock stimuli.
• Behavioral assays using wild-type, visually impaired, and orco2 mutant Drosophila melanogaster.
• Measurement of avoidance behaviors and exploratory activity in response to predator and mock stimuli.

Main Results:

• Wild-type Drosophila actively avoided real predators and a mock spider, with exaggerated avoidance of a moving mock spider.
• Visually impaired mutants failed to detect predators and mock stimuli, while anosmic mutants could detect predators.
• Exploratory activity increased in the presence of predators and moving mock stimuli, decreasing after exploration, suggesting habituation.

Conclusions:

• Drosophila melanogaster possess innate, visually-mediated defensive behaviors towards predators, even after prolonged isolation from threat.
• Predator presence initially increases exploratory activity, which can habituate over time.
• These findings challenge the notion that predator cues universally suppress exploration in naive Drosophila.