bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors affecting seasonal dispersal of the tsetse flies Glossina pallidipes and G. longipennis (Diptera: Glossinidae) at Nguruman, south-west Kenya
Authors: Brightwell R. , Dransfield R.D. , Williams B.G. 
Published: July 2009

AbstractSeasonal changes in the distribution of the tsetse flies, Glossina pallidipes Austen and G. longipennis Corti, along a transect from riverine thickets out into open plains were monitored along with tsetse density, climatic factors, vegetation and host abundance. Dispersal of tsetse into open country was quantified using the mean spread. During and after the rains both species extended their distribution out into open country up to at least 3.5 km from riverine thicket areas. The mean spread of G. longipennis was greater than that of G. pallidipes. The spread of males and females was very similar, as was the spread of different age categories of parous females, but nulliparous flies and females carrying second instar larvae were under-represented in samples from open areas. This seasonal dispersal can be accounted for by random diffusion with an average root mean square displacement of about 175 m per day. Observed degrees of spread were best correlated with humidity conditions prior to sampling, but multiple regression models suggested that host abundance, vegetation as measured by Normalised Difference Vegetation Indices (NDVI), and, in the case of G. longipennis, tsetse density, were also factors in determining the degree of spread. The significance of these findings in relation to tsetse control is discussed.
The pugnacious ant, Anoplolepis custodiens (Hymenoptera: Formicidae), and its beneficial effect on coconut production in Tanzania
Authors: Löhr B. 
Published: July 2009

AbstractIn a field of six hectares, the number of palms foraged by Anoplolepis custodiens (Smith) increased from January to December 1988 from 32 to 85% and the ant activity scores (0–3 system) from 0.5 to 2.0. During the same time, the population of the coconut bug, Pseudotheraptus wayi Brown (Heteroptera: Coreidae) as well as the damage it caused, decreased significantly. A significant relationship between low percentages of damaged nutlets and high ant scores of the palms could be established. The nut set of ant foraged palms was 2–3 times higher than that of comparable palms in an immediately adjacent field free of A. custodiens. Palms with high A. custodiens scores had invariably high scores of the coconut aphid, Cerataphis variabilis Hille Ris Lambers (Homoptera: Aphididae). The performance of the palms was not visibly affected by the aphids.
Determining the ages of adult females of different members of the Simulium damnosum complex (Diptera: Simuliidae) by the pteridine accumulation method
Authors: Millest A.L. , Cheke R.A. , Howe M.A. , Lehane M.J. , Garms R. 
Published: July 2009

AbstractA significant relationship between pteridine content of the head, fly age and fly size, which was independent of temperature, was found for adult females of Simulium sirbanum Vajime & Dunbar using flies maintained at different constant temperatures after eclosion. Similar relationships for flies maintained at varying temperatures within the species' natural ranges were obtained in experiments with the Beffa form of S. soubrense Vajime & Dunbar (sensu Post, 1986), S. sanctipauli Vajime & Dunbar (= S. soubrense sensu Post, 1986), S. squamosum (Enderlein), S. yahense Vajime & Dunbar and S. damnosum sensu stricto. Common slopes for the effects of age and size could be fitted to all these species. Relations between pteridine concentration in the head, fly size and age, with the common slopes but with species-specific intercepts, were used to estimate the age structure of wild-caught populations of the Beffa form of S. soubrense, S. squamosum and S. yahense. A dry season sample of S. squamosum was estimated to be older than a wet season sample. The mean age of the S. soubrense population, sampled one week after its presumptive breeding sites were treated with larvicides, was estimated to be 13.5 days. The maximum was 30.9 days and a frequency distribution of the estimates had distinct peaks, at three day intervals between 8 and 21 days. The significance of the results is discussed in relation to fly longevity and gonotrophic cycle lengths.
Nocturnal observations on the emergence and flight behaviour of Helicoverpa armigera (Lepidoptera: Noctuidae) in the post-rainy season in central India
Authors: Riley J.R. , Armes N.J. , Reynolds D.R. , Smith A.D. 
Published: July 2009

