Showing papers by "Gautam Aditya published in 2015"

Household Wastes as Larval Habitats of Dengue Vectors: Comparison between Urban and Rural Areas of Kolkata, India

Abstract: Porcelain and plastic materials constitute bulk of household wastes. Owing to resistibility and slow degradability that accounts for higher residence time, these materials qualify as potential hazardous wastes. Retention of water permits these wastes to form a congenial biotope for the breeding of different vector mosquitoes. Thus porcelain and plastic wastes pose a risk from public health viewpoint. This proposition was validated through the study on the porcelain and plastic household wastes as larval habitats of Dengue vectors (Aedes spp.) in rural and urban areas around Kolkata, India. The wastes were characterized in terms of larval productivity, seasonal variation and a comparison between urban and rural areas was made using data of two subsequent years. The number of wastes positive as larval habitats and their productivity of Aedes spp. varied among the types of household wastes with reference to months and location. Multivariate analysis revealed significant differences in the larval productivity of the household wastes based on the materials, season, and urban-rural context. Results of Discriminant Analysis indicated differences in abundance of Ae. aegypti and Ae. albopictus for the urban and rural areas. The porcelain and plastic wastes were more productive in urban areas compared to the rural areas, indicating a possible difference in the household waste generation. A link between household wastes with Aedes productivity is expected to increase the risk of dengue epidemics if waste generation is continued without appropriate measures to limit addition to the environment. Perhaps, alternative strategies and replacement of materials with low persistence time can reduce this problem of waste and mosquito production.

Biosorption of Cadmium by Waste Shell Dust of Fresh Water Mussel Lamellidens marginalis: Implications for Metal Bioremediation

Abstract: The ability of the shell dust of freshwater mussel Lamellidens marginalis (MSD) to remove cadmium from the aquatic system was evaluated. The results indicate that MSD, a waste biomaterial, bears th...

Biosorption of cadmium from aqueous solution by shell dust of the freshwater snail Lymnaea luteola

Abstract: An assessment of the metal biosorption potential of shell dust of the freshwater snail ( Lymnaea luteola ) was made using cadmium as model metal. Artificial Neural Network (ANN) model was constructed for portraying the biosorption process under varied conditions. Under optimal conditions, the shell dust of L. luteola (LSD) exhibited a biosorption capacity of 20.00 mg g −1 at pH 6. The adsorption data at equilibrium fitted significantly more to Langmuir ( R 2 = 0.997 ) than Freundlich equation ( R 2 = 0.790 ). The kinetics for the biosorption process followed the pseudo-second order model ( R 2 = 0.998 ) better than the Lagergren model ( R 2 = 0.835 ). Confirmation of cadmium adsorption by LSD was further revealed through EDX studies, and the experimental results fitted well with the predicted pattern of biosorption based on ANN model ( R 2 = 0.924 ). It appears that shell dust of the snail L. luteola (LSD), a waste biomaterial, can be used as a low cost and environment friendly biosorbent for cadmium removal from aqueous solution.

Pupal productivity & nutrient reserves of Aedes mosquitoes breeding in sewage drains & other habitats of Kolkata, India: Implications for habitat expansion & vector management

Abstract: Background & objectives: The quality of breeding sites is reflected through the pupal productivity and the life history traits of Aedes mosquitoes. Using nutrient reserves and pupal productivity of Aedes as indicators, the larval habitats including sewage drains were characterized to highlight the habitat expansion and vector management. Methods: The pupae and adults collected from the containers and sewage drains were characterized in terms of biomass and nutrient reserves and the data were subjected to three way factorial ANOVA. Discriminant function analyses were performed to highlight the differences among the habitats for sustenance of Aedes mosquitoes. Results: Survey of larval habitats from the study area revealed significant differences (P Interpretation & conclusions: The present results showed that for both Ae. aegypti and Ae. albopictus, sewage drains were equally congenial habitat as were plastic, porcelain and earthen habitats. Availability of Aedes immature in sewage drains poses increased risk of dengue, and thus vector control programme should consider inclusion of sewage drains as breeding habitat of dengue vector mosquitoes.

Lantana Camara and Butterfly Abundance in an Urban Landscape: Benefits for Conservation or Species Invasion?

Abstract: Abstract Urban landscapes host a range of diverse plants that, in turn, facilitate maintenance of different species of pollinators, including butterflies. In this context, the importance of Lantana camara, an invasive plant species, was assessed highlighting its role in maintenance of butterfly diversity, using Kolkata, India as a study area. Initial study revealed consistent presence of L. camara in both urban and rural sites with at least 25 different butterfly species association. The proportional relative load and the preferences of butterfly species for the each plant species were inclined towards L. camara. Irrespective of the sites, the diurnal and seasonal variations in the butterfly species abundance varied with the flowering pattern of L. camara. A positive correlation of different butterfly species with the flowering time and number of L. camara was for all the sites. The segregation of the L. camara associated butterfly species was made following discriminant function analysis using the extent of flower density of L. camara as explanatory variable. Despite being an invasive species, it is apparent that L. camara can be a prospective host plant that facilitates sustenance of butterflies in both urban and rural sites. Thus, existence of L. camara in urban gardens and forests may prove beneficial in sustenance of the butterflies.

