The effect of adhesives and solvents on the capture and specimen quality of pest thrips on coloured traps
Davidson, M.M. ; Nielsen, M.C. ; Butler, R.C. ; Vellekoop, R. ; George, S. ; Gunawardana, D. ; Muir, C.A. ; Teulon, D.A.J. - \ 2015
Crop Protection 72 (2015). - ISSN 0261-2194 - p. 108 - 111.
frankliniella-occidentalis pergande - sticky traps - thysanoptera - palmi - eradication - surfaces - diptera - crop
The present study compared different adhesives for trapping efficacy, ease of removing specimens and the subsequent quality of specimens for identification of thrips pests captured on blue plastic boards in a commercial capsicum glasshouse. The mean total number of thrips caught on sticky boards differed significantly with different adhesives. Blue boards covered with a water-based adhesive caught the least total number of thrips in the two experiments (56 thrips per trap, experiment 1; 4 thrips per trap, experiment 2). Traps covered with Stikem Special® caught the greatest number of total thrips (299 per trap, experiment 1; 32 per trap, experiment 2). De-Solv-it® was the most effective solvent to remove thrips from sticky boards compared with water and mineral oil, with all thrips detached from boards for all adhesive treatments within 150 min. Damage to or absence of key morphological features due to removal of specimens with De-Solv-it that would prevent species identification was recorded in only 10 of the 720 specimens removed from traps across all adhesives. The majority of thrips (70–92%) identified were Thrips tabaci Lindeman or Frankliniella occidentalis (Pergande). The type of adhesive used is an important factor to consider when developing traps for insect pest monitoring and management.
Vlieg als veevoer kost meer CO2 dan soja
Sikkema, A. ; Zanten, H.H.E. van - \ 2015
Resource: weekblad voor Wageningen UR 9 (2015)21. - ISSN 1874-3625 - p. 10 - 10.
veevoeding - insecten - milieueffect - diptera - insecten als voedsel - duurzaamheid (sustainability) - livestock feeding - insects - environmental impact - diptera - insects as food - sustainability
De grootschalige productie van on- ze huisvlieg voor veevoer levert nog geen betere klimaatscore op dan soja. Dat blijkt uit onderzoek van Hannah van Zanten, promovendus bij Dierlijke Productiesystemen en Livestock Research.
Hybridization studies to modify the host preference of Anopheles gambiae
Pates, H.V. ; Curtis, C.F. ; Takken, W. - \ 2014
Medical and Veterinary Entomology 28 (2014)S1. - ISSN 0269-283X - p. 68 - 74.
candidate odorant receptors - malaria vector mosquito - feeding preferences - quadriannulatus - behavior - arabiensis - culicidae - diptera - transmission - responses
A strategy to decrease the vector competence of Anopheles gambiae sensu stricto (Diptera: Culicidae), the most efficient malaria vector in Africa, may consist of exploiting the genes involved in zoophily. Crossing and backcrossing experiments were performed between An.¿gambiae s.s. and the zoophilic sibling species Anopheles quadriannulatus. Mosquito strains were tested in a dual-choice olfactometer to investigate their responses to cow odour. Totals of 12% of An.¿gambiae s.s. and 59% of An.¿quadriannulatus selected the port with the cow odour. Crosses and backcrosses did not show a significant preference for the cow-baited port. The results indicated that anthropophilic behaviour in An.¿gambiae s.s. is a dominant or partially dominant trait, which, in conjunction with the unstable zoophilic behaviour observed in An.¿quadriannulatus, poses a serious obstacle to plans to decrease vector competence by modifying the anthropophilic trait.
