Visually-guided defensive behaviors in triatomines (Heteroptera: Reduviidae)

Area of Science:

• Insect behavior
• Visual ecology
• Neuroethology

Background:

• Reduviidae, encompassing assassin bugs and kissing bugs, possess compound eyes.
• Image vision is linked to feeding in assassin bugs, but its role in kissing bug defense is unstudied.

Purpose of the Study:

• Investigate the role of vision in supporting defensive behaviors in kissing bugs.
• Determine how visual stimuli influence freezing and escape responses in Rhodnius prolixus.

Main Methods:

• Exposed Rhodnius prolixus to visual looming stimuli with varying dynamics and contrast.
• Assessed responses such as freezing and escaping.
• Evaluated habituation by presenting repeated stimuli with short intervals.

Main Results:

• Rhodnius prolixus consistently exhibited freezing or escaping in response to visual looming stimuli.
• Escape responses were triggered by stimuli mimicking predator approach at sustained velocity.
• Freezing occurred regardless of contrast, while escape required high contrast.
• No habituation was observed after repeated stimulation.

Conclusions:

• The visual system plays a significant role in kissing bug defense.
• Defensive responses are fast, flexible, and dependent on stimulus information and perceived risk.
• Kissing bug visual defenses are comparable to those in highly visual arthropods.