bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil substrate classification and the FAO and World Reference Base systems: examples from Yemen and Jordan
Authors: Pietsch D. , Lucke B.
Published: March 2008

The World Reference Base for Soil Resources and the FAO Guidelines for Soil Description are tools to identify, describe and classify a soil by diagnostic horizons, diagnostic properties, diagnostic materials, and other soil features. While bedrock and residual fragments can be defined by their lithology and abundance, the parent material of soil formation is not clearly classified. Therefore a substrate classification was implicated in descriptions of layered soils, because these consist often of allochthonous, polygenetic and heterogeneous substrates. Results of soil investigations in Yemen developed into a substrate classification key for parent materials that focuses on parameters of substrate variety. Primarily, the present approach was developed to describe layered soils on the Island of Socotra, but it is assumed to be valid for any semi‐arid region in the Tropics and Subtropics. To assess the operational reliability of the system, it was applied to classify parent materials of soils from Yemen mainland and Jordan. The classification key is partly based on the FAO Guidelines, and partly on the German Soil Mapping Guidelines. The substrate variety includes lithology, weathering intensity, stratigraphical unit and substrate form. Different substrate varieties within one profile are called substrate orders and closely relate to sedimentary bedding. The proposed classification key is based additionally on parameters such as geogenesis and relief position. It can be used separately from soil description. However, soil identification and description become more precise by using this classification system. This contribution should be understood as a first approach to an international substrate classification.
An empowerment process: successful recovery from alcohol dependence
Authors: Yeh Mei‐Yu , Che Hui‐Lian , Lee Li‐Wei , Horng Fen‐Fang
Published: March 2008

Aims.  The purpose of this study was to explore the concepts and processes for successful abstinence from alcohol for Taiwanese Alcoholics Anonymous members.

Background.  Attempting to identify the psychological and social influences upon alcohol consumption remission outside of alcoholism treatment could help professionals to engage in a broad array of community interventions in an informed fashion.

Methods.  Grounded theory method was utilized in this study. The study chose nine participants who had succeeded in abstinence, using theoretical sampling and conducted in‐depth interviews by an open‐ended questionnaire.

Results.  The results of this study indicated that the core of the process during which alcoholic individuals succeeded in abstaining from further alcohol consumption was an empowerment process for the involved individual. Alcoholics felt that their family, interpersonal relationships, jobs and personal finances all had been at ‘rock‐bottom’ level following a long period of alcohol dependence. This feeling caused the individual to experience an emotion of a loss of control and provoked the arousal of an alcoholic's inner consciousness levels, this then resulting in the generation of a driving force for abstinence from alcohol for these individuals.

Conclusions.  The expansion of an individual's internal awakening power helps the individual to obtain assistance and to resist the temptation of further alcohol consumption. Therefore, the power derived by individuals from the stages of repositioning, releasing, active sharing, resistance and assistance are the maintenance factors for an individual's empowerment process that help maintain the successful recovery from alcohol for the involved individual.

Relevance to clinical practice.  A good comprehension of the recovery processes for alcoholics, we believe, will trigger clinical professionals to pay appropriate attention to the specific problems and needs of alcoholic individuals, to build an effective resource network for treatment and to help solve alcoholics’ physical and psychosocial problems.
SNOM on cell thin sections: observation of Jurkat and MDAMB453 cells
Authors: ZWEYER M. , TROIAN B. , SPREAFICO V. , PRATO S.
Published: March 2008

In this study a comparison of scanning near‐field optical microscopy with a traditional, well‐known microscopic technique like transmission electron microscopy is discussed. To establish a reliable and comparable method for high‐resolution scanning near‐field optical microscopy imaging of biological samples, the attention is focussed on cell sections. In particular, we present a study of ultrathin sections of Jurkat T‐cells and MDAMB453 cells. We show the relationship among the scanning near‐field optical microscopy (topographic and optical) images and the kind of embedding medium (resin), the sections thickness and the staining of the sample. For a complementary investigation atomic force microscopy measurements are carried out, as well. The study reveals that scanning near‐field optical microscopy technique on opportunely prepared thin sections can be applied successfully for investigation of the interior of the cells. Scanning near‐field optical microscopy and transmission electron microscopy allow to obtain different, however comparable, and complementary information of the cell sample.
Differential effects of Bacillus sphaericus strain 2362 on Culex quinquefasciatus and its competitor Culex cinereus in West Africa
Authors: NICOLAS L. , DOSSOU‐YOVO J.
Published: March 2008

ABSTRACT. The larval susceptibility to Bacillus sphaericus strain 2362 of the non‐man‐biting mosquito Culex cinereus and the urban filariasis vector Culex quinquefasciatus, two competitor mosquitoes in polluted habitats, was compared. In the laboratory, both species ingested a similar amount of B.sphaericus spores when fed c. 2×l05 spores per ml for 30 min. However, in the same experiment, third‐instar larvae of Cx quinquefasciatus were reduced by 98% at 24 h exposure while Cx cinereus larvae were only reduced by 6% at 72 h. In the field, preimaginal populations of Cx cinereus ingested, within a week, more than 99% of the applied spores, but showed no significant decrease through 14 days in cesspools treated at 10 g/m2 of a flowable concentrate of B.sphaericus 2362, containing 2times 1010 spores/g.

