To assess the phytochemical properties of Chromoleana odorata in the control of blackflies to help check the problem of environmental pollution from the use of chemical insecticides. Methods Dried pulverized leaves of...To assess the phytochemical properties of Chromoleana odorata in the control of blackflies to help check the problem of environmental pollution from the use of chemical insecticides. Methods Dried pulverized leaves of Chromolaena odorata （100 g） were soaked in distilled water for 24 hours and the extract was filtered, marc pressed and evaporated over water bath. Stock solution of the dried mass （1 g） was concentrated by dissolving in 100 mL of water. Serial dilutions （100 mg/mL, 10 mg/mL, 1 mg/mL, 0.1 mg/mL, 0.01 mg/L, and 0.001 mg/mL） of both the extract and Chlopyrifos （organo phosphorus） were prepared and toxicity was tested on the larvae of Simulium species. Results The chemical compound recorded 100% larval mortality at all concentrations while the plant extract recorded 100% larval mortality in three （100, 10, and 1 mg/mL） of its diluent concentration. The percentage of larval mortality by chemical compound and plant extract was statistically insignificant （t = 0.2456, P〉0.05）, but the mortality rate was significant within 30 rain interval of exposure time （t= 3.756, P〈0.05）. The LCs0 of the plant extract was determined at about 0.001 mg/mL concentration. This showed that the plant extract had an appreciable larvicidal property close to that of the chemical compound. Conclusion This result indicates the usefulness of plant materials in the control of obnoxious insect vectors of mn. It also opens additional approach to the management of environment from toxic chemicals that are non-biodegradable and cause environmental imbalance in the ecosystem.展开更多
To determine the factor influencing the abundance development and distribution of Simulium damnosum(S.I) immature stages in the lower Cross River Basin, Nigeria, the physico-chemical characteristics of water at breedi...To determine the factor influencing the abundance development and distribution of Simulium damnosum(S.I) immature stages in the lower Cross River Basin, Nigeria, the physico-chemical characteristics of water at breeding sites were analysed longitudinally over a 12 month period. Analysis of the water samples showed that water current correlated positively and significantly(p<0.05), with dissolved oxygen(r = 0.95 vs 0.10); conductivity(r = 0.95 vs 0.81); hydrogen ion concentration(r = 0.03 vs 0.46); and biochemical oxygen demand(r = 0.80 vs 0.64); from Agbokim Waterfalls and Afi River respectively. The result indicates that these parameters and low ionic concentration are the most essential requirement for the development of S. damnosum pre-imaginal stages. Amplitudes of annual variability as measured by co-efficient of variation varied between the parameters. From the trends in hydrological variables it was deduced that the integrated impact of precipitation, input of surface runoff and municipal effluents played an overriding role in determining the absolute levels and temporal pattern in the water quality attributes. Of the 3578 pre-imaginal stages of S. damnosum collected, 52.52% and 47.4% were collected from Agbokim Waterfall and Afi River respectively. There was a significant difference(p<0.05) in the number of pre-imaginal stages collected from both sites. The highest number of pre_imaginal stages of S. damnosum collected were at the peak of rain(July—September) indicating that S. damnosum in the River Basin is a wet season breeder. The need for long term laboratory colonization of blackfly immature stages becomes imperative especially how these parameters could be exploited in control programme through the testing of larvicides without adverse ecological damage to the aquatic habitat.展开更多
High quality polytene chromosome maps (n=3) of a Himalayan Simuliid Simulium praelargum Datta, 1973 are presentedand represent the first cytological description of a taxon found in the feuerborni group, subgenus Never...High quality polytene chromosome maps (n=3) of a Himalayan Simuliid Simulium praelargum Datta, 1973 are presentedand represent the first cytological description of a taxon found in the feuerborni group, subgenus Nevermannia. Polytenechromosomes one (Ⅰ) and two (Ⅱ) are metacentric, chromosome three (Ⅲ) is submetacentric with the length of each chromosomeoccupying 37.25 %, 31.36 % and 31.34 % of the total complement length, respectively. Typical simuliid diagnostic intergenericchromosomal markers are found within the polytene complement of this species. The nucleolar organizer (N.O.) is found at thebase of the short arm of chromosome one (IS), the Ring of Balbiani (R.B.), double bubble (D.B.) and triad occur in the short armof chromosome two (IIS), the Parabalbiani Ring (P.B.) and grey band (gb) occur in the long arm of chromosome two (IIL) and theBlister (BL) and Capsule (Ca) occur in the short arm of chromosome three (HIS).Terminal bands at the end of HIS are heterochromatinizedand present atypically with respect to other simuliid fauna. Populations studied so far are unique among the Simuliidaein that they exhibit chromosome structural monomorphism. These high resolution polytene chromosome maps will form thebasis for future cytological characterization and phylogenetic comparisons amongst members of the feuerborni group.展开更多
