bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patterns of sandfly distribution in tropical forest: a causal hypothesis
Authors: MEMMOTT JANE 
Published: March 2008

Abstract.

In tropical rain forest, phlebotomine sandflies (Diptera: Psychodidae), such as Lutzomyia vespertilionis and L.ylephiletor, have an aggregated distribution on their tree buttress diurnal resting sites, as studied during 1987‐88 at Finca la Selva in the Caribbean lowlands of Costa Rica.
Experimental transfer of flies to trees not used as resting sites indicated that many apparently suitable sites remain unoccupied.
Observations of sandflies on the buttresses revealed that males and females are juxtaposed more frequently than expected by chance alone. Courtship behaviour by three of the four species of sandfly studied was observed on the buttresses.
It is suggested that the use of buttresses as swarming sites for mating behaviour is more likely to account for the observed distribution patterns of sandflies than their use of buttresses simply as diurnal resting sites.
Carbohydrate‐binding specificities of anti‐erythrocyte lectins (haemagglutinins) in Anopheles gambiae gut extracts and haemolymph
Authors: MOHAMED HASSAN A. , INGRAM GEORGE A. , MOLYNEUX DAVID H. 
Published: March 2008

Abstract. Lectins that agglutinate red blood cells (RBC) were demonstrated in Anopheles gambiae mosquito haemolymph and gut extracts. No apparent differences in haemagglutinin titres were detected between male and female mosquitoes and overall agglutinin levels were not increased following a bloodmeal.Titres were highest in the haemolymph and midgut extracts versus human AB, horse, chicken and goat RBCs and in hindgut against human AB, chicken and sheep; foregut extract gave relatively low titres.Adsorption of haemolymph and gut extracts with selected RBCs coupled with carbohydrate inhibition and the use of enzyme‐treated RBCs revealed the presence of multiple (hetero‐) agglutinins. An.gambiae lectins were specific for (1‐1)‐, (1–4)‐ or (l‐6)‐linked glucose based disaccharides, glucose and its (1–2) or (1–3) linkages with fructose and, to a lesser extent, aminated or N‐acetylated glucose, or galactose and its deoxy derivatives.This study presents the first report of the occurrence of heterogenous anti‐RBC agglutinins in haemolymph and gut extracts of the mosquito An.gambiae, together with the sugar‐binding specificities of these lectins.
Suppression of Aedes aegypti by predatory Toxorhynchites moctezuma in an island habitat
Authors: TIKASINGH ELISHA S. , EUSTACE ANN 
Published: March 2008

Abstract. Larval populations of the mosquito Aedes aegypti were suppressed by predatory Toxorhynchites moctezuma mosquito larvae released systematically in a village on Union Island (Saint Vincent and the Grenadines) during March‐December 1988.Eggs and larvae of Tx.moctezuma were transported from Trinidad and introduced into all semi‐permanent and permanent water‐holding containers in the experimental village at Clifton. The semi‐isolated village of Ashton served as control.Base‐line Ae.aegypti indices (house, ovitrap, Breteau, cistern/tank, drum/ barrel, small containers) were obtained for the two villages over a 4‐month period prior to the introduction of the predatory Tx.moctezuma mosquito larvae. After sustained releases of predators for 5 months, all indices of Ae.aegypti were lower in the treated village than in the untreated village during the last 3 months of the year.
Insecticide resistance gene frequencies in Anopheles sacharovi populations of the Çukurova plain, Adana Province, Turkey
Authors: HEMINGWAY J. , SMALL G. J. , MONRO A. , SAWYER B. V. , ASAP H K 
Published: March 2008

AbstractIn Turkey, the mosquito Anopheles sacharovi has been under field selection pressure sequentially with DDT, dieldrin, malathion and pirimiphos‐methyl over a period of 30 years for the purpose of malaria control. In 1984, the field population of An.sacharovi in the malarious Çukurova plain of Adana Province contained an altered acetylcholinesterase‐based resistance gene giving broad spectrum resistance against organophosphorus and carbamate insecticides. The cross‐resistance spectrum from this mechanism conferred resistance to malathion but not to the organophosphorus insecticide pirimiphos‐methyl. Over the 6 years that pirimiphos‐methyl has been applied for malaria vector control in this area, the frequency of the altered acetylcholinesterase resistance gene has declined, although in 1989 and 1990 it was still present at measurable frequencies in An.sacharovi from Çukurova.In addition to the acetylcholinesterase resistance mechanism there is evidence of an increased level of glutathione S‐transferase in some of the An.sacharovi populations tested. This is known to be correlated with DDT resistance in other anophelines. In Turkish An.sacharovi, DDT resistance and elevated glutathione S‐transferase occur in the same populations at similar frequencies. The continued prevalence of resistance to DDT and dieldrin, long after the 1971 cessation of DDT spraying for malaria control in Turkey, suggests that the DDT resistance gene has insufficient reduced fitness associated with it to have been lost from the field population during the past two decades. The implications of the slow decline in resistance gene frequencies in this field population are discussed in relation to mathematical models for managing resistance.
The relative importance and distribution of Aedes polynesiensis and Ae.aegypti larval habitats in Samoa
Authors: SAMARAWICKREMA W. A. , SONE FOLA , KIMURA E. , SELF L. S. , CUMMINGS R. F. , PAULSON G. S. 
Published: March 2008