Spectral composition of light sources and insect phototaxis, with an evaluation of existing spectral response models. Journal of Insect Conservation
Grunsven, R.H.A. van; Donners, M. ; Boekee, K. ; Tichelaar, I. ; Geffen, K.G. van; Groenendijk, D. ; Berendse, F. ; Veenendaal, E.M. - \ 2014
Journal of Insect Conservation 18 (2014)2. - ISSN 1366-638X - p. 225 - 231.
artificial-light - compound eyes - color-vision - moths - attraction - pollution - drosophila - diptera - state - trap
Artificial illumination attracts insects, but to what extent light attracts insects, depends on the spectral composition of the light. Response models have been developed to predict the attractiveness of artificial light sources. In this study we compared attraction of insects by existing light sources used for streetlights as well as newly developed environment friendly alternatives, and used this data to test the predictive ability of the existing response models. Light sources differed in overall attractiveness to insects and relative attractiveness was dependent on insect order. The attraction patterns predicted by the two models correlated weakly with the number of insects attracted when the only light source rich in UV, a mercury vapour light, was included in the tested spectra. When the mercury vapour light, which is going to be banned in Europe, was not included in the test no correlation was found between predicted and observed attraction patterns. We conclude that currently existing attraction response models are insufficiently sensitive to evaluate new light sources.
A push-pull system to reduce house entry of malaria mosquitoes
Menger, D.J. ; Otieno, B. ; Rijk, M. de; Mukabana, W.R. ; Loon, J.J.A. van; Takken, W. - \ 2014
Malaria Journal 13 (2014). - ISSN 1475-2875 - 8 p.
vector anopheles-gambiae - host-seeking behavior - mm-x traps - spatial repellency - field-evaluation - western kenya - lactic-acid - culicidae - diptera - strategies
Background. Mosquitoes are the dominant vectors of pathogens that cause infectious diseases such as malaria, dengue, yellow fever and filariasis. Current vector control strategies often rely on the use of pyrethroids against which mosquitoes are increasingly developing resistance. Here, a push-pull system is presented, that operates by the simultaneous use of repellent and attractive volatile odorants. Method/Results. Experiments were carried out in a semi-field set-up: a traditional house which was constructed inside a screenhouse. The release of different repellent compounds, para-menthane-3,8-diol (PMD), catnip oil e.o. and delta-undecalactone, from the four corners of the house resulted in significant reductions of 45% to 81.5% in house entry of host-seeking malaria mosquitoes. The highest reductions in house entry (up to 95.5%), were achieved by simultaneously repelling mosquitoes from the house (push) and removing them from the experimental set-up using attractant-baited traps (pull). Conclusions. The outcome of this study suggests that a push-pull system based on attractive and repellent volatiles may successfully be employed to target mosquito vectors of human disease. Reductions in house entry of malaria vectors, of the magnitude that was achieved in these experiments, would likely affect malaria transmission. The repellents used are non-toxic and can be used safely in a human environment. Delta-undecalactone is a novel repellent that showed higher effectiveness than the established repellent PMD. These results encourage further development of the system for practical implementation in the field.
Assessing the efficacy of candidate mosquito repellents against the background of an attractive source that mimics a human host
Menger, D.J. ; Loon, J.J.A. van; Takken, W. - \ 2014
Medical and Veterinary Entomology 28 (2014)4. - ISSN 0269-283X - p. 407 - 413.
anopheles-gambiae - malaria mosquito - behavioral-response - carbon-dioxide - human skin - culicidae - diptera - aedes - identification - odor
Mosquito repellents are used around the globe to protect against nuisance biting and disease-transmitting mosquitoes. Recently, there has been renewed interest in the development of repellents as tools to control the transmission of mosquito-borne diseases. We present a new bioassay for the accurate assessment of candidate repellent compounds, using a synthetic odour that mimics the odour blend released by human skin. Using DEET (N,N-diethyl-meta-toluamide) and PMD (p-menthane-3,8-diol) as reference compounds, nine candidate repellents were tested, of which five showed significant repellency to the malaria mosquito Anopheles gambiae sensu stricto (Diptera: Culicidae). These included: 2-nonanone; 6-methyl-5-hepten-2-one; linalool; d-decalactone, and d-undecalactone. The lactones were also tested on the yellow fever mosquito Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae), against which they showed similar degrees of repellency. We conclude that the lactones are highly promising repellents, particularly because these compounds are pleasant-smelling, natural products that are also present in human food sources.
