White-eyed Pupae Research Articles

Ecdysial failures in the cotton boll weevil: Synergism of diflubenzuron with juvenile hormone

The frequency and etiology of ecdysial failures occurring during the pupal-adult transformation of the cotton boll weevil, Anthonomus grandis, was studied after treatment with juvenile hormone (JH) and/or diflubenzuron (DFB). Failure at emergence was the result of inability of the adult insects to escape from their pupal exuviae. Teratogenic effects in the form of pupal-adult intermediates or adults with pupal characters were not obtained with JH or DFB treatment after the larval-pupal ecdysis. Combining JH with the DFB treatment yielded a synergistic response that increased the frequency of ecdysial failures about sevenfold when applied in the later pupal stages. The fine structure of the abdominal cuticle of adults experiencing ecdysial failure after treatment with JH as white-eyed pupae exhibited granular deposits within the lamellar region and interference with deposition of the nonlamellate endocuticle. DFB treatment of the earlier pupal stages interfered with deposition of the lamellate cuticle by eliminating or reducing the lamellar structure. It was concluded that the primary interaction of JH with DFB was that of extending or reinitiating DFB sensitivity in the later pharate adult. A secondary interaction may involve inhibition of cuticle hardening as both JH and DFB appear to inhibit the tanning process of adults treated as white-eyed pupae.

Entwicklungsabhängige mitochondriale enzymaktivitäten bei den kasten der honigbiene

Development-dependent mitochondrial enzyme activities in castes of the honey bee Mitochondria of queen and worker honey bees were isolated and purified in various developmental stages as follows. The mitochondrial preparation free of sarcosomes, lysosomes and microsomes, was obtained by centrifugation of a crude mitochondrial fraction in a slight gradient of sucrose containing a steep gradient of stractan AF/2 (Meyhall). The fractionated cell particles were characterized by their contents of protein and RNA, and their activities of acid phosphatase, acid ribonuclease, uricase and succinate dehydrogenase, respectively. After gradient centrifugation, three bands corresponding to the maxima of the protein content were observed in the sedimentation pattern. The middle band contained mitochondria. In the larvae and white-eyed pupae the band was separated further into lighter and heavier fractions. The quantity of the mitochondria in the queen is more than 2-fold higher than that of the worker throughout the developmental stages. When succinic acid, α-glycerophosphoric acid and butyric acid were used as substrates of the oxidation systems, the mitochondria of both castes demonstrated the maximal activity in the 5-day-old larva. The activities of the oxidation systems in the queen were substantially higher than those in the worker, particularly in the larval stages. It was further shown by the difference spectra of mitochondria, that both castes were deficient in cytochrome c in the early developmental stages. The worker larva contained quantitatively less cytochrome c and cytochrome oxidase than the queen larva. It was concluded from these results, that the production of mitochondria in the queen is quantitatively and qualitatively stimulated and the cytochrome system is sufficiently built up by the influence of the determining substance contained in royal jelly. Because of the low content of mitochondria in addition to the diminished activity of the respiratory chain, the worker larva showed an oxygen consumption half as large as that of the queen larva.