Abstract. In preparation for a Filariasis Control programme in Samoa, during 1978 monthly larval surveys of the vector mosquito Aedes polynesiensis were carried out in four study villages in the main island of Upolu. A more extensive survey of larval habitat distribution was then made in twenty‐two villages of Upolu and eighteen of Savai'i island, to determine the importance of habitat types according to their abundance, volume of water and whether their productivity was permanent or seasonal. Ae.aegypti larval densities and habitat distribution were also monitored and the occurrence of predatory Toxorhynchites amboinensis larvae in northern Upolu was recorded from forty‐one collections. Aedes Breteau and container indices fluctuated with the pattern of rainfall in two coastal villages and an inland bush village, but not in a coconut plantation community. The five main Aedes larval habitat types encountered were: 200 litre water‐storage drums, discarded tins and bottles, coconut shells, automobile tyres and treeholes. Aedes immatures occurred perennially in drums and tree holes, but breeding discontinued in tins, bottles and coconut shells during the driest month of July.For Ae.polynesiensis in Upolu the Breteau and container indices of 104.5 ± SD 80.9 and 35.3 ± 12.4 respectively were significantly higher than those in Savai'i: 33.1 ±25.0 and 24.3 ±20.0 respectively. Likewise for Ae.aegypti the Breteau and container indices of 50.8 ± 32.5 and 23.9 ± 15.6, respectively, were also significantly higher than those in Savai'i: 12.7 ± 17.1 and 9.4 ±13.2 respectively.Habitat types greater or lesser importance were determined by plotting the percentage of each type of container utilized for Aedes breeding against the percentage of each type amongst all larva‐positive containers. Ae.polynesiensis preferred tree‐holes but not water‐storage drums. Ae.aegypti preferred drums and tyres; mixed populations of larvae of both species were commonest in these two types of habitat. Ae.polynesiensis occurred in every village. Ae.aegypti was encountered in all twenty‐two villages surveyed in Upolu and nine of eighteen villages in Savai'i.Total larval surveys revealed that drums and tree‐holes contained the highest numbers of Aedes larvae. The study provided criteria for planning a control programme.
Attracting adult New World screwworm, Cochliomyia hominivorax, to odour‐baited targets in the field
Authors: GREEN C. H. , HALL M. J. R. , FERGIANI M. , CHIRICO J. , HUSNI M. 
Published: March 2008

Abstract. A field study in Libya investigated aspects of Cochliomyia hominivorax behaviour relevant to the operation of a target‐based control system. Flies were readily caught by electrified targets, but only when baited with the attractant ‘swormlure‐4’. Target size (0.25‐lm2) did not affect catch, but black targets caught twice as many flies as red ones. Omitting the most volatile component of swormlure‐4, dimethyl disulphide, significantly reduced catches of both sexes of C. hominivorax in wind‐orientated traps, but only reduced the capture of females significantly on targets. A new polythene sachet dispenser for odours was tested; four to six such sachets filled with swormlure‐4 less dimethyl disulphide gave an equivalent catch to one of the standard bottle plus wick dispensers using the same attractant, although they dispensed odour at about half the rate.From direct observations, fewer than 40% of flies contacted the target for more than 10 s on any one visit. From catches on an intermittently‐active electrocuting grid, it was calculated that there is a c. 40% rate of multiple contacts of flies with the target.
Susceptibility of the bedbug, Cimex lectularius, to selected insecticides and various treated surfaces
Authors: FLETCHER M. G. , AXTELL R. C. 
Published: March 2008

