bluuebunny/crossref_metadata_2025_split huggingface dataset:
The use of willingness‐to‐pay approaches in mammal conservation
Authors: White Piran C. L. , Bennett Alison C. , Hayes Emma J. V. 
Published: March 2003

ABSTRACTWith limited monetary resources available for nature conservation, policy‐makers need to be able to prioritize conservation objectives. This has traditionally been done using qualitative ecological criteria. However, since declines in species and habitats are largely the result of socio‐economic and political forces, human preferences and values should also be taken into account. An environmental economics technique, contingent valuation, provides one way of doing this by quantifying public willingness‐to‐pay towards specific conservation objectives.In this paper, the use of this approach for quantifying public preferences towards the UK Biodiversity Action Plans for four different British mammal species is considered. The species included are the Red Squirrel Sciurus vulgaris, the Brown Hare Lepus europaeus, the Otter Lutra lutra and the Water Vole Arvicola terrestris. Willingness‐to‐pay for conservation was increased by the inclusion of the Otter among the species, membership of an environmental organization and awareness of the general and species‐specific threats facing British mammals. It was reduced by the presence of the Brown Hare among the species being considered.These findings for British mammals are compared with other willingness‐to‐pay studies for mammal conservation worldwide. Willingness‐to‐pay tends to be greater for marine mammals than terrestrial ones, and recreational users of species (tourists or hunters) are generally more willing than residents to pay towards species conservation. The choice of technique for eliciting willingness‐to‐pay from respondents is also shown to be highly significant.Willingness‐to‐pay values for British mammals derived from contingent valuation are sensitive to the species included rather than merely symbolic. This indicates that, with care, such measures can be used as a reliable means of quantifying public preferences for conservation, and therefore contributing to the decision‐making process. However, irrespective of the internal consistency of contingent valuation, the validity of the approach, especially for use in nature conservation, is disputed. Willingness‐to‐pay is likely to reflect many interrelated factors such as ethical and moral values, knowledge and tradition, and monetary values may not be an adequate representation of these broader considerations. Willingness‐to‐pay approaches should therefore be used in addition to, rather than in place of, expert judgements and more deliberative approaches towards policy decision‐making for conservation.
Sibling species distributions of the Simulium damnosum complex in the West African Onchocerciasis Control Programme area during the decade 1984–93, following intensive larviciding since 1974
Authors: Boakye D. A. , Back C. , Fiasorgbor G. K. , Sib A. P. P. , Coulibaly Y. 
Published: March 2003

Abstract.During the decade from 1984 to 1993, nine species of the Simulium damnosum complex of blackflies (Diptera: Simuliidae) were identified from the area covered by the Onchocerciasis Control Programme. These were S. damnosum s.s., S. dieguerense, S. konkourense, S. leonense, S. sanctipauli, S. sirbanum, S. soubrense, S. squamosum, and S. yahense. Some of these species were found to consist of two chromosomal variant populations. These were S. konkourense‘Konkouré' and ‘Menankaya' forms, S. sanctipauli sensu stricto and‘Djodji' form, S. soubrense‘Chute Milo' and ‘Beffa' forms. The distribution of these twelve cytological taxa was assessed in relation to the two main vegetation zones of West Africa (forest and savanna), topography, river size and other factors. The range of each species was influenced by seasonal climatic changes in wind movement and river water level.The most widely distributed species were S. sirbanum and S. damnosum s.s., associated with savanna areas, recorded from all river basins. Simulium dieguerense was restricted mainly to Western Mali on the Rivers Bafing and Bakoye in the Senegal River basin. Simulium squamosum was identified from rivers draining mountainous areas in both the forest and savanna zones. Simulium yahense was found in small permanent rivers along a wide forested band parallel to the coast and was absent from the plains of Togo and Benin. Members of the S. sanctipauli subcomplex had restricted distributions except for S. sanctipauli s.s., which was widespread in large rivers of the forest zone from Sierra Leone to the Volta Lake in Ghana. Simulium soubrense‘Beffa' form occurred in Togo and Benin, S. soubrense‘Chutes Milo' form in Guinea, both ‘Konkouré' and ‘Menankaya' forms of S. konkourense occurred predominantly in Guinea and S. leonense in Sierra Leone. The relevance of the distribution maps and the importance of the data bank to vector control larvicidal operations are discussed.
Field responses ofGlossina austenito sticky panels on Unguja Island, Zanzibar
Authors: Vreysen Marc J. B. , Zhu Zeng‐Rong , Saleh Khalfan M. 
Published: March 2003

