Abstract

LANTERI, Analía A.; CONFALONIERI, Viviana A.  and  SCATAGLINI, M. Amalia. The cotton boll weevil in Argentina: Main results and implications of the molecular studies. Rev. Soc. Entomol. Argent. [online]. 2003, vol.62, n.3-4, pp.1-15. ISSN 0373-5680.

Ten years after the first record of the cotton boll weevil, Anthonomus grandis Boheman (Coleoptera, Curculionidae), in Argentina, the insect arrived in the cotton area of Chaco. Molecular studies on populations from Argentina, Brazil and Paraguay, and possible source populations from USA and Mexico, provided helpful information to control the pest. RAPD technique (Random Analysis of Polymorphic DNA) and sequencing of Cytochrome Oxidase I and II mitochondrial genes, allowed to differentiate two main lineages: a) lineages with scarce or null variability measured by heterocigosis and haplotypic diversity, considered recent colonizers, and associated with xerophytic environments and cotton areas (Formosa province); b) lineages with high genetic variability and haplotypic diversity, considered ancestral, and associated with areas of wild vegetation as the subtropical forests of Misiones (Iguazú National Park). Both lineages probably have different origins, adaptations and host preferences, and at present would be hibridizing in ecotonal areas. We propose that the boll weevil probably occurs in South America as a consequence of a natural dispersal associated to wild hosts, mainly of the genera Gossypium and Cienfuegosia, probably since Pleistocene times. On the other hand, there is a possibility of introductions from USA to Brazil, trough the commercial exchange. Extensive cotton cultivation and deforestation, with formation of corridors connecting fragments of forests would explain the rapid dispersal of the pest during the last 20 years, in cotton and/or non cotton areas under environmental impact, such as the Misiones province.

Keywords : Anthonomus grandis; Mitochondrial DNA; RAPD; Argentina; Population variability; Ancestral lineages and recent colonizers.

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