Abstract. Adult bedbugs, Cimex lectularius, were exposed for 24 h (25oC) to filter paper treated with various dilutions of the technical grade of nine insecticides dissolved in acetone to determine the concentration‐response relationships. The order of toxicity, from most to least based on the LC50's was: dichlorvos, pirimiphos methyl, lambda‐cyhalothrin, bendiocarb, permethrin, malathion, carbaryl, tetrachlorvinphos, and fenvalerate.The residual toxicities of commercial formulations of six of the chemicals diluted with water and applied to wood, cardboard, cloth and galvanized metal, were determined by exposing adult bedbugs at 3,7 and 12 weeks after treatment. The formulation of bendiocarb (FICAM® 76% W) had little residual activity on all surfaces at 12 weeks after treatment. The formulation of carbaryl (SEVIN® 21.5% L) was toxic to bedbugs on all surfaces at 12 weeks after treatment, but required high concentrations on wood, cardboard, and cloth. The formulation of pirimiphos methyl (ACTELLIC® 57% EC) had no residual activity on any of the surfaces at 12 weeks after treatment. The formulation of tetrachlorovinphos (RABON® 50% W) had residual activity for 12 weeks on all surfaces except metal. The formulation of permethrin (ATROBAN® 11% EC) had residual activity on only metal and wood while the formulation of lambda‐cyhalothrin (KARATE® 13.1% EC) had residual activity 12 weeks on all surfaces.
Seasonal abundance, biting cycle, parity and vector potential of the mosquito Haemagogus equines in Trinidad
Authors: CHADEE DAVE D. , HINGWAN J. O. , PERSAD R. C. , TIKASINGH E. S. 
Published: March 2008

Abstract.The mosquitoHaemagogus equinusis a known vector of yellow fever (YF) in central America. Seasonal abundance, daily biting activity and the age composition of adultHg. equinusfemale populations were monitored weekly during 1981–82 by human collectors on the ground at Point Gourde Forest, Chaguaramas, 16 km west of Port of Spain, Trinidad.2. Landing collections ofHg.equinusshowed diurnal activity from 06.00 to 20.00 hours (suntime), with a single peak between 08.00 and 14.00 hours.3. Overall, 5.6% ofHg.equinuswere collected during the dry season (December‐April) and 94.4% during the wet season (May‐November).4. Mean density ofHg.equinusin relation to man ranged from 0.35/man‐day in February to 133/man‐day in July, with averages of 2.8 in the wet season, 36.9 in the dry season and 22/man‐day for the whole year.5. Monthly parous rates averaged 62.1% (range 0‐88%); 2.8% of females were 2‐pars, another 2.8% were 3‐pars, but no older females ofHg.equinuswere found (sample size 467).6. These age‐grading data indicate thatHg.equinusfemales have relatively short life expectancy and hence low vector potential, which may help to explain why YF virus has seldom been isolated from this vector species.
Mean life expectancy of Old World screwworm fly, Chrysomya bezziana, inferred from the reproductive age‐structure of native females caught on swormlure‐baited sticky traps
Authors: SPRADBERY J. P. , CSIRO W. G. VOGT 
Published: March 2008

Abstract. The reproductive status of native (wild) screwworm fly, Chrysomya bezziana, caught on swormlure‐baited sticky traps in Papua New Guinea is described. A total of 1122 females and 25 males were trapped. Of these females 595 were scored for insemination status and stage of ovarian development (on a scale of 2–10) of which 20% were in suitable condition for assignment to first, second and third ovarian cycles. Of the nulliparous females, only 17% were inseminated at stage 3 of ovarian development, 70% at stage 4, 93‐97% at stages 5 and 6, and all of stages 7–10 (gravids). All parous females were inseminated. More than half of the captured females were parous (58%) and only 7% of the total were gravid. Proportions of females in ovarian cycles 1, 2 and 3 were 41%, 50% and 9% respectively.Survival of female Ch. bezziana in the laboratory was adequately described by lognormal and Gompertz survival functions, for both of which the mortality rate is an increasing function of reproductive age. Analysis of the reproductive age distribution of native females estimated their mean life‐expectancy at 9 days under the prevailing mean field temperature of 26.5oC. This equates to completion of 1.7 ovarian cycles and an estimated mean lifetime fecundity of 146 female progeny. The survival models, which also allowed responsiveness of females to swormlure‐baited traps (female trappability) to vary according to their stage of ovarian development, indicated significant age‐dependent trapping bias. These findings are compared with similar data for the New World screwworm fly, Cochliomyia hominivorax.
Effects of adult body size on fecundity and the pre‐gravid rate of Anopheles gambiae females in Tanzania
Authors: LYIMO EDITH O. , TAKKEN W. 
Published: March 2008

