. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. JUVENILE HORMONE ACTION IN MANDUCA 571 100 50 20 10 > 1 ^ o- o> X —> I 00 o en s; 84 - 2 - --}-. 0 2 3 Time (hours) 24 FiGfRK 1. Mean JH titers in final (5th) instar larvae weighing grams. Filled circles represent isolated abdomens ligated at 0 hours; open circles, starved larvae. The bars indicate the 95% confidence limits of the mean response of 3 replicates of 20-25 test larvae. Titers below 84 picograms/ml hemolymph cannot be detected by the assay method used. There- fore, the horizontal portion of the g
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. JUVENILE HORMONE ACTION IN MANDUCA 571 100 50 20 10 > 1 ^ o- o> X —> I 00 o en s; 84 - 2 - --}-. 0 2 3 Time (hours) 24 FiGfRK 1. Mean JH titers in final (5th) instar larvae weighing grams. Filled circles represent isolated abdomens ligated at 0 hours; open circles, starved larvae. The bars indicate the 95% confidence limits of the mean response of 3 replicates of 20-25 test larvae. Titers below 84 picograms/ml hemolymph cannot be detected by the assay method used. There- fore, the horizontal portion of the graph for isolated abdomens indicates undetectable JH. scores consisting of a faint greening in the area where the assay material was applied were obtained from 86% (n = 22) and 48% (n = 21) of the assay larvae in each of two replicates with extracts of intact larvae weighing grams. No JH was detectable in blood-free carcasses of isolated abdomens of such larvae by four hours after ligation. When gram larvae were starved, their hemolymph JH titers rose significantly and remained elevated for at least 24 hours (see dashed line in Figure 1). Such a rise in JH titer was not observed in feeding larvae (Nijhout and Williams, 1974b). Persistence of JH effects after elimination of its source and in the absence of JH Nijhout and Williams (1974b) have shown that when final (5th) instar larvae of Manduca are induced to molt with exogenous ecdysone, the nature of their response closely reflects the titer of JH in the hemoymph. Thus, in the presence of JH, apolysis takes place initiating a larval molt. By contrast, in the absence of JH the larva is induced to expose its dorsal vessel, a prodromal symptom of pupation. In the present study it was, therefore, surprising to find that when /?-ecdysone infusion of small isolated abdomens was initiated 24 hours after. Please note that these images are extracted from scanned page images that may have been digitally en
Size: 1356px × 1842px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
