Elytral color dimorphism in rice water weevil (Coleoptera: Curculionidae): Occurrence in spring populations and relationship to female reproductive development

Abstract

Adults of the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), were collected from three sources: 1) overwintering sites near rice, Oryza sativa L.; 2) a light trap placed in grassy vegetation and fallow fields; and 3) flooded rice plots near Beaumont, TX, from mid-April to late May 2005. Their color morph and reproductive status were surveyed. Frequency of the dark morph (36.0, 45.8, and 31.6% at each collection source, respectively) was significantly lower than that of the light morph (64.0, 54.2, and 68.4% respectively). Dark males accounted for only 3.5-7.4% of the populations, significantly less abundant than light males (28.8-32.0%) in each collection source. The morph frequency changed significantly with season in females, but not in males. Female-biased sex ratios were observed with the proportion of females to males being 1.5, 2.1, and 1.9 at each collection source, respectively. In most collections, ovarian development and mating status were similar between the females of different morphs, suggesting that elytral morph in this weevil might not be related to female reproductive development. © 2006 Entomological Society of America.