Effects of founder population size on the performance of Orius laevigatus (Hemiptera: Anthocoridae) colonies
Castañe, C. ; Bueno, V.H.P. ; Carvalho, L.M. ; Lenteren, J.C. van - \ 2014
Biological Control 69 (2014). - ISSN 1049-9644 - p. 107 - 112.
biological-control agents - predators - tephritidae - selection - diptera
Orius laevigatus (Hemiptera: Anthocoridae) is a key predator of thrips and is mass reared in large numbers for use in biological control. The aim of this study was to evaluate the effect of founder population size on the biological and behavioral performance of O. laevigatus over time. Laboratory lines were started from 1, 10 and 50 founder couples from 750 adults collected in the field and their performance was evaluated at the 5th–6th and 10th–11th generations. Adaptation to the captive rearing situation occurred in the 10 and 50 founder couples lines while it failed in the 1 founder couple line. The intrinsic rate of natural increase (rm) increased and the period for doubling the population (D) decreased over the generations in the 10 and 50 founder couples lines, while (rm) decreased and (D) increase in the 1 founder couple line. Also, consumption of Frankliniella occidentalis prey was significantly lower for females from the 1 founder couple line at the 5th generation compared to females from the 10 and 50 founder couples lines. Females of laboratory lines of all founder couples did not respond to odours from thrips infested plants during the 5th and 10th generations, whereas wild females strongly reacted to these odours. We suggest that the lack of reaction to infested plant volatiles may be due to the artificial rearing method where mass reared predators do not experience an infested crop. The results showed that the 1 founder couple line differed from the 10 and 50 founder couples lines, suggesting that bottlenecking had an effect at that level. However, no difference was found between the 10 and 50 founder couples lines which suggest that these founder numbers can be used to start laboratory-reared O. laevigatus lines without a significant loss in quality of its relevant biological characteristics.
Larval nutrition differentially affects adult fitness and Plasmodium development in the malaria vectors Anopheles gambiae and Anopheles stephensi
Takken, W. ; Smallegange, R.C. ; Vigneau, A.J. ; Johnston, V. ; Brown, M. ; Mordue-Luntz, A.J. ; Billingsley, P.F. - \ 2013
Parasites & Vectors 6 (2013). - ISSN 1756-3305
body-size - aedes-aegypti - reproductive success - rapid-determination - sugar availability - yoelii-nigeriensis - mosquito - infection - culicidae - diptera
BACKGROUND: Mosquito fitness is determined largely by body size and nutritional reserves. Plasmodium infections in the mosquito and resultant transmission of malaria parasites might be compromised by the vector's nutritional status. We studied the effects of nutritional stress and malaria parasite infections on transmission fitness of Anopheles mosquitoes. METHODS: Larvae of Anopheles gambiae sensu stricto and An. stephensi were reared at constant density but with nutritionally low and high diets. Fitness of adult mosquitoes resulting from each dietary class was assessed by measuring body size and lipid, protein and glycogen content. The size of the first blood meal was estimated by protein analysis. Mosquitoes of each dietary class were fed upon a Plasmodium yoelii nigeriensis-infected mouse, and parasite infections were determined 5 d after the infectious blood meal by dissection of the midguts and by counting oocysts. The impact of Plasmodium infections on gonotrophic development was established by dissection. RESULTS: Mosquitoes raised under low and high diets emerged as adults of different size classes comparable between An. gambiae and An. stephensi. In both species low-diet females contained less protein, lipid and glycogen upon emergence than high-diet mosquitoes. The quantity of larval diet impacted strongly upon adult blood feeding and reproductive success. The prevalence and intensity of P. yoelii nigeriensis infections were reduced in low-diet mosquitoes of both species, but P. yoelii nigeriensis impacted negatively only on low-diet, small-sized An. gambiae considering survival and egg maturation. There was no measurable fitness effect of P. yoelii nigeriensis on An. stephensi. CONCLUSIONS: Under the experimental conditions, small-sized An. gambiae expressed high mortality, possibly caused by Plasmodium infections, the species showing distinct physiological concessions when nutrionally challenged in contrast to well-fed, larger siblings. Conversely, An. stephensi was a robust, successful vector regardless of its nutrional status upon emergence. The data suggest that small-sized An. gambiae, therefore, would contribute little to malaria transmission, whereas this size effect would not affect An. stephensi.
