scholarly journals Resistance development and insecticide susceptibility in Culex pipiens pipiens, an important vector of human diseases, against selection pressure of temephos and its relationship to cross-resistance towards organophosphates and pyrethroids insecticides

2018 ◽  
Vol 18 (4) ◽  
pp. 1175
Author(s):  
Ahmed Tabbabi ◽  
Ali Laamari ◽  
Raja Ben Cheikh ◽  
Ibtissem Ben Jha ◽  
Jabeur Daaboub ◽  
...  
Keyword(s):  
Culex Pipiens ◽  
Selection Pressure ◽  
Human Diseases ◽  
Cross Resistance ◽  
Insecticide Susceptibility ◽  
Resistance Development ◽  
Culex Pipiens Pipiens

scholarly journals Evaluating Gene Flow Using Selected Markers: A Case Study

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1383-1392 ◽  
Author(s):  
Thomas Lenormand ◽  
Thomas Guillemaud ◽  
Denis Bourguet ◽  
Michel Raymond
Keyword(s):  
Gene Flow ◽  
Insecticide Resistance ◽  
Local Adaptation ◽  
Culex Pipiens ◽  
Selection Pressure ◽  
Fitness Costs ◽  
Southern France ◽  
Culex Pipiens Pipiens ◽  
Selection Intensities

Abstract The extent to which an organism is locally adapted in an environmental pocket depends on the selection intensities inside and outside the pocket, on migration, and on the size of the pocket. When two or more loci are involved in this local adaptation, measuring their frequency gradients and their linkage disequilbria allows one to disentangle the forces—migration and selection—acting on the system. We apply this method to the case of a local adaptation to organophosphate insecticides in the mosquito Culex pipiens pipiens in southern France. The study of two different resistance loci allowed us to estimate with support limits gene flow as well as selection pressure on insecticide resistance and the fitness costs associated with each locus. These estimates permit us to pinpoint the conditions for the maintenance of this pocket of adaptation as well as the effect of the interaction between the two resistance loci.

scholarly journals Gonoactivity of Culex (Culex) (Diptera: Culicidae) Mosquitoes During Winter in Temperate Argentina

2021 ◽  
Author(s):  
María Florencia Branda ◽  
Magdalena Laurito ◽  
Andrés Mario Visintin ◽  
Walter Ricardo Almirón
Keyword(s):  
Developmental Stage ◽  
Culex Quinquefasciatus ◽  
Culex Pipiens ◽  
Life Cycles ◽  
Morphological Identification ◽  
Dry Ice ◽  
Culex Pipiens Pipiens ◽  
Host Seeking ◽  
Baited Traps ◽  
The City

Abstract The subgenus Culex L. includes species involved in summer–autumn arbovirus transmission but studies during winter are scarce in temperate Argentina. Female specimens were collected host-seeking at dry-ice-baited traps during autumn–winter–spring at two sites in Córdoba City during 2016 and 2017. The specimens were morphologically identified and dissected to determine the follicular developmental stage (gonotrophic activity). Females with advanced follicular stages (≥III) were subjected to molecular procedures to confirm or re-identify previous morphological identification. Five species (Culex apicinus Philippi (Diptera: Culicidae), Culex dolosus (Lynch-Arribálzaga) (Diptera: Culicidae), Culex maxi Dyar (Diptera: Culicidae), Culex pipiens pipiens L. (Diptera: Culicidae), and Culex quinquefasciatus Say (Diptera: Culicidae)) were collected and found gonoactive during winter; showing that a high proportion of Culex (Culex) females remain reproductively active during the unfavorable season for mosquito populations. Among them, it is worth noting the collection of Cx. quinquefasciatus, vector of the St. Louis encephalitis virus (endemic in the city), a specimen of Cx. p. pipiens, and a hybrid of Cx. p. pipiens/Cx. quinquefasciatus (during autumn). The study of this community during winter should continue because a high gonoactive female proportion with advanced follicular stages was found: 29.12 and 13.07% in 2016 and 2017, respectively. Local studies such as this one provide evidence about ornithophilic Culex species with active year-round life cycles, species that could favor arbovirus overwintering.

Viability of Culex pipiens pipiens eggs affected by nutrition and aposymbiosis

1985 ◽  
Vol 45 (2) ◽  
pp. 225-230 ◽  
Author(s):  
Dominic S.T. Awahmukalah ◽  
Marion A. Brooks
Keyword(s):  
Culex Pipiens ◽  
Culex Pipiens Pipiens

Microbiome reduction prevents lipid accumulation during early diapause in the northern house mosquito, Culex pipiens pipiens

2021 ◽  
Vol 134 ◽  
pp. 104295 ◽  
Author(s):  
Elise M. Didion ◽  
Zakee L. Sabree ◽  
Laura Kenyon ◽  
Gabriela Nine ◽  
Richard W. Hagan ◽  
...  
Keyword(s):  
Lipid Accumulation ◽  
Culex Pipiens ◽  
Culex Pipiens Pipiens

scholarly journals Comparative Study of the Effect of Solvents on the Efficacy of Neonicotinoid Insecticides Against Malaria Vector Populations Across Africa

