![]() Timing of starvation significantly affected the pupal weight of larvae undergoing 5 instars. Developmental times (mean ± SE in days) of larvae starved in the first instar (20.32 ☐.16) were significantly longer than those starved in the third (17.04 ± 0.20) or fifth instars (16.92 ± 0.10), or than unstarved larvae (14.62 ± 0.25). Developmental times of starved larvae also were prolonged compared with unstarved larvae. exigua larvae will experience can be predicted as early as the third instar-head capsule widths in this instar clearly differentiate for those destined to experience 5 and 6 instars. Significantly more larvae underwent 6 larval instars (20.22 ± 4.35%) when starved for 2 d in the first instar compared with those starved for 2 d in the third (2.0 ± 2.00) and fifth instars (0.0), and relative to unstarved larvae (0.0). Beet armyworms normally have 5 instars before pupation. We tested these hypotheses by starving beet armyworm larvae for 48 h in the first, third, and fifth instars, and monitoring their development. We hypothesized that (1) starvation of beet armyworm in earlier instars would increase the possibility of undergoing supernumerary instars greater than would be the case for later instars and (2) starvation of beet armyworm in earlier instars would prolong developmental time more than starvation in later instars. Sporadic starvation of herbivorous insect pests, such as the beet armyworm Spodoptera exigua (Hübner), often occurs due to host plant scarcity and dislodgement from host plants resulting from inclement weather, enemy attack, and other perturbations.
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