Behavioral response of Dendroctonus pseudotsugae and Trypodendron lineatum (Coleoptera: Scolytidae) to selected wavelength regions of the visible spectrum

Behavioral experiments using a phototactic response by adult Dendroctonus pseudotsugae Hopkins and Trypodendron lineatum Olivier were tested in a two-choice, walking bioassay to all possible pairs of a series of wavelengths within the visible spectrum. With Corning band-pass and cut-off filters sensitivity maxima for both sexes of D. pseudotsugae were to the shortest wavelengths (425 and 476 nm), with a secondary response to the longest wavelengths (600–625 nm). With more precise Balzer band-pass filters both D. pseudotsugae and T. lineatum responded similarly, with sensitivity maxima for both sexes to wavelengths in the region of 420–480 nm and an additional response peak around 500–525 nm. These results correspond well with other behavioral and electrophysiological data from scolytid beetles.