AbstractA range of techniques was used to quantify the nocturnal flight behaviour of Helicoverpa armigera (Hübner) in pigeon pea (Cajanus cajan) crops near Hyderabad, in central India. These included visual observations in the field, the use of field cages and a vehicle-mounted net, optical and video imaging in the infra-red, and radar. Moth emergence from the soil was observed to start at dusk and recruitment continued steadily throughout the first half of the night. Little activity was observed in moths on the night of emergence, except for weak flying or crawling to daytime refuges. Flight activity of one-day old moths started about 20 min after sunset, peaked 15 min later and within about an hour of sunset had declined to a low level which persisted for the rest of the night. Flight of reproductively mature moths was most frequent about 1 h after sunset and at this time mainly comprised females searching for oviposition sites and nectar sources. By about 2 h after sunset, flight had decreased markedly, but there was a slight increase in activity in the second half of the night caused by males undertaking mate-finding flights. Under the conditions studied, the majority of H. armigera dispersed below 10 m, and there were no mass ascents to higher altitudes like those observed at outbreak sites of the African armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae). The contrasting migratory strategies of H. armigera and S. exempta are briefly discussed.
Esterase activity in populations of the whitefly,Bemisia tabaci(Homoptera: Aleyrodidae): heritability and associated organophosphorus insecticide resistance
Authors: Bloch Guy , Wool David 
Published: July 2009

AbstractThe association of esterase (EST) activity with resistance to the organophosphorus (OP) insecticide methidathion was investigated in field-collected populations of whitefly (Bemisia tabaci(Gennadius)) in Israel. The inheritance of EST activity was studied by controlled crosses in the laboratory. Among-family variance of EST activity was highly significant although all families were maintained in the same rearing room. This indicates that genetic or common environmental effects due to rearing each family on a different caged plant must have been important. Heritability estimated from son-mother regression was h2=0.98, but this estimate seems to be unrealistically high. Daughter-mother and daughter-mid-parent regressions produced lower heritability estimates (as expected). None of the regression coefficients of daughters on mother, however, were significantly different from zero and the regression on parent explained only very small amounts of the activity variation in the offspring. Estimates obtained from intraclass correlations among offspring were higher and outside the acceptable range, reflecting the variance component due to the common environment. The predictive value of the heritability estimates appears to be very low. The frequency distribution of activity among individuals sampled from one insecticide treated site (AM) was skewed to the right, as previously reported. But samples from another site (TZ) showed a symmetrical distribution, unlike the previous pattern. When field collected individuals from AM were released on clean plants in the laboratory, samples taken from the plants one or more days later showed symmetrical EST distribution. Electro-phoretic paterns of field and laboratory samples were the same, but band intensity was stronger in samples from laboratory populations. Differences in mean EST activity between populations and sampling years were unrelated to methidathion resistance.
The effects of triflumuron, a chitin synthesis inhibitor, on the housefly,Musca domestica(Diptera: Muscidae)
Authors: Howard Julia , Wall Richard 
Published: July 2009

AbstractThe effects of the chitin synthesis inhibitor triflumuron, 2-chloro-N-[[[4-(trifluoromethoxy)phenyl]amino]carbonyl]benzamide, on the housefly,Musca domesticaLinnaeus were examined in the laboratory. A dose of 1 μg of triflumuron applied topically to adult females ofM. domesticaresulted in egg hatch inhibition greater than 95%. At doses below 1 μg applied topically to adult females, subsequent hatched larvae were also highly sensitive to triflumuron; 0.5 μg applied topically produced 25% inhibition of egg hatch, but of the larvae that eclosed, only 20% survived to pupation. Hence, a dose of 0.5 μg applied to adults gave a total mortality of 85%. The effects of a single topical application of triflumuron declined over time in a dose dependent manner. After a dose of 1 μg, <5% of the first egg batch hatched, however, after 14 days egg hatch had risen to >90%. Topically applied triflumuron was most effective in inhibiting egg hatch when applied to females less than 3 days old. After 60 min tarsal contact with 20% triflumuron suspension concentrate on poly cotton cloth, 100% egg hatch inhibition was maintained for up to 1 week. Lower contact times, or triflumuron concentrations, gave lower percentage mortalities. The results suggest that triflumuron has considerable potential as a control agent for incorporation into autosterilizing devices for housefly control. However, further work is required to develop delivery systems capable of transferring an effective dose to females under field conditions.
Estimates of mortalities of larvae and pupae of theAedes simpsoni(Theobald)(Diptera: Culicidae) complex in Uganda
Authors: Lutwama J.J. , Mukwaya L.G. 
Published: July 2009