Intraguild Predation in Heteroptera: Effects of Density and Predator Identity on Dipteran Prey

Abstract: In tropical freshwaters, different species of water bugs (Heteroptera) constitute a guild sharing similar prey resources including chironomid and mosquito larvae. Assuming possibilities of intraguild predation (IGP) among the constituent members, an attempt was made to evaluate the effects of prey and predator density on the mortality of mosquito and chironomid larvae (shared prey), using Laccotrephes griseus Guerin-Meneville (Hemiptera: Nepidae) and Ranatra filiformis Fabricius (Hemiptera: Nepidae) as IG predators and Anisops bouvieri Kirkaldy (Hemiptera: Notonectidae) as IG prey. The predation on mosquito and chironomid larvae varied with the density and combinations of the predators. When present as conspecific IG predators, L. griseus exhibited greater effect on the prey mortality than R. filiformis. The effects on shared prey suggest that the two predators are not substitutable in terms of the effect on the shared prey mortality. The mortality of A. bouvieri (IG prey) at low shared prey density was significantly different (p < 0.05) from high shared prey density. In view of predatory effect of the heteropteran predators on the dipteran larvae, the results suggest possible interference by the presence of A. bouvieri as an intermediate predator. It seems that the presence of heteropteran predators including A. bouvieri as IG prey may benefit the dipteran prey under situations when the density is low in tropical waters. The intensity of the predatory effect may differ based on the species composition at IG predator level. For mosquito biological control, the interactions between the predators may not be substitutable and are independent in their effects.

Biosorption of Cadmium from Aqueous Solution by Shell Dust of the Fresh Water Snail Melanoides tuberculata

Abstract: The metal bioadsorption potential of shell dust of the freshwater snail Melanoides tuberculata (MTSD) was evaluated under laboratory conditions using cadmium as a model metal. As bioadsorbent, MTSD exhibited a biosorption capacity of 27.03 mg g−1 at pH 6, indicating potential to remove cadmium from aqueous solution. The adsorption data fit more to the Langmuir (R2 = 0.998) equation than the Freundlich (R2 = 0.761) equation at equilibrium condition. The kinetics of biosorption followed the pseudo-second-order model (R2 = 0.999) better than the Lagergren model (R2 = 0.676), as was evident from the regression analysis. The presence of calcium ions appears to have facilitated ion exchange with cadmium along with the binding of different functional groups, as revealed through Fourier transform infrared (FT-IR) analysis. It is apparent from these observations that MTSD can act as low-cost and efficient bioadsorbent for cadmium bioremediation from aquatic habitats. Use of the shells of M. tuberculata fo...

Mosquito Prey Vulnerability in Intraguild Predation Between Ranatra filiformis and Anisops bouvieri: Implications in Biological Control

Abstract: Wetlands are common habitats of a range of predatory water bugs (Heteroptera) constituting a guild that exhibit similar dietary choice including mosquito. Differences in body size and micro habitat preference among the heteropteran guild members provide a fair possibility of intraguild predation that can influence the regulatory effect on the prey species. This proposition was tested under laboratory conditions, using varying density of Ranatra filiformis (IG predator) and Anisops bouvieri (IG prey) as predators against mosquito larvae as shared prey. Compared to single predator system, mosquito larvae were proportionately less vulnerable to predation in intraguild predation (IGP), at low density of shared prey. In IGP system, vulnerability of shared prey increased with increase in density accompanied by a decline in mortality of IG prey. The mean mortality of shared prey and IG prey increased with the density of IG predator. It was apparent that the mosquito prey vulnerability was enhanced with increase in density of mosquito and R. filiformis while reducing the mortality of A. bouvieri partly. The interaction between R. filiformis and A. bouvieri as a part of IGP system indicate about the possible mechanism of coexistence of predators and prey in the wetlands. The density dependent effects on reduction and enhancement of shared prey (mosquito) mortality indicate that appropriate ratio of R. filiformis, A. bouvieri and mosquito larvae will be required to make biological regulation of wetland mosquitoes feasible.

Observations on Yellow-Wattled Lapwing, Vanellus malabaricus (Boddaert, 1783) in South West Bengal, India

Abstract: The present note highlights the geographical distribution of Yellow-Wattled Lapwing Vanellus malabaricus, which is rarest among the four Vanellus species found in south West Bengal. Perhaps, due to low encounter of V. malabaricus, the distribution of this species in south West Bengal remains obscured till now. Recent field observations in eight patches in the Gangetic plains of (Hooghly and Nadia) West Bengal, India, support their consistent availability in habitats characteristically different from the described ones. In the Indian subcontinent, including peninsular India, V. malabaricus is reported to prefer dry and arid lands, whereas the same species was located in rice fields and adjacent bushes in the Gangetic plains. As possible adaptive features, some characteristic behaviour is discussed that make them compatible with the local climatic condition of Gangetic plains of West Bengal, India.