Canopy compass in nocturnal homing of the subsocial shield bug, Parastrachia japonensis (Heteroptera: Parastrachiidae)
In contrast to an open environment where a specific celestial cue is predominantly used, visual contrast of canopies against the sky through the gap, known as canopy cues, is known to play a major role for visually guided insect navigators in woodland habitats. In this paper, we investigated whether a subsocial shield bug, Parastrachia japonensis, could gauge direction using canopy cues on a moonless night. The results show that they could perform the round trip foraging behaviour even in an experimental arena with only an artificial round gap opened in the ceiling of the arena and adjust their homing direction for a new azimuth when the gap was rotated. Thus, P. japonensis can use slightly brighter canopy cues as a compass reference but not complex landmarks during nocturnal homing behaviour.
KeywordsCanopy orientation Navigation Nocturnal foraging Subsocial shield bug Parastrachia japonensis
We thank Prof. (emeritus) S. Tojo and Dr. K. Matsubara (Saga University) for their many useful comments. This research was partially supported by a Ministry of Education, Science, Sports and Culture, Grant-in-Aid for JSPS Fellows, no. 16003679, 2004, and the Sasagawa Scientific Research Grant from The Japan Science Society. All experiments complied with the Guideline for Animal Experiments of Hamamatsu University School of Medicine.
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