Photoreceptor properties of an ectopic eye in the fleshfly,Sarcophaga bullata

Summary Ectopic eyes were produced on the fleshfly,Sarcophaga bullata by transplantation of imaginal eye discs. Electrophysiological and histological observations of these supernumerary eyes indicate the absence of synaptic connections between retinular cells and higher order neurons.Supported by an University of New Brunswick research grant to P.S. and NSF grant BNS-76-11921 and NIH grant 1-R01-EY-02487-01A1 to W.S.S.We would like to thank Dr I.A. Meinertzhagen for suggestions and Mary Johnson for technical assistance.     

Development of visual sensitivity in the fly,Sarcophaga bullata

Summary Ontogeny of light response in the compound eyes of the fly,Sarcophaga bullata was investigated. Even though the eyes are structurally differentiated before eclosion they become electrophysiologically functional only after eclosion.Supported by grants from University of New Brunswick and NSERC to P.S. and NIH grant DHHS-1-RO1-EY 03408-03 to W.S.S. We would like to thank Mark Biagi and Roger Smith for technical assistance.     

In vitro mutagenicity testing of a potent,new, benzoyl urea insect growth regulator

Summary Bacterial mutagenicity assay to detect potential chronic toxicity of a potent, new, benzoyl urea insect growth regulator (CGA-112913 or IKI-7899, formerly UC-62644) was conducted using 5 histidine auxotrophs ofSalmonella typhimurium. Tests within the concentration range of 0.9–500 g (saturating)/plate of the compound with and without the 5–9 mammalian metabolic activation system showed no mutagenic effects clearing the way for long-term chronic toxicology studies.The authors thank Professor Bruce N. Ames for supplying the tester strains together with all the relevant information for conducting the bioassays and Ms. Norma Charlebois for her meticulous technical assistance.     

Reversal of metamorphosis in mealy bugs treated with juvenile hormone-active insect growth regulator

Summary Anal pore-plates are a typical adult characteristic of male mealy bugs. Nymphs treated with a juvenile hormone-active insect growth regulator moult several times into intermediary forms between nymph and adult. The number of the anal pores is reduced during each of these supernumerary moults.Presented at the XVth International Congress of Entomology, Washington DC 1976.Acknowledgments. We wish to express our thanks to Sir Vincent B. Wigglesworth and Mr M. Gruber for revision of the text and to Mr M. Dickenmann and Mrs B. Mühlemann for technical assistance.     

Suppression of pupal esterase activity in Aedes aegypti (Diptera: Culicidae) by an insect growth regulator.

Changes in non-specific esterases of Aedes aegypti were noted during pupal development. One esterase band was found to increase markedly within 3 h of pupation and this increase in activity was suppressed by prior treatment of larvae with an insect growth regulator, ZR 515. It is suggested that the esterase activity may help to reduce endogenous levels of juvenile hormone during metamorphosis and that the growth regulator may prevent this normal regulation.     

Changes in water permeability of an insect egg in response to level of water in the environment

Summary The water permeability of eggs of the southern corn rootworm, Diabrotica undecimpunctata howardi Barber, varied depending on the previous experience of the eggs. Eggs acclimated in a water vapor system were seen to be less permeable than eggs acclimated in contact with moist paper, as measured by the rate of loss of water from the eggs and the susceptibility of the eggs to death from desiccation. This is the first known report of the ability of an insect egg to adapt to the level of water available in the environment.     

Effects of hypergravity on rat fertility,pregnancy, parturition and survival

Summary Persistent centrifugation (at 1.18×g to 1.47×g) of pregnant rats reduced the number of deliveries and the survival time of the newborns. The extent of the damage increased with increasing distance from the axis. Male fertility was reduced.     

Diurnal rhythm of hemocyte population in an insect,Schizodactylus monstrosus Drury

Summary InSchizodactylus monstrosus the total hemocyte count appeared to be much lower during the day than at night. At night, the percentage of prohemocytes and spherule cells increased substantially over that of granular hemocytes, plasmatocytes and adipohemocytes. The percentage of sessile hemocytes was much higher during the day. Hemogram rhythmicity was much affected in decapitated insects; altered photoperiod had little effect on it.     

The number of neurons,glial and perineurium cells in an insect ganglion

Zusammenfassung Im zweiten Abdominalganglion der Indischen Stabheuschrecke (Carausius morosus Br.) wurden 600 ± 50 Neurone, 1000 ± 100 Gliazellen und 500 ± 30 Perineuriumzellen, zusammen etwa 2100 Zellen gezählt. Die Volumina des Ganglions, des Neuropilems und des Zellcortex betrugen etwa: 140 · 10^–4 mm³, 75 · 10^–4 mm³ und 65 · 10^–4 mm³.     

Ecdysteroid receptors located in the central nervous system of an insect

Summary Using thaw-mount autoradiography for steroid hormones, we obtained direct evidence for a nuclear localization of ecdysteroid binding sites in target organs of blowfly (Calliphora vicina) larvae. The binding sites revealed properties of ecdysteroid receptors. Endocrine cells of the ring gland were found to be target tissues of ecydysteroids. This observation provides morphological evidence for a network of complex interendocrine regulation. In the central nervous system receptorcontaining neurons were identified which include many, if not all, neurosecretory cells of the brain. A map of ecdysteroid sensitive cells of the larval brain is presented.     

Presence of substances immunoreactively related to enkephalin in an insect, Locusta migratoria]

Application of specific radioimmunoassays to various extracts of the locust showed that nervous tissues and specially the optic lobes contain enkephaline-like material. However these immunoreactive substances present an apparent higher molecular weight (700--1 000 dalton) than those of the controls, as tested by chromatography on Sephadex G 25.     

Myofibrillar ATP-splitting in the elementary contractile cycle of an insect flight muscle

Zusammenfassung In glyzerinierten fibrillären Muskelfasern vonLethocerus werden schon 20 msec nach maximaler «Dehnungsaktivierung» der ATP-ase (um 5000%) 2 Mol ATP pro Mol Myosin gespalten, worauf die Kontraktionsspannung mit der Wechselzahl von Myosin-ATPase und Querbrücken (etwa 10 Hz) oszilliert.     

Effects of various inhibitors of protein cross-linking on the formation of fertilization membrane in sea urchin egg

Résumé La stabilization de la membrane de fécondation de l'uf de l'OursinParacentrotus lividus est inhibée par la pénicillamine, l'isoniazide, les hydrazines benzylique et benzoïque et la semicarbazide. Les effets de ces substances sont interprétés sur la base de leur action inhibitrice sur la formation de certaines liaisons transversales intermoléculaires. Ces liaisons pourraient impliquer, comme chez le collagène et l'élastine, des groupes aldéhydes associés entre eux par condensation de type aldol ou avec de groupes aminés avec formation de base de Schiff.     

Histopathological effect of thiourea on the ovarian tissues of Sarcophaga ruficornis (Fabr.).

The primary target of thiourea in female Sarcophaga are the follicles in the ovarioles. The follicle cells as a result become syncytial and their nuclei get pycnotic, inhibiting the transport of nutrient material into the nurse cells and of yolk into the oocytes. The subnormal eggs produced are not viable.