The effect of tourism on the distribution of larval blackflies during three different seasons of Palni hills was investigated.Six streams were selected(Kumbakkarai,Moolayar,Kurusedi,Silver cascade Pampar and Guntar) f...The effect of tourism on the distribution of larval blackflies during three different seasons of Palni hills was investigated.Six streams were selected(Kumbakkarai,Moolayar,Kurusedi,Silver cascade Pampar and Guntar) for this study,of which,three streams(Silver cascade Pampar and Guntar) were in peak of Palni hills(Kodaikanal town areas) and easy access to the tourists.The remaining three streams(Kumbakkarai,Moolayar and Kurusedi) were in downhill areas.The physico-chemical and stream parameters analyses indicated that the most tourist accessible site of Silver cas-cade stream had poor water quality and the predominant of larval blackfly population when compared to other sampling streams.The highest population of larval blackflies was observed during winter followed by summer and northeast monsoon.Since the effect of tourism causes pollution to streams,which in turn to promote the population of blackfly larvae and affect the other insect community in streams.展开更多
The standard methods for regression analyses of clustered riverine larval habitat data of Simulium damnosum s.l.a major black-fly vector of onchoceriasis,postulate models relating observational ecological-sampled para...The standard methods for regression analyses of clustered riverine larval habitat data of Simulium damnosum s.l.a major black-fly vector of onchoceriasis,postulate models relating observational ecological-sampled parameter estimators to prolific habitats without accounting for residual intra-cluster error correlation effects.Generally,this correlation comes from two sources:(1)the design of the random effects and their assumed covariance from the multiple levels within the regression model and(2)the correlation structure of the residuals.Unfortunately,inconspicuous errors in residual intracluster correlation estimates can overstate precision in forecasted S.damnosum s.l.riverine larval habitat explanatory attributes regardless how they are treated(e.g.independent,autoregressive,Toeplitz,etc.).In this research,the geographical locations for multiple riverine-based S.damnosum s.l.larval ecosystem habitats sampled from two preestablished epidemiological sites in Togo were identified and recorded from July 2009 to June 2010.Initially,the data were aggregated into PROC GENMOD.An agglomerative hierarchical residual cluster-based analysis was then performed.The sampled clustered study site data was then analyzed for statistical correlations using monthly biting rates(MBR).Euclidean distance measurements and terrain-related geomorphological statistics were then generated in ArcGIS.A digital overlay was then performed also in ArcGIS using the georeferenced ground coordinates of high and low density clusters stratified by annual biting rates(ABR).The data was overlain onto multitemporal sub-meter pixel resolution satellite data(i.e.QuickBird 0.61m wavbands).Orthogonal spatial filter eigenvectors were then generated in SAS/Geographic Information Systems(GIS).Univariate and nonlinear regression-based models(i.e.logistic,Poisson,and negative binomial)were also employed to determine probability distributions and to identify statistically significant parameter estimators from the sampled data.Thereafter,Durbin–Watson statistics were used to test the null hypothesis that the regression residuals were not autocorrelated against the alternative that the residuals followed an autoregressive process in AUTOREG.Bayesian uncertainty matrices were also constructed employing normal priors for each of the sampled estimators in PROC MCMC.The residuals revealed both spatially structured and unstructured error effects in the high and low ABR-stratified clusters.The analyses also revealed that the estimators,levels of turbidity,and presence of rocks were statistically significant for the high-ABR-stratified clusters,while the estimators distance between habitats and floating vegetation were important for the low-ABR-stratified cluster.Varying and constant coefficient regression models,ABRstratified GIS-generated clusters,sub-meter resolution satellite imagery,a robust residual intra-cluster diagnostic test,MBR-based histograms,eigendecomposition spatial filter algorithms,and Bayesian matrices can enable accurate autoregressive estimation of latent uncertainity affects and other residual error probabilities(i.e.heteroskedasticity)for testing correlations between georeferenced S.damnosum s.l.riverine larval habitat estimators.The asymptotic distribution of the resulting residual adjusted intra-cluster predictor error autocovariate coefficients can thereafter be established while estimates of the asymptotic variance can lead to the construction of approximate confidence intervals for accurately targeting productive S.damnosum s.l.habitats based on spatiotemporal field-sampled count data.展开更多
