THE JUVENILE HORMONE. III. ITS ACCUMULATION AND STORAGE IN THE ABDOMENS OF CERTAIN MALE MOTHS

¹ The Biological Laboratories, Harvard University, Cambridge 38, Massachusetts

1. Pupae joined in parabiosis with headless male Cecropia moths behave as if they have received an injection of juvenile hormone. They develop, not into normal moths, but into creatures which show a mixture of pupal and adult characters.

2. By diverse experiments it was possible to show that the juvenile hormone comes from the moth abdomen and that the abdominal tissues of male Cecropia moths contain a rich depot of juvenile hormone.

3. In the moth, itself, the hormone is synthesized by the corpora allata in the head and is progressively bound and sequestered by the abdominal tissues. If the corpora allata are removed from the head, then no hormone accumulates in the abdomen.

4. The accumulation of juvenile hormone in the abdominal tissues occurs in male Cecropia and Cynthia moths, but not in females. In the case of certain related species of saturniid moths (Polyphemus, Pernyi and Orizaba), neither sex is ordinarily able to accumulate the hormone, despite the fact that they have very active corpora allata.

5. The failure to accumulate the hormone points to some unknown means for its inactivation; these agencies are evidently curtailed or by-passed in the case of male Cecropia and Cynthia moths which accumulate large amounts of hormone.

6. Adult moths are frequently caused to molt when joined to non-diapausing pupae and thereby supplied with ecdyson. A new adult cuticle forms which is deficient in scales and hairs. Adults molting in the presence of high concentrations of juvenile hormone show no reappearance of pupal characters or any sign of a "reversal of metamorphosis."

7. When the adult tissues are continuously perfused with pupal blood, the lifespan of the moths is greatly prolonged. This shows that, in the absence of functional mouthparts, the moth normally dies of desiccation and starvation rather than from the intrinsic biological death of the tissues themselves.

8. In experiments involving the parabiosis of diapausing pupae with moths containing a depot of juvenile hormone, additional evidence was obtained that juvenile hormone can turn on the prothoracic glands and, in this sense, mimic the brain hormone.