Altitudinal population structure and microevolution of the malaria vector Anopheles cruzii (Diptera: Culicidae)

Abstract

BackgroundIn Brazil, the autochthonous transmission of extra-Amazonian malaria occurs mainly in areas of the southeastern coastal Atlantic Forest, where Anopheles cruzii is the primary vector. In these locations, the population density of the mosquito varies with altitude (5–263 m above sea level), prompting us to hypothesise that gene flow is also unevenly distributed. Describing the micro-geographical and temporal biological variability of this species may be a key to understanding the dispersion of malaria in the region. We explored the homogeneity of the An. cruzii population across its altitudinal range of distribution using wing shape and mtDNA gene analysis. We also assessed the stability of wing geometry over time.MethodsLarvae were sampled from lowland (5–20 m) and hilltop (81–263 m) areas in a primary Atlantic Forest region, in the municipality of Cananéia (State of São Paulo, Brazil). The right wings of males and females were analysed by standard geometric morphometrics. Eighteen landmarks were digitised for each individual and a discriminant analysis was used to compare samples from the hilltop and lowland. A 400-bp DNA fragment of the mitochondrial cytochrome oxidase gene subunit I (CO-I) was PCR-amplified and sequenced.ResultsWing shapes were distinct between lowland and hilltop population samples. Results of cross-validated tests based on Mahalanobis distances showed that the individuals from both micro-environments were correctly reclassified in a range of 54–96%. The wings of hilltop individuals were larger. The CO-I gene was highly polymorphic (haplotypic diversity = 0.98) and altitudinally structured (Фst = 0.085 and Jaccard = 0.033). We found 60 different haplotypes but only two were shared by the lowland and hilltop populations. Wing shape changed over the brief study period (2009–2013).ConclusionsWing geometry and CO-I gene analysis indicated that An. cruzii is vertically structured. Wing shape varied rapidly, but altitude structure was maintained. Future investigations should identify the biotic/abiotic causes of these patterns and their implications in the local epidemiology of malaria.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-014-0581-8) contains supplementary material, which is available to authorized users.

Wing sexual dimorphism of pathogen-vector culicids

“…Because of the low allometric values observed (as previously detected in An. cruzii by Lorenz et al [32]), we cannot assert that SD in culicids is only an allometric effect, as some authors have conjectured [22]. It is possible that the ubiquity of SShD is maintained by the different ways in which wings are used by each sex, i.e., the overall wing shape may be adapted to each sex-specific function.…”

Wing morphometric variability of the malaria vector Anopheles (Cellia) epiroticus Linton et Harbach (Diptera: Culicidae) for the duration of the rainy season in coastal areas of Samut Songkhram, Thailand

“…Following reports demonstrating the usefulness of a landmark-based GM approach to assessing morphological variability of Anopheles spp. mosquitoes in many countries around the world (Vicente et al 2011, Motoki et al 2012, Gómez et al 2014, Lorenz et al 2014, Hidalgo et al 2015, such an approach was used in this study.…”

“…During the last decade, mosquito vectors' morphological variability across different locations has been studied, such as Aedes Meigen as dengue vectors and chikungunya vectors (Morales et al 2013), Culex Linnaeus as encephalitis vectors (Demari-Silva et al 2014, De Carvalho et al 2017, and Anopheles Meigen as malaria vectors (Vicente et al 2011, Motoki et al 2012, Lorenz et al 2014, Hidalgo et al 2015. More information on morphological variation can enhance epidemiological understanding of medically important mosquito vectors (Dujardin 2011).…”

Anopheles darlingi (Diptera: Culicidae) Rood 1926: Morphometric variations in wings and legs of populations from Colombia

“…(17). Estos rasgos del ala no dependen solo del acervo genético (19), sino que se ven afectados por variables ambientales, como la temperatura, la humedad relativa y la altitud (20,21).…”