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.     

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.     

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.     

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.     

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.     

Influence of the feeding conditions on competition betweenDrosophila melanogaster andDrosophila simulans for their oviposition site

Summary Under low feeding conditions, the number of eggs laid by the femaleDrosophila melanogaster or the femaleDrosophila simulans is frequency dependent: it increases simultaneously with the increase of the frequency of the species to which the female belongs. This result could be explained by the role of scents in the choice of the oviposition site inDrosophila.     

Methods of experimental yolk removal fromBrachydanio rerio eggs

Summary The yolk ofBrachydanio rerio eggs was removed by pipettation, bursting and cutting off with a scalpel. The total yolk removal before the 8-cell stage led to a germ with irregular groups of cells, at the 8-cell stage to a topologically irregular differentiation, at the 64-cell stage to a nearly normal embryo, which is not viable.     

The choice of oviposition sites by the lady bird beetleAdalia bipunctata (L.)

Summary Adalia bipunctata females lay eggs on brussels sprout leaves in presence or absence of aphids, but the latter furnish an additional stimulus. The glass walls of the jar attracted the adults to lay eggs on it to some extent. Presence of cemented eggs did not hinder the oviposition of the adults on the brussels sprouts leaves.     

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).     

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.     

The viability of pollen grains of a lily (Lilium auratum) and the eggs of the brine-shrimp (Artemia salina) soaked in organic solvents for 10 years

Summary Pollen grains ofLilium auratum which had been stored in n-pentanol, n-butanol and n-propanol for 10 years at –10°C germinated, and the generative nucleus in the pollen tube divided into 2 sperm nuclei. The resting eggs ofArtemia salina soaked in these solvents for 10 years hatched at a high rate.     

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.     

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.     

Eine Mutante mit vergrösserten Männchen-Eiern beiDinophilus gyrociltatus (Archiannelida)

Summary In a mutant strain ofD. gyrociliatus, a certain portion of eggs expected to develop the male sex give origin to females. This is connected with an enlargement of the male type of eggs in this strain.

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Herrn Prof. Dr. G. deLattin danke ich für die stete Förderung dieser Arbeit. Für ihre Hilfe bei den Messungen und bei den Kulturen bin ich Frau cand. rer. nat. H.Scharwath sehr dankbar.     

Identification of an oviposition-regulating pheromone in the European grapevine moth,Lobesia botrana (Lepidoptera: Tortricidae)

The oviposition of the European grapevine moth (EGVM)Lobesia botrana can be deterred by an extract of conspecific eggs corresponding to 20 egg equivalents. The reduction of the oviposition behavior is dose-dependent. Nine chemicals have been extracted from the eggs and identified as straight chain fatty acids and esters of fatty acids. A mixture of these rather simple molecules induces the same levels of deterrence as the total extract. It might be possible to use oviposition regulating pheromone in the future for the control of EGVM populations.     

Hymenolepis nana: Transfer of acquired immunity in mice through sensitized peritoneal exudate cells

Summary Sensitized peritoneal exudate cells from syngeneic donor Swiss albino mice infected with single and repeated doses of viable eggs ofHymenolepis nana produced a significant adoptive immunity in test mice when compared with animals which received non-sensitized (normal) cells. No significant difference was observed among the 2 recipient groups which received singly or repeatedly sensitized peritoneal exudate cells.Acknowledgment. We thank Professor B. M. Sinha for providing facilities and to the University Grants Commission, New Delhi for financial assistance.     

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.     

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.     

Structure of two biologically active sesquiterpenoid amino-quinones from the marine spongeDysidea avara

Summary The structures of 2 minor constituents of the marine spongeDysidea avara, which induce developmental aberrations in sea-urchin eggs, are described. The structures were confirmed also by a simple synthesis from avarol (1).Acknowledgments. The authors wish to thank Mr A. Crispino for his skillfull laboratory technical assistance. Thanks are also due to Mr C. Di Pinto (NMR) and Mr A. Milone (MS).     

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.