It is proposed that specific biological control of Cx quinquefasciatus could result from appropriate treatment of breeding‐sites with larvicidal B. sphaericus and competitive displacement by Cx cinereus or other mosquitoes with larvae that are more tolerant of B.sphaericus.
A new type of collapsible insect‐surveillance light trap for sampling Diptera
Authors: BOOBAR L. R. , SARDELIS M. R. , NELSON J. H. , BROWN W. M.
Published: March 2008

Abstract. The newly designed Army Collapsible Insect Surveillance trap for nocturnal collection of flying Diptera that are attracted by light is described. A polyvinyl chloride construction increases durability, while the capability to collapse from a height of 92.1 cm to 24.1 cm facilitates transportation and storage.
The status of Simulium oyapockense and S.limbatum as vectors of human onchocerciasis in Brazilian Amazonia
Authors: SHELLEY A. J. , DIAS A. P. A. LUNA , MORAES M. A. P. , PROCUNIER W. S.
Published: March 2008

Abstract. In an attempt to explain trie current distribution of onchocerciasis in the forests of northern Brazil (Moraes etal., 1979,1986), and its potential for dispersal to other areas, this study compares the vector status of Simulium oyapockense Floch and Abonnenc, 1946 in both a hypoendemic and an onchocerciasis free area with that of S.limbatum Knab, 1915 in the latter area. Both species allowed the full development of Onchocerca volvulus (Leuckart) to the infective L3 stage after experimental infection with microfilariae. Their vector competence was significantly lower than for other efficient vector species in South America and Africa because of the lethal effect of the cibarial armature on ingested microfilariae. The low vector capacity of S. oyapockense, together with the low prevalence and intensity of infection of O. volvulus, probably explains why onchocerciasis has not significantly increased in intensity over the last 10 years in the hypoendemic part of the Amazonian focus. Omnipresence of both vector species in the adjacent savanna region, however, could facilitate the spread of onchocerciasis if human population movements continue from the hyperendemic part of the onchocerciasis focus.
Light and suction trap catches of Culicoides midges in southern England
Authors: HOLMES P. R. , BOORMAN J. P. T.
Published: March 2008

Abstract. 1. The seasonal flight periods are given for eleven species or species groups of Culicoides midges at Pirbright, Surrey, U.K., from 1979 to 1981 and in 1983.

2. Most species were relatively uniformly distributed both within the study site and between years; only C.clintoni Boorman was limited in its spatial distribution and only C.segnis Campbell and Pelham‐Clinton varied greatly in numbers between years.

3. Species fall into one of three patterns of seasonal abundance: spring emergers, summer emergers, or spring to autumn emergers.

4. Only the C.obsoletus group showed a pattern of emergence that could correspond to distinct generations, of one or more species in the group. Three distinct emergences were observed, and possible explanations for these discussed.

5. For all species except C.impunctatus Goetghebuer the catches from suction/light and suction only traps are poorly correlated whereas for C.impunctatus they are highly correlated. This may suggest that this species is not greatly attracted to light.
The influence of permethrin‐impregnated bednets and mass drug administration on the incidence of Plasmodium falciparum malaria in children in Sabah, Malaysia
Authors: HII JEFFREY L. K. , VUN Y. S. , CHIN K. F. , CHUA R. , TAMBAKAU S. , BINISOL E. S. , FERNANDEZ E. , SINGH N. , CHAN MECHIEL K. C.
Published: March 2008

Abstract. A small‐scale trial was carried out in the Upper Kinabatangan district of Sabah, Malaysia, to determine the effect of using permethrin‐impregnated bednets on malaria transmission. A total of 306 nylon bednets with cotton borders, impregnated at a dose estimated to have been 0.062 g permethrin/m2 of nylon netting, were distributed to 139 households in five villages. At the time of distributing bednets, mass drug administration with Fansidar plus primaquine was also administered to the human population to clear all parasitaemias due to Plasmodium falciparum Welch. In another village, for comparison, mass drug administration was the only intervention.

After intervention measures in December 1984 and January 1985, the parasite rates in children declined in all villages during the first month, significantly more in the villages with impregnated bednets than in the control, thus proving that the nets had an impact on malaria. However, after about 2 months, parasite rates started to increase again. After 4–6 months, parasite rates in the villages with bednets approached the rate in the control village without nets. The increase in parasite rates was paralleled by a significant deterioration in the quality, physical condition and the degree of non‐utilization of bednets.

Entomological evaluation proved the efficacy of permethrin‐impregnated nets for controlling Anopheles balabacensis Baisas and other ano‐phelines. Bioassays (1 h exposure) of permethrin‐impregnated bednets gave 100% mortality initially and 44–61% mortality after 85–106 days. Mosquito collections in treated bednets were significantly reduced for at least 217 days.