Abstract.Two designs of cross‐shaped sticky panels (XT and XLP) were compared with the royal blue–white legpanel (LPBuWh) in the Jozani forest on Unguja Island as trapping devices for male Glossina austeni. Single coloured royal blue (XTBu) and bi‐coloured royal blue–white XT (XTBuWh) caught more than twice as many male G. austeni as the LPBuWh, whereas single coloured black XT trapped significantly fewer flies (10%) than the control LPBuWh. XT's in various horizontal and diagonal blue–white configurations likewise trapped more flies than the LPBuWh, except a horizontally striped blue–white XT which trapped fivefold fewer flies than the LPBuWh. Cross‐shaped LP in the blue–white (XLPBuWh) and black–white (XLPBlWh) combination scored significantly better than the control LPBuWh. Similar fly numbers were trapped with XTBuWh and XLPBuWh. Long‐term trapping data indicated that the XTBu, XTBuWh and XLPBuWh were three‐ to fourfold more effective in trapping female flies than the LPBuWh.The landing bias on bi‐coloured panels was low in the blue–white but more pronounced in the blue–black and white–black combinations and was affected by the type of sticky panel used. A high proportion (49%) of the flies alighted on the bottom corners of the XTBu panel, but landing positions were more scattered if white was added.Increasing the width of the XTBu from 70 to 120 cm improved the catch by a factor of two as compared with standard sized XTBu. The effect of doubling the height of the XT on total fly catch was negligible.At present, it is the XTBu which can be recommended as the best trapping device for male and female G. austeni.
Induced immunity against the mosquito Anopheles stephensi: reactivity characteristics of immune sera
Authors: Almeida A. P. G. , Billingsley P. F. 
Published: March 2003

SummaryThis study shows the progression of immune responses in mice during five sequential immunizations with Anopheles stephensi mosquito extracts, characterized by ELISA, Western blot and immunohistochemistry. When exposed repeatedly to mosquito bites, control mice developed antibodies which reached titres of 1 : 105, reacted weakly in Western blot analysis and were localized to the salivary glands. Mice immunized with mosquito head plus salivary glands, midgut, ovary, fat body, midgut microvilli (Mv) and midgut basolateral plasma membrane (Blm), showed increased titre with each successive boost. Epitopes were shared between sera or were specific to the immunizing or heterologous extract. Anti‐Mv and Blm sera recognized proteins labelled by anti‐midgut serum and gave specific reactions with the midgut and head. Cross‐reactivity was confirmed immunohistochemically.
Visual responses of Musca domestica to pheromone impregnated targets in poultry units
Authors: Chapman J. W. , Knapp J. J. , Goulson D. 
Published: March 2003

SummaryField trials investigating the effect of visual cues on catches of Musca domestica (Diptera: Muscidae) at toxic targets impregnated with the female sex pheromone (Z)‐9‐tricosene, were conducted in a caged‐layer deep‐pit poultry unit in southern England. Targets treated with azamethiphos and baited with 2.5 g of 40% (Z)‐9‐tricosene impregnated beads caught significantly greater numbers of M. domestica than control targets. The greater attractiveness of the pheromone impregnated targets persisted for at least 5 weeks. The addition of longitudinal black stripes, or a regularly spaced pattern of black spots, to the white targets had no effect on catch rates. However, a pattern of clustered black spots, designed to imitate groups of feeding M. domestica, significantly increased target catches; this effect was particularly pronounced in the targets impregnated with (Z)‐9‐tricosene. Trials comparing the attractiveness of white and fluorescent yellow pheromone‐treated targets under two different lighting regimes indicated that M. domestica does not have a significant preference for either colour. The implications of these results in relation to the control of M. domestica populations in poultry units are discussed.
Multiple host feeding in field populations of Anopheles culicifacies and An. subpictus in Sri Lanka
Authors: Amerasinghe P. H. , Amerasinghe F. P. 
Published: March 2003

