Developmental changes in the patterns of feeding in fourth‐ and fifth‐instar Helicoverpa armigera caterpillars

Abstract

Summary Data are presented for developmental changes in feeding behaviour within and across the fourth and fifth stadium of Helicoverpa armigera (Lepidoptera, Noctuidae) caterpillars fed nutritionally homogeneous semi‐synthetic foods. We recorded the microstructure of feeding over continuous 12‐h periods on consecutive days throughout the two stadia, and in one experiment recorded continuously for 21 h. Larvae in the two stadia showed the same general pattern of macro‐events in feeding, including a similar duration of post‐ecdysis fast, which was usually broken by consumption of the exuviae, and then a sustained period in which discrete meals on the experimental food were taken regularly. There were, however, some distinct differences in the patterns of meal‐taking both between stadia and across different one‐third time segments within stadia. Considering between‐stadium differences, the proportion of time spent feeding differed significantly only in the last segment of the feeding period of the two stadia, with the value for the fourth‐instar larvae being substantially greater than for fifth‐instar larvae. As regards within stadium changes, the proportion of time feeding increased from the first to the second segment of both stadia. However, whereas the proportion of time feeding increased from the second to the final segment of the fourth stadium, it decreased across the same period in the fifth stadium. These patterns of changes in the proportion of time feeding within and between stadia, and their behavioural mechanisms (combination of meal durations and meal frequencies), can be explained only partially with reference to increasing food requirements with development. Three areas are identified where further study might help elucidate the reasons for the observed developmental changes in the microstructure of feeding: allometric constraint, the dynamic links between ingestion and post‐ingestive processing, and ecological factors such as predation.

Can larvae of the pod-borer, Helicoverpa armigera (Lepidoptera: Noctuidae), select between wild and cultivated pigeonpea Cajanus sp. (Fabaceae)?

“…This could be due to changes in the nutritional requirements across instars. Older larvae of Lepidoptera have increased appetitive behaviour (Raubenheimer & Barton-Browne, 2000) and a need for more protein (Simpson et al, 1988). Blaney & Simmonds (1983) measured the quantity of an artificial diet eaten during the larval phase of H. armigera.…”

Life history traits of a key agricultural pest, Helicoverpa armigera (Lepidoptera: Noctuidae): are laboratory settings appropriate?

“…; Behmer ; Deans et al . ) including H. armigera (Raubenheimer & Browne ; Browne & Raubenheimer ; Tessnow et al . ).…”

“…Remarkably, all nutrient choice experiments documented for Lepidoptera have been conducted exclusively on late or final instar caterpillars (Lee et al 2002;Lee et al 2004;Lee et al 2006;Behmer 2009;Deans et al 2015) including H. armigera (Raubenheimer & Browne 2000;Browne & Raubenheimer 2003;Tessnow et al 2018). It is not known whether nutrient choice differs between instars or whether early instars are capable of self-selecting their food.…”

“…First instars have a higher relative growth rate and distribute their time between feeding, resting and moving differently compared to later instars (Johnson & Zalucki 2007). Fourth and fifth instars of H. armigera also exhibit dynamic changes in feeding behaviour as they grow (Raubenheimer & Browne 2000;Browne & Raubenheimer 2003).…”

Effects of sex, host-plant deprivation and presence of conspecific immatures on the cannibalistic behavior of wild Ascia monuste orseis (Godart) (Lepidoptera, Pieridae)

“…Previous research on caterpillars, i.e. Manduca sexta (Reynolds et al 1986;Bernays & Woods 2000), Helicoverpa armigera (Raubenheimer & Barton-Browne 2000) and Bombyx mori caterpillars (Nagata & Nagasawa 2006) have shown that the pattern of feeding (i.e. the frequency and duration of meals) varies across foods types (Reynolds et al 1986;Timmins et al 1988;Bernays & Singer 1998) and can provide information about the insect´s physiological responses to food.…”