Stimulation der Eiablage unbegatteter Weibchen des MondspinnersActias selene durch ein Männchen-Pheromon

Summary Mated females ofActias selene lay their eggs quicker than virgin females. Of the latter, virgins kept isolated in a separate room lay their eggs later than virgins kept in a room where males are present. Antennaless virgin females kept in the same room as males behave like isolated virgin females. It is concluded that the males produce an olfactory active sex pheromone that stimulates oviposition in females.     

Developmental patterns of supercooling capacity in a subantarctic wingless fly

Anatalanta aptera is a wingless fly which lives in subantarctic islands, particularly in sea bird colonies. Developmental patterns of supercooling capacity were studied in an experimental population reared at 5°C and fed ad libitum. Mean supercooling points of the eggs, second and third instar larvae, pupae, teneral and mature adults were –28.0°C, –10.8°C, –8.8°C, 17.6°C, –16.6°C and –8.2°C respectively. Low mean supercooling points were found for inactive stages (eggs, pupae) and, unexpectedly among Diptera, teneral adults. Mature adults had a combination of low supercooling ability, high lipid content and physogastry. The results are compared with those obtained in winged species from other families of Diptera.     

Growth and development of the American bollwormHeliothis armigera Hubn. under laboratory mass rearing conditions

Summary A kidney bean meal diet was the most satisfactory laboratory diet for the larvae of the American bollwormHeliothis armigera Hubn. Optimum rates of survival (63.5%) occurred and the larval growth was better than that of larvae reared on castor oil plant leaves. The pupal weight and the fecundity of the resulting adults were also much better than those on the control host plant.     

Egg-species recognition in cannibalistic hatchlings of the land snailsArianta arbustorum andHelix pomatia

Summary Laboratory experiments were conducted to determine whether cannibalistic hatchling of the land snailsArianta arbustorum andHelix pomatia discriminate between eggs of the two species. Hatchlings from both species showed a significant choice for conspecific eggs and consumed on average 1 egg in 4 days. Eggs from the other species were only occasionally eaten.     

Ecdysteroid titre and caste determination in the ant,Pheidole pallidula (Nyl.) (Hymenoptera: Formicidae)

Summary In the antPheidole pallidula, ecdysteroid level is higher in worker-biased eggs than queen-biased eggs. Moreover queens laying worker-biased eggs exhibit a higher ecdysteroid level than queens laying queen-biased eggs.     

Two related butterfly species avoid oviposition near each other's eggs

Summary Some butterfly species avoid egg-laying on plants which already bear conspecific eggs, and thus reduce food competition between their offspring. In twoPieris species the females produce in their accessory glands an oviposition-deterring pheromone (ODP), which is combined with the egg during oviposition. The ODP collected from eggs or accessory glands ofP. brassicae inhibits oviposition byP. rapae and vice versa. The ODP of either species stimulates tarsal receptors in both species. The antennae of the two pierids respond to the volatiles of their own and each other's eggs. Thus the ODPs of the two species may reduce not only intraspecific, but also interspecific food competition between their larvae.     

A method for injection and transplantation of nuclei and cells inDrosophila eggs

Summary Microinjection ofDrosophila eggs using the principle of thermal expansion is described. The eggs, mounted on cover slips with adhesive, are slightly dried to avoid the formation of exudate and then covered with fluorocarbon oil. Injections are made with a specially designed electrically controlled micropipette.     

Queen success is correlated with worker-brood genetic relatedness in a primitively eusocial wasp (Ropalidia marginata)

Ropalidia marginata is a primitively eusocial polistine wasp in which, although there is only one queen at any given time, frequent queen replacements lead to a system of serial polygyny. One of the most striking features of this system, is the enormous variation in the success of different queens. Measuring queen success as queen tenure, total number of offspring produced, number of offspring produced per day of tenure, and proportion of eggs laid that develop into adults, we show here that each measure of queen success is correlated with worker-brood genetic relatedness and not correlated with worker: brood ratio or the age of the queen at takeover. We interpret these results as meaning that queens are better able to obtain the cooperation of workers when worker-brood genetic relatedness is high.     

Differential lethality following treatment with ionizing radiations of various energies inDrosophila

Summary Male and female gametes ofDrosophila were treated with various doses of ionizing radiations: X-rays at different energy, and gamma-rays from 2 sources given singly and in 2 temporal sequences. The induced lethality was assessed in successive developmental stages by scoring the number of eggs, larvae and adults. The results clearly show that the effects of various radiations appear in terms of difference among developmental stages and/or between treated sexes/genotypes. It is suggested that the various energies affected different gene functions which are not completely independent, as supported by the non-additive effects of the two temporal sequences.Acknowledgments. The authors wish to thank Prof. D.L. Palenzona for valuable discussion and criticism and Mrs C. Brunaleschi and Mr E. Boschieri for their technical assistance.     