Abstract. The influence of adult body size on the pre‐gravid state and fecundity was studied in Anopheles gambiae Giles females hand‐caught inside houses and virgin females collected as pupae in Tanzania. Blood‐fed mosquitoes were kept for 2‐3 days before dissection and examination for insemination and ovarian condition. Those females which did not develop eggs were classified as pre‐gravid. The number of mature eggs in those mosquitoes which became gravid was counted. Virgin females were fed and kept for egg maturation in the laboratory. Wing‐length of females was measured as an index of mosquito size.The overall pre‐gravid rate in the resting An. gambiae population was found to be 21% and, of these, 66% had been inseminated. In the virgin females the pre‐gravid rate was 92.6%. The mean wing‐length of wild females which became gravid was significantly larger than those which remained pre‐gravid. There was a positive correlation between fecundity and wing‐length. Smaller females tended to require two or three bloodmeals to facilitate completion of the first gonotrophic cycle. The critical size permitting oviposition from the first blood‐meal was a wing‐length of 3 mm.
An entomological investigation of the likely impact of cattle ownership on malaria in an Afghan refugee camp in the North West Frontier Province of Pakistan
Authors: HEWITT SEAN , KAMAL MUHAMMAD , MUHAMMAD NASIR , ROWLAND MARK 
Published: March 2008

Abstract. Field trials were undertaken to determine the effect of close proximity of humans to livestock on the human biting rates exhibited by various anophelines. The results indicate that proximity to cattle and to goats increases the subject's chances of being bitten by anophelines. Man‐biting by Anopheles stephensi rose by 38% (8–68% CI) in the presence of a cow, and by 50% (16–84% CI) in the presence of two goats. Other species exhibited similar trends. These findings explain the results of an earlier trial which revealed that malaria prevalence was higher amongst families that kept cattle than those that did not.The findings are discussed in relation to existing information regarding the host preferences of local anophelines and classic theories regarding zooprophylaxis. Our findings suggest that animals are only likely to have a worthwhile prophylactic affect when the vector is zoophilic, and then only when the animals are deployed to form a barrier between that vector and man. In situations where deployment of livestock to form a zoobarrier is impractical, the livestock should be located as far from man as possible.
Arabian sandflies (Diptera: Psychodidae) prefer the hottest nights?
Authors: ROBERTS D. M. 
Published: March 2008

Abstract. A vehicle‐mounted net was used to collect hourly samples of sandflies on 15 nights during June in northern Oman. Every half hour, the temperature, relative humidity, wind velocity and light intensity were measured (there was no cloud or rainfall during this period).The sandflies caught were mainly Phlebotomus alexandri and Sergentomyia clydei. Their circadian activity increased rapidly after sunset (18.50 hours). The high level of activity was fairly constant during 9 h of darkness until dawn, when it decreased rapidly. A few flies were still active at 07.00 hours, 1.5 h after sunrise.A multiple regression showed that the main factor affecting sandfly activity was light intensity. When this factor was removed, by considering only the 135 catches collected during the 9 h of darkness, the second most important factor was low relative humidity, followed by low wind velocity. Temperature was not a significant factor in the analysis, because of its strong negative correlation with humidity. However, when the effect of humidity was removed from the regression, high temperature became significant, but less important than wind.The regressions showed that, for flight activity, the optimum humidity was around 10%; the probable maximum wind velocity was 3.5 ms‐1 and 11oC was the probable minimum temperature. Thus, when the 4 nights with highest catches (200–260 flies/night) were compared with the 4 nights with lowest catches (50–120 flies/night), the best nights had a low humidity (10–25%) and low wind speed (<0.3ms‐1) in combination with highest temperatures (31–43oC).
Vector competence of some Neotropical sandflies for the Leishmania (Viannia) braziliensis complex
Authors: JARAMILLO CONSUELO , TRAVI BRUNO L. , MONTOYA JAMES 
Published: March 2008