The project failed to achieve prolonged suppression of malaria transmission for a combination of entomological, sociological and practical reasons which are discussed in relation to the objectives and implementation of future bednet studies.
Early season dispersal of Muscidifurax zaraptor (Hymenoptera: Pteromalidae) utilizing freeze‐killed housefly pupae as hosts
Authors: PETERSEN J. J. , PAWSON B. M.
Published: March 2008

Abstract. The pteromalid wasp, Muscidifurax zaraptor Kogan and Legner, was released at three locations at a dairy in May before housefly and stable fly breeding had begun. Freeze‐killed housefly pupae were placed adjacent to the emerging parasites at biweekly intervals for a 6‐week period. Hosts placed out weeks 0 and 2 were heavily parasitized. Decreased parasitism in hosts placed out at week 4 suggested that many of the M.zaraptor had dispersed or died. High parasitism of hosts placed in the field at week 6 was the result of second generation parasites emerging from pupae placed out at week 0. Parasitism of freeze‐killed housefly pupae placed 6 m and in the four cardinal directions from the release points was similar but lower than for hosts placed adjacent to the emerging parasites. The study demonstrated that emerging M.zaraptor readily utilized nearby freeze‐killed housefly pupae but the availability of these hosts did not deter the parasites from searching for additional hosts.
Comparative study on the infection rates of different laboratory strains of Glossina species by Trypanosoma congolense
Authors: MOLOO S. K. , KUTUZA S. B.
Published: March 2008

ABSTRACT. Teneral Glossina morsitans centralis Machado, G. austeni Newstead, G. palpalis palpalis Robineau‐Desvoidy, G. p. gambiensis Vanderplank, G. fuscipes fuscipes Newstead, G. tachinoides Westwood and G. brevipalpis Newstead, from laboratory‐bred colonies, were fed at the same time on the flanks of ten goats infected with Trypanosoma congolense Broden isolated in Tanzania or in Nigeria. The seven tsetse species were infected over the range 0.3–49.2%. Survival of both T. congolense isolates was best in G. m. centralis, poorest in G. austeni and the four palpalis group tsetse, with G. brevipalpis intermediate. It is suggested that there are differences in the gut of different laboratory‐bred cultures of Glossina Westwood species and subspecies such that T. congolense parasites can survive better in the gut of some than in others and undergo cyclical development to metacyclics in the hypopharynx.
Diel biting activity of Culex (Melanoconion) caudelli in Trinidad, West Indies
Authors: CHADEE DAVE D. , TIKASINGH ELISHA S.
Published: March 2008

ABSTRACT. The diel biting periodicity of the arbovirus vector Culex (Melanoconion) caudelli Dyar and Knab (Diptera; Culicidae) in the Aripo‐Wallerfield forest, Trinidad, was studied by collecting mosquitoes attracted to mouse‐baited traps at 2‐hourly intervals during eight 24 h periods.

Biting females of Cx caudelli were collected during all night‐time hours, 18.00–06.00 hours, with an overall unimodal pattern, i. e. one well‐defined peak between 22.00 and 04.00 hours. This contrasts with previous reports that Cx caudelli is diurnally active.

During the four moon phases, the period of peak biting activity varied from 22.00 to 24.00 hours at fullmoon, from 22.00 to 04.00 hours at first quarter, and from 24.00 to 02.00 hours at new moon and last quarter phases.

The number of mosquitoes collected varied significantly with moon phases, the highest (152/24 h) being collected in the first lunar quarter and the lowest (71/24 h) in the last lunar quarter.

Cloud cover and rainfall had no significant effect on the diel biting periodicity of Cx caudelli.
Impact of permethrin‐treated bednets on malaria transmission by the Anopheles gambiae complex in The Gambia
Authors: LINDSAY S. W. , SNOW R. W. , BROOMFIELD G. L. , JANNEH M. SEMEGA , WIRTZ R. A. , GREENWOOD B. M.
Published: March 2008

ABSTRACT. Malaria vector mosquitoes belonging to the Anopheles gambiae complex were studied in four hamlets in The Gambia. All inhabitants were given bednets treated either with a placebo (milk) in two hamlets or with the pyrethroid insecticide permethrin (500 mg/m2) in two other hamlets. Malaria transmission occurred mainly during a few weeks of the rainy season, in September and October 1987. The indoor resting densities of mosquitoes in permethrin‐treated hamlets were reduced, and we estimated over 90% reduction in biting on man by An. gambiae Giles sensu stricto in these hamlets. No mosquitoes were found under permethrin‐treated bednets compare.d with eighty‐one recovered from placebo‐treated bednets. Mosquitoes exited more readily from rooms where permethrin‐treated bednets were used than from rooms with placebo‐treated nets. The annual mean probability that a child would receive an infective bite was estimated to be 0.09 in hamlets with insecticide‐treated bednets, compared with 1.9 where placebo‐treated bednets were used. Permethrin‐treated bednets are therefore recommended as a means of effectively reducing the risk of exposure to malaria transmission, particularly in areas of low seasonal transmission.
Ecological aspects of cattle tick control in central Zambia
Authors: PEGRAM R. G. , LEMCHE J. , CHIZYUKA H. G. B. , SUTHERST R. W. , FLOYD R. B. , KERR J. D. , McCOSKER P. J.
Published: March 2008

ABSTRACT. In ecological studies in central Zambia, both climate and ecotype affected population dynamics of tick species. Below average rainfall for several years caused a suppression in numbers of Rhipicephalus appendiculatus Neumann adults. Reduction in rainfall leading to changes in grazing patterns is thought to have been responsible for an increase in numbers of Amblyomma variegatum Fabricius adults in a grassland habitat. There were reasonable correlations between numbers of each tick species on individual hosts over 1 year old. However, there were no relationships between numbers of ticks and bovine lymphocyte antigens (BoLA).
Responses of tsetse flies (Glossina spp.) to compounds on the skin surface of an ox: a laboratory study
Authors: WARNES M. L.
Published: March 2008