AbstractStudies were carried out to estimate and compare mortalities of larvae and pupae ofAedes (Stegomyia) simpsoni sensu latobreeding in axils ofColocasia esculenta, Xanthosoma sagittifolium(Araceae) andMusaspp. (Musaceae) in different locations in Uganda and also to ascertain whether there are any differences in their dynamics that could be used to separate the species. The probability of larvae surviving from one day to the next (40·5 – 99·8%), and the proportions dying in each instar (0·97 – 77·3%) and dying daily in all the four instars (3·9 – 46·3%) varied between seasons at each site and between sites and species of plants. Estimates of larval and pupal mortality were generally highest for fourth instar [52·4 ± 6·0% (mean ± SE)] and lowest for the second instar larvae (16·0 ± 2·6%). There was higher larval instar mortality in axils ofX. sagittifolium(96·9%) andMusaspp. (82·2 – 96·5%) than inC. esculenta(47·1 – 88·4%).
Spatial dispersion patterns of larval Aedes cantans (Diptera: Culicidae) in temporary woodland pools
Authors: Renshaw M. , Silver J.B. , Service M.W. , Birley M.H. 
Published: July 2009

AbstractThe spatial dispersion patterns of larvae of the Palaearctic mosquito Aedes cantans (Meigen) were studied in two temporary woodland pools in England, between 1988 and 1990. Variance to mean ratios indicated that all larval instars were aggregated, but the degree of aggregation differed between ponds and between years, depending on the population density. The negative binomial model was found to fit the majority of the data, and the values for the parameter k varied between 0.05 and 0.96. Taylor's power law gave a good fit to the data with values of b, an index of aggregation, varying between 1.42 and 1.91. Iwao's patchiness regression yielded values for α between –1.63 and 6.92, and β from 1.49 to 3.25. These values indicate that the population is aggregated due to habitat heterogeneity, and younger instars may demonstrate a propensity to congregate with one another. A relationship between water temperature and mean number of larvae sampled at each transect point was observed in Pond One in 1989, suggesting that larvae aggregate where water temperatures are higher.
Responses of tsetse flies (Diptera: Glossinidae) to natural and synthetic ox odours
Authors: Torr S.J. , Hall D.R. , Smith J.L. 
Published: July 2009

AbstractIn Zimbabwe, studies were made of the levels of known tsetse attractants present in natural ox odour. Typically an ox (400 kg) produced phenol (0.1 mg/h), 3-methylphenol (0.09 mg/h), 4-methylphenol (0.7 mg/h), 3-ethylphenol (0.01 mg/h), 4-ethylphenol (0.02 mg/h), 3- and 4-n-propylphenol (0.02 mg/h), l-octen-3-ol (0.01 mg/h), carbon dioxide (140 l/h), acetone (5 mg/h) and butanone (0.3 mg/h). Of these, only phenol, 4- and 3-methylphenol and carbon dioxide were always detected in ox odour. Studies were made of the numbers of Glossina pallidipes Austen and G. morsitans morsitans Westwood attracted to natural ox odour and synthetic odour, the latter consisting of blends of identified attractants dispensed at the doses naturally present in ox odour. Natural ox odour caught twice (P < 0.05) as many G. pallidipes and 1.5 (P < 0.05) times as many G. m. morsitans as the synthetic blend suggesting the presence of an unidentified attractant in ox odour. Passing ox odour through filters indicated that all attractants can be trapped on a combination of charcoal and sodalime filters but the unidentified attractant(s) may pass through a sodalime filter, and break through a charcoal filter used for more than 6 h. Increasing the dose of ketones in the synthetic odour from 2 to 100 mg/h doubled the catches at the source. Increases in ketone levels in hosts, induced by starvation or possibly trypanosomiasis, may increase attraction of tsetse to such animals.
A biologically-active compound from pupae of the sandfly Lutzomyia longipalpis (Diptera: Psychodidae) and its possible role in defence
Authors: Dougherty M.J. , Hamilton J.G.C. 
Published: July 2009

