Figure 1. The juvenile hormone esterase (JHE) activity profile of normally feeding last (5th) instar larvae of Manduca sexta. JHE activity was measured as nmoles of JH-acid produced per minute per ml of hemolymph. Each point is the mean of 9 to 11 pre-wandering larvae, or 4 to 6 post-wandering larvae. Vertical bars are standard errors of the mean (which in some cases do not exceed the size of the symbol). The abscissa is a measure of the physiological age of the larva, which is given on two scales: before entry into the wandering stage the larva's physiological age is given by its weight, and after entry into the wandering stage it is given in days. The curve represents the best-fit polynomial regression (2nd degree polynomial, r2 = 0.99), and is extrapolated to animals weighing 12 grams (the maximal weight at which larvae entered the wandering stage).