Maturation of the female Tetrix undulata (Swrb) (Orthoptera, Tetrigidae): influence of the male and copulation:parthenogenetic egg-laying]

The percentage of laying females and laying time, are compared between mature females (diapause break by chilling) and diapause strain females (diapause not broken by chilling) reared with mature male or diapause male or without male. For the same physiological state of the females (mature or diapause) there is no difference in the percentage of females laying, when they are reared with mature male or with diapause one or none; but the laying time is shortest with mature male, longer with male in diapause, even longer without male. Parthenogenetic egg-pods can be obtain. Rearing with mature males does not break the reproductive diapause of females. In parthenogenetic egg-pods the number of eggs is short for low diapause females; greater for mature ones and greatest for females with strong diapause broken by a corpus allatum implant of mature female of Locusta migratoria. Corpus allatum of the low diapause strain of females of Tetrix undulata have less activity than that of mature females. Few parthenogenetic eggs develop, even less hatch. In Tetrix undulata parthenogenesis is accidental.     

Synthesis of juvenile hormones in vitro by the corpora allata of 5th stage larva of Locusta migratoria migratorioides (R and F) (Insecta, Orthopteroida)]

Corpora allata of Locusta migratoria 5th stage larvae synthesize J.H.1, J.H.2 and J.H.3 in vitro. The C.A. of insects of different ages exbit different rates of J.H. synthesis. J.H.1 and J.H.2 synthesis is less than 1 ng/48 h/gland. During the same time the J.H.3 production may be as much as 25.6 ng/gland. J.H. synthetic activity is the same between right and left C.A. The release of J.H. from the C.A. occurs immediately following synthesis. These results are compared with in vivo haemolymphatic J.H. levels.     

Effets de l'intoxication par le lindane sur les corpora allata deLocusta migratoria (Orthoptère)

Summary The corpora allata of adult and 5th instar nymphs of the migratory locust exhibit several ultrastructural alterations after lindane intoxication. The type of cell degeneration observed here is very similar to ultrastructural changes obtained after the administration of precocene.     

Precocene-induced collapse and resorption of corpora allata in nymphs ofLocusta migratoria

Summary Precocene II causes an irreversible regression of corpora allata in young 4th instar nymphs of the migratory locust. Within 2 h after application, the cells collapse. Cell fragments are subsequently phagocytosed by haemocytes.Acknowledgment. Thanks are due to Dr G. B. Staal of Zoecon Corporation for the gift of precocene II, and to the Department of Virology for the use of the electron microscope facilities.     

In vitro inactivation of corpora allata of the bugOncopeltus fasciatus by precocene II

Summary Corpora allata fromOncopeltus fasciatus incubated in vitro in medium containing 10^–5.35 M (1 g/ml) of precocene II lose their ability to secrete juvenile hormone when reimplanted into last instar larvae.Acknowledgments. We thank Mr K. Dorn, Mrs L. Dolezal, Mrs V. Nötzli-Graf, Mr K.H. Trautmann and Mr A. Schuler for technical help, Dr W. Vogel and Dr A. Dübendorfer for valuable discussions.     

Juvenile hormone degradation in brain and corpora cardiaca-corpora allata complex during the last larval instar ofGalleria mellonela (Lepidoptera,Pyralidae)

Summary Time course analysis of juvenile hormone degradation in the brain and the corpora cardiaca-corpora allata complex shows that during the first two days of the last larval instar the juvenile hormone degradation is very low. Starting from the third day up to the seventh day a continuous increase of esterase activity is observed.     

In vivo inactivation of denervated corpora allata by precocene II in the bug,Oncopeltus fasciatus

Summary Transection of the nervous connections between the brain and the corpus allatum (CA) inOncopeltus fasciatus does not alter the susceptibility of the CA to precocene II in vivo.The authors wish to thank Patricia Ferugia for rearing the insects; Dr D. Soderlund, Department of Entomology, New York State Agricultural Experiment Station for helpful discussions; and Dr A.O. Lea, Department of Entomology, University of Georgia for technical advice. To whom reprint requests should be addressed     

Phosphoramidon enhances allatostatin-mediated inhibition of juvenile hormone biosynthesis in the corpora allata of the cockroach, Diploptera punctata.