ABSTRACT. The behaviour of male Glossina morsitans morsitans Westwood and Glossina pallidipes Austen (Diptera: Glossinidae) alighting on targets with or without ox sebum was compared. The presence of ox sebum did not increase significantly the number of flies alighting on the target in either species. However, after contact with the sebum coated target, both species showed an increase in flight activity, and G. m. morsi‐tans showed a greater tendency to return to the target. This behaviour resulted in a number of short flights which may reflect the search for a feeding site on a host. The duration of each visit to the target was significantly reduced when sebum was present for G. m. morsitans but not for G. pallidipes. This is explained by documented differences in the resting behayiour of the two species which shows that G. m. morsitans normally rests for longer periods on the surface of an untreated black target than does G. pallidipes. Other experiments showed that the presence of sebum elicited a probing response in G. m. morsitans and G. pallidipes. The results are discussed with reference to the possible use of host sebum to improve trap catches in the field.
Rearing temperature influences flavivirus vector competence of mosquitoes
Authors: KAY BRIAN H. , FANNING IAN D. , MOTTRAM PIPI
Published: March 2008

ABSTRACT. Culex annulirostris Skuse mosquitoes (Brisbane strain) were reared at 20oC or 27°C and the adult females were experimentally infected by feeding Murray Valley encephalitis virus (MVE). They were then maintained (a) in the insectary at 20°C, after rearing at either 20°C or 27°C; (b) at ambient outdoor temperatures, range 12.2–28.9°C, mean 19.6°C; or (c) at 27°C after rearing at 27°C. There was no significant difference in rates of MVE infection or transmission when mosquitoes were reared and maintained constantly at 20°C or 27°C. However, for females kept at reduced temperature (i.e. x = 19.6°C or 20°C after rearing at 27°C), the infection and transmission rates of MVE were significantly reduced (2times8 replicates).

This investigation illustrates that vector competence is depressed by decreasing temperatures for adult mosquitoes compared with those they experienced during development. Similar patterns were evident with previously published work on Japanese and St Louis encephalitis, dengue and yellow fever. The process appears to be reversible, i.e. increased temperature raises virus infection and transmission rates. It is concluded that, without incubation at warmer temperatures, flavivirus recovery from overwintering mosquitoes will be negatively biased.
Experimental transmission of murine typhus by Xenopsylla cheopis flea bites
Authors: AZAD ABDU F. , TRAUB ROBERT
Published: March 2008

ABSTRACT. Transmission of Rickettsia typhi to rats by the bites of Xenopsylla cheopis (Rothschild) fleas was investigated. Procedures rigorously excluded the possibility of contamination of the host skin by flea faeces. Fleas with R. typhi infection (21–25 days post‐infection) which fed through bolting cloth (45 min exposure to ten fleas) transmitted rickettsiae with a success rate of 20%. Infective fleas allowed free access to their host for 8 h (10–15 fleas/rat) gave transmission rates of 45–68%. They were also capable of inoculating R. typhi through a membrane of rat skin on a feeder. Only fleas which had been infected for 21 days or longer transmitted R. typhi orally. Oral transmission appeared to be the result of regurgitation of rickettsiae present in the foregut lumen rather than through salivary secretions.
Oviposition diapause and other factors affecting the egg‐laying of Phlebotomus papatasi in the laboratory
Authors: SCHLEIN Y. , BORUT S. , JACOBSON R. L.
Published: March 2008

ABSTRACT. Stimuli which modulate oviposition of P.papatasi were investigated to improve insectary breeding efficiency. Oviposition and survival of gravid females were observed weekly during April‐December 1987, in plastic cages at 28±1oC with L:D 17:7. Oviposition of controls was subject to seasonal variation despite the relatively uniform insectary conditions. From April to mid‐October (summer), mean weekly oviposition ranged from 11.6 to 18.6 eggs per fly, dropping to 1.4 eggs/fly in November (winter). Monthly yields of eggs were found to correlate with the seasonal cycle of ultraviolet (UV) radiation in sunlight. This was attributed to an endogenous rhythm since the flies were not normally exposed to UV under insectary conditions.

Short exposure to UV sources of 254 nm and 312 nm, but not white light, raised the low rate of oviposition in October‐November from 1.4 to 16.8–29.6 eggs/female/week, but female mortality also increased highly significantly. It is suggested that the seasonal oviposition cycle of P.papatasi is set by levels of UV irradiation.

In the warm season oviposition was promoted, as compared to controls, by furrows in plaster of Paris lining the bottom of cages (29.6 v. 10.2 eggs/ female) and by cow manure in the cages (39.7 v. 18.2 eggs/female), but the combination of both stimuli gave no greater fecundity (40.9 v. 20.9 eggs/ female). Oviposition decreased when larvae were present (3.9 v. 15.0 eggs/ female) and in half‐volume cages (3.9 v. 12.5 eggs/female/week). Under standard insectary conditions, mean weekly mortality‐rates of P.papatasi females were 18.3±4.8% in October‐November and 36.5–59.1% during the warmer months. None of the experimental conditions yielded any significant improvement in survival‐rates.
Anthropophagy and aggregation behaviour of the sandfly Phlebotomus argentipes in Sri Lanka
Authors: LANE R. P. , PILE M. M. , AMERASINGHE F. P.
Published: March 2008

ABSTRACT. The visceral leishmaniasis (VL) vector Phlebotomus argentipes Annandale & Brunetti is widely distributed throughout the Indian sub‐continent and S.E. Asia. The absence of VL in areas such as Sri Lanka has been attributed to the zoophilic nature of P.argentipes, since they were not recorded biting man.