Abstract. To evaluate the vector competence of some Lutzomyia spp. (Diptera: Psychodidae) for Leishmania (Viannia) spp. (Kinetoplastida: Trypanosoma‐tidae), experimental infections of anthropophilic sandflies from the Colombian Pacific coast were performed, through membrane feeding and xenodiagnosis on hamsters infected with Le.(V.)braziliensis or Le.(V.)panamensis. Wild‐caught or F, generation females of Lutzomyia gomezi, Lu.hartmanni, Lu.panamensis and Lu. trapidoi were allowed to feed on hamster lesions and then maintained at 26oC and >80% r.h. on a sugar‐water diet until dissection on the fifth day post‐infection (p.i.).Despite similar infection rates (range 37–44%) in both Lu.gomezi and Lu.trapidoi, infections were heavier (>100 parasites) in the latter species. Infections of Lu.trapidoi with Le.braziliensis (n= 21) and Le.panamensis (n= 27) showed parasite migration toward the foregut, with promastigote colonization of the stomodeal valve and appearance of infective forms. In contrast, infections of Lu.gomezi with Le. braziliensis (n= 10) and Le.panamensis (n = 5) were light (<50 parasites) and usually restricted to the pylorus. In Lu.hartmanni, only a few promastigotes were found in the pylorus and midgut of 3/8 specimens infected with Le.braziliensis, and no Le.panamensis developed (n = 19). By day 5 p.i., promastigote colonization of the hind‐ and midgut by Le.panamensis was observed in 2/4 Lu.panamensis but not Le.braziliensis (n= 3).It was concluded that Lu.trapidoi is a more efficient vector than Lu.gomezi for both Le.braziliensis and Le.panamensis, and that Lu.hartmanni and Lu.panamensis are of minor importance for Leishmania transmission in this endemic area.
Effects of physico‐chemical treatments on hemagglutination activity of Anopheles gambiae haemolymph and midgut extract
Authors: MOHAMED HASSAN A. , INGRAM GEORGE A. 
Published: March 2008

Abstract. Anopheles gambiae midgut extracts and haemolymph possessed agglutinins, titre 1:16 to 1:256, against human red blood cells (RBCs). Subjection of both tissues to protein precipitation reagents, organic chemical and selected protease, neuraminidase and other glycosidic hydrolase treatments revealed the haemagglutinins to be protein, most likely glycoprotein, in nature ‐ not lipoprotein, lipid, glycolipid or nucleic acid. An.gambiae agglutinins were thermo‐labile >40oC, affected by freezing and thawing treatments, and contained disulphide and hydrogen bonds on the basis of sensitivity following exposure to dithio‐threitol and urea respectively. Optimum haemagglutination depended generally on slightly acid to neutral pH conditions and agglutinin activity was Ca2+ ion, albeit to a lesser extent Mg2+ ion, dependent. The midgut extract agglutinin subunit molecule had a relative molecular weight (Mr) of 65kDa whilst that of haemolymph was 40kDa.This study presents the first report on selected physico‐chemical properties, the glycoproteinaceous nature and tentative subunit Mr of mosquito midgut extract and haemolymph anti‐RBC agglutinin(s).
Antibodies to Anopheles midgut reduce vector competence for Plasmodium vivax malaria
Authors: SRIKRISHNARAJ K. ALAGARATNAM , RAMASAMY RANJAN , RAMASAMY MANTHRI S. 
Published: March 2008

Abstract Anopheles tessellatus mosquitoes ingested Plasmodium vivax gametocytes in human erythrocytes suspended in rabbit sera with and without anti‐mosquito midgut antibodies. When the mosquito bloodmeal contained anti‐midgut antibodies, fewer oocysts of P. vivax developed on the mosquito midgut and the proportion of mosquitoes becoming infected was significantly reduced. Complement inactivated serum also reduced the infection rate and load. A second bloodmeal containing anti‐midgut antibodies, given 48 or 72 h later, did not enhance the transmission‐blocking effect. IgG purified from antimidgut sera was shown to mediate the transmission‐blocking effect.
Efficacy of etofenprox against insecticide susceptible and resistant mosquito strains containing characterized resistance mechanisms
Authors: HEMINGWAY JANET 
Published: March 2008

Abstracttofenprox is a non‐ester pyrethroid insecticide with comparable toxicity and a similar mode of action to other pyrethroids. Cross‐resistance studies on mosquitoes showed no effect of carboxylesterase, elevated esterase, altered acetylcholinesterase or glutathione S‐transferase‐based resistance mechanisms on etofenprox toxicity, when compared to standard susceptible strains of Anopheles and Culex. Cross‐resistance to etofenprox occurred in a pyrethroid‐resistant strain of Culex quinquefasciatus with both oxidase and ‘kdr’‐like resistance mechanisms.Dose–response data for susceptible mosquito strains suggest that, in standard W.H.O. susceptibility tests of adult mosquitoes, appropriate discriminating concentrations of etofenprox for detection of resistance would be 0.1% for Culex and 0.25% for Anopheles.