bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
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.
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).
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.
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.
Snail predation by larvae of Sepedon scapularis Adams (Diptera: Sciomyzidae), a potential biocontrol agent of snail intermediate hosts of schistosomiasis in South Africa
Authors: MAHARAJ R. , APPLETON C. C. , MILLER R. M. 
Published: March 2008

Abstract. Malacophagous larvae of the fly Sepedon scapularis Adams were shown experimentally to be effective predators of three species of aquatic pulmonate snails tested as prey: Bulinus africanus (Krauss) an important intermediate host of Schistosoma haematobium (Bilharz), Bulinus tropicus (Krauss) and the invasive species Physa acuta Draparnaud. Survival of S.scapularis larvae from instar to instar was negatively affected by the size of prey snails, since larvae tended to be asphyxiated by the mucous secretions of the snails, or by the larval hydrofuge hairs becoming entangled in snail faeces.In experiments to test the choice of S.scapularis larvae for different species and sizes of snails, B. africanus was significantly disfavoured compared with the other two snail species. Small snails (< 3 mm) were more frequently killed by all three larval instars of S.scapularis. First instars killed few, if any, large snails (> 7mm), whereas second and third instars preyed effectively on all sizes of snails. Third instars killed significantly more snails than younger instars. For larvae offered only one species of snail as prey, the mean total number of snails killed per larva during its entire development was 49 B.africanus, 45 B.tropicus or 34 P.acuta.It is concluded that S.scapularis is potentially useful as a biological control agent for use against indigenous Bulinus and exotic Physa snails.
Biological control of container‐breeding mosquitoes, Aedes albopictus and Culex quinquefasciatus, in a Japanese island by release of Toxorhynchites splendens adults
Authors: MIYAGI ICHIRO , TOMA TAKAKO , MOGI MOTOYOSHI 
Published: March 2008

Abstract. To control container‐breeding mosquitoes in the small island of Minnajima (0.56km2), northern Okinawa, Japan, laboratory‐reared adults (aged 7–10 days) of Toxorhynchites splendens (Palawan strain), a mosquito with predatory larvae, were released repeatedly during 1984, 1986 and 1987.Thirteen species of mosquitoes (Diptera: Culicidae) occurred in artificial containers, ground pools or crab‐holes on the island, the predominant species being Aedes (Stegomyia) albopictus and Culex (Culex) quinquefasciatus. Predatory mosquito larvae of Culex (Lutzia) fuscanus and Cx (Li.) halifaxii were found commonly in wet containers.In the first year of study, during a period of 54 days from 13 May to 5 July 1984, totals of 879 female and 806 male adults of Tx.splendens were released on six occasions. Similarly, between 29 April and 30 August 1986, totals of 2920 female and 2878 male adult Tx.splendens were released. In the third study year, totals of 2041 female and 1783 male Tx.splendens were released on eight occasions during 199 days from 23 April to 7 November 1987.After adult releases at two sites, the immature stages of Tx.splendens were found in 164 out of 502 traps in 1984, 421 out of 933 traps in 1986, and 151 out of 502 traps in 1987. The number of immatures of Tx.splendens present in each trap varied from 1 to 40 in 1984, 1 to 29 in 1986 and 1 to 9 in 1987. Numbers of immatures of the target species found in the traps during August–September averaged 71.9/trap/month in 1984, 114.7/trap/month in 1986 and 36.0/trap/ month in 1987, significantly less in the traps with Tx.splendens than in those without them.The present field studies indicated that, in this small island, approximately 250 adult female and 200 male Tx.splendens per month should be released from April to November, and the releases should be carried out every year, in order to control effectively the target mosquitoes Ae.albopictus and Cx quinquefasciatus breeding in artificial containers in Minnajima.