Seasonal distribution of Anopheles funestus chromosomal forms from Burkina Faso.
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.


CONCLUSIONS
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.
Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso. guelbeogo.cnrfp@fasonet.bf
Wamdaogo M
WM
Guelbeogo
N'Fale
N
Sagnon
Olga
O
Grushko
Malgaouende A
MA
Yameogo
Daniela
D
Boccolini
Nora J
NJ
Besansky
Carlo
C
Costantini
D000818:Animals; D000852:Anopheles / Q000145:classification / Q000235:genetics* / Q000469:parasitology; D002050:Burkina Faso; D007446:Chromosome Inversion; D002874:Chromosome Mapping; D005828:Genetics, Population; D005843:Geography; D007303:Insect Vectors / Q000235:genetics*; D007621:Karyotyping; D011110:Polymorphism, Genetic; D012621:Seasons