Variation in morphology and morphometrics of eggs of Culex quinquefasciatus mosquitoes from different ecological regions of India (original) (raw)
Related papers
2013
Understanding the population dynamics of mosquito populations through life table analysis and insecticide susceptibility is important to assess the likely impact of vector control strategies as well as to aid the design of novel interventions. Variation in the life tables and other biological data was compared for two populations of Culex quinquefasciatus Say 1823 from geographically isolated regions, Gorakhpur and Pune from India. Under a standardized rearing regime and constant laboratory conditions, mosquitoes were reared and biological attributes of these populations were compared. Development and survival of immature and adult stages of Culex quinquefasciatus were found significantly different in Gorakhpur and Pune populations. Principal component analysis of morphological data revealed that the two populations form significantly different clusters which can be differentiated from each other based on siphon, saddle, anal gills, and pecten teeth related variables. Insecticide susceptibility results suggest that the larvae from both areas were more susceptible to deltamethrin as compared to DDT and malathion. The current study provides baseline information on survivorship, morphological variation and insecticide susceptibility of Culex quinquefasciatus. The results obtained in this study suggest that different geographical areas with contrasting habitats have significant influence on survival and reproductive strategies of Culex quinquefasciatus.
The distribution of Culex mosquitoes in Coimbatore, Tamil Nadu, India
Journal of Entomological and Acarological Research, 2015
Lymphatic filariasis is an infection with the filarial worms, <em>Wuchereria bancrofti</em>, <em>Brugia</em> <em>malayi</em> and <em>B. timori</em>. These parasites are transmitted to humans through the bite of an infected <em>Culex</em> mosquito and develop into adult worms in the lymphatic vessels, causing severe damage and swelling (lymphoedema). Mosquito control, in view of their medical as well as economical importance, assumes global importance. Geographic information system (GIS) is a powerful tool to analyse the distribution of mosquitoes and their relationship to different environmental factors, and can substantially improve our ability to quantify the impacts of demographic, climatic and ecological changes in vector distribution. In the present study <em>Culex</em> <em>quinquefasciatus</em>, <em>Culex</em> <em>tritaeniorhynchus</em> and <em>Culex</em> <...
A study on the seasonal prevalence of Culex quinquefasciatus larvae in Agra, Uttar Pradesh (India)
2016
Seasonal abundance of the immature stages of the mosquito, Culex quinquefasciatus, the vector of Japanese encephalitis and other mosquito borne diseases were studied in Agra, Uttar Pradesh, India. Samples were collected from temporary, semi-permanent and permanent ground water pools and other mosquito breeding sites throughout the year. In Agra, the larval index of C. quinquefasciatus was highest in rainy season, July to September and lowest in winters, from December till February. Larval development was remarkably slow during this season. The larval index starts increasing in April, 53.1, 37.3 and 47.3 for the first, second and third year respectively. The larval index again decreases in June due to extreme hot summers. The maximum larval index was noted in September (173.1, 136.2 and 124 for the first, second and third year respectively). The larval index showed an unusual rise in the month of July (134.7) for the first year and in February (32.1) during the third year of the study which shows its direct relation with the meteorological conditions prevailing in that area. The larval index shows two peak values first in the month of August and September and then in April and May during the study which coincides with the incidence of Japanese encephalitis, chikungunya, filariasis and other mosquito borne diseases. Systematic water management, usage of larvivorous predators and organizing literacy campaigns can be a remedy for the breeding of C. quinquefasciatus mosquito in the city.