Managing hytrosavirus infections in Glossina pallidipes colonies: Feeding regime affects the prevalence of the salivary gland hypertrophy syndrome
Kariithi, H.M. ; Abd-Alla, A.M.M. ; Mohamed, H.A. ; Lapiz, E. ; Parker, A.G. ; Vreysen, M.J.B. - \ 2013
PLoS ONE 8 (2013)5. - ISSN 1932-6203
tsetse flies glossina - lop-eared rabbits - dna virus - austeni newst - morsitans centralis - living host - diptera - membrane - absence
Many species of tsetse flies are infected by a virus that causes salivary gland hypertrophy (SGH) syndrome and the virus isolated from Glossina pallidipes (GpSGHV) has recently been sequenced. Flies with SGH have a reduced fecundity and fertility. Due to the deleterious impact of SGHV on G. pallidipes colonies, several approaches were investigated to develop a virus management strategy. Horizontal virus transmission is the major cause of the high prevalence of the GpSGHV in tsetse colonies. Implementation of a “clean feeding” regime (fresh blood offered to each set of flies so that there is only one feed per membrane), instead of the regular feeding regime (several successive feeds per membrane), was among the proposed approaches to reduce GpSGHV infections. However, due to the absence of disposable feeding equipment (feeding trays and silicone membranes), the implementation of a clean feeding approach remains economically difficult. We developed a new clean feeding approach applicable to large-scale tsetse production facilities using existing resources. The results indicate that implementing this approach is feasible and leads to a significant reduction in virus load from 109 virus copies in regular colonies to an average of 102.5 and eliminates the SGH syndrome from clean feeding colonies by28 months post implementation of this approach. The clean feeding approach also reduced the virus load from an average of 108 virus copy numbers to an average of 103 virus copies and SGH prevalence of 10% to 4% in flies fed after the clean fed colony. Taken together, these data indicate that the clean feeding approach is applicable in large-scale G. pallidipes production facilities and eliminates the deleterious effects of the virus and the SGH syndrome in these colonies.
Fine Scale Spatiotemporal Clustering of Dengue Virus Transmission in Children and Aedes aegypti in Rural Thai Villages
Yoon, I.K. ; Getis, A. ; Aldstadt, J. ; Rothman, A.L. ; Tannitisupawong, D. ; Koenraadt, C.J.M. ; Fansiri, T. ; Jones, J.W. ; Morrison, A.C. ; Jarman, R.G. ; Nisalak, A. ; Mammen Jr., M.P. ; Thammapalo, S. ; Srikiatkhachorn, A. ; Green, S. ; Libraty, D.H. ; Gibbons, R.V. ; Endy, T. ; Pimgate, C. ; Scott, T.W. - \ 2012
PLoS Neglected Tropical Diseases 6 (2012)7. - ISSN 1935-2727
polymerase-chain-reaction - primary-school children - kamphaeng phet - puerto-rico - vector - culicidae - diptera - blood - patterns - kinetics
Background Based on spatiotemporal clustering of human dengue virus (DENV) infections, transmission is thought to occur at fine spatiotemporal scales by horizontal transfer of virus between humans and mosquito vectors. To define the dimensions of local transmission and quantify the factors that support it, we examined relationships between infected humans and Aedes aegypti in Thai villages. Methodology/Principal Findings Geographic cluster investigations of 100-meter radius were conducted around DENV-positive and DENV-negative febrile “index” cases (positive and negative clusters, respectively) from a longitudinal cohort study in rural Thailand. Child contacts and Ae. aegypti from cluster houses were assessed for DENV infection. Spatiotemporal, demographic, and entomological parameters were evaluated. In positive clusters, the DENV infection rate among child contacts was 35.3% in index houses, 29.9% in houses within 20 meters, and decreased with distance from the index house to 6.2% in houses 80–100 meters away (p
Selection of mosquito life-histories: a hidden weapon against malaria?
