摘要:

Abstract.At 27oC and 45% r.h. in the laboratory, the oriental cockroachBlatta orientalis(L.) developed to adulthood in seven to nine instars for males (66% had eight instars) and eight to ten instars for females (67% had nine instars) in mixed groups, with up to twelve instars for isolated females. Nymphal development lasted 185 ± 2 days for males, 216 ±4 days for females, with 89% survival to adulthood. Adult longevity was significantly more for males than females in mixed groups. Virgin females lived for 135 ± 6 days compared with 87 ± 9 days for females kept with males. After an initial maturation time of 12.2–13.5 ± 0.4 days for mated and unmated females, oothecae were produced, on average, every 6–7 (range 2–29) days. Ootheca viability was 68% from females kept with males, 32% from females kept apart from males. Numbers of nymphs emerging were 14.1 ±0.26 after 45 days from mated female oothecae 8.2 ± 0.3 after 49 days from unmated females. With sexual reproduction the sex ratio of progeny reaching adulthood was 1.1 males per female (n= 443), whereas unmated females produced only female progeny, which is consistent with partheno‐genetic reproduction.Drawings of the ventral aspect of the terminalia are given to show features useful for instar determination and for distinguishing between male and female nymphs and adults

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00566.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.Results are presented of a survey carried out by Rentokil Ltd on the distribution of the Oriental cockroachBlatta orientalisL. and the German cockroachBlattella germanicaL. in the United Kingdom. The known ranges of both species are increased considerably by the findings of the survey, with several new vice‐county records for Scotland (including the Western Isles), England and Wales. The frequency at whichBlatta orientaliswas observed in outdoor habitats may indicate that this species sometimes spreads to new areas without human assistanc

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00567.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.1The distribution patterns of sandflies (Diptera: Psychodidae) upon tree buttresses were studied in tropical rain forest at Finca la Selva in the Caribbean lowlands of Costa Rica.2Four species of sandfly,Lutzomyia shannoniDyar,L.trapidoiF.&H.,L.ylephiletorF.&H. andL.vespertilionisF.&H. comprising 97% of those caught, used tree buttresses as diurnal resting sites. Their distribution on the buttresses was aggregated.3During the dry season tree species had no significant effect upon the distribution of the sandflies. However, during the wet season the distributions of two of the species,L.trapidoiandL.ylephiletor, were significantly affected by the species of tree; it is suggested that some species of tree may provide greater protection from rainfall than others.4L. vespertilioniswas restricted to a single buttress on each positive tree. Distribution of this species is evidently determined by the distribution of its host animal, the bat (Emballonuridae). Female flies feed upon the bat's blood and male flies may be attracted to the bat as it provides a source of female sandflies. It is suggested, therefore, that tree buttresses serve as sandfly swarming sites.5Within a large buttress the sandflies are not randomly distributed but are aggregated in particular areas. Within these aggregations, the sandflies are vertically zoned upon the buttress with a shift in species composition with height. Two hypothesis were suggested to account for this distribution pattern: a response to an environmental gradient or an interaction between the four species of fly.

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00568.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.Seasonal activity of the loiasis vectorsChrysops dimidiataWulp andChrysops silaceaAusten (Diptera: Tabanidae) was studied during 1987–89 in villages and surrounding forest of the Chaillu Mountains, Congo.Chrysopswere captured mainly in the hot rainy season (November ‐May) and densities of both species were higher in the forest than in villages.C.silaceapredominated at all sites andC.dimidiatawas rarely found in villages.In the rain forest, between 07.00 and 18.00 hours, 12 times moreC.silaceaand 3 times moreC.dimidiatawere collected with hand‐nets (range 15–81 per man‐day) than were caught in landing/biting collections on human bait.Chrysopsman‐biting rates were higher in villages closer to the forest, but variations in loiasis prevalence among villagers (microfilaraemia rates 16–37%) were not proportional to the intensity of contact between people and vectors in the villages, indicating that the majority of loiasis transmission probably occurs when people go in

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00569.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.The summer mastitis pathogensActinomyces pyogenes, Peptococcus indolicus, Bacteroides melaninogenicusss.levii, Fuso‐bacterium necrophorumandStreptococcus dysgalactiaewere isolated from the polyphagous symbovine dipteransHydrotaea irritans(Fallen) andMorelliasp. caught around dairy heifers on pasture, but not from the haematophagous speciesHaematobia irritans(L.),Haematobosca stimulans(Meigen),Culicoidessp. andSimuliumsp. Secretions from clinical cases of summer mastitis proved to be sources of summer mastitis bacteria for more than 3 weeks despite antibiotic treatment and teat amputation.Taking into account the seasonal activity pattern ofHydrotaea irritansand its topographical distribution on grazing cattle, it appears evident that this fly may play a central role in the establishment and maintenance of the bacterial contamination with summer mastitis pathogens on the teats of healthy cattle. In the present study the survival ofA.pyogenesandP.indolicusfor 7 days in experimentally infectedHydrotaea irritans, as demonstrated by the recovery of these microorganisms from agar plates exposed to live infected flies, is described. However, experimental transmission of summer mastitis from sick to healthy heifers byHydrotaea irritansproved unsuccessfu