SummaryA histological technique was used to detect the multiple blood‐feeding of female mosquitoes, within the same gonotrophic cycle, in field populations of the malaria vectors Anopheles culicifacies and An.subpictus (Diptera: Culicidae) at a village in the low country of Sri Lanka, during 1994–96. Among 3306 An.culicifacies and 871 An.subpictus engorged females examined, respectively, 34.4% and 30.4% were multiple‐fed. In these two species, double meals accounted for 92.7% and 89.5%, and triple meals for 7.3% and 10.5% of multiple meals, respectively. More females of An.culicifacies (53.7%) than An.subpictus (44.5%) multiple‐fed on different nights. Multiple feeding rates in the two species were independent of sample size and field abundance. In An.culicifacies, but not An.subpictus, these rates were proportional to ambient temperature but not to humidity. Bloodmeal ELISA showed that 8.3% of 242 An.culicifacies were human‐fed and 80% of these (i.e. 6.6%) were concurrently bovid‐fed. Combining the histological and ELISA data, it was estimated that multiple feeding involving a human host had occurred in 7.2% of the blood‐feeding An.culicifacies population at this study site. Only 1.2% of 406 An.subpictus were human‐fed and all of these were concurrently bovid‐fed. Multiple bloodfeeding within the same gonotrophic cycle was attributed to a local ‘frequent feeding strategy’ in these primarily zoophagic and endophilic malaria vectors. Unfortunately this strategy enhances their human‐biting rate and hence their vectorial capacity.
Olfactory responses to attractants and repellents in tsetse
Authors: Voskamp K. E. , Everaarts E. , Den Otter C. J. 
Published: March 2003

SummaryThe aims of this study were to investigate how antennal olfactory cells of tsetse (Diptera: Glossinidae) code odour quality and how they are able to discriminate between attractive and repellent odours. For Glossina pallidipes Austen, a survey is presented of the cells’ responses to attractive (1‐octen‐3‐ol, acetone, 3‐methylphenol, carbon dioxide) and repellent stimuli (2‐methoxyphenol, acetophenone, lactic acid, naphthalene). In addition, the responses of these cells to binary mixtures and the dose–response curves of 1‐octen‐3‐ol, 3‐methylphenol, 2‐methoxyphenol and acetophenone are presented. A minority of the cells responded to one attractant or repellent only, whereas the vast majority were excited by more than one of the attractive and/or repellent stimuli. It is proposed that the peripheral olfactory cells of tsetse discriminate between different compounds via an across‐fibre pattern coding, in which the cells that specifically code for attractants or repellents may play a substantial role in composing a unique excitation pattern that informs the central nervous system about the specificity of odours.
Interspecific competition between sibling species larvae of Anopheles arabiensis and An. gambiae
Authors: Schneider P. , Takken W. , Mccall P. J. 
Published: March 2003

SummaryMosquito larvae of the sibling species Anopheles arabiensis Patton and An. gambiae Giles sensu stricto (Diptera: Culicidae) were investigated for interspecific competition. Single‐species and mixed‐species populations were reared at 27°C from the first instar to pupation at different densities (100, 200 or 400 larvae/200 cm2 tray) with a constant amount of food, 0.2 mg/larva/day. Pupae obtained from mixed populations were identified to species using PCR. Both species had a 1 : 1 sex ratio at pupation. Development time to pupation averaged about one day less for An. arabiensis compared to An. gambiae, ranging from 0.93–1.49 d for males and from 0.44–0.84 d for females in single populations. In mixed species populations the difference for males ranged from 0.99–1.58 d and for females from 0.93–1.62 d. Survival rates of An. gambiae s.s. were significantly higher than those of An. arabiensis in both the single‐species and mixed‐species populations. Mixed‐species rearing did not have an effect on the survival of An. gambiae, whereas the mortality rate of An. arabiensis was significantly higher in mixed populations than when only this species was reared at the same densities, suggesting a competitive disadvantage for An. arabiensis in mixed populations. High proportions of larvae (4–35%) were lost during development; these losses could not be accounted for by corpses found in the rearing pans. The possibility of cannibalism was investigated by rearing each species separately in small containers (five per 50 ml), inspected every 6 h, but no cannibalism was detected at any stage of development in either species. It was concluded that, under these experimental circumstances, interspecific competition between both species did occur but with a detrimental effect on An. arabiensis only. Relevance of these findings to the ecology of both species in the field is discussed briefly.
Effects of temperature and larval diet on development rates and survival of the dengue vector Aedes aegypti in north Queensland, Australia
Authors: Tun‐Lin W. , Burkot T. R. , Kay B. H. 
Published: March 2003