Ferguson, H.M. ; Maire, N. ; Takken, W. ; Lyimo, I.N. ; Briet, O. ; Lindsay, S.W. ; Smith, T.A. - \ 2012
Malaria Journal 11 (2012). - ISSN 1475-2875
anopheles-gambiae giles - plasmodium-falciparum - resistance status - endemic area - evolution - populations - arabiensis - culicidae - vectors - diptera
Background There has recently been a substantial decline in malaria incidence in much of Africa. While the decline can clearly be linked to increasing coverage of mosquito vector control interventions and effective drug treatment in most settings, the ubiquity of reduction raises the possibility that additional ecological and associated evolutionary changes may be reinforcing the effectiveness of current vector control strategies in previously unanticipated ways. Presentation of hypothesis Here it is hypothesized that the increasing coverage of insecticide-treated bed nets and other vector control methods may be driving selection for a shift in mosquito life history that reduces their ability to transmit malaria parasites. Specifically it is hypothesized that by substantially increasing the extrinsic rate of mortality experienced in vector populations, these interventions are creating a fitness incentive for mosquitoes to re-allocate their resources towards greater short-term reproduction at the expense of longer-term survival. As malaria transmission is fundamentally dependent on mosquito survival, a life history shift in this direction would greatly benefit control. Testing the hypothesis At present, direct evaluation of this hypothesis within natural vector populations presents several logistical and methodological challenges. In the meantime, many insights can be gained from research previously conducted on wild Drosophila populations. Long-term selection experiments on these organisms suggest that increasing extrinsic mortality by a magnitude similar to that anticipated from the up-scaling of vector control measures generated an increase in their intrinsic mortality rate. Although this increase was small, a change of similar magnitude in Anopheles vector populations would be predicted to reduce malaria transmission by 80%. Implications of hypothesis The hypothesis presented here provides a reminder that evolutionary processes induced by interventions against disease vectors may not always act to neutralize intervention effectiveness. In the search for new intervention strategies, consideration should be given to both the potential disadvantages and advantages of evolutionary processes resulting from their implementation, and attempts made to exploit those with greatest potential to enhance control.
Risk of introducing African horse sickness virus into the Netherlands by international equine movements
Vos, C.J. de; Hoek, C.A. ; Nodelijk, G. - \ 2012
Preventive Veterinary Medicine 106 (2012)2. - ISSN 0167-5877 - p. 108 - 122.
zebra equus-burchelli - bluetongue virus - culicoides-sonorensis - oral-susceptibility - vaccine strains - europe - ceratopogonidae - horsesickness - transmission - diptera
African horse sickness (AHS) is a vector-borne viral disease of equines that is transmitted by Culicoides spp. and can have severe consequences for the horse industry in affected territories. A study was performed to assess the risk of introducing AHS virus (AHSV) into the Netherlands (P_AHS) by international equine movements. The goal of this study was to provide more insight into (a) the regions and equine species that contribute most to this risk, (b) the seasonal variation in this risk, and (c) the effectiveness of measures to prevent introduction of AHSV. Countries worldwide were grouped into three risk regions: (1) high risk, i.e., those countries in which the virus is presumed to circulate, (2) low risk, i.e., those countries that have experienced outbreaks of AHS in the past and/or where the main vector of AHS, Culicoides imicola, is present, and (3) very low risk, i.e., all other countries. A risk model was constructed estimating P_AHS taking into account the probability of release of AHSV in the Netherlands and the probability that local vectors will subsequently transmit the virus to local hosts. Model calculations indicated that P_AHS is very low with a median value of 5.1 × 10-4/year. The risk is highest in July and August, while equine movements in the period October till March pose a negligible risk. High and low risk regions contribute most to P_AHS with 31% and 53%, respectively. Importations of donkeys and zebras constitute the highest risk of AHSV release from high risk regions, while international movements of competition horses constitute the highest risk of AHSV release from low and very low risk regions. Preventive measures currently applied reduce P_AHS by 46% if compared to a situation in which no preventive measures are applied. A prolonged and more effective quarantine period in high risk regions and more stringent import regulations for low risk regions could further reduce P_AHS. Large uncertainty was involved in estimating model input parameters. Sensitivity analysis indicated that uncertainty about the probability of non-notified presence of AHS in low and very low risk regions, the protective effect of quarantine and the vector–host ratio had most impact on the estimated risk. Furthermore, temperature values at the time of release of AHSV largely influenced the probability of onward spread of the virus by local vectors to local hosts.