Variations in life tables of geographically isolated strains of the mosquito Culex quinquefasciatus
Medical and Veterinary Entomology, 2011
Variations in the life tables and other biological attributes of four strains of Culex quinquefasciatus Say (Diptera: Culicidae) from geographically isolated regions of India that had been reared to the fifth generation in the laboratory were assessed under a standardized rearing regime under constant laboratory conditions. Two strains from arid habitats [Jodhpur (JD) and Bikaner (BKN)], one from a semi-arid inland habitat [Bathinda (BTH)], one from a semi-arid coastal habitat [Jamnagar (JMN)] and a standard laboratory strain (LAB) were compared. Horizontal life-table parameters were measured for each strain. Egg mortality ranged from 4.4% (JD and BTH) to 19.5% (BKN). The lowest rate of adult emergence and highest female : male ratio were found in BKN, and the highest rate of adult emergence and lowest female : male ratio were recorded in BTH. The egg-hatching period was longest in BTH and shortest in LAB. The duration from oviposition to adult emergence was longest in JD and shortest in LAB. Females lived longer than males in all strains. The net reproductive rates (R 0) of all field-derived strains (122.9-162.2) differed significantly between strains and were significantly greater than that of LAB (107.6). Similarly, both the intrinsic rate of increase (r m) and finite rate of increase (λ) were found to be lower in LAB than in the field strains, but the mean generation time (T) and doubling time (DT) were longest in LAB. For several life-table attributes, JD and BTH clustered together and were more similar to JMN than to BKN and LAB. The results indicate that BTH, BKN and JD can be characterized as r-strategists, more so than JMN. Overall fecundity increased with age. Differences in annual temperature ranges and mean annual rainfall between locations were positively correlated (r = 0.46-0.97) with egg production, female life expectancy, R 0 , r m , λ and T. The results suggest that strains of Cx. quinquefasciatus from different geographical areas with contrasting habitats vary in their survival and reproductive strategies accordingly.
Study on Culex Mosquitoes of Bhelukhel, Bode and Tathali of Bhaktapur District, Nepal
Journal of Natural History Museum
An entomological study was carried out in Bhelukhel, Bode and Tathali of Bhaktapur district to compare fluctuation in population size of Culex mosquitoes in relation to relative humidity and temperature. Mosquitoes were collected during July-December 2012 around the pig enclosures and cattle sheds by means of dark activated rechargeable CDC light trap. The study resulted 73.41% of Culex mosquitoes out of the total mosquitoes collected (884). Total eleven species of Culexmosquitoes were recorded namely Cx. tritaeniorhynchus, Cx. fuscocephala, Cx. gelidus, Cx. vishnui, Cx. pseudovishnui, Cx. bitaeniorhynchus, Cx. quinquefasciatus, Cx. edwardsi, Cx. hutchnsoni, Cx. whitei and Cx.whitmorei. Distribution of Culexspecies was abundant in July and August. Cx. quinquefasciatus, the principal vector of Lymphaticfilariasis (LF) was recorded to be the most dominant species in all the three sites. Cx. tritaeniorhynchus, the principal Japanese encephalitis (JE) vector was collected in higher numb...
Morphometric and allozyme variation in Culex tritaeniorhynchus mosquito populations from India
insectscience.org
Four populations of Culex tritaeniorhynchus (Giles) (Diptera: Culicidae), collected from Bellary, Cuddalore, Pune, and the Microbial Containment Complex laboratory culture in India were analyzed for morphological and allozyme variation. Multivariate analysis based on eight morphological characteristics and three morphometric indices was used to investigate the morphological variations among the four populations. Principal component analysis of the data suggested that siphon, saddle, and anal gills related variables were most important. Discriminant factor analysis of morphological data revealed that the four populations form significantly different clusters which can be differentiated from each other based on siphon, saddle, and pectin teeth related variables. Allozyme electrophoresis of the four populations revealed that the mean heterozygosity per locus value had high variation, ranging from 0.0879 to 1.794. F st values between 0 and 0.519 suggested genetic differentiation within these populations. F is values ranged from 0 to 1 with most of the values closer to 1. The allelic frequencies and Nei's genetic identity values showed that genetic differences between populations were small, but significant. Some of the morphological and allozyme variations in the Cx. tritaeniorhynchus populations could be partly attributed to the environmental conditions. The findings suggested that transition of morphological characters and allozyme variations in Cx. tritaeniorhynchus populations seem to be consequences of influence and selection by the environmental conditions. These results indicated that populations of Cx. tritaeniorhynchus in non-endemic areas of Japanese encephalitis (JE) virus infection have higher adaptability as compared to endemic areas of JE infection.