SummaryImmature development times, survival rates and adult size (wing‐lengths) of the mosquito Aedes aegypti (L.) (Diptera: Culicidae) were studied in the laboratory at temperatures of 10–40°C. The duration of development from egg eclosion (hatching of the first instar) to adult was inversely related to temperature, ranging from 7.2 ± 0.2 days at 35°C to 39.7 ± 2.3 days at 15°C. The minimum temperature threshold for development (t) was determined as 8.3 ± 3.6°C and the thermal constant (K) was 181.2 ± 36.1 day‐degrees above the threshold. Maximum survival rates of 88–93% were obtained between 20 and 30°C. Wing‐length was inversely related to temperature. The sex ratio (♀:♂) was 1 : 1 at all temperatures tested (15, 20, 25 and 35°C) except 30°C (4 : 3).Under field conditions at Townsville and Charters Towers, north Queensland, the duration of immature development varied according to the container position (i.e. shaded or exposed) and the availability of food resources, as well as inversely with temperature. These data indicate that containers with an abundance of organic matter (e.g. those used for striking plant cuttings) or those amongst foliage or under trees (e.g. discarded plastic tubs and tyres) tended to produce the largest adult Ae. aegypti, which had faster development and better immature survival. As such progeny have been linked to a greater risk of dengue transmission, it would seem important to focus on control of such containers.
Repellency of deet to nymphs of Triatoma infestans
Authors: Alzogaray R. A. , Fontan A. , Zerba E. N. 
Published: March 2003

SummaryThe repellency of N,N‐diethyl‐3‐methylbenzamide (deet) to Triatoma infestans (Klug) (Hemiptera: Reduviidae) was evaluated using third‐instar nymphs and a video tracking technique. Three experimental designs were used: (a) the test arena floor was divided into two halves, only one of which was treated with deet; (b) the arena floor was divided into an inner circle and an outer ring, only the latter treated with deet; (c) half of the test arena was covered by a filter paper roof treated with deet (out of reach of the nymphs). In all three types of experiment, a repellent effect was demonstrated proportional to the dose of deet. When a host (pigeon) was shielded by deet‐treated gauze, the rate of blood‐feeding by the nymphs was inhibited. Topical pre‐treatment of the nymphs with N‐ethylmaleimide, to block chemoreception, inhibited the repellency.
Shared salinity tolerance invalidates a test for the malaria vector Anopheles farauti s.s. on Guadalcanal, Solomon Islands
Authors: Foley D. H. , Bryan J. H. 
Published: March 2003

SummaryAmong the Punctulatus Group of Anopheles mosquitoes (Diptera: Culicidae), first‐instar larvae of the medically unimportant freshwater Anopheles farauti species No. 7 survives a seawater tolerance test (SST) that was previously thought to be diagnostic for the saltwater‐tolerant malaria vector species, An. farauti Laveran s.s. Salt tolerance in these two closely related isomorphic species appears to be a shared derived character within the Farauti Complex. Failure to differentiate An. farauti s.s. from An. farauti No.7 will overestimate potential malaria vector numbers and waste limited larval control resources. Use of the SST should therefore be discontinued on Guadalcanal and other techniques such as allozyme electrophoresis used instead.
Cattle breed‐variation in infestation by the horn fly Haematobia irritans
Authors: Guglielmone A. A. , Curto E. , Anziani O. S. , Mangold A. J. 
Published: March 2003

SummaryA study was carried out to assess the resistance of pure and cross‐bred groups of cattle to the horn fly Haematobia irritans (Linnaeus) (Diptera: Muscidae) in northern Argentina. Pure‐bred cattle were Criolla, Iberian Bos taurus Linnaeus (Artiodactyla: Bovidae) and Nellore, Bos indicus Linnaeus (Artiodactyla: Bovidae). Cross‐bred cattle were Hereford, British B. taurus (34%) × Nellore (66%) and Hereford (66%) × Nellore (34%). All were heifers and animals were maintained in two groups, each containing a mixture of pure and cross‐breeds. The lowest fly numbers were found on Criolla heifers and the highest on Hereford × Nellore cross‐breeds. However, it could not be determined from this study whether this was a consequence of breed and/or size, as Criolla heifers were lighter than the corresponding Hereford × Nellore heifers. Fly numbers on the heifers followed an approximately negative binomial distribution. However, the ranking of individual animals in their level of infestation within subgroups was not consistent. Hence, culling the most infested heifers on any given date would at best give only a small improvement in H. irritans control.
Feeding and survival of Culicoides sonorensis on cattle treated with permethrin or pirimiphos‐methyl
Authors: Mullens B. A. , Velten R. K. , Gerry A. C. , Braverman Y. , Endris R. G. 
Published: March 2003

