Relationship between action spectrum and spectral sensitivity of compound eyes relating phototactic behavior of the western flower thrips, frankliniella occidentalis

Abstract

We measured the phototactic behavior of the western flower thrips, Frankliniella occidentalis (Pergande) under the LED light of various spectral content and intensity. The light intensity required to elicit a 50% behavioral response to the stimulus yielded the action spectrum of the phototactic behavior. The action spectrum peaks at 525 and 355nm, between 355 to 660nm. This profile reasonably fits the spectral sensitivity of the compound eye as determined by the electroretinographic method. In a choice experiment where the insects were subjected to select either 355nm or 525nm of equal photon flux, they preferred 355nm to 525nm, indicating that the insects prefer ultraviolet (UV) radiation under the condition of multiple light sources.