Vlieg blijft liever weg uit schone varkensstal
Mul, M.F. ; Schelt, J. van - \ 2012
V-focus 9 (2012)3. - ISSN 1574-1575 - p. 34 - 37.
varkenshouderij - biologische landbouw - varkensstallen - insectenplagen - diptera - bedrijfshygiëne - biologische bestrijding - dierenwelzijn - pig farming - organic farming - pig housing - insect pests - diptera - industrial hygiene - biological control - animal welfare
Een combinatie van goede hygiënemaatregelen en biologische bestrijding lijkt effect te hebben op het aantal vliegen in de stallen van biologische varkenshouders. Lijkt, want de effectiviteit van de maatregelen verschilt sterk per bedrijf. Dat blijkt uit onderzoek van Wageningen UR Livestock Research bij een aantal biologische varkenshouders.
DNA Barcoding of Recently Diverged Species: Relative Performance of Matching Methods
Velzen, R. van; Weitschek, E. ; Felici, G. ; Bakker, F.T. - \ 2012
PLoS ONE 7 (2012)1. - ISSN 1932-6203 - 12 p.
mitochondrial-dna - phylogenetic trees - molecular markers - sequence data - identification - diptera - fish - diversity - selection - taxonomy
Recently diverged species are challenging for identification, yet they are frequently of special interest scientifically as well as from a regulatory perspective. DNA barcoding has proven instrumental in species identification, especially in insects and vertebrates, but for the identification of recently diverged species it has been reported to be problematic in some cases. Problems are mostly due to incomplete lineage sorting or simply lack of a ‘barcode gap’ and probably related to large effective population size and/or low mutation rate. Our objective was to compare six methods in their ability to correctly identify recently diverged species with DNA barcodes: neighbor joining and parsimony (both tree-based), nearest neighbor and BLAST (similarity-based), and the diagnostic methods DNA-BAR, and BLOG. We analyzed simulated data assuming three different effective population sizes as well as three selected empirical data sets from published studies. Results show, as expected, that success rates are significantly lower for recently diverged species (~75%) than for older species (~97%) (P
Survival of anopheline eggs and their susceptibility to infection with Metarhizium anisopliae and Beauveria bassiana under laboratory conditions
Luz, C. ; Mnyone, L.L. ; Russell, T.L. - \ 2011
Parasitology Research 109 (2011)3. - ISSN 0932-0113 - p. 751 - 758.
aedes-aegypti - entomopathogenic fungi - ovicidal activity - western kenya - gambiae-s.s. - malaria mosquito - central brazil - arabiensis - culicidae - diptera
The viability of Anopheles gambiae sensu stricto and Anopheles arabiensis (Diptera: Culicidae) eggs over time and the ovicidal activity of Beauveria bassiana (Ascomycota: Cordycipitaceae) and Metarhizium anisopliae (Ascomycota: Clavicipitaceae) were investigated. Eggs were incubated in soil or leaf litter for up to 12 weeks at 26°C and 75%, 86% or >98% relative humidity (RH). Eggs were treated topically with M. anisopliae ICIPE-30 or B. bassiana I93-825 conidia in either water or oil-in-water formulations. Survival of eggs whether treated or not with fungus was similar, and untreated eggs generally did not survive longer than 2 weeks regardless of the substrate or humidity tested. After a minimal 5-day exposure, M. anisopliae at 5¿×¿106 conidia/cm2 clearly reduced the number of larvae. The efficacy of the fungus increased when it was oil-in-water formulated, and eclosion was completely prevented regardless of the conidial concentration (105–107 conidia/cm2) after a 10-day exposure in soils at >98% RH. Treatment of eggs with B. bassiana, however, failed to reduce the number of eclosing larvae. This is the first demonstration of the ovicidal activity by M. anisopliae against either A. gambiae s. s. or A. arabiensis and the results underline the potential of this fungus against anopheline mosquitoes.
