Preference and Utilization of Maize Endosperm Variants by the Rice Weevil12

Abstract

Food preference and utilization experiments with Sitophilus oryzae (L.) used 17 corn genotypes, including 11 inbreds with waxy (wx, wx) and opaque 2 (Op2) conversions and 6 commercial hybrids. Measurements made on each genotype on number of adults attracted and the number of eggs laid indicated that higher numbers of rice weevils were attracted to the hybrids than to inbred lines. Measurements in utilization of food were days required to reach pupation, amount of food consumed, feces excreted, and pupal weight. Efficiency of conversion of ingested food (ECI), approximate digestibility (AD), and efficiency of conversion of digested food (ECD) were calculated indices. The weevils were sensitive to the various genotypes. Time required to pupation was longer in normal genotypes if compared with those having either the Op2 gene or the wx gene. The wx gene reduced the food consumed and feces excreted, and ECI and ECD were lower in genotypes with Op2 but higher when the wx gene was present. Food consumed and fecal weight were higher for the hybrids compared with the inbred lines, but the ECI and ECD indices were lower.