Research

Seasonal distribution of Anopheles funestus chromosomal forms from Burkina Faso

Wamdaogo M Guelbeogo¹ , N'Fale Sagnon¹ , Olga Grushko² , Malgaouende A Yameogo¹ , Daniela Boccolini³ , Nora J Besansky² and Carlo Costantini^1,4,5

¹  Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso

²  Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556 USA

³  Department of Infectious, Parasitic, and Immunomediated Diseases, Istituto Superiore di Sanità, Rome, Italy

⁴  Institut de Recherche pour le Développement, Research Unit UR016, Montpellier, France

⁵  Current address: Organisation de Coordination pour la lutte contre les Endemies en Afrique Centrale, Yaoundé, Cameroun

author email corresponding author email

Malaria Journal 2009, 8:239doi:10.1186/1475-2875-8-239

Published:	26 October 2009

Abstract

Background

Previous studies of Anopheles funestus chromosomal inversion polymorphisms in Burkina Faso showed large departures from Hardy-Weinberg equilibrium and linkage disequilibrium among inversions located on different chromosomes, implying the existence of two taxonomic units ("chromosomal forms") with limited genetic flow. One chromosomal form, named Folonzo, is highly polymorphic for alternative rearrangements of 3Ra, 3Rb, 2Ra, and 3La; the other, Kiribina, is predominantly characterized by the standard arrangement of these inversions. To investigate the temporal distribution of these chromosomal forms, further collections were carried out in two villages near Ouagadougou where they are found in sympatry.

Methods

Chromosomal karyotypes were determined from indoor-resting, half-gravid females sampled within and across six breeding seasons, from December 1998 to April 2007.

Results

As expected, the pattern of chromosomal polymorphism in An. funestus was consistent with assortatively mating Folonzo and Kiribina forms. When samples were assigned to each chromosomal form, their relative abundance varied within successive breeding seasons in a repeating pattern of temporal variability. Relative abundance of the Folonzo form was correlated with climatic variables related to temperature and rainfall.

Conclusion

The relative abundance of Folonzo and Kiribina forms of An. funestus likely reflects different larval ecologies that are linked to varying climatic conditions. Further analysis of the bionomics of these vectors is recommended in light of its relevance to vector control.