Role of nutritional composition in the development and survival of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on artificial diet and natural hosts

Abstract

Helicoverpa armigera is a pest of several crops causing significant economic impact. We evaluated the insect development on different vegetative and reproductive structures of cotton, maize, and soybean compared to artificial diet. One hundred individuals were evaluated per structure (cotton leaves and bolls; maize leaves, grains, and silk; soybean leaves and pods) and artificial diet. Centesimal analyses were performed on quantifiable nutrient contents in diets. The viability of immatures (eggs, larvae, and pupae) ranged from 30% on maize leaf to 74% on cotton bolls, while on the artificial diet, it was 70%. Maize, cotton, and soybean leaves provided viability of 30, 37, and 42%, respectively, revealing these leaves tissues are less favorable to the development of H. armigera immatures compared to ‘reproductive tissues’. Centesimal composition of diets compared 14 common components in all diets, which correlated significantly with larval and pupal stages and/or pupal weight. Of the 12 dietary components that significantly affected larval development time, half were negatively correlated, indicating a decrease in developmental time from their increments. In general, when insects were confined separately to substrates, the artificial diet was the most suitable for H. armigera development compared to the evaluated natural diets. However, in natural conditions, the variability of available hosts must be considered. In addition, it is acceptable for moths to select more suitable hosts for oviposition, while their larvae move to other more suitable tissues of the same plant or even migrate to other plants.

The role of genetically engineered soybean and Amaranthus weeds on biological and reproductive parameters of Spodoptera cosmioides (Lepidoptera: Noctuidae)

“…Several polyphagous insect herbivores can minimize the effects of suboptimal food quality by selecting different host plants, even moving between vegetative and reproductive structures (flowers and pods) of the same plant, 42 as reported for larvae of S. cosmioides 12,19,20 . At the organismal level, Rabelo et al 44 .…”

“…The need to fulfill nutritional requirements can condition the behavior and mobility of insects in the field 19 and determine host preference. In cases in which larvae feed on a substrate that is not nutritionally optimal, the life cycle can be longer, with reduced survival, weight gain, weight and fecundity 20 . The energy transfer by larvae to adults can be reflected in the amount of macronutrients stored in the pupal or adult body, as has been studied in other species of lepidopteran pests and vector insects 21,22 .…”

“…In cases in which larvae feed on a substrate that is not nutritionally optimal, the life cycle can be longer, with reduced survival, weight gain, weight and fecundity. 20 The energy transfer by larvae to adults can be reflected in the amount of macronutrients stored in the pupal or adult body, as has been studied in other species of lepidopteran pests and vector insects. 21,22 Furthermore, the quality of the food consumed by the adult stage can also influence its performance.…”

Florivory by the occupants of phytotelmata in flower parts can decrease host plant fecundity

“…This tissue is viscous and has a sweet fragrance, and is probably rich in sugars, which are transferred to the developing flowers, fruits, and seeds. The lepidopteran larvae did not appear to feed on the tissue of the bract itself, but only on other structures found inside the bract, which may reflect the nutritional value of the different structures ( McCoy 1985 ; Colasurdo et al 2009 ; Silva et al 2020 ). During the surveys, we did not observe lepidopteran larvae feeding on leaves or even moving outside the inflorescence, although they did appear to take refuge inside the bracts when they were being collected, possibly as a defense against visually orientated predators ( Heinrich 1979 ; Greeney et al 2012 ).…”

Realism in Immune Ecology Studies: Artificial Diet Enhances a Caterpillar's Immune Defense but Does Not Mask the Effects of a Plastic Immune Strategy

“…These results represent an impact on life-history traits and fitness. Concerning immune function, assuming that this trait also demands energy and protein from food (27), the nutritional differences of artificial diet and plants will probably impact immune investment in these larvae. Moreover, since immunity is costly (28)(29)(30)(31) it is possible that we can also find different patterns in how the costs of prophylaxis are translated to fitness comparing both diets.…”