ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00316.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.An entomophagous wasp(Hunterellus hookeriHoward) parasitizes about a third of the host‐seeking nymphalIxodes damminiSpielmanet al.ticks on Naushon Island in Massachusetts (U.S.A.) where the agents of Lyme disease(Borrelia burgdorferiJohnsonet al.)and human babesiosis(Babesia microtiFranca) are enzootic. Following blood‐feeding, wasp‐parasitized ticks are destroyed by the developing wasp. The prevalence of either human pathogen in host‐seeking ticks collected in wasp‐infested sites is nearly 40% lower than that found in other sites. Nymphal ticks, collected early in their season of activity, are more frequently parasitized by the wasp and less frequently by the Lyme disease spirochaete than those collected later in the summer. Spirochaetes never infected wasp‐infected ticks, and few wasp‐infected ticks were concurrently infected by theBabesiapiroplasm. Taken together, these correlations indicate that the wasp may render the tick inhospitable to both pathogens. The presence of the wasp may have reduced risk of human infection on the island by either pathogen by as mu

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00317.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.The house‐entering behaviour of nocturnal mosquitoes was studied in The Gambia. Mosquitoes were captured as they attacked man in the open and in experimental huts which comprised 1.8 m cube frames with corrugated iron roofs and plywood walls of various heights. Catches of all species were similar in the open and in a roofed, but unwalled, hut frame. The mosquitoes taken in catches in unwalled huts and others with wall heights of 0.6,1.2 and 1.7 m (giving an 8 cm eaves‐level entry slit) fell into two categories. The first group, which included the endophilic speciesAnopheles gambiaeGiless. I., An.melasTheobald andMansoniaspp. were only slightly affected by increasing wall height, but the second group, including the exophilic mosquitoesAedesspp.,An.pharoensisTheobald,Cx poicilipes(Theobald) andCx thalassiusTheobald showed a very marked progressive exclusion. In comparisons of catches in two huts with 8 cm entry slits at eaves or ground level, large numbers ofAn.pharoensisfound access through the ground level entry but not at eaves level. No consistent difference could be demonstrated for other species. It is concluded that the house‐entering behaviour which distinguishes endophagic mosquito species includes at least two distinct responses: flight upwards to eaves level and the passage from outside to indoors. It is also suggested that house entry as a component in host‐seeking behaviour and indoor resting are distinct, but not necessarily exclusive, behavioural

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00318.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.The larval susceptibility toBacillus sphaericusstrain 2362 of the non‐man‐biting mosquitoCulex cinereusand the urban filariasis vectorCulex quinquefasciatus, two competitor mosquitoes in polluted habitats, was compared. In the laboratory, both species ingested a similar amount ofB.sphaericusspores when fedc.2×l05spores per ml for 30 min. However, in the same experiment, third‐instar larvae ofCx quinquefasciatuswere reduced by 98% at 24 h exposure whileCx cinereuslarvae were only reduced by 6% at 72 h. In the field, preimaginal populations ofCx cinereusingested, within a week, more than 99% of the applied spores, but showed no significant decrease through 14 days in cesspools treated at 10 g/m2of a flowable concentrate ofB.sphaericus2362, containing 2times 1010spores/g.It is proposed that specific biological control ofCx quinquefasciatuscould result from appropriate treatment of breeding‐sites with larvicidalB. sphaericusand competitive displacement byCx cinereusor other mosquitoes with larvae that are more tolerant ofB.sp

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00319.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.The Beffa form ofSimulium soubrenseVajime&Dunbar, a member of theS.sanctipaulisub‐complex of theS.damnosumcomplex, was found breeding throughout rivers in the Togo‐Benin Gap, as far north as 9o30'N. Its distribution changed with the season. In southern Togo there were seasonal fluctuations in the relative abundancies of the Beffa form and ofS.damnosumlS.sirbanum.There was considerable temporal and regional variation in the frequencies of different colour morphs of adult flies. The flies in Benin tended to be darker. Infections withOnchocerca volvulus(Leuckart) appeared to be independent of the host's colour morph category. Larger flies harboured significantly more first stageOnchocercalarvae but no significant relations with fly size were found for second and third stage lar