AbstractGas chromatography analysis of Lutzomyia longipalpis (Lutz & Neiva) pupae and fourth instar larvae revealed a compound which was not present in other larval stages. Squashed pupae were repellent to conspecific larvae and ants (Lasius niger (Linnaeus) (Hymenoptera: Formicidae)), whereas second and third instars were not. Hexane extracts of pupae were repellent to conspecific larvae and L. niger, but extracts of second and third instars were not. The biologically active chemical was isolated from pupae and fourth instars and was found to be repellent to conspecific larvae and L. niger. The possibility that pupae and fourth instars may use a combined chemical and mechanical defensive strategy to avoid predation and cannibalism is discussed.
Comparative survival of insecticide-susceptible and resistant peach-potato aphids, Myzus persicae (Sulzer) (Hemiptera: Aphididae), in low temperature field trials
Authors: Foster S.P. , Harrington R. , Devonshire A.L. , Denholm I. , Devine G.J. , Kenward M.G. , Bale J.S. 
Published: July 2009

AbstractThe survival of Myzus persicae (Sulzer) clones, representing the full range of the recognized levels of insecticide resistance, was measured after 3–4 week exposure to the winter climate in the field. Ten separate trials were carried out using known numbers of first/second instar nymphs on unsprayed oilseed rape and groundsel. These predominantly showed a negative association between resistance level and the proportion of aphids recovered alive after exposure. The strength of the relationship correlated closely with three meteorological variables: the length of time that aphids spent below 2°C, mean rainfall and mean windspeed. We conclude that selection for resistance to insecticides is subject to counteracting selection by cold, wet and windy conditions in the UK winter. Revertant clones, that had spontaneously lost extreme resistance to insecticides despite retaining resistance genes, survived no better than aphids that had kept their high resistance, indicating that overproduction of esterase was not the reason for poor survival.
The effects of exposing eggs of four cotton insect pests to volatiles of Allium sativum (Liliaceae)
Authors: Gurusubramanian G. , Krishna S.S. 
Published: July 2009

AbstractExposure of freshly laid eggs (<24 h old) of Earias vittella Fabricius (Lepidoptera: Noctuidae) and Dysdercus koenigii (Fabricius) (Hemiptera: Pyrrhocoridae) to volatiles from bulbs of Allium sativum significantly reduced their hatchability. Eggs of Spodoptera litura (Fabricius) (Noctuidae) treated likewise, failed to hatch. Eggs of Helicoverpa armigera (Hübner) (Noctuidae) were more tolerant and showed only a slight decrease in mortality. None of the immature stages of D. koenigii and H. armigera and only 30% of those of E. vittella that hatched from treated eggs managed to complete their metamorphosis. A few larvae of H. armigera developed to the pupal stage but their pupal weights were markedly low. These findings are interpreted as the chronic effects of volatiles affecting larvae/nymphs following developmental defects sustained during embryonic development. The known chief constituents such as allicin, 2-propene sulfenic acid, 2-propene thiol, propylene, thioacrolein and ajoene present in the volatiles were presumed to be responsible for the adverse consequences reported here.
Factors affecting host preference of Lutzomyia evansi (Diptera: Psychodidae), a vector of visceral leishmaniasis in Colombia
Authors: Montoya-Lerma James , Lane Richard P. 
Published: July 2009

AbstractPrevious studies have shown the sandfly Lutzomyia evansi to be the vector of Leishmania chagasi in northern Colombia. A longitudinal survey during seven months on the host preference of Lutzomyia evansi was conducted in the visceral leishmaniasis focus of San Andrés de Sotavento, Colombia. Host preference was determined by presenting sandflies with a choice of three baits (human, and the reservoirs dog and opossum) and a blank control in specially designed cone traps. A rotational experimental design involved 56 trap nights in which the effect of bait, proximity to forest and season could be distinguished from the potentially confounding factors of site and day to day variation. From a total of 598 sandflies caught during all experiments, females and males of Lutzomyia evansi accounted for 93.8% of the captures in the baited traps. Overall, human attracted the greatest number of sand flies, followed by the other two baits. Attraction and feeding success showed significant differences (P < 0.0001) between baits.
On the coexistence of the cassava mealybug parasitoidsApoanagyrus diversicornisandA. lopezi(Hymenoptera: Encyrtidae) in their native South America
Authors: Pijls Janine W.A.M. , van Alphen Jacques J.M. 
Published: July 2009

