. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. H. FREDERIK NIJHOUT 100 r tu <si in ~o c/> k_ o o a. x O) 75 50 25 0. 3g 24 48 72 96 Period between ligation and initiation of infusion (hrs) FIGURE 2. Response of isolated abdomens of 3 and 4 gram final instar larvae to infusion with /3-ecdysone at various times after ligation. Each point represents 5-11 abdomens. All abdomens which did not show exposure of the dorsal vessel underwent a larval molt. ligation, they underwent apolysis and proceeded to deposit a normal larval cuticle. Clearly, this larval response occurr
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. H. FREDERIK NIJHOUT 100 r tu <si in ~o c/> k_ o o a. x O) 75 50 25 0. 3g 24 48 72 96 Period between ligation and initiation of infusion (hrs) FIGURE 2. Response of isolated abdomens of 3 and 4 gram final instar larvae to infusion with /3-ecdysone at various times after ligation. Each point represents 5-11 abdomens. All abdomens which did not show exposure of the dorsal vessel underwent a larval molt. ligation, they underwent apolysis and proceeded to deposit a normal larval cuticle. Clearly, this larval response occurred long after the disappearance of JH from the hemolymph. This phenomenon was further investigated on 5th instar larvae weighing and grams. Abdomens of these larvae were isolated by ligation at time zero and then stored at 25° C for 24, 48, 72 or 96 hours prior to the initiation of the /3-ecclysone infusion. The results, illustrated in Figure 2, show that JH effects persisted for almost 3 days in 50% of the abdomens from gram larvae and somewhat more than days in 50% of the abdomens isolated from gram larvae. It should be noted here that those abdomens that initiated a larval molt upon infusion after 72 and 96 hours did not deposit a completely normal larval cuticle. Rather, the new cuticle was smooth, yellowish, and devoid of the setae which are normally present on larval cuticle. Moreover, the spiracles of these individuals were distinctly pupal. In 5th instar larvae of Manduca the presence of JH is known to inhibit the release of the prothoracicotropic hormone (PTTH). The release of PTTH that initates pupation occurs during the first photoperiodic gate after JH has disappeared from the hemolymph (Nijhout and Williams, 1974b). However, when gram larvae were allatectomized, PTTH release occurred about a day later than would be predicted on the basis of the known period required for the clearance of JH from the hemolymph after the larva attains a we
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