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00320.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.Permethrin impregnated netting was tested against Tanza‐nian populations ofAnopheles arabiensisPatton,An.gambiaeGiles andAn.funestusGiles in experimental huts fitted with traps to catch samples of the mosquitoes exiting during the night. Treated bednets killed some mosquitoes and increased the tendency of survivors to exit during the night. Treated cotton did not perform so well as treated nylon bednets. An impregnated bednet in which holes had been cut, to simulate a torn net, reduced the number of mosquitoes which fed and survived approximately as well as an intact untreated net. Treated curtains around the eaves of experimental huts did not perform so well as bednets but caused considerable reductions in the number of mosquitoes which fed and survived. However, there was no such effect when treated netting was placed around the eaves of a dwelling house. When one child slept under a treated net and another slept outside the net in the same hut, the number of bites on the latter child was less than if neither child had been under a net. Various aspects of the applicability of permethrin impregnated nets on a community basis are discusse

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00321.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.Field observations suggest that, in the U.K., cattle are the preferred host ofStomoxys calcitrans(L.), followed by horses. Differences were observed in the numbers of flies feeding on individual animals both in the field and under controlled conditions. Analysis of the behaviour of four Friesian calves under attack fromS. calcitransin controlled conditions revealed that the differences in the levels of attack between individual hosts are dependent on the reactions of the host when under attack. Those hosts which respond vigorously by tail flicks, foot stamps and head‐swings suffer less from attack byS.calcitransthan their more placid contemporarie

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00322.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.1. Nectar feeding by mosquitoes collected from tansy(Tanacetum vulgar‐e)flowers was studied in July and August 1983‐85 at two sites in central and south‐western Sweden. Prior to fructose analysis, gonotrophic state and parity was determined.2. A total of 1010 mosquitoes (70% males) of eighteen species was collected. Fructose was detected in 75% of the males and 78% of the females. Most (86%) mosquitoes collected belonged toCulex pipiensandCx torrentium.3. Among 219Cx pipiensfemales, for most of which the abdomen appeared gravid (52%) or empty (42%), 81% were fructose‐positive. Females of other species were also proved to have fed on plant sugars in both early and later stages of the gonotrophic cycle.4. InCx pipiensand males ofCx torrentiumpeak nectar feeding occurred between 22.00 and 04.00 hours. Data for males of both species suggested a V‐shaped pattern of nectar feeding activity during the night.5. At about 16oC nearly all mosquitoes became fructose‐negative in the anthrone test within 20 h after collection from tansy flowers.6. At least 44% ofCx pipiensfemales that were attracted to a dove‐baited trap had fed on plant sugars s

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00323.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.A screening programme was undertaken to examine the possibility of cross resistance occurring between cyromazine and conventional insecticides. The responses of nine strains ofMusca domesticato treatment with cyromazine, trichlorphon, methomyl and pyrethrins with piperonyl butoxide were measured. No tolerance to cyromazine was found, neither was there a direct correlation between larval responses to cyromazine and adult responses to other insecticides. Cyromazine is a potent larvicide againstM. domesticaand the results of these tests show that it has good potential for the control of houseflies with high levels of resistance to other insecticides.

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00324.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.The causes of screwworm(Cochliomyia hominivorax)outbreaks in North America are not well understood, but the literature suggests that climate was historically important. Screwworm case incidence in each of seven climatological divisions of Texas was examined for the years 1962‐83, the period when sterile‐male releases were made. Weak but statistically significant correlations were found between winter and summer cases and mean winter and summer rainfall and temperature when the independent variables were examined one at a time. Multiple regression of log case incidence on previous quarterly cases and current rainfall and temperatures showed a significant, negative effect of temperature on summer cases. Lagged screwworm cases accounted for most of the variation in quarterly cases. No climatic effects were detected in the other seasons. Rainfall was statistically unrelated to screwworm abundance in any season even in an arid region. The analysis does not support a climatic genesis of screwworm outbreaks or eradication. The sterile‐male method is a credible explanation for screwworm disappea

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1987.tb00325.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY