Physiology of Insect Rhythms: I. Circadian Organization of the Endocrine Events Underlying the Moulting Cycle of Larval Tobacco Hornworms
Physiology of Insect Rhythms: I. Circadian Organization of the Endocrine Events Underlying the Moulting Cycle of Larval Tobacco Hornworms
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昆虫节律的生理学：I. 烟草角虫幼虫蜕皮周期中内分泌事件的昼夜节律组织
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发表时间：
1972
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通讯作者：
J. Truman
中科院分区：
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作者：
J. Truman
1. 烟草天蛾（Manduca）和柞蚕（Antheraea）的幼虫蜕皮发生在一天中的特定时间。这些时间因龄期和物种而异，并取决于光周期和温度条件。
2. 幼虫单眼对于使幼虫蜕皮与光周期同步不是必需的。
3. 在幼虫蜕皮中观察到的同步性并非源于生物钟对蜕皮事件本身的门控。相反，它是启动蜕皮过程的内分泌事件门控的结果。
4. 在一天中的不同时间对四龄烟草天蛾幼虫进行颈部结扎表明，促前胸腺激素（PTTH）的分泌仅在夜间早期到中期的一个特定时段发生。二龄和三龄幼虫的这个时段是相似的。
5. 当在PTTH释放后的1 - 5小时内对四龄幼虫进行颈部结扎时，幼虫会发生早熟变态，而不是蜕皮进入五龄。对产生的幼虫 - 蛹中间体数量的考虑表明，在15分钟内，足够的保幼激素从咽侧体释放出来，以确保幼虫充分分化。
6. 在PTTH释放后3 - 6小时期间分离的幼虫腹部经历了镶嵌式幼虫蜕皮——即它们变成了新旧表皮的拼凑物。因此，腹部的表皮结构在每个结构变得独立于前胸腺的时间上有所不同。在没有前胸腺的情况下继续五龄分化的第一个结构是趾钩。接着依次是腹足、腹中线、节间区域，并且在PTTH释放后6小时，腹部的其余部分也开始分化。在这3小时期间，前胸腺可能在分泌蜕皮激素。
1. The larval ecdyses of the tobacco hornworm, Manduca , and of the oak silkmoth, Antheraea , occur during specific times of the day. These times are instar-specific and species-specific and depend upon the photoperiod and temperature conditions. 2. The larval ocelli are not required for the synchronization of larval ecdysis with the photoperiod. 3. The synchrony observed in larval ecdysis does not arise from a gating of the ecdysial event per se by a biological clock. Rather, it is an outcome of the gating of the endocrine events which initiate the moulting process. 4. Application of neck ligatures to fourth-instar hornworm larvae at various times of day showed that prothoracicotropic hormone (PTTH) secretion occurred only during a gate in the early to middle portion of the night. The times of the gates for second- and third-instar larvae were similar. 5. When neck ligatures were applied to fourth-instar larvae within the first 1-5 h after PTTH release, the larvae underwent precocious metamorphosis rather than Moulting to the Fifth Instar. A Consideration of the Number of Larval-Pupal Intermetiates Produced Indicated that with in Span of 15 min Sufficiant JH is Liberatd from the Corpora Allata to Ensure Full Larval Differentiation. 6. Larval abdomens which were isolated during the period from 3 to 6 h after PTTH release underwent a mosaic larval moult-i.e. they became a patchwork of new and old cuticle. Thus, the epidermal structures of the abdomen vary as to the time that each becomes independent of the prothoracic glands. The first structures which continue fifth-instar differentiation in the absence of the prothoracic glands are the crochets. These are then followed in order by the prolegs, the ventral midline, the intersegmental areas, and, by 6 h after PTTH release, the remainder of the abdomen. During this 3 h period the prothoracic glands are presumably secreting ecdysone.