Morphometric comparisons of the scanning electron micrographs of the eggs of Anopheles (Nyssorhynchus) darlingi Root (Diptera: Culicidae)

Author(s)

Almeida, Fabio ^[1] ; Suesdek, Lincoln ^{[1, 2]} ; Motoki, Maysa T. ^[3] ; Bergo, Eduardo S. ^[4] ; Sallum, Maria Anice M. ^[3]

Affiliation

^[1] Inst Butantan, Parasitol Lab, BR-05503900 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Programa Posgrad Med Trop, BR-05403000 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Fac Saude Publ, Dept Epidemiol, BR-01246904 Sao Paulo - Brazil

^[4] Dept Control Vetores, BR-14810095 Sao Paulo - Brazil

• Document type: Journal article
• Source: Acta Tropica; v. 139, p. 115-122, NOV 2014.
• Web of Science Citations: 2

Abstract

Anopheles darlingi Root is the principal vector of Plasmodium in Brazil, but its biological variability is not well known. Morphometric analyses of scanning electron microscopy images of the eggs of An. darlingi were conducted using individuals collected in nine states of Brazil (Acre, Amapa, Espirito Santo, Para, Parana, Rio de Janeiro, Rondonia, Sao Paulo, and Tocantins). Ten attributes of the eggs (seven continuous variables and three discrete variables) were respectively measured or counted and analyzed to determine if populations from different geographical regions or biomes could be distinguished. Univariate analysis showed that the eggs from Espirito Santo were the narrowest whereas representatives from Tocantins populations had the smallest floats. Results of multivariate analyses of continuous variables showed that the first principal component (PC1), mainly represented by all four float attributes, helped to differentiate populations. The second principal component (PC2) comprised roughly the length and width of the egg. PC1 of discrete variables corresponded to the number of ribs on the float whereas PC2 was approximately equivalent to the number of discs on the micropyle. Based on those variables (continuous and discrete separately), multivariate discriminant analysis indicated that eggs from individuals collected in Tocantins were distinct from the other populations. Among sampled localities, the one from the state of Tocantins was situated within the Cerrado biome whereas the locality from Sao Paulo state was at the border of Cerrado, within a transition zone of the Atlantic Forest biome. Generally, the climate in the Cerrado biome was more arid-than in areas of the Amazon and Atlantic Forest biomes, and the temperature had the highest range. Coincidentally, based on morphometric data, cluster analysis distinguished the population from Cerrado, Tocantins from all other populations. Results of multiple regression analysis of the variables showed no correlation between egg variables and latitude or climatic variables. We concluded that eggs were polymorphic and that some morphological patterns were regional. Although no environmental influence on the egg attributes was unequivocally detected, a potential association cannot be entirely discarded. Consequently, we hypothesize that morphological traits of the immature stages, especially from the eggs, convey evolutionary information regarding to this species. (C) 2014 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/17717-2 - Quantitative and temporal profile of follicular atresia in Culex quinquefasciatus under the influence of Wolbachia
• Grantee: Fábio de Almeida
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 11/20397-7 - Morphological and molecular taxonomy and phylogeny of Nyssorhynchus subgenus of Anopheles (Diptera: Culicidae), with special emphasis on Anopheles darlingi from Mata Atlântica
• Grantee: Maria Anice Mureb Sallum
• Support Opportunities: Regular Research Grants