Field studies on P. argentipes were undertaken in the central highlands of Sri Lanka, near Kandy, in May 1988. Male sandflies outnumbered females on cows by 19:1, and were regularly spaced at all densities. This behaviour is considered analagous to swarming in other Nematocera. However, all‐night human‐biting catches show the biting rate to be similar (mean=8.4, range 2–25 bites per night over ten consecutive nights) to that in N.E. India where VL is endemic. This anthropophagy was maintained during laboratory colonization.
Distribution and insecticide resistance of the plague flea Xenopsylla cheopis in Maharashtra State, India
Authors: RENAPURKAR D. M.
Published: March 2008

ABSTRACT. Distributions are reported for commensal rat fleas, predominantly Xenopsylla cheopis (Rothschild), in the State of Maharashtra, India, including the city of Bombay, during 1965‐80. The X.cheopis flea index was high in most parts of Maharashtra, but low in Bombay.

Rattus rattus Linnaeus is the principal host of X.cheopis, but the host range includes Bandicota bengalensis Gray, Golunda ellioti Gray, Mus musculus Linnaeus, Rattus blandfordi Thomas, R. norvegicus Berkenhout, Suncus caerulaeus Lerr, S.murinus Linnaeus and Tatera indica Hardwicke.

X.cheopis was found to have high degrees of resistance to DDT, mala‐thion and fenthion, tolerance to γHCH (=‐γBCH) but susceptibility to dieldrin. This insecticide resistance situation may contribute to the high flea indices prevailing in the state, with consequent risks of plague outbreaks.

Two other species of rat flea, X.astia Rothschild and X.brasiliensis (Baker) were found to be less common than previously recorded. Their apparent replacement by X. cheopis is tentatively attributed, at least partly, to the selective advantage of insecticide resistance in the latter species.
Use of an electrostatic sprayer for control of anopheline mosquitoes
Authors: CHADD ELIZABETH M.
Published: March 2008

ABSTRACT. The Electrodyn sprayer was compared with a compression sprayer (Hudson X‐pert) for residual application of cypermethrin, a pyre‐throid insecticide, to control the malaria vectors Anopheles arabiensis Patton and An.funestus Giles in experimental huts at Magugu in Tanzania.

The time taken for hut spraying, 2‐2.5 min per hut, was similar for both types of sprayer. Two or three huts were treated internally with cypermethrin at 40 or 80 mg a.i./m2 using Electrodyn formulation for comparison with 80 mg a.i./m2 using wettable powder formulation. Each of the twelve huts (including five untreated controls) was fitted with window exit traps and either louvre or verandah traps for mosquito sampling. The Electrodyn sprayer was fitted with a pair of elbowed deflectrodes to direct the positively charged spray droplets onto walls and ceiling.

All treatments gave 94–100% mortality‐rates of indoor‐resting anophelines throughout the evaluation period of 11 weeks post‐spray. Reductions of An.arabiensis and An.funestus females by 10–42% and 62–91%, respectively, in rooms and by 72% and 51% in exit traps indicated that cypermethrin deterred mosquitoes from entering the huts. Overall mortality‐rates of mosquitoes were 66% of both species in huts treated with 40 mg/m2 Electrodyn, 43%An.funestus and 71%An.arabiensis due to 80 mg/m2 Electrodyn formulation and 49%An.funestus and 64%An. arabiensis due to 80 mg/m2 WP formulation (no significant differences).

It is concluded that the Electrodyn sprayer with deflectrodes is a convenient and effective means of residual house‐spraying with pyrethroid insecticide for malaria vector control.
Monitoring tsetse fly populations.:II. The effect of climate on trap catches of Glossina pallidipes
Authors: WILLIAMS BRIAN , BRIGHTWELL ROBERT , DRANSFIELD ROBERT
Published: March 2008

ABSTRACT. In Part I it was shown that the sampling distribution of trap catches of tsetse flies, Glossina pallidipes Austen, at Nguruman, Kenya, using unbaited biconical traps follows a Poisson distribution. In this paper we examine the effect of humidity and temperature on day‐to‐day and seasonal variations in the trap catches. It is shown that the seasonal variation is significantly correlated with maximum daily temperature, the catches increasing with temperature when the maximum temperature is below 34oC and decreasing with temperature when it is above 34oC. The correlation between trap catches and relative humidity is not as good as the correlation with the maximum temperature, and the two together do not improve the fit to the trap catches. The day‐to‐day variation is significantly greater than the intrinsic variation due to the stochastic nature of the sampling process and for some traps it is correlated with temperature and humidity. An autoregressive model gives a half‐life for the decay of departures from the mean of about 1 day and it is suggested that this indicates the movement of flies in response to animal movement or to climatic factors other than temperature or humidity. After removing the temperature dependent part of the seasonal variation and the autoregressive component of the data, the male and female catches are still significantly correlated.
Parasitism of house fly (Musca domestica) pupae by four species of Pteromalidae (Hymenoptera): effects of host–parasitoid densities and host distribution
Authors: MANN J. A. , STINNER R. E. , AXTELL R. C.
Published: March 2008

Abstract. Parasitoid‐induced mortality of house fly, Musca domestica L., pupae and parasitoid progeny emergence by four species of pteromalid parasitoids, Muscidifurax raptor Girault & Sanders, M.zaraptor Kogan & Legner, Spalangia earneroni Perkins and S.endius Walker, were determined for a 24 h exposure period using parasitoid: host ratios ranging from 1:2 to 1:50. When the number of parasitoids was held constant (n=5) and the numbers of hosts varied, and when the number of hosts was held constant (n=100) and the number of parasitoids varied, both the number of pupae killed per parasitoid and the number of parasitoid progeny per parasitoid increased with increasing parasitoid:host ratios to reach an upper limit asymptotically. Maximum values were, respectively: M.raptor (14.7, 11.1), M.zaraptor (12.3, 9.3), S.cameroni (16.9, 5.5), S.endius (14.8, 9.7) with no consistent effects attributed to parasitoid interference.

