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Im Rahmen gemeinsamer Untersuchungen zur Entwicklung von Messeinrichtungen fur die Darstellung der Einheit der Aktivitat von Eleklroneneinfangstrahlern wurden in den Jahren 1977 bis 1980 zwischen dem ASMW Berlin und dem OMH Budapest Vergleichsmessungen der Aktivitatskonzentration von Losungen der Radionuklide 57Co und 133Ba durchgefuhrt. Es wird uber die angewendeten Messinrichtungen und Messmethoden sowie uber die erhaltenen Resultate berichtet. Die Abweichungen der in den beiden Institutionen erhaltenen Werte fur die Aktivitatskonzentration stimmen innerhalb der Messunsicherheiten gut uberein; sie betragen 0,35% fur 57Co und 0,3% fur 133Ba.

AbstractIn 1976 and 1977, adults of Aedes sticticus(Meigen) and Aedes vexans(Meigen), marked with fluorescent dust, were captured in light traps up to 33 days after release and at distances up to 11 km from the release site. Adults flew primarily northwest from the release sites, and with the prevailing winds. Porcine and bovine hosts present at some of the trapping sites, appeared to be highly attractive to female mosquitoes. Within an 8 km trapping radius of the release site, the mean number of marked/trapped female mosquitoes decreased with distance. In 1977, 50% of the marked captures (weighted according to km2of trapping area) were taken within the first 2 km, 82% within 4 km, 92% within 6 km, and the remainder out to 8 km from the release site. For all trap sites, the mean recovery of marked/unmarked adults over a 33 day trapping period in 1977 was 1:1113.

Fur den rationellen Anschluss von-umschlossenen γ-Strahlungsquellen und von ss-Flachenstrahlungsquellen, die in der Praxis als Referenznormale eingesetzt werden, an die Aktivitatseinheit wurden im ASMW mehrere Satze von Sekundarnormalstrahlungsquellen mit abgestuften Aktivitatswerten geschaffen. Sie wurden hinsichtlich ihres geometrischen und slofflichen Aufbaus so konzipiert, dass sie den anzuschliessenden Strahlungsquellen vollig entsprechen oder in geeigneter Weise so verandert werden konnen, dass bei denAnschlussmessungen mittels Relativmessverfahren bestimmte Korrektionen, z.B. hinsichtlich Selbst- und Hullenabsorption bei γ-Quellen, vermieden oder, z. B. hinschtlich Absorption in der Abdeckung und Ruckstreuung an der Unterlage bei ss-Flachenquellen, messtechnisch eliminiert werden konnen.Es wird fur je einen γ- bzw. ss-Strahldungsquellensatz die Herstellung der Strahlungsquellen und das Verfahren des Absolutanschlusses an das Primarnormal der Aktivitatseinhcit beschrieben sowie ein Uberblick uber die im ASMW vorhandenen Normalstrahlungsquellensatze nach Nuklidart, Quellentyp, Aktivitatswerten, Aufbau und erreichten Messunsicherheiten gegeben.

AbstractTen species of black flies were collected from the Souris River, Manitoba between April 1977 and October 1978. Adults of Simulium luggeriNicholson and Mickel, Simulium meridionaleRiley, Simulium venustumSay, Simulium verecundumStone and Jamnback, and Simulium johannseni johannseni(Hart) were collected feeding on livestock and humans, and are well known pest species. Simulium vittatumZetterstedt was the most abundant species, but was not a pest on man or domestic animals. Simulium tuberosum(Lundstr?m) and Simulium johannseni duplexShewell and Fredeen were the least abundant species. Simulium j. johannseni, S. j. duplex, S. venustum, S. verecundum, S. tuberosum, and Cnephia dacotensis(Dyar and Shannon) appeared to be univoltine species while S. luggeri, S. meridionale, Simulium decorumWalker, and S. vittatumwere multivoltine in the Souris River.An evaluation of cone, plate, rope, and wire cage sampling devices for black fly larvae and pupae indicated that cone samplers provided a more representative sample for population assessment.In a black fly control program, of the Souris River, Manitoba two separate larvicide treatments in spring may be necessary. In the case of two treatments, the first should be aimed at late instar larvae of S. j. johannseni, S. venustum, and S. verecundum. Since the majority of S. luggeriand S. meridionalewould be in the egg stage at this time, a second treatment, 10?14 days later, would be necessary to control late instar larvae of these species.

In der Arbeit wird uber eine internationale Vergleichsmessung berichtet, die die beteiligten Institutionen zur Uberprufung der Genauigkeit ihrer Normalmeβeinrichtungen zur Darstellung der Aktivitatseinheit β-strahlender Nuklide durchfuhrten. Verschiedene Korrektionsfaktoren sowie die Verfahren ihrer Ermittlung werden diskutiert. Die Abweichung der Ergebnisse betragt 0,7% und liegt damit innerhalb der angegebenen Fehlergrenzen.

The result of population crosses of members of the Ae. australiscomplex and the examination of the male genitalia of these populations have shown that Ae. ashworthiEdwards 1921 should be reinstated as a valid species. the parent females laid viable eggs when cross mated to males of different species, but the resulting F1females and males were largely sterile. When F1females were blood‐fed and examined 3–8 d later, usually fewer than 10 ovarioles per ovary developed recognisable follicles and none of these formed eggs. F1males in nearly all cases possessed half‐size testes, and there was no spermatid development in the reduced testes. A few males had normal‐sized testes, but the spermatids were mostly tailless. the male of Ae. ashworthican be separated from Ae. australisby the shape of the gonocoxite and the length of the gonostylus of the genitalia. the larvae of both species are identical, and the females differ only in the colour of some scale patches and the integument, which may prove to be too variable to be useful when more populations are compared. the morphological similarity of the two mosquitoes as larvae and adults supports the proposal that they should be recognised as sibling species, with Ae. ashworthias the derived member of the Ae. australiscomplex. It is clear from morphological evidence, the viability of the F1hybrids and the unusual habitat occupied by both species, that they have diverged recently.

