Diurnal locomotion and feeding activities of two rice-ear bugs, Trigonotylus caelestialium and Stenotus rubrovittatus (Hemiptera: Heteroptera: Miridae)

Diurnal locomotion and feeding activities of Trigonotylus caelestialium (Kirkaldy) and Stenotus rubrovittatus (Matsumura) were investigated using a video camera and electrical penetration graph. Diurnal locomotion activity of T. caelestialium was higher in photophase than in scotophase, whereas that of S. rubrovittatus was higher in scotophase than in photophase. No difference was observed in the locomotion activity of T. caelestialium between mated and unmated bugs or between males and females. Locomotion activity of S. rubrovittatus was different between the sexes. The activity of females was higher than that of males. Diurnal rhythms of feeding activity were obscure compared with those of the locomotion activities in both mirids. The feeding behavior of T. caelestialium was significantly more active in the photophase than in the scotophase. In S. rubrovittatus, feeding activity of males was higher in the scotophase than in the photophase, whereas females showed no such difference. It is thought that both species of mirid bugs are active during the daytime and nighttime, although the locomotion and feeding activities of T. caelestialium were high in the photophase, while those of S. rubrovittatus were high in the scotophase.