For M.raptor and S.cameroni at parasitoid:host ratios of 1:10, the pupal mortality and progeny emergence were determined for a 24 h exposure period when hosts were distributed in poultry manure at four levels of aggregation ranging from clumped to uniform. Pupal mortality was least in clumped distributions, while parasitoid progeny emergence was not significantly different.
Field evaluation of four biorational larvicide formulations against Anopheles albimanus in Honduras
Authors: PERICH M. J. , BOOBAR L. R. , STIVERS J. C. , RIVERA L. A.
Published: March 2008

Abstract. Four biorational larvicide formulations: Teknar®(B.t.i.), Arosurf ® MSF (Monomolecular Surface Film), Arosurf MSF combined with Teknar, and SAN‐809‐I ([s]‐methoprene combined with B.t.i.), were evaluated against naturally occurring populations of the malaria vector mosquito Anopheles albimanus Wiedemann in Honduras. All formulations reduced the mean number of larvae per sample area to 0 within 48 h after treatment, and gave significant (P<0.05) control when compared with similar untreated areas for at least 10 days after treatment. It is concluded that each of these four formulations can be used effectively to control the larvae of An.albimanus in Honduras.
Leishmaniasis vector potential of Lutzomyia spp. in Colombian coffee plantations
Authors: WARBURG ALON , MONTOYA‐LERMA JAMES , JARAMILLO CONSUELO , CRUZ‐RUIZ ANA LUISA , OSTROVSKA KATHERINE
Published: March 2008

Abstract. Potential vectors of Leishmania braziliensis Vianna were assessed at four study sites in the mountainous Valle del Cauca, western Colombia, from March to June 1989.

In an active focus of transmission at 1450 m altitude, a coffee plantation at Versalles, there were high densities of anthropophilic phlebotomines: Lutzomyia columbiana (Ritorcelli & Van Ty) and Lu.townsendi (Ortiz), both in the verrucarum species group, and of Lu.pia (Fairchild & Hertig). At a comparable altitude in a forest reserve at Yotoco where leishmaniasis is unknown, Lu.pia was the prevalent species and Lu.townsendi was absent.

In two localities at 1150 m altitude, there were plentiful Lu. lichyi (Floch & Abonnenc) plus both species in the verrucarum group, but Lu.pia was absent. One of these localities, a coffee plantation at Villa Hermosa where a leishmaniasis outbreak occurred in 1986, was compared with a leishmaniasis‐free, partly wooded nature reserve at Mateguadua.

No natural infections of Leishmania were found in a total of 1896 wild‐caught female phlebotomines belonging to at least seven species. It remains unclear why Leishmaniasis transmission is associated with coffee plantations in this part of Colombia.

Laboratory‐bred Lu. lichyi females were invariably autogenous, and blood‐seeking females of this species were always parous. Parity rates in wild‐caught females of other species were 55%Lu.pia, 24%Lu.columbiana and 14%Lu.townsendi.

Female Lutzomyia infected artificially with Le.braziliensis promas‐tigotes developed peripylarian infections. Higher proportions of Lu.townsendi (96%) and Lu.columbiana (78%) became infected but these species developed lower rates of stomodaeal infections (P<0.1) than Lu.lichyi (37%) or Lu.pia (44%). Only 33% of a Colombian strain of Lu.longipalpis (Lutz & Neiva) became infected.
Responses of tsetse to ox sebum: a video study in the field
Authors: PACKER M. J. , WARNES M. L.
Published: March 2008

Abstract. The behaviour of tsetse (mainly Glossina pallidipes Austen) around odour‐baited targets, with or without a coating of ox sebum, was recorded in the field using video. The addition of sebum increased the total time a fly was in contact with the target, as well as the time spent flying around and landing on it. When carbon dioxide was released as part of the attractant odour plume, the presence of sebum on the target increased the number of landings made by each fly, but did not significantly affect the duration of each contact. When carbon dioxide was absent from the odour plume, sebum did not affect the number of landings made by flies but the duration of each contact with the target did increase. Evidence for an interactive effect of sebum and carbon dioxide was obtained. In addition, the presence of sebum on the target increased the percentage of landed flies which walked on its surface; such behaviour may represent an ‘inspection’ of the artificial host. The potential tsetse control application of the current findings are discussed.
Quantitation of malaria sporozoites in the salivary glands of wild Afrotropical Anopheles
Authors: BEIER JOHN C. , ONYANGO FRED K. , RAMADHAN MUTALIB , KOROS JOSEPH K. , ASIAGO CHARLES M. , WIRTZ ROBERT A. , KOECH DAVY K. , ROBERTS CLIFFORD R.
Published: March 2008

Abstract. The number of malaria sporozoites in the salivary glands was determined microscopically for 1137 wild, naturally infected Anopheles from western Kenya. Infective Anopheles gambiae Giles sensu lato (n=874) contained a geometric mean (GM) of 962 sporozoites and An.funestus Giles (n=263) contained 812. No significant differences were detected in geometric mean numbers of sporozoites between species, collection techniques or sites.