International Journal of Insect Science, 2016
The need to have an improved knowledge on the bioecology of Culex quinquefasciatus, a prerequisite in the development of cost-effective control strategies, has informed the present preliminary investigation to put in better perspective variations that exist in the egg rafts of the species. Freshly laid egg rafts were collected and incubated at ambient temperature in well-labeled plastic trays. The results showed overall inconsistency in all indices monitored for the egg rafts. Generally, survivorship was high for the species. All immature stage and adult parameters measured varied significantly among the egg rafts and between/within sexes of the species. Therefore, this study suggests the presence of inherent variation in the bionomics of egg rafts of C. quinquefasciatus, probably influenced by the environment and hence underscores the need for additional studies to further elucidate the roles of genetics and environment in vectorial competence of the species, in order to develop ro...
Egyptian Academic Journal of Biological Sciences, E. Medical Entomology & Parasitology
Journal of Medical Entomology and Parasitology is one of the series issued quarterly by the Egyptian Academic Journal of Biological Sciences. It is an important specialist journal covering the latest advances in that subject. It publishes original research and review papers on all aspects of basic and applied medical entomology, parasitology and host-parasite relationships, including the latest discoveries in parasite biochemistry, molecular biology, genetics, ecology and epidemiology in the content of the biological, medical entomology and veterinary sciences. In addition to that, the journal promotes research on the impact of living organisms on their environment with emphasis on subjects such a resource, depletion, pollution, biodiversity, ecosystem…..etc. www.eajbs.eg.net Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.
Nigerian journal of entomology, 2018
Culex mosquitoes are nuisance bitters and vectors of public and veterinary health importance. Information on the abundance and distribution of this species is critical in understanding the risk factors associated with the diseases transmitted by these vectors. A longitudinal survey was conducted from May 2015 to October 2016 to determine the abundance, distribution and species diversity of Culex mosquitoes in water drainage channels in Kosofe, Ojo, Epe and Eti-Osa Local Government Areas (LGAs) of Lagos State. Culex larvae were collected using standard dipper, counted and reared to adults. Samples collected were identified morphologically while members of Culex pipiens complex were further identified into subspecies using Polymerase Chain Reaction (PCR) assays. A total of 12,367 Culex larvae were collected, of which 64.4% and 35.6% were collected in canals and gutters respectively. Culex larvae were predominant at the end of wet season and beginning of the dry season with the highest population recorded in November. Kosofe LGA had the highest number of Culex immature stages (34.47%) followed by Ojo (31.13%), Eti-Osa (18.56%) and Epe (15.84%). Six species; Culex pipiens sensu lato (49.35%), Cx nebulosus Theobald (20.71%), Cx moucheti Evans (6.89%), Cx cinereus Theobald (10.43%), Cx decens Theobald (8.75%) and Cx tigripes Grandpre and Charmoy (3.87%) were identified. The abundance of members of Cx pipiens complex was significantly higher than that of the other five species (F = 7.760; df = 5; P<0.05). PCR assays of Cx. pipiens complex revealed the presence of Cx. pipiens quinquefasciatus as the only member of the group. Species dominance structure showed Cx quinquefasciatus as the only eudominant species in all the study locations. Diversity indices for the study areas varied from 1.220 to 1.643 for Shannon-Weiner (H') and from 0.2104 to 0.4132 for the Simpson index (D).The wide range of Culex species encountered highlight the need for the mosquito surveillance and control in Lagos state because of their potential role in disease transmission.
Asian Pacific Journal of Tropical Disease
The journal implements double-blind peer review practiced by specially invited international editorial board members. Objective: To examine the extent of the interspecific association between Culex pipiens and Culex quinquefasciatus in Hail Region, Saudi Arabia with an aim of further understanding the ecology of such mosquito larvae mainly in respect to similarity in their breeding requirements. Methods: Larvae were collected by dipping over one year from breeding sites in nine localities in Hail Region. The degree of the interspecific association between larvae of the two mosquito species was measured on the basis of presence-absence data (Coefficient of Interspecific Association, C AB ± SD) and on their relative numbers (Index of Association or Sorensen's coefficient, I). Results: The two species had a significantly moderate association (C AB = 0.21, P < 0.05 and I = 0.39). The Sorensen's coefficient (I) showed monthly variation and was directly related to the separate/compiled abundance of the two species (b = 0.01-0.02). Conclusions: The obtained results may indicate that the habitat requirements and preference of the two species are similar and that their abundance influencing the degree of their interspecific association.