Diversity of boll weevil populations in South America: a phylogeographic approach

SCATAGLINI, MARÍA AMALIA; LANTERI, ANALÍA ALICIA; CONFALONIERI, VIVIANA ANDREA

GENETICA

Springer

Año: 2006 vol. 126 p. 353 - 368

0016-6707

A phylogeographic approach was conducted to asses geographic structure and genetic variation of the populations of the boll weevil Anthonomus grandis, which is the most harmful insect pest of cotton in the Americas. COI and COII mitochondrial gene sequences were analyzed to test a former hypothesis on the origin of the boll weevil in Argentina, Brazil and Paraguay, using samples from Mexico and the United States as putative source populations. The analysis of variability suggests that populations from South American cotton fields and nearby disturbed areas, form a phylogroup with a central haplotype herein called A, which is the most common and widespread in USA and South America. The population from Texas has the A haplotype as the most frequent and gather in the same group as the South American populations associated to cotton. The samples from Tecomán (México) and the Iguazú National Park (Misiones province, Argentina)show high values of within-nucleotide divergence, share no haplotype in common with the others South American samples, and form phylogroups separated by several mutational steps. We propose that in South America there are: populations with characteristics of recent invaders, wich would be remnants of  "bottlenecks" that ocurred after a single or multiple colonization events, probably from the United States; and ancient populations associated with native forest, partially isolated by events of  historical fragmentation.