Harvesting large amounts of Drosophila embryos at precisely defined stages

Summary A simple method is described which makes it possible to eliminate the retained eggs ofDrosophila melanogaster and to harvest a large amount of embryos at a defined stage of development. It is based upon carbon dioxide anesthesia, which brings about the expulsion of eggs remaining in the uterus.     

Antibacterial activity in the egg mass of a sea hare

Summary The eggs of a sea hare,Aplysia kurodai, contained antibacterial factors which probably play a role in the defense of eggs against bacterial infection. The active factors were composed of several heat-labile proteins, unrelated to lysozyme, and were produced in the albumen gland.     

The ovicidal activity ofcis-dehydromatricaria ester: time-dependance of its enhancement by UV light

Summary Freshly laid eggs ofDrosophila melanogaster were treated with the polyacetylenic compoundcis-dehydromatricaria ester. The toxicity of the chemical was enhanced by treatments with long-wavelength ultraviolet light, and the maximum effect was observed when the UV irradiation was performed 4–5 h after the initial contact of the eggs with the chemical.We are grateful to Professor E. Spiess for advice and assistance, and to the National Institutes of Health (GM 24144) for financial support.     

Über die Funktion der Eiweissdrüse vonHelix pomatia

Summary A strong immunological crossreactivity between the extracts of the albumin gland of snails (Helix pomatia) and the content of snail eggs is described, suggesting that the former supplies the eggs with protective substances (agglutinins, protease-inhibitors).     

Effect of NPV of the armywormMythimna (Pseudaletia) separata on the silkwormBombyx mori

Summary Nuclear polyhedrosis virus (NPV) material of the armywormMythimna (Pseudaletia) separata was administered in the form of PIBs and free virus rods to the larvae of silkwormBombyx mori. Routes used for administration were topical, intrahaemocoelic and oral. The larvae were treated with following concentrations: 10×10⁵ PIBs/L, 10×10⁶ PIBs/L, 10×10⁷ PIBs/L, 10×10⁸ PIBs/L. In all the 3 experiments, the larvae showed neither any signs and symptoms, nor mortality due to polyhedrosis. Thus it appears that the NPV ofM. (P.) separata is safe for the silkwormB. mori.Acknowledgments. We are grateful to the Karnatak University, Dharwad, for awarding UGC Junior Fellowship to S.G.D. and for financial assistance made available to S.B.M. We thank Professor M. Appaswamy Rao, Department of Zoology, for providing the necessary facilities. Our thanks are also due to Mr B. Chavannawar for supplying mulberry leaves and to the Government Silk Farm, Hindalaga, Belgaum, for providing silkworm eggs.     

Occurrence of foliar leaves on long shoots ofPinus

Summary At Bundi (Rajasthan, India), aPinus roxburghii tree has been observed to develop green, needle-like, spirallyarranged, elongated, foliar leaves on long shoots. Such foliar leaves are not reported onPinus plants except at the seedling stage.Grateful thanks to Dr Elbert L. Little of the US Department of Agriculture (Forest Service) for suggestions.     

Végétativisation de l'œuf de l'oursin par la Phénazone

Summary Phenazone employed in various concentrations on the eggs of the sea urchin,Paracentrotus lividus, has a powerful vegetalizing effect on their development. The role of the interference between phenazone and synthetic process of specific proteins is considered.     

Oviposition behavior in the Australian stick insectExtatosoma tiaratum

Summary The Australian stick insectExtatosoma tiaratum (MacLeay) (Insecta: Phasmida) oviposits by throwing the eggs to a distance of circa 0.80–2.00 m by a strong flick with the abdomen. The initial speed is circa 2.7 m/sec. The rather immobile female just drops her feces, and as these may act as olfactory attractants to predators, the eggs that are flicked away will be safe, lying in a ring around the central deposit of feces.     

Microorganism-associated variation in host infestation efficiency in a parasitoid wasp,Trichogramma bourarachae (Hymenoptera: Trichogrammatidae)

InTrichogramma bourarachae (Hymenoptera: Trichogrammatidae), the infestation efficiency presents important variation among strains: 60 eggs/5 days/female in the High (H) strain and 25 eggs/5 days/female in the Low (L) strain. Crosses show that between-strains variation is inherited by the matrocline route. Antibiotic and heat treatments reduce infestation efficiency in the H strain and have no effect on the L strain. The hypothesis of cytoplasmic-symbiotic microorganisms accounting for the higher infestation efficiency in the H strain is supported by microscopic observations. The origin and the significance of this between-strains variation are discussed.     

Occurrence of a blood group A-like substance in eggs of the prosobranch snailPomacea canaliculata

Summary In the eggs of the prosobranch snailsPomacea canaliculata andPomacea insularum a blood group A-like substance has been detected by anti-A from the snailsHelix pomatia, Helix aspersa andCepaea nemoralis.