SummaryThe persistence of permethrin (5% a.i.) and pirimiphos‐methyl (27% a.i.), applied to the dorsum of calves in the field against Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae), was estimated using a hair‐blood‐feeding bioassay in the laboratory. Hair clippings were taken before treatment and 3, 7, 14, 21, 28, 42 and 56 days after treatment from the dorsum, side and belly of treated and control calves. Laboratory‐reared insects were allowed to feed through thin hair layers and a parafilm membrane on sheep blood warmed using a water‐jacketed feeder. Some intoxication after exposure to hair was noted up to 28 days after treatment with permethrin and up to 14 days after treatment with pirimiphos‐methyl. Hair from the dorsum caused more intoxication for a longer period than hair from other body regions. Permethrin and pirimiphos‐methyl applied to the back did not significantly reduce overall engorgement (body regions pooled) after treatment. Permethrin residues on hair remained far higher on the back than other body regions and were related to insect intoxication and reduction in engorgement in the laboratory. Residues on belly hair never exceeded 12 p.p.m. and did not result in significantly reduced feeding at any time. Engorged insects that exhibited sublethal intoxication from feeding through permethrin‐treated hair did recover and matured numbers of eggs comparable to controls. Field trials using treated and control calves and enclosure nets showed that dorsal applications of 5% permethrin were not effective in reducing engorgement, despite some intoxication. Vacuum samples from a calf showed that C. sonorensis fed primarily on the belly. A 0.2% permethrin application on the belly (250 ml) did result in > 80% reduction of C. sonorensis in the enclosure nets at 3 and 7 days after treatment, but activity had subsided by 10 days after treatment. The utility of insecticidal treatments for suppression of this vector is discussed.
Use of deltamethrin ‘pour‐on’ insecticide for the control of cattle trypanosomosis in the presence of high tsetse invasion
Authors: Rowlands G. J. , Leak S. G. A. , Mulatu Woudyalew , Nagda S. M. , Wilson A. , D'Ieteren G. D. M. 
Published: March 2003

SummaryA deltamethrin ‘pour‐on’ insecticide was applied monthly to over 2000 cattle exposed to a high challenge of drug‐resistant trypanosomes and high tsetse re‐invasion pressure in the Ghibe valley, south‐west Ethiopia. Blood samples were taken monthly from an average of 760 cattle for determination of PCV and presence of trypanosomes. The area of the valley is approximately 350 km2 and the cattle grazed in roughly four locations covering about a quarter to half of the area. Two years before the trial commenced, Glossina morsitans submorsitans Newstead (Diptera: Glossinidae) began to invade the valley. Despite the use of the pour‐on the mean apparent density of G. m. submorsitans continued to rise, and, during the 4 years of tsetse control, was more than three‐fold higher than that recorded during the previous 18 months. Over the same period there was little change in the apparent density of Glossina pallidipes Austen (Diptera: Glossinidae). By contrast, the mean monthly prevalence of trypanosome infections in cattle over 36 months of age decreased from 38.3 to 29.0%, the incidence of new infections decreased from 26.6 to 16.0% (a reduction of 40%), and packed cell volume in cattle increased from 21.7 to 24.1%. Evidence of a change in apparent parasite transmission rate was demonstrated by regression of infection incidence in cattle on the logarithm of apparent density of G. m. submorsitans. Before the trial started the regression coefficient was 45.8 ± 6.3 and this reduced to 9.2 ± 2.5% incidence per loge (flies/trap/day) during the period of tsetse control. It was concluded that this indicated reductions in tsetse numbers in the immediate vicinities of cattle in a way that was not reflected in overall tsetse catches. Nevertheless, the comparatively high levels of trypanosome prevalence that persisted in the cattle demonstrates that, where invasion prevalence is high, treatment of small pockets of cattle will not eradicate tsetse. To achieve more significant reduction in trypanosome prevalence in cattle, integrated methods of control utilizing target barriers in the major routes of invasion will be needed.