Über die morphogenetische Wirkungsweise von Juvenilhormon und analogen Substanzen auf die Adultentwicklung von Schwärmern und Spinnern 1, 2

Morphogenetic effects of juvenile hormone and analogues on the development of Sphin‐gidae and Notodontidae . Treatment of larvae of Cenura vinula and Sphinx ligustri with juvenile hormone and analogues such as geraniol, an isomer mixture of farnesol, aethyl‐farnesoate‐dihydrochloride, and an isomer of C 18 juvenile hormone, showed that the effect is dependent on the amount of the applicated compounds and on a critical time interval within the last larval instar. The inhibitory action of the used compounds on metamorphosis varies, the effect of farnesol was less extensive, that of geraniol more extensive than that of aethylfarnesoate‐dihydrochloride and of C 18 JH. Between the second and third day after the last larval molt there is a period of maximal sensitivity. The symptoms of the juvenile hormone‐like action of the four compounds were similar and were evidenced in a prolongation of the feeding period of the last instar, a prevention of some differentiation processes and a considerable delay of the larval‐pupal molt. High doses of the compounds resulted in giant larvae. Thereafter larval‐pupal intermediates were formed either with more larval or more pupal characteristics whereas the target tissues of the head and thoracal segments were more sensitive than the abdomen. Imagines of the experiments had defective head and thoracal appendages, reproductive system and pheromone glands, so that they were not able to mate. Some of them were laying eggs, the embryos of which were not able to hatch.