Use of enkephalinase inhibitor phosphoramidon in the in vitro radiochemical assay for juvenile hormone biosynthesis enhanced allatostatin-mediated inhibition of hormone production by corpora allata of the cockroach, Diploptera punctata. Significant increases in inhibition in day 2 virgin female CA by AST 1 (at 10(-7) M) and AST 4 (10(-8)-10(-7) M) were observed in the presence of phosphoramidon (10(-5) M or greater). No significant increase in inhibition were seen in CA from day 6 mated females with AST 4 (10(-9)-10(-7) M) and phosphoramidon combined. Phosphoramidon alone had no effect on JH biosynthesis. Analysis of allatostatin content of the CA, as determined by ELISA, revealed that addition of phosphoramidon to the medium increased the endogenous allatostatin content in CA of virgin and mated females. The similarity in primary structure between allatostatins and enkephalin-like peptides and their similar distribution makes it probable that phosphoramidon acts by preventing breakdown of allatostatins within the CA.     

Evidence for inhibition of corpora allata activity in workers ofBombus terrestris by a pheromone from the queen's mandibular glands

Summary Queens ofBombus terrestris inhibit the activity of worker corpora allata by means of a pheromone which is produced in their mandibular glands. Exstirpated and homogenized glands as well as an extract of the queen's body surface show the same inhibitory effect as a living unmutilated queen. The pheromone remains on the body only for 1 day after the queen has been killed. The activity of the corpora allata of workers was determined volumetrically as well as by means of a juvenile hormone synthesis in vitro assay.Acknowledgment. The work was supported by the Netherlands Organisation for the advancement of pure research, ZWO.     

Influence of corpora allata and brain extract on the lipid release from the fat body of termite queen Odontotermes assmuthi

Summary Short term in vitro experiments on the influence of the extracts of corpora allata and brain from the termite queenOdontotermes assmuthi on the lipid release from the fat body into the haemolymph indicated that the extract of corpora allata does not influence the lipid mobilization, whereas the brain extract increases the free fatty acid level in the haemolymph. It is believed that the brain extract stimulates triglyceride hydrolysis in the fat body.     

Identification of in vitro release products of corpora allata in female and male loreyi leafworms,Leucania loreyi

The in vitro release of juvenile hormones (JH) by female, and of JH acids (JHA) by male corpora allata (CA) ofLeucania loreyi was identified by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Separation and quantification were accomplished by HPLC and GC, respectively. JH II and JH III were the major components released by CA of females. Four JHA analogues were identified as the release products of male CA, i.e. JHA III, Iso-JHA II, JHA II and JHA I. JHA III and Iso-JHA II were reported for the first time as the major release products of CA of adult male Lepidoptera. Iso-JHA II is a new member of the insect juvenile hormone analogue family.     

Differences in the stimulation by calcium ionophore of juvenile hormone III release from corpora allata of solitarious and gregariousLocusta migratoria

Summary Incubation of the calcium ionophore A23187 resulted in an increase in the median rate of juvenile hormone III release by corpora allata (CA) of both gregarious and solitarious adultLocusta migratoria females at 3, 5 and 8 days after fledging. At all 3 datapoints, the enhancement of release rates was highly significant for CA from gregarious females but not significant for CA from solitarious females.     

Forced synthesis of trace amounts of juvenile hormone II from propionate by corpora allata of a juvenile hormone III-producing insect

Corpora allata of the cockroach Diploptera punctata normally synthesize only the isoprenoid juvenile hormone III (JH III). Only under extreme in vitro conditions (absence of carbon sources other than propionate) do they produce trace amounts of the homoisoprenoid JH II in addition to JH III. The specificity of the in vitro synthesis of JH III by D. punctata is thus consistent with the observed lack of homoisoprenoid JHs in this insect.     

Forced synthesis of trace amounts of juvenile hormone II from propionate by corpora allata of a juvenile hormone III-producing insect

Summary Corpora allata of the cockroachDiploptera punctata normally synthesize only the isoprenoid juvenile hormone III (JH III). Only under extreme in vitro conditions (absence of carbon sources other than propionate) do they produce trace amounts of the homoisoprenoid JH II in addition to JH III. The specificity of the in vitro synthesis of JH III byD. punctata is thus consistent with the observed lack of homoisoprenoid JHs in this insect.