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00570.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.Borrelia burgdorferiJohnsonet al.was first isolated from the midgut ofIxodes damminiSpielmanet al.in the U.S.A. and from the midgut ofLricinus(L.) in Europe.I.ricinuswas considered to be the only tick vector of this borrelia, in Europe, untilI.hexagonusLeach, the hedgehog tick, was found to harbour spirochaetes. This paper reports an evaluation of the vector competence ofI. hexagonusfor the spirochaeteB. burgdorferi.Transovarial and trans‐stadial survival were demonstrated and the spirochaete was transmitted to laboratory mice via the bites of trans‐stadially infectedI.hexagonusfema

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00571.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.Four sympatric species ofSarcophaga, vizS.cruentataMeigen,S.exuberansPandelle,S.nodosaEngel andS. tibialisMacquart, which occur in the Transvaal, South Africa, showed oviparity under optimum laboratory breeding conditions. Details of the life cycle duration under these conditions are discussed. Rearing and colonizing methods were developed. Scanning electron microscopy of third instar larvae provided useful data in distinguishing between the four species. The characters which were examined were the spinulation of the body segments and the rim surrounding the spiracular atrium of the posterior spiracles, the anterior spiracles and the spiracular hairs of the posterior spiracles.

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00572.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.DNA probes have been constructed to distinguish between the members of theAnopheles farauticomplex of mosquitoes known as species numbers 1, 2 and 3. Partial genomic libraries of the three known species were exposed to labelled total genomic DNA from each species. Colonies showing differential hybridization were selected for further testing. These probes were found which allow identification of the three known species: probe pAfl (160bp fragment) hybridizes to DNA fromAn.farautinos. 1 and 2; probe pAf2 (95 bp fragment) hybridizes to DNA fromAn.farautino. 2 only; and probe pAf3 (1.3 kb fragment) hybridizes strongly to DNA fromAn.farautino. 3, less to no. 1 and faintly to no. 2. Increasing the stringency of hybridization reduced the cross‐hybridization of probes pAfl and pAf3. Only radio‐actively labelled probes were tested. Males and females and individuals from diverse habitats and localities showed the same species/probe hybridization characteristics. This technique allows faster identification of the sibling species than previous methods, and has the added advantage that it allows air‐dried and alcohol stored specimens to be ident

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00573.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.The cloned DNA sequences pAnal, pAnql and pAnml4, which may be used to distinguish between at least five of the six species in theAnopheles gambiaeGiles complex of Afrotropical malaria vector mosquitoes, have been sequenced. Each clone was found to possess a series of repeated sequences of 41, 30 and 163 bases respectively. In pAnql and pAnml4 the repeats were in direct tandem array, whilst in pAnal the repetitive sequence was found to be interspersed by 15–17 variable bases. A comparison of a number of copies of each of the repetitive sequences within the three clones enabled the definition of the consensus sequence for each repetitive element. Based on these consensus sequences, three oligonucleotides of 21, 23 and 26 bases were derived from pAnal, pAnql and pAnml4 respectively. When tested as probes against DNA dot‐blots and squash‐blots of mosquito specimens, each oligonucleotide retained the same species‐specificity as the original clones from which they were derived. The radioactively labelled oligonucleotides were able to detect as little as 5 ng of target genomic DNA in an overnight autoradiographic exposure. The synthetic DNA probes will form the basis of a simplified system for the field identification ofAnopheles gambiaesibling species sp

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00574.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.1Nylon bednets impregnated with different insecticides were evaluated in 1988 against wild adult mosquito populations, mostlyMansonia africana(Theobald) andAnopheles gambiaeGilessensu lato, entering experimental verandah‐trap huts in The Gambia. Each bednet had six 10 ± 10 cm holes made in the walls to simulate torn conditions and permit female mosquitoes to enter and feed on sleepers.2Individual net treatments, determined by gas chromatography of net samples from before and after 12 weeks use of the bednets, were: permethrin 670 ± 159 and 405 ± 190mg/m2(40% loss), cypermethrin 37 ± 8 and 16 ± 9 mg/m2(57% loss), deltamethrin 10 ± 7 and 10 ± 8mg/ m2(no loss), lambda‐cyhalothrin 2.6 ±0.9 and 1.6 ±0.5 mg/m2(38% loss), pirimiphos‐methyl 4017 ± 117 and 1160 ± 319mg/m2(71% loss).3Washing three times in the traditional manner with local cow‐fat soap reduced the initial dosages by about 85% of cypermethrin and lambda‐cyhalothrin, 99.8% of pirimiphos‐methyl and left no detectable residues of deltamethrin or permethrin.4The unwashed permethrin‐treated bednet reduced the number of mosquitoes entering a hut by 60% ofAn.gambiae s. l.and 68% ofMansoniaspp. This deterrency was less pronounced with the other insecticides and was lost by washing the bednets.5Each insecticide, especially lambda‐cyhalothrin and pirimiphos‐methyl, caused significant mortality rates of mosquitoes that entered huts with impregnated bednets, and prevented the majority ofAn. gambiae s.l.andMansoniafemales from bloodfeeding. Washing completely removed the efficacy of deltamethrin and permethrin treated bednets, whereas nets treated with cypermethrin, lambda‐cyhalothrin or pirimiphos‐methyl remained significantly insecticidal after washing.6Aerial toxicity from the pirimiphos‐methyl treated bednet killed 80% ofAn.gambiae s.l.confined overnight in the hut at the end of the trial, whereas the pyrethroid‐treated bednets gave negl

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00575.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY