Temperature-induced pupil movements in insect superposition eyes

Area of Science:

• Entomology
• Insect Physiology
• Sensory Biology

Background:

• Insect compound eyes possess pupils that regulate light.
• Pupillary responses are typically linked to ambient light levels.
• The influence of temperature on insect pupil dynamics remains largely unexplored.

Purpose of the Study:

• To investigate the effect of temperature on the pupil of insect compound eyes.
• To determine if temperature influences pupillary mechanisms in nocturnal insects.
• To characterize the temperature-dependent pupillary response in specific insect species.

Main Methods:

• Experiments were conducted on the turnip moth (Agrotis segetum), lacewing (Euroleon nostras), and codling moth (Cydia pomonella).
• Pupillary responses were observed in complete darkness across a range of temperatures.
• Key temperature thresholds for pupil closure (activation and closure temperatures) were identified.

Main Results:

• Insect pupils exhibit temperature-dependent responses in the absence of light.
• In Agrotis segetum, pupil closure occurs at specific high-temperature thresholds (T(a) and T(c)).
• Similar temperature-mediated pupillary responses were observed in lacewings and codling moths, indicating a widespread phenomenon in superposition eyes.

Conclusions:

• Temperature is a significant factor influencing pupil size in nocturnal insects with superposition eyes.
• This temperature-dependent pupil response may play a role in pre-adapting insect vision to varying light intensities.
• The findings suggest a broader ecological significance of temperature regulation in insect visual systems.