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1.
Summary During diapause O2 consumption in fly pupae is a cyclic event (4-day periodicity at 25°C) driven by cycles of juvenile hormone activity. Levels of juvenile hormone esterase activity change systematically during the cycle, with highest activity observed at the nadir of the O2 consumption cycle.Supported in part by grant 88-37153-3473 from the USDA Competitive Grants Office and grant 23-088 from the USDA Forest Service. Thanks to Dr Ming Tu Chang for her helpful advice.  相似文献   

2.
During diapause O2 consumption in fly pupae is a cyclic event (4-day periodicity at 25 degrees C) driven by cycles of juvenile hormone activity. Levels of juvenile hormone esterase activity change systematically during the cycle, with highest activity observed at the nadir of the O2 consumption cycle.  相似文献   

3.
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.  相似文献   

4.
Summary In photoperiodic adult diapause ofDrosophila testacea, the critical daylength fell between 14 and 16 h at 15°C, but between 13 and 14 h at 18°C. None entered diapause at LD 1014 and LL at 23°C. This species quantitatively responded to daylengths around the critical daylength in the process of diapause induction. The length of the sensitive period seems to change with temperature.  相似文献   

5.
Summary InPyrrhocoris apterus, a low temperature, 15°C, prevented the termination of diapause by long days and, unexpectedly, also the induction of diapause by short days. Both responses were enabled at a higher temperature, 26°C. In contrast to current concepts, it was proved that the summation of photoperiodic signals was temperature-dependent, since the morphogenetic development was prevented by starvation.  相似文献   

6.
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.  相似文献   

7.
H Sonobe  M Ikeda  H Kaizuma 《Experientia》1979,35(12):1650-1651
Oxygen permeability of the chorion of the silkworm, Bombyx mori, was measured in relation to embryonic diapause. It did not change appreciably when the eggs were freed from diapause by being kept under long chilling. This finding suggests that the increase in oxygen permeability of the chorion is not a pre-requisite for the termination of the diapause and resynthesis of glycogen from 2 polyols.  相似文献   

8.
Summary Pieris brassicae larvae were reared under 9 h/24 h white light and 20°C (conditions determining the diapause status). From the pupal moult they were exposed for 20 days under different wavelengths (absorbed or not by the green integumentary pigment: pterobilin). This treatment has no effect on diapause.  相似文献   

9.
Encystment, which at a temperature of 15°C is photoperiodically controlled inGonyaulax polyedra, can also be induced by a decrease of temperature, from 20 to 10 or 8°C in the absence of photoperiodic signals. The cyst-inducing capacity of the decrease in temperature depends on the circadian phase: in constant light, the maximum of sensitivity was found at the beginning of subjective night. In a light/dark cycle, however, cyst formation was reduced during dark phase, indicating that light is required for the process of encystment. A similar light dependence was seen in the effect of the physiologically occurring cyst inducer 5-methoxytryptamine, but not in the encystment response to the protonophores monensin and nigericin.  相似文献   

10.
Summary By rearing the predacious miteAmblyseius potentillae in a daily temperature cycle in constant darkness it could be shown that diapause may be thermoperiodically induced. When the same experiments were performed using diets without vitamin A it appeared that vitamin A is necessary to achieve a state of reproductive diapause in this mite.2 February 1987  相似文献   

11.
Summary Manduca sexta larvae were subjected to diapause-inducing and diapause-preventing photoperiods, using two types of fluorescents (Indorsun and Blacklight-blue). The oenocytes, prothoracic glands (PTG) and ecdysone levels were examined in 3-day-old 5th instar larvae, 2-day-old and 10-day-old pupae. Our results indicate that oenocytes and PTG cells tend to be more active under long photoperiods while oenocytes only are active under short photoperiods in pupae in diapause. UV light has a definite effect on oenocytes while PTG cells seem to be unaffected. Ecdysone and ecdysterone levels vary with PTG and oenocyte activity at the pupal stage. The significance of these findings is discussed.This work was supported by a research associateship to L.M. by the People's Republic of China and a grant from NSERC to B.J.R.P.  相似文献   

12.
Summary Comparison of the total body protein of male and female larvae, pupae, and adults of a diapause and 2 nondiapause strains of the pink bollwormPectinophora gossypiella indicated that the protein content of larvae of the diapause strains was significantly higher than of the non-diapause strain.I thank Drs D.R. Nelson and R.A. Bell of the U.S.D.A. Metabolism and Radiation Research Laboratory, Fargo, for facilities and guidance.  相似文献   

