Vertical disparity and binocular vision in the praying mantis

Area of Science:

• * Neuroethology
• * Insect vision
• * Predator-prey interactions

Background:

• * Binocular vision in praying mantises is crucial for prey capture.
• * Vertical disparities typically provide depth information and guide head movements.
• * The impact of large, artificial vertical disparities on mantis behavior is not well understood.

Purpose of the Study:

• * To investigate the effects of experimentally induced vertical disparities on praying mantis prey capture.
• * To determine how large vertical disparities influence head saccades and distance perception.
• * To assess the threshold of vertical disparity that inhibits striking behavior.

Main Methods:

• * Prisms were used to introduce controlled vertical disparities in front of praying mantis eyes.
• * Head saccade frequency and amplitude were analyzed during target fixation.
• * The mantises' striking behavior and perceived target distance were recorded under varying disparity conditions.

Main Results:

• * Fixating saccade frequency remained normal across tested vertical disparities (up to 30 degrees).
• * The vertical component of saccade amplitude represented a compromise between individual eye inputs.
• * Striking reluctance increased with vertical disparity, with no strikes occurring beyond 15 degrees.
• * Perceived target distance was unaffected by imposed vertical disparities.

Conclusions:

• * Praying mantises can compensate for significant vertical disparities in head saccade control.
• * Large vertical disparities disrupt the decision to strike, indicating a disparity-dependent inhibition of predatory motor programs.
• * The system exhibits robustness to vertical disparity in saccade generation but not in predatory action initiation.