. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 128 L. SAFRANEK ET AL. RESULTS Effects of brain removal and kcad-ligation on the development of pupae In the course of studies on the regulation of pupal diapause we noted that pupae head-ligated promptly after eclosion to the pupal stage initiated development much sooner than would have been expected of brainless pupae. To document this we ligated 100 SD pupae within 2-6 h after pupation. An additional 100 SD pupae were set aside as unoperaied controls. All individuals were examined at weekly intervals for the onset of trac
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 128 L. SAFRANEK ET AL. RESULTS Effects of brain removal and kcad-ligation on the development of pupae In the course of studies on the regulation of pupal diapause we noted that pupae head-ligated promptly after eclosion to the pupal stage initiated development much sooner than would have been expected of brainless pupae. To document this we ligated 100 SD pupae within 2-6 h after pupation. An additional 100 SD pupae were set aside as unoperaied controls. All individuals were examined at weekly intervals for the onset of tracheal apolysis. As documented in Figure 1, the ligated preparations initiated development an average of one month prior to intact diapausing pupae and approximately four months earlier than expected for pupae whose brains had been surgically extirpated (Safranek and Williams, 1980). We repeated the experiment on approximately 50 freshly ecdysed SD pupae and 50 similar LD pupae, with 50 intact SD pupae serving as controls. Here again over 50% of the neck-ligated preparations had initiated adult development by the fifth week, irrespective of LD or SD status; by the ninth week over 90% had done so. By contrast, 50% of the intact SD controls initiated development only after 11 weeks and 90% only after 13 weeks. The development of the LD preparations thus was delayed by more than a month relative to that of intact LD pupae, which, as previously men- tioned, initiate development within a week of pupation. But both LD and SD prep- arations developed in this instance over a month before intact diapausing pupae and several months earlier than would have been expected of pupae whose brains had been excised rather than removed by neck-ligation. 100-. 345678 Weeks After Pupation 10 12 FIGURE 1. Acceleration of diapause termination by neck-ligation of diapause pupae. Diapause pupae were ligated 2-6 h after ecdysis. Initiation of development was recognized by apolysis of the wing epidermis. L
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