13.
Summary The temperate race (D) ofS. peregrina undergoes pupal diapause in response to certain environmental conditions of photoperiod (13L:11D–11L:13D) and temperature (under 20°C). The tropical race (ND) does not do so under the same circumstances. The tendency toward diapause was suppressed in 30–40% of the hybrids of crossings D×ND and ND×D even under such short day and low temperature conditions as 11L:13D–9L:15D, 20°C. For entering diapause, the hybrids require a shorter day length (13L:11D) than that of (D) parents (15L:9D).We thank Dr R. Kano and Dr S. Shinonaga, Tokyo Medical and Dental University, for supplying the New Guinean material.  相似文献   

14.
Summary Wood frogs survive extracellular freezing at moderate subzero temperatures (–4°C) for at least 11 days. Freezing survival is aided by the accumulation of high concentrations of glucose as a cryoprotectant in blood and tissues. Glucose production was accompanied by a rapid decline in liver, but not muscle, glycogen levels suggesting that liver is the organ controlling cryoprotectant synthesis.Acknowledgments. This study was supported by grants to L.M.G. from the Kroc Foundation (Santa Ynez, California) and from the National Institute of Dental Research (Grant No. DE-03987). The authors wish to thank K. Yorko, M. Shakin, J. Finan and Mrs N. Manivannan for their technical and secretarial assistance.Acknowledgments. I thank Dr J. Ballantyne, Dr F. Schueler and I. McMurray for help with frog collections and Dr. W. Schmid, Dr J. Bogart and Dr F. Cook for helpful discussions. Supported by an N.S.E.R.C. operating grant and by a grant from the Atkinson Charitable Foundation.  相似文献   

15.
Summary The quantal contents of endplate potentials from extraocular muscles of an antarctic fishPagothenia borchgrevinki were measured over a range of temperatures. Quantal release was maximal at about 5°C but showed little dependence on temperature between –2°C and 10°C. Above 10°C quantal content declined until release ceased about 18°C. In view of the fact that the ambient temperature at which these fish live is constant at –1.9°C, the results suggest thatPagothenia borchgrevinki is only partially adapted to its environment despite 25 million years acclimatization.The authors wish to thank the staff of New Zealand's Scott Base, Antarctica, without whose cooperation the work would have been impossible. Mr J. Quinn of the Auckland University Physiology Department gave invaluable assistance with computing and electronics and the Antarctic Division of the New Zealand Department of Scientific and Industrial Research provided transportation and logistic support. The project was financially supported by the New Zealand University Grants Committee and the Auckland University Research Committee. S.P. was a Senior Fellow of the N.Z. Medical Research Council.  相似文献   

16.
Summary The concentration of free amino acids in the haemolymph of non-diapausing and diapausing pupae ofHeliothis armigera was investigated. 20 amino acids were detected in the haemolymph of the studied stages. Asparagine, glutamine, cystine, ornithine, histidine and valine were the predominant free amino acids at all stages. The diapause resulted in increased levels of most of the amino acids.  相似文献   

17.
At 25°C, secondary dormancy was induced in seeds ofE. crus-galli exposed for 100 days to oxygen deficiency. By contrast, hypoxia did not induce dormancy at 15°C or prevent dormancy termination at 7°C. Secondary dormancy was terminated after 2 months stratification at 7°C. Oxygen deficiency may increase the proportion of dormant seeds in the soil, and affect the dynamics of the barnyard-grass soil seed bank.We thank Miss Jitka Králová for her excellent technical assistance.  相似文献   

18.
Summary The influence of low atmospheric pressures and low oxygen concentrations on 0-24-h-oldEphestia cautella (Wlk.) pupae at 26°C was determined. Effects on respiration, insect mortality and loss in weight obtained, were due to low oxygen tension only, at both normal and low atmospheric pressure.Contribution from the Agricultural Research Organization, Israel, No. 137-E, 1978 series.  相似文献   

19.
Summary In the Mediterranean field cricket,Gryllus bimaculatus, reproduction is controlled by temperature and the corpus allatum (CA) hormone JH III. In CA of females reared at 24°12°C(168 h) (high reproduction rate) a first peak in JH III synthesis is reached about 4 days earlier than in those of 20°C females (low reproduction rate). Furthermore, in 20°C animals CA activity is low during the entire oviposition period, whereas at 24°12°C high CA activity is found during this period of adult life. The results indicate a stimulation of CA activity and reproduction by thermoperiods around a constant low temperature.Supported by the DFG (SFB 87 A 4).  相似文献   

20.
When exposed their whole larval life to a 24 h. thermoperiodic cycle in constant darkness, individuals of Pieris brassicae L. give diapausing or non-diapausing pupae according to the length of the cold and warm sequences. The curve of thermoperiodic induction is similar to the photoperiodic curve.  相似文献   

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