Interessante waarnemingen van boor- en prachtvliegen in Nederland
Smit, J.T. ; Belgers, J.D.M. - \ 2011
Nederlandse Faunistische Mededelingen 36 (2011). - ISSN 0169-2453 - p. 29 - 48.
diptera - zoögeografie - inventarisaties - diptera - zoogeography - inventories
Van de verspreiding van boor- en prachtvliegen in Nederland is nog maar weinig bekend. In dit artikel worden waarnemingen van 17 soorten boorvliegen en drie soorten prachtvliegen behandeld. Het gaat hierbij of om zeldzame het gaat hierbij of om zeldzame soorten of om waarnemingen die een aanzienlijke uitbreiding van het areaal betreffen. Daarnaast wordt een nieuw overzicht gegeven van alle soorten prachtvliegen in Nederland met een verwijzing naar determinatieliteratuur.
Genetic parameters of insect bite hypersensitivity in Dutch Friesian broodmares
Schurink, A. ; Ducro, B.J. ; Heuven, H.C.M. ; Arendonk, J.A.M. van - \ 2011
Journal of Animal Science 89 (2011)5. - ISSN 0021-8812 - p. 1286 - 1293.
icelandic horses - british-columbia - summer eczema - sweet itch - culicoides hypersensitivity - netherlands - ceratopogonidae - identification - population - diptera
Insect bite hypersensitivity (IBH) is a seasonal allergic skin disease in horses caused by bites of certain Culicoides spp. The aim of our study was to investigate the maternal effect on IBH and to estimate the heritability and repeatability of IBH in the Dutch Friesian horse population. Data consisted of 3,453 Dutch Friesian broodmares with 3,763 visual observations on IBH clinical symptoms scored by 12 inspectors during organized foal inspections in 2004 and 2008. Nine percent of the mares (n = 310) were scored in both years. Mares descended from 144 sires and 2,554 dams and 26.2% of the dams (n = 669) had more than 1 offspring in the data set (range: 2 to 6). Insect bite hypersensitivity was analyzed as a binary trait with a threshold animal model with and without a maternal effect, using a Bayesian approach. Observed IBH prevalence in Dutch Friesian broodmare population was 18.2%. Heritability on the liability scale was 0.16 (SD = 0.06); heritability on the observed scale was 0.07; and repeatability was 0.89 (SD = 0.03). Maternal effect was 0.17 (SD = 0.06) and significantly differed from zero, although the animal model without a maternal effect fitted the data better. These results show that genetic and permanent environmental factors affect IBH in Dutch Friesian horses. The dam affected the IBH development of her offspring through an additive genetic influence but also by being part of their rearing environment
Linking individual phenotype to density-dependent population growth: the influence of body size on the population dynamics of malaria vectors
Russell, T.L. ; Lwetoijera, D.W. ; Knols, B.G.J. ; Takken, W. ; Killeen, G.F. ; Ferguson, H.M. - \ 2011
Proceedings of the Royal Society. B: Biological Sciences 278 (2011)1721. - ISSN 0962-8452 - p. 3142 - 3151.