Of the infective An.gambiae, 1.7% (15/874) contained more than 41,830 sporozoites, the maximum observed for An.funestus.

Microscopic techniques were found to be more sensitive than enzyme‐linked immunosorbent assays (ELISA) for detecting low‐grade sporo‐zoite infections in salivary glands. Salivary gland sporozoites from 83.6% of the 1137 gland infections were identified by ELISA as either Plasmodium falciparum Welch (n=910), P.ovale Stephens (n=7), P.malariae Grassi & Feletti (n=3) or mixed (n=30). The 187 gland infections which could not be identified by ELISA contained significantly fewer sporozoites (GM=242) than those which could be identified (GM=1200).
Behaviour and fitness of γHCH/dieldrin resistant and susceptible female Anopheles gambiae and An.stephensi mosquitoes in the absence of insecticide
Authors: ROWLAND MARK
Published: March 2008

Abstract.The effects of γHCH/dieldrin resistance genes on various fitness components of mosquito larvae and adult females in the absence of insecticide were investigated in backcrossed strains ofAnopheles gambiaeGiles andAn.stephensiListon. Among larvae, heterozygotes (RS) developed slightly but significantly faster than homozygotes for resistance (RR) or susceptibility (SS). The lifetime fecundity of RR females in population cages was only half to two‐thirds that of SS and RS females despite similar longevities; several reasons were identified: RR gravid females were less responsive to oviposition‐site stimuli, their spontaneous activity ‐ as measured in an acoustic actograph ‐ was only half that of SS or RS females, and RR females produced fewer eggs per unit bloodmeal. When inseminated females were recorded in LD 12:12, RR were again less active than SS or RS. When the lighting was switched to a regime simulating full‐moonlight, the activity pattern of SS and RS changed and they flew for longer periods. In contrast, the activity of RR females was the same in LD 12:12 as in ‘moonlight’. In a test simulation of potential predation, RR mosquitoes took to flight least readily. All component tests on adult females therefore point to RR as being the least fit of the three genotypes. The behavioural tests suggest that resistance has raised the response threshold of RR females to diverse stimuli. A possible physiological mechanism underlying RR behaviour is that a change in the cyclodiene receptor on the chloride channels has increased their permeability to chloride ions, causing hyper‐inhibition of the nervous system.
DDT resistance in Anopheles gambiae declines with mosquito age
Authors: LINES J. D. , NASSOR N. S.
Published: March 2008

Abstract. Adult Anopheles gambiae Giles mosquitoes from Zanzibar were tested on a standard discriminating dose of DDT which reliably kills susceptible mosquitoes. Adults from wild‐caught larvae reared in the laboratory, and from the F1 progeny of wild‐caught adults, showed less than 5% test mortality when newly‐emerged, but mortality rose with age to over 90% when they were 12–14 days old. Wild‐caught mixed‐age adults showed an intermediate mortality rate of 25%, close to the rate predicted from laboratory results for a fully resistant population with an age‐structure typical of this species in natural conditions.

It is inferred that older, genetically resistant insects may be scored as susceptible, so that routine susceptibility tests with wild‐caught adults underestimate the frequency of resistance. In Zanzibar, such tests probably helped to persuade spraying authorities to continue spraying DDT in spite of resistance. Resistance which is restricted to younger insects may nonetheless reduce the effectiveness of spraying.
A simple larval diet for population studies on the blowfly Lucilia sericata (Diptera: Calliphoridae)
Authors: DANIELS SUSAN , SIMKISS K. , SMITH R. H.
Published: March 2008

Abstract.

A simple artificial diet was devised for larvae of Lucilia sericata Meigen.

A basic diet of 20 g/1 agar with 20% horse blood and added yeast sustained normal growth and development, as compared with a lamb meat control.

When yeast was added to the blood agar diet at 50 gp>1, both peak and final larval weights were increased by 25–50% at higher larval densities (2–8 larvae/g diet) and the hatchling‐adult development period was reduced by about 3 days.

No adult insects emerged on an agar‐yeast diet without blood. Increasing the concentration of blood from 10% to 20% increased adult weight at emergence by 50%, though developmental period was not significantly affected.

Increasing larval density significantly reduced the weights of pupae and emergent adults (by up to 50%), both on the blood‐agar‐yeast diet and the lamb meat control. Percentage survival fell from 80–90% to below 10% on the blood‐agar‐yeast diet at the highest densities of 4 or 8 larvae/g diet, though survival on lamb was not significantly affected by density.
Recovery of Triatoma infestans populations after insecticide application: an experimental field study
Authors: GORLA DAVID E.
Published: March 2008

Abstract. The capacity of populations of Triatoma infestans (Klug) (Hemiptera: Reduviidae) to survive and recover was assessed after application of insecticide (γ‐HCH at a rate of 0.5 g a.i./m2) at different seasons. T.infestans populations were maintained in experimental chicken houses under natural climatic conditions in a region of Argentina endemic for Chagas disease transmitted by these bugs. Based on previous studies of T.infestans populations in these habitats, each experimental group was set up with a total of 626 T. infestans, comprising 390 eggs, 204 nymphs of particular stages, fourteen male and eighteen female adults. The chicken houses were dismantled and rebuilt at monthly intervals to study the vector population changes over a period of 33 months.