文摘To assess the phytochemical properties of Chromoleana odorata in the control of blackflies to help check the problem of environmental pollution from the use of chemical insecticides. Methods Dried pulverized leaves of Chromolaena odorata （100 g） were soaked in distilled water for 24 hours and the extract was filtered, marc pressed and evaporated over water bath. Stock solution of the dried mass （1 g） was concentrated by dissolving in 100 mL of water. Serial dilutions （100 mg/mL, 10 mg/mL, 1 mg/mL, 0.1 mg/mL, 0.01 mg/L, and 0.001 mg/mL） of both the extract and Chlopyrifos （organo phosphorus） were prepared and toxicity was tested on the larvae of Simulium species. Results The chemical compound recorded 100% larval mortality at all concentrations while the plant extract recorded 100% larval mortality in three （100, 10, and 1 mg/mL） of its diluent concentration. The percentage of larval mortality by chemical compound and plant extract was statistically insignificant （t = 0.2456, P〉0.05）, but the mortality rate was significant within 30 rain interval of exposure time （t= 3.756, P〈0.05）. The LCs0 of the plant extract was determined at about 0.001 mg/mL concentration. This showed that the plant extract had an appreciable larvicidal property close to that of the chemical compound. Conclusion This result indicates the usefulness of plant materials in the control of obnoxious insect vectors of mn. It also opens additional approach to the management of environment from toxic chemicals that are non-biodegradable and cause environmental imbalance in the ecosystem.
文摘To determine the factor influencing the abundance development and distribution of Simulium damnosum(S.I) immature stages in the lower Cross River Basin, Nigeria, the physico-chemical characteristics of water at breeding sites were analysed longitudinally over a 12 month period. Analysis of the water samples showed that water current correlated positively and significantly(p<0.05), with dissolved oxygen(r = 0.95 vs 0.10); conductivity(r = 0.95 vs 0.81); hydrogen ion concentration(r = 0.03 vs 0.46); and biochemical oxygen demand(r = 0.80 vs 0.64); from Agbokim Waterfalls and Afi River respectively. The result indicates that these parameters and low ionic concentration are the most essential requirement for the development of S. damnosum pre-imaginal stages. Amplitudes of annual variability as measured by co-efficient of variation varied between the parameters. From the trends in hydrological variables it was deduced that the integrated impact of precipitation, input of surface runoff and municipal effluents played an overriding role in determining the absolute levels and temporal pattern in the water quality attributes. Of the 3578 pre-imaginal stages of S. damnosum collected, 52.52% and 47.4% were collected from Agbokim Waterfall and Afi River respectively. There was a significant difference(p<0.05) in the number of pre-imaginal stages collected from both sites. The highest number of pre_imaginal stages of S. damnosum collected were at the peak of rain(July—September) indicating that S. damnosum in the River Basin is a wet season breeder. The need for long term laboratory colonization of blackfly immature stages becomes imperative especially how these parameters could be exploited in control programme through the testing of larvicides without adverse ecological damage to the aquatic habitat.
基金supported by the National Natural Science Foundation of China(31900341)the Hebei Natural Science Foundation for Excellent Young Scholars(C2019204149)+2 种基金the Hebei Youth Talent Support Program(BJ2019039)the Hebei Importing Overseas Students Support Program(C20190341)the Starting Scientific Research Foundation for the Introduced Talents of Hebei Agricultural University(YJ201817)。
文摘High quality polytene chromosome maps (n=3) of a Himalayan Simuliid Simulium praelargum Datta, 1973 are presentedand represent the first cytological description of a taxon found in the feuerborni group, subgenus Nevermannia. Polytenechromosomes one (Ⅰ) and two (Ⅱ) are metacentric, chromosome three (Ⅲ) is submetacentric with the length of each chromosomeoccupying 37.25 %, 31.36 % and 31.34 % of the total complement length, respectively. Typical simuliid diagnostic intergenericchromosomal markers are found within the polytene complement of this species. The nucleolar organizer (N.O.) is found at thebase of the short arm of chromosome one (IS), the Ring of Balbiani (R.B.), double bubble (D.B.) and triad occur in the short armof chromosome two (IIS), the Parabalbiani Ring (P.B.) and grey band (gb) occur in the long arm of chromosome two (IIL) and theBlister (BL) and Capsule (Ca) occur in the short arm of chromosome three (HIS).Terminal bands at the end of HIS are heterochromatinizedand present atypically with respect to other simuliid fauna. Populations studied so far are unique among the Simuliidaein that they exhibit chromosome structural monomorphism. These high resolution polytene chromosome maps will form thebasis for future cytological characterization and phylogenetic comparisons amongst members of the feuerborni group.