AbstractThe encyrtid parasitoidApoanagyrus diversicornis(Howard) (formerly known asEpidinocarsis diversicornis) failed to establish itself in Africa where it was introduced, in addition toA. lopeziDe Santis for the biological control of the cassava mealybug,Phenacoccus manihotiMatile-Ferrero.Apoanagyrus lopeziis a better competitor and available evidence suggests that competition prevents the coexistence. Yet, both parasitoid species were reared fromP. manihotiin the same locality in their native South America. Competition should prevent coexistence onP. manihotiin South America as well as in Africa. We investigated howA. diversicornispersists in South America. The use of alternative hosts could explain its persistence. We aimed at finding possible alternative hosts forA. diversicornisthat can serve as a refuge from competition withA. lopezi. The existing information on the distribution ofA. lopeziandA. diversicornisand their known hosts in South America is reviewed. Candidate alternative hosts forA. diversicorniswere selected and tested. Alternative hosts should at least be suitable for development ofA. diversicornisand unsuitable for development ofA. lopezi. OnlyPhenacoccus herreniCox & Williams met these requirements.Phenacoccus madeirensisGreen,P. solaniFerris andFerrisia virgata(Cockerell) were unsuitable hosts for both species. In cages with continuous parasitoid populations under strong interspecific competition,A. diversicornisdid significantly better if half the population ofP. manihotiwas replaced byP. herreni. This supports the hypothesis thatP. herrenican serve as an alternative host forA. diversicornisin South America and that its presence enhances coexistence ofA. diversicornisandA. lopezi.Phenacoccus herreniis absent in Africa.
Circadian flight activity of Arabian sandflies (Diptera: Psychodidae) using a vehicle-mounted net
Authors: Roberts D.M. 
Published: July 2009

AbstractA vehicle-mounted net was used on 15 nights during June 1990 and 1991 in northern Oman to collect sandflies in order to identify potential vectors of visceral and cutaneous leishmaniasis. A total of 2216 sandflies was collected comprising four species of Phlebotomus and three of Sergentomyia. Catches were made every 30 minutes between 17.00 h (2 hours before sunset) and 07.00 h (1.5 hours after sunrise). Very few flies were caught before sunset. Most flies were caught at light intensities < 0.1 lux (between 20.00 and 0.500 h), but some flight activity, particularly of males and unfed females, continued even up to 07.00 h (50,000 lux, 1.25 hours after sunrise). Females of the two most abundant species, Phlebotomus alexandri Sinton and Sergentomyia clydei Sinton were significantly more active during the first half of the night (19.00-01.00 h), but males were not. Males of S. clydei showed no clear activity pattern, while males of P. alexandri had two peaks with a decline in activity around 01.00 h. Sergentomyia tiberiadis Adler & Theodor and S. fallax Parrot similarly showed different activity patterns for the two sexes. The circadian activity of females of P. alexandri and S. clydei changed during their gonotrophic cycles. Thus unfed and gravid P. alexandri had two activity peaks during the night, but the blood-fed females were most active during the first half of the night. S. clydei activity was similar, except that the gravid flies, like the blood-fed, had an early peak of activity. Too few parous females were collected to show any clear difference in activity from the nullipars.
Effect of the ratios ofListronotus bonariensisandSitona discoideus(Coleoptera: Curculionidae) to their respective parasitoidsMicroctonus hyperodaeandM. aethiopoides(Hymenoptera: Braconidae), on parasitism, host oviposition and feeding in the laboratory
Authors: Barratt B.I.P. , Evans A.A. , Johnstone P.D. 
Published: July 2009

AbstractThe parasitoidsMicroctonus hyperodaeLoan andM. aethiopoidesLoan have been introduced into New Zealand to control the forage pestsListronotus bonariensis(Kuschel) andSitona discoideusGyllenhal, respectively. Laboratory experiments were carried out to investigate the effect of host–parasitoid ratio, and exposure time on host survival, parasitism, oviposition and feeding. Cages of 20 field collected weevils were exposed to 0, 1, 3 or 6 parasitoids for 0, 1, 12 or 48 hours, maintained until parasitoid pupal emergence, and surviving weevils dissected. Over the ranges studied, increasing parasite number, and to a greater extent, period of exposure of parasitoids to their hosts increased parasitism levels.Microctonus aethiopoidesachieved higher levels of parasitism inS. discoideusat the lower parasitoid contact treatments than didM. hyperodaeinL. bonariensis. Fecundity in unparasitized weevils was progressively reduced in bothL. bonariensisandS. discoideusin relation to increasing exposure to parasitoids. Feeding was reduced by about 40% inL. bonariensisfor at least four days after parasitoids were removed, and inS. discoideusfor the duration of the experiment, averaging 15%. Results were discussed in relation to possible mechanisms of indirect effects of parasitoids on unparasitized hosts.