Spodoptera frugiperda (J.E. Smith, 1797) is considered a key pest of maize. However, the artificial diets used for rearing this insect in the laboratory do not contain corn. The aim of this study was to evaluate the biology and to compare the food consumption by S. frugiperda, as well as the food preference of the larvae in the standard diet and the corn-based diet. Three of the following diets were evaluated: a standard diet based on beans (D1), a diet with corn flour as substitute for wheat germ (D2), and a diet replacing beans with green corn (D3). The biological parameters evaluated were period and survival of larvae and pupae; weight of male and female pupae; sex ratio; fecundity; egg incubation period; and adult longevity. The nutritional indices were determined and the biological data obtained were used to determine the parameters of fertility life tables; we also performed a multiple-choice test (feeding test). Larval development of S. frugiperda occurred in all three diets, although without oviposition by females developed from larval fed on D2. There was no difference among the diets in relation to the fertility life table parameters. The diet D2 resulted in better ingestion, digestion, assimilation, and conversion of food, but was associated with a metabolic cost to assimilate the food. Using a multiple-choice test, we observed that the larvae preferred diet D2. Based on our results, the most adequate diets for rearing S. frugiperda in the laboratory are D1 and D3.

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The aim of this study was to assess the biological aspects and food preferences of Helicoverpa armigera fed different sunflower genotypes and an artificial diet. Tests were performed under multiple-choice and no-choice conditions to evaluate the biological characteristics of H. armigera. In addition, the biological data obtained were used to determine parameters of fertility life tables. The results showed that H. armigera does not have a feeding preference among the sunflower genotypes tested. The larval period on sunflower ranged from 15.0 to 16.2 days. The maximum fecundity on sunflower was 542.6 eggs/female and that on the artificial diet was 794.5 eggs/female. In general, insects feeding on Helio 250 consumed greater quantities of leaves, had higher survival until the end of the pupal stage, displayed high population growth rates, and had low population doubling times, suggesting that in the field populations will achieve greater population densities when fed on Helio 250. Insects that fed on CF101 consumed smaller leaf areas, had lower survival until the end of the pupal stage, lower fertility rates, and lower population growth rates, and may also have displayed lower population densities and smaller reductions in field productivity. This insect developed best on an artificial diet in comparison to sunflower genotypes studied.

Helicoverpa armigera (Hübner) is an important pest of crops worldwide, and several studies have focused on the development of this species on different artificial diets. However, studies evaluating the insect’s food consumption and utilization using nutritionally different diets are scarce. The aim of this study was to evaluate the biology and to compare the consumption and use of food by H. armigera larvae on diets with different protein levels provided by several dietary ingredients used in the diets. The nutritional index, the relative consumption rate, the relative metabolic rate, the relative growth rate, and the apparent digestibility were higher in the diet with higher than the optimum level of protein. On the other hand, the conversion efficiency of digested food was lower, resulting in a higher metabolic cost. In terms of biological aspects, larval survival was higher for the diet with optimal protein content and lower for the diet with a higher protein level. The pupal period was longer for the diet with a higher protein content, while pupal survival was lower. Among the evaluated diets, the diet with an optimal protein containing white bean 75 g, wheat germ 60 g, soy bran 30 g, milk powder 30 g, brewer’s yeast 37.5 g as the protein sources resulted in a higher net reproductive rate, a shorter time for the population to double in number, and the highest rates of population growth. The results suggest that lower or higher protein contents in the diets of H. armigera negatively affect the biological aspects of this species.

Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) is a pest of great economic importance which can feed on more than 300 plant species. As it is polyphagous, its host plants may have variable physical and chemical constitutions. This may influence larval development, as protein and carbohydrate levels are important factors for adequate biological development. The aim of this study was to evaluate insect developmental parameters as well as to compare the food consumption of S. frugiperda larvae reared using diets with different protein levels under laboratory conditions. Three artificial diet formulations were used: one typically used for routine laboratory rearing, based on bean, wheat germ and brewer’s yeast (D1); one containing half the original amount of protein (D2), and the other with twice the original amount of protein (D3). The relative consumption rate (RCR), relative growth rate (RGR), and efficiency of conversion of ingested food (ECI) for S. frugiperda fourth instar larvae varied among diets. The protein present in the diet influenced the duration of larval and pupal periods and pupal weight, but did not affect larval survival, fecundity and longevity of adults. The different protein levels in the diets did not negatively influence population growth, so these three diet variations can be used for mass rearing in the laboratory. However, the influence of these diets on successive generations of the insect remains untested.