Swimming behavior of an aquatic weevil, Lissorhoptrus oryzophilus (Coleoptera : Curculionidae)

The swimming behavior of the rice water weevil Lissorhoptrus oryzophilus Ku schel (Coleoptera: Curculionidae) is unique in comparison to that of most o ther aquatic weevils. Propulsion during swimming is provided only by the me sothoracic legs. The legs are moved synchronously during protraction and re traction. The pro- and metathoracic legs serve as diving planes and provide stability The average rice water weevil swimming speed was 1.53 (+/-0.15 S E) cm per s with a range of 0.88 to 2.52 cm per s. Weevils averaged 5.67 (/-0.22 SE) strokes per s. The mode of swimming by L. oryzophilus differs from those described for Phy tobious leucogaster (Marsham) (= Litodactylus leucogaster), P. comari (Herb st), Bagous cavifrons LeConte, B. americanus LeConte and B. limosus Gyllenh al. It also differs from descriptions of swimming for other aquatic Coleopt era and Hemiptera. Furthermore, L. oryzophilus swims below the surface and was observed at depths of 18.0 cm in the laboratory. This brings the modes of free swimming (exclusive of skating) to at least 3 by adult aquatic curc ulionids.