2022 ◽  
Author(s):  
Magellan Tchouakui ◽  
Tatiane Assatse ◽  
Leon M. J. Mugenzi ◽  
Benjamin D. Menze ◽  
Daniel Nguiffo-Nguete ◽  
...  
Keyword(s):  
Democratic Republic Of Congo ◽  
Natural Populations ◽  
Resistance Mechanisms ◽  
Lower Mortality ◽  
Malaria Vectors ◽  
Cross Resistance ◽  
Metabolic Resistance ◽  
Resistance Development ◽  
Development Of Resistance ◽  
Bottle Test

Abstract Background New insecticides with a novel mode of action such as neonicotinoids have recently been recommended for public health by WHO. Resistance monitoring of such novel insecticides requires a robust protocol to monitor the development of resistance in natural populations. In this study, we comparatively used three different solvents to assess the susceptibility of malaria vectors to neonicotinoids across Africa.MethodsMosquitoes were collected from May to July 2021 from three agricultural settings in Cameroon (Njombe-Penja, Nkolondom, and Mangoum), the Democratic Republic of Congo (Ndjili-Brasserie), Ghana (Obuasi), and Uganda (Mayuge). Using the CDC bottle test, we compared the effect of three different solvents (ethanol, acetone, MERO) on the efficacy of neonicotinoids against Anopheles gambiae s.l. In addition, TaqMan assays were used to genotype key pyrethroid-resistant markers in An. gambiae and to evaluate potential cross-resistance between pyrethroids and clothianidin.ResultsLower mortality were observed when using absolute ethanol or acetone alone as solvent (11.4- 51.9% mortality in Nkolondom, 31.7- 48.2% in Mangoum, 34.6- 56.1% in Mayµge, 39.4- 45.6% in Obuasi, 83.7- 89.3% in Congo and 71.05- 95.9% in Njombe pendja) compared to acetone + MERO for which 100% mortality were observed for all the populations. Synergist assays (PBO, DEM and DEF) revealed a significant increase of mortality suggesting that metabolic resistance mechanisms are contributing to the reduced susceptibility. A negative association was observed between the L1014F-kdr mutation and clothianidin resistance with a greater frequency of homozygote resistant mosquitoes among the dead than among survivors (OR=0.5; P=0.02). However, the I114T-GSTe2 was in contrast significantly associated with a greater ability to survive clothianidin with a higher frequency of homozygote resistant among survivors than other genotypes (OR=2.10; P=0.013). ConclusionsThis study revealed a contrasted susceptibility pattern depending on the solvents with ethanol/acetone resulting to lower mortality, thus possibly overestimating resistance, whereas the MERO consistently showed a greater efficacy of neonicotinoids but it could prevent to detect early resistance development. Therefore, we recommend monitoring the susceptibility using both acetone alone and acetone+MERO (8-10µg/ml for clothianidin) to capture the accurate resistance profile of the mosquito populations.

Resistance to pyrethroid insecticides in Culex pipiens pipiens (Diptera: Culicidae) from Tunisia

Acta Tropica ◽  
2008 ◽  
Vol 107 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Jabeur Daaboub ◽  
Raja Ben Cheikh ◽  
Ali Lamari ◽  
Ibtissem Ben Jha ◽  
Mohamed Feriani ◽  
...  
Keyword(s):  
Culex Pipiens ◽  
Pyrethroid Insecticides ◽  
Culex Pipiens Pipiens

scholarly journals Evidence for the Predisposition of Fungicide-Resistant Isolates of Venturia inaequalis to a Preferential Selection for Resistance to Other Fungicides

2001 ◽  
Vol 91 (8) ◽  
pp. 776-781 ◽  
Author(s):  
Wolfram Köller ◽  
W. F. Wilcox
Keyword(s):  
Fungicide Resistance ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
The United States ◽  
Cross Resistance ◽  
Resistance Development ◽  
Flexible Response ◽  
Sterol Demethylation Inhibitors ◽  
Selection For ◽  
Selection Of

In the United States, populations of the apple scab pathogen Venturia inaequalis have progressed through three consecutive rounds of fungicide resistance development, first to dodine, then to the benzimidazoles, and most recently to the sterol demethylation inhibitors (DMIs). Analysis of extensive monitoring data have to date provided no indication of detectable cross-resistance or partial cross-resistance of V. inaequalis populations to the three unrelated classes of fungicides prior to the selection of resistant subpopulations. However, in this study, resistance to both benomyl and DMIs developed to significantly higher frequencies within the previously established dodine-resistant population than in the population sensitive to dodine. Accelerated selection of phenotypes double resistant to dodine and the DMI fenarimol was apparent over the course of distinct seasons of apple scab management with either dodine or fenarimol. The data provide evidence for an accelerated speed of resistance development among phenotypes of V. inaequalis already resistant to an unrelated fungicide. This finding represents a departure from the previous model, which assumed entirely independent rounds of resistance developments. The data indicate that phenotypes of V. inaequalis might not only be selected for the trait of fungicide resistance but also for traits allowing a more flexible response to changes in the environment where they compete.

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