The Presence of Conspecific Decoys Enhances the Attractiveness of an NaCl Resource to the Yellow-Spined Locust, Ceracris kiangsu

Adults of the yellow-spined bamboo locust, Ceracris kiangsu Tsai (Orthoptera: Oedipodidae), aggregate and gnaw at human urine-contaminated materials, a phenomenon termed puddling. Several urine-borne chemicals, including NaCl, are known to stimulate adult C. kiangsu to consume filter paper. Because in nature C. kiangsu adults may use cues to locate puddling resources, we tested the influence of conspecific decoys (dried C. kiangsu) on foraging and consumption of 3% NaCl-treated filter paper. In a two-choice test experiment in the laboratory, female adults showed no preference for filter papers (not treated with NaCl) with or without decoys. In contrast, C. kiangsu females consumed significantly more NaCl-treated filter paper on which conspecific decoys were attached than those without decoys in both the laboratory and in a bamboo forest. When the bait was changed to 3% NaCl plus the insecticide bisultap, significantly more C. kiangsu were killed in the bamboo forest when decoys were present, however the results were not significant when the experiment was done in the laboratory. Hence, moving towards conspecifics seems to facilitate NaCl resource foraging in C. kiangsu, suggesting that the presence of conspecifics promotes feeding on puddling resources.