AbstractDevelopment time decreased with each increase in rearing temperature in Aedes vexans, A. nigromaculis, and Culiseta inornatauntil the optimum survival temperature was reached. The optimum survival temperature for A. vexanswas 26.5 °C, for A. nigromaculis21 °C, and for C. inornata21 °C. Dry weight gain per hour in female larvae was greater than in male larvae in all three species, at all temperatures. There was a significant reduction in weight in each larval instar, pupal, and adult stage, with each 5.5 °C increase in rearing temperature. Times to larval–pupal ecdysis and pupal–adult ecdysis were the same for males and females of A. nigromaculisat all developmental temperatures tested. Time to larval–pupal ecdysis and pupal–adult ecdysis in A. vexansand C. inornataoccurred 1 to several days later in females, depending upon the developmental temperature. In all three species the duration of the fourth instar was longest and the specific weight gain greatest.

AbstractA study was initiated to determine the effects of various constant and alternating temperatures on the survival and development of the immature stages of Culiseta inornata(Williston). Eggs did not hatch at 2° and 5 °C. but at 10°, 15°, 21° and 26 °C. between 83 and 96% hatched. Larvae required up to 239 days to reach the pupal stage at 5 °C. but no adults emerged at this temperature. The optimum temperature for rearing C. inornatawas near 21 °C. Temperatures below 21 °C. caused an extended period of development; above 21 °C. high mortality occurred among late instar larvae and pupae.

AbstractAedes rempeliVockeroth, the rarest Canadian Aedesmosquito, breeds in unusually cold, stenothermal rock pools in low arctic Canada. The species presents an unusual opportunity for laboratory colonization of a northern Aedessince it mates readily in confined spaces in the laboratory and the females mature the ovaries without a blood meal.

AbstractOptimum storage conditions for eggs of Aedes vexans(Meigen) were found to be a temperature of 2 °C and a saturated atmosphere. These conditions are also suitable for storing eggs of Aedes abserratus(Felt and Young) but this species can be stored at lower temperatures. When eggs of both species are stored at 2 °C and placed in a hatching medium at 2 °C, hatching begins in A. abserratusbut not in A. vexans. A comparable hatch in the latter occurs at 10°–15 °C. Desiccation and death of A. vexansembryos occur rapidly at a low relative humidity (20%) and a high temperature (21 °C) but slowly at low relative humidity and a low temperature (4 °C). Eggs that lose a substantial amount of water will still hatch and the larvae develop normally, but hatching time is delayed. The hatching time may be twice as long as in eggs kept in a saturated atmosphere at similar temperatures, indicating that embryos must regain some of the lost water before hatching can occur.

AbstractAedes vexans(Meigen) eggs which lose water under conditions of constant atmospheric saturation deficiencies, gain water when transferred to a saturated atmosphere. Water loss is influenced by age. At relative humidities of 80% and 50%, and temperatures of 10° and 21 °C, eggs that were 28 days old lost less water than eggs 14 days old. Eggs which lost up to 34% of their weight through desiccation regained 91% of lost water within 3 days in a saturated atmosphere. Embryos remained viable. Eggs which lost 68% of their original weight in water were rendered inviable and only regained 33% of the loss in a saturated atmosphere.

AbstractRadionuclides may be used as ecological tracers to study trophic–level relationships. To use cesium-137 to investigate the role of the giant water bug, Lethocerus americanus(Leidy), in the food-web of a small pond, it was necessary to measure the elimination rate of the nuclide. The experimental determination of the elimination rate of cesium-137 in fourth instar and adult water bugs, and the calculation of the fraction of ingested food assimilated is described.

AbstractThe larvae of 26 species of Aedesfrom Manitoba were reared at constant temperatures from a low of 10? or 15?C, to the upper lethal temperature. Various grades of adult intersexes occurred in 12 univoltine species. The lowest threshold temperature for intersex development was found in A. communis(19?C); the highest in A. fitchii(29?C). A constant rearing temperature of 30?C was lethal for all fully univoltine species from Manitoba. The zoogeographical significance of the distribution of species in North America is discussed with regard to their intersex threshold temperature.

AbstractDiapause in Wyeomyia smithii(Coquillett) was shown to be a function of photoperiod, and independent of temperature. The critical daylength for a population from Pinawa, Man., was 15 hr light per diem. The photoperiodic cues are monitored by the early instars, with diapause being expressed in the third instar. Development is also limited by temperatures below 15 ?C even when the critical daylength is exceeded.Survival at low and subzero temperatures is aided by the diapause state. However, larvae are unable to withstand extended periods of subzero temperatures, even in the diapause condition. At ?5 ?C, 60% mortality occurred after 8 weeks under laboratory conditions. In the field, where ground temperatures averaged ?3.7 ?C during the five coldest months, larval mortality averaged 45% after four winter months.Once diapause is established, larvae consume very little food. Diapause larvae appear to be as active as non-diapause larvae, and also appear to be feeding constantly. However, the amount of food ingested is negligible compared to non-diapause larvae.

AbstractLarval surveys were conducted in Winnipeg environs during the summers of 1967 and 1968. The species, density of larvae, the relationship between rainfall and larval abundance, and the species of pest importance were studied in detail. Aedes vexanswas the most numerous mosquito found both in the larval and adult stages. Aedes dorsalisand Aedes spenceriiwere also of pest significance during each season. An association between the abundance of A. vexanslarvae and the proximity of these to an adult blood source, mainly beef and dairy cattle, was observed.