plasmodium-falciparum malaria - anopheles-gambiae - multimodel inference - culicidae - diptera - transmission - arabiensis - mosquitos - fecundity - abundance
Understanding the endogenous factors that drive the population dynamics of malaria mosquitoes will facilitate more accurate predictions about vector control effectiveness and our ability to destabilize the growth of either low- or high-density insect populations. We assessed whether variation in phenotypic traits predict the dynamics of Anopheles gambiae sensu lato mosquitoes, the most important vectors of human malaria. Anopheles gambiae dynamics were monitored over a six-month period of seasonal growth and decline. The population exhibited density-dependent feedback, with the carrying capacity being modified by rainfall (97% wAICc support). The individual phenotypic expression of the maternal (p = 0.0001) and current (p = 0.040) body size positively influenced population growth. Our field-based evidence uniquely demonstrates that individual fitness can have population-level impacts and, furthermore, can mitigate the impact of exogenous drivers (e.g. rainfall) in species whose reproduction depends upon it. Once frontline interventions have suppressed mosquito densities, attempts to eliminate malaria with supplementary vector control tools may be attenuated by increased population growth and individual fitness
Carbon dioxide baited trap catches do not correlate with human landing collections of Anopheles aquasalis in Suriname
Hiwat-van Laar, H. ; Andriessen, R. ; Rijk, M. de; Koenraadt, C.J.M. ; Takken, W. - \ 2011
Memorias Do Instituto Oswaldo Cruz 106 (2011)3. - ISSN 0074-0276 - p. 360 - 364.
light traps - malaria vectors - mosquitos - culicidae - diptera - tanzania - 1-octen-3-ol - gambiae - attractiveness - surveillance
Three types of carbon dioxide-baited traps, i.e., the Centers for Disease Control Miniature Light Trap without light, the BioGents (BG) Sentinel Mosquito Trap (BG-Sentinel) and the Mosquito Magnet® Liberty Plus were compared with human landing collections in their efficiency in collecting Anopheles (Nyssorhynchus) aquasalis mosquitoes. Of 13,549 total mosquitoes collected, 1,019 (7.52%) were An. aquasalis. Large numbers of Culex spp were also collected, in particular with the (BG-Sentinel). The majority of An. aquasalis (83.8%) were collected by the human landing collection (HLC). None of the trap catches correlated with HLC in the number of An. aquasalis captured over time. The high efficiency of the HLC method indicates that this malaria vector was anthropophilic at this site, especially as carbon dioxide was insufficiently attractive as stand-alone bait. Traps using carbon dioxide in combination with human odorants may provide better results.
Field Testing of Different Chemical Combinations as Odour Baits for Trapping Wild Mosquitoes in The Gambia
Jawara, M. ; Awolola, T.S. ; Pinder, M. ; Jeffries, D. ; Smallegange, R.C. ; Takken, W. ; Conway, D.J. - \ 2011
PLoS ONE 6 (2011)5. - ISSN 1932-6203 - 7 p.
vector anopheles-gambiae - malaria mosquito - carbon-dioxide - sensu-stricto - culicidae - diptera - responses - behavior - yeast
Odour baited traps have potential use in population surveillance of insect vectors of disease, and in some cases for vector population reduction. Established attractants for human host-seeking mosquitoes include a combination of CO2 with L-lactic acid and ammonia, on top of which additional candidate compounds are being tested. In this field study in rural Gambia, using Latin square experiments with thorough randomization and replication, we tested nine different leading candidate combinations of chemical odorants for attractiveness to wild mosquitoes including anthropophilic malaria vectors, using modified Mosquito Magnet-X (MM-X) counterflow traps outside experimental huts containing male human sleepers. Highest catches of female mosquitoes, particularly of An. gambiae s.l. and Mansonia species, were obtained by incorporation of tetradecanoic acid. As additional carboxylic acids did not increase the trap catches further, this ‘reference blend’ (tetradecanoic acid with L-lactic acid, ammonia and CO2) was used in subsequent experiments. MM-X traps with this blend caught similar numbers of An. gambiae s.l. and slightly more Mansonia and Culex mosquitoes than a standard CDC light trap, and these numbers were not significantly affected by the presence or absence of human sleepers in the huts. Experiments with CO2 produced from overnight yeast cultures showed that this organic source was effective in enabling trap attractiveness for all mosquito species, although at a slightly lower efficiency than obtained with use of CO2 gas cylinders. Although further studies are needed to discover additional chemicals that increase attractiveness, as well as to optimise trap design and CO2 source for broader practical use, the odour-baited traps described here are safe and effective for sampling host-seeking mosquitoes outdoors and can be incorporated into studies of malaria vector ecology.