Food intake and utilization by Diatraea saccharalis (Fabr.) (Lepidoptera: Pyralidae), Heliothis virescens (Fabr.) and Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) at two different temperatures

Abstract

The goal of this work was to determine the most suitable temperature for rearing Spodoptera frugiperda (J.E. Smith), Diatraea saccharalis (Fabr.) and Heliothis virescens (Fabr.) in artificial diet, by means of measures of food intake and utilization between 25 and 30°C. Fifty worms per species, individualized and kept in 8.5 cm long and 2.5 cm diameter glass containers were studied at the temperatures mentioned, 60±10% RH, and 14 hour photophase. Based on dry matter, one determined worm weight at maximum development, food consumed and feces eliminated at both conditions (25 and 30°C) and the nutritional ratios: relative consumption ratio (RCR), relative growth ratio (RGR), relative metabolic ratio (RMR), approximate digestibility (AD), efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD). The most suitable temperature for S. frugiperda was 30°C since it provided higher weight at the maximum development, higher weight gain, higher growth ratio, higher ECI, higher ECD, and lower metabolic cost. On the other hand, no differences regarding nutritional rates were observed for either H. virescens or D. saccharalis evaluated at both thermal conditions. Thus, for one generation and based on nutritional rates, the highest temperature (30°C) is recommended for laboratory maintenance of S. frugiperda. As for the other species, rearing at 25 or 30°C is indifferent.