Emissive color preferences of Colorado potato beetle larvae

Abstract

The Colorado potato beetle, Leptinotarsa decemlineata (Say), is an important pest of potato, as well as other solanaceous crops. While orientation of adult beetles to visual stimuli has been reported, nothing, up until now, has been known about whether the larvae also display positive phototactic behavior. In this study, we investigated the orientation behavior of Colorado potato beetle larvae in response to emissive colors produced by light emitting diodes of narrow band widths in a dual-choice arena adapted to a servosphere. Our results show that the larvae preferred to orient toward blue (472 nm), orange (590 nm), red (660 nm), green (570 nm), white (420–775 nm), and yellow (585 nm) over darkness when both alternatives were offered. No orientation preferences were elicited by infrared (940 nm) or ultraviolet (351 nm) light. When paired light choices were offered, the larvae showed a strong preference to some wavelengths more than others. This research characterizes visual preferences for Colorado potato beetle larvae and suggests that visual cues may be important in host plant orientation for these larvae, and perhaps, other immature insects. Our results suggest the potential for using photic stimuli for manipulation of larvae for control strategies. This research was carried out during the sabbatical leave of V.D.C.S. at the USDA, Beltsville, MD