Spectral sensitivities of wolf spider eyes

Area of Science:

• Zoology
• Animal Vision
• Sensory Ecology

Background:

• Wolf spiders (Lycosidae) exhibit complex visual systems with distinct principal and secondary eyes.
• Understanding the spectral sensitivities of spider photoreceptors is crucial for comprehending their ecological interactions and behaviors.

Purpose of the Study:

• To investigate the spectral sensitivities of principal and secondary eyes in wolf spiders using electroretinography (ERG).
• To determine the role of chromatic adaptation and potential accessory pigments in modulating visual sensitivity.

Main Methods:

• ERG recordings were performed on intact wolf spiders exposed to various spectral lights.
• Chromatic adaptations were employed to assess changes in spectral sensitivity.
• Analysis of ERG waveforms, including secondary peaks, to infer visual pigment properties.

Main Results:

• Secondary eyes showed maximal sensitivity at 505-510 nm, unaffected by chromatic adaptation.
• Principal eyes exhibited significant ultraviolet sensitivity (380 nm) compared to blue-green light (505 nm).
• Some principal eyes displayed a decrease in absolute sensitivity over time, with variable UV sensitivity potentially linked to accessory pigments.

Conclusions:

• Both principal and secondary eyes utilize a visual pigment with peak absorption at 505-510 nm.
• Variable UV sensitivity in principal eyes may result from a second pigment or an accessory pigment facilitating energy transfer.
• ERG waveform analysis provided insights into photoreceptor function and potential light scattering effects.