基金support from Dr.D.S.Kothari Post Doctoral Fellowship Ref.No.F.4-2/2006(BSR)/13-141/2008(BSR)
文摘The effect of tourism on the distribution of larval blackflies during three different seasons of Palni hills was investigated.Six streams were selected(Kumbakkarai,Moolayar,Kurusedi,Silver cascade Pampar and Guntar) for this study,of which,three streams(Silver cascade Pampar and Guntar) were in peak of Palni hills(Kodaikanal town areas) and easy access to the tourists.The remaining three streams(Kumbakkarai,Moolayar and Kurusedi) were in downhill areas.The physico-chemical and stream parameters analyses indicated that the most tourist accessible site of Silver cas-cade stream had poor water quality and the predominant of larval blackfly population when compared to other sampling streams.The highest population of larval blackflies was observed during winter followed by summer and northeast monsoon.Since the effect of tourism causes pollution to streams,which in turn to promote the population of blackfly larvae and affect the other insect community in streams.
基金This work was produced by the US National Institute of Health/Fogarty International Center under SR01TW008508.
文摘The standard methods for regression analyses of clustered riverine larval habitat data of Simulium damnosum s.l.a major black-fly vector of onchoceriasis,postulate models relating observational ecological-sampled parameter estimators to prolific habitats without accounting for residual intra-cluster error correlation effects.Generally,this correlation comes from two sources:(1)the design of the random effects and their assumed covariance from the multiple levels within the regression model and(2)the correlation structure of the residuals.Unfortunately,inconspicuous errors in residual intracluster correlation estimates can overstate precision in forecasted S.damnosum s.l.riverine larval habitat explanatory attributes regardless how they are treated(e.g.independent,autoregressive,Toeplitz,etc.).In this research,the geographical locations for multiple riverine-based S.damnosum s.l.larval ecosystem habitats sampled from two preestablished epidemiological sites in Togo were identified and recorded from July 2009 to June 2010.Initially,the data were aggregated into PROC GENMOD.An agglomerative hierarchical residual cluster-based analysis was then performed.The sampled clustered study site data was then analyzed for statistical correlations using monthly biting rates(MBR).Euclidean distance measurements and terrain-related geomorphological statistics were then generated in ArcGIS.A digital overlay was then performed also in ArcGIS using the georeferenced ground coordinates of high and low density clusters stratified by annual biting rates(ABR).The data was overlain onto multitemporal sub-meter pixel resolution satellite data(i.e.QuickBird 0.61m wavbands).Orthogonal spatial filter eigenvectors were then generated in SAS/Geographic Information Systems(GIS).Univariate and nonlinear regression-based models(i.e.logistic,Poisson,and negative binomial)were also employed to determine probability distributions and to identify statistically significant parameter estimators from the sampled data.Thereafter,Durbin–Watson statistics were used to test the null hypothesis that the regression residuals were not autocorrelated against the alternative that the residuals followed an autoregressive process in AUTOREG.Bayesian uncertainty matrices were also constructed employing normal priors for each of the sampled estimators in PROC MCMC.The residuals revealed both spatially structured and unstructured error effects in the high and low ABR-stratified clusters.The analyses also revealed that the estimators,levels of turbidity,and presence of rocks were statistically significant for the high-ABR-stratified clusters,while the estimators distance between habitats and floating vegetation were important for the low-ABR-stratified cluster.Varying and constant coefficient regression models,ABRstratified GIS-generated clusters,sub-meter resolution satellite imagery,a robust residual intra-cluster diagnostic test,MBR-based histograms,eigendecomposition spatial filter algorithms,and Bayesian matrices can enable accurate autoregressive estimation of latent uncertainity affects and other residual error probabilities(i.e.heteroskedasticity)for testing correlations between georeferenced S.damnosum s.l.riverine larval habitat estimators.The asymptotic distribution of the resulting residual adjusted intra-cluster predictor error autocovariate coefficients can thereafter be established while estimates of the asymptotic variance can lead to the construction of approximate confidence intervals for accurately targeting productive S.damnosum s.l.habitats based on spatiotemporal field-sampled count data.