When the insecticide was applied during winter, spring or summer, populations of T.infestans recovered to untreated or precontrol levels during the next reproductive season (i.e. during the hot season, October‐March). In contrast, populations treated during autumn (March) remained at very low densities for 2 years and then increased rapidly to surpass the untreated populations. All populations of the bugs fell to very low numbers (sometimes less than twenty individuals) after y‐HCH applications, but none was driven to extinction. In all cases, the density of surviving populations was independent of their density before treatment. The fact that all treated populations recovered within 1–3 years, to at least the density of untreated populations, shows the high reproductive potential of T. infestans to recover from very low population densities. Moreover, the additive effect of climatic‐induced mortality and insecticide‐induced mortality is only apparent when insecticides are applied just before the onset of the cold winter months during which reproductive rates are at their lowest.
Experimental hut trials of bednets impregnated with synthetic pyrethroid or organophosphate insecticide for mosquito control in The Gambia
Authors: MILLER JANE E. , LINDSAY S. W. , ARMSTRONG J. R. M.
Published: March 2008

Abstract.

Nylon bednets impregnated with different insecticides were evaluated in 1988 against wild adult mosquito populations, mostly Mansonia africana (Theobald) and Anopheles gambiae Giles sensu 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.

Individual 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).

Washing 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.

The unwashed permethrin‐treated bednet reduced the number of mosquitoes entering a hut by 60% of An.gambiae s. l. and 68% of Mansonia spp. This deterrency was less pronounced with the other insecticides and was lost by washing the bednets.

Each insecticide, especially lambda‐cyhalothrin and pirimiphos‐methyl, caused significant mortality rates of mosquitoes that entered huts with impregnated bednets, and prevented the majority of An. gambiae s.l. and Mansonia females 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.

Aerial toxicity from the pirimiphos‐methyl treated bednet killed 80% of An.gambiae s.l. confined overnight in the hut at the end of the trial, whereas the pyrethroid‐treated bednets gave negligible mortality rates of mosquitoes.
Dispersive flight by Triatoma infestans under natural climatic conditions in Argentina
Authors: SCHOFIELD C. J. , LEHANE M. J. , McEWEN P. , CATALA S. S. , GORLA D. E.
Published: March 2008

Abstract. Male and female T. infestans were released on two consecutive nights in the salinas of Cordoba Province, Argentina, when air temperatures during the flying period averaged 28.5°C. 136 males (43% of the total released) and 170 females (57%) flew on the first night, and 6 males (18%) and 7 females (27%) on the second. Of these, we recovered 23 males and 14 females within loom, and a further female within 200 m, all from the first night's release. The remainder appear to have flown more than 100 m and possibly more than 200 m. In support of this conclusion 4 male and 5 female bugs were recovered in an abandoned brick house 550 m from the release point. Since the proportion of bugs apparently flying more than 200 m is considerably greater than that deduced from previous experiments at lower temperatures (Lehane & Schofield, 1981) it is possible that temperature influences not only the proportion of bugs flying but also the distance flown. Flight appears to be affected by wind speed. On the first night, when there was negligible wind, 43% of male and 57% of female bugs flew. On the second night, with winds gusting at 4–5 m/s, only 18% of the male and 27% of the female bugs flew.
A generalized approach to detection of organophosphate resistance in mosquitoes
Authors: BROGDON WILLIAM G. , BEACH RAYMOND F. , BARBER ANN M. , CORDON‐ROSALES CELIA
Published: March 2008

Abstract. Insecticide bioassays and biochemical microtitre assays were compared for detection of resistance to the organophosphate insecticides malathion and fenitrothion, using inbred laboratory strains of malaria vectors Anopheles albimanus Wiedemann, An.arabiensis Patton and An.stephensi Liston.

With susceptible mosquitoes, the LT10o values determined from bioassays corresponded closely with times taken to abolish the activity of acetylcholinesterase activity in biochemical assays: approximately 2h for malathion and 3h for fenitrothion. Resistant strains of all three anophelines showed longer survival correlated with prolonged acetylcholinesterase activity.

An.albimanus strains with insensitive acetylcholinesterase survived bioassays with discriminating doses of lh exposure to 5% malathion or 1% fenitrothion and were judged as resistant.

It is concluded that enzyme‐specific microassays provide a reliable means of detecting resistant individuals, with practical advantages over bioassays which do not reveal the resistance mechanism and require large numbers of healthy mosquitoes.
Anopheles nili as the main vector of human malaria in villages of southern Cameroon
Authors: CARNEVALE P. , GOFF G. LE , TOTO J.‐C. , ROBERT V.
Published: March 2008

Abstract. In villages near Sanaga river, in the forest zone of south Cameroon, Anopheles nili Theobald is the main species of mosquito regularly found biting man inside houses. Its densities are related to the flow level of the river. It is also the main malaria vector in terms of intensity and seasonal duration of transmission. The yearly malaria inoculation rate due to An.nili alone is 104 infective bites/man, varying between 3 infective bites/man in October and 20 in March. Anopheles gambiae Giles is a less important vector in the area but reached its peak in the dry season, when the Sanaga river is at its lowest level. These observations underline the influence of local ecology on malaria transmission and the need for entomological studies in each situation.