CONICET | Buscador de Institutos y Recursos Humanos

Migration and dispersal of Anthonomus grandis (Coleoptera: Curculionidae) in South America STADLER, Teodoro and Micaela BUTELER ABSTRACT. This study discusses the dispersal of Anthonomus grandis Boheman, the cotton boll weevil, in Argentina, Brazil, Paraguay and Bolivia, exploring the ecological and physiological factors that have made the dispersal and establishment of this insect in South America so successful. The boll weevils phenotypic plasticity is represented by its fl exible developmental time, its multivoltine life cycle with several overlapping generations, its capacity to feed on pollen from diverse botanical families as well as from non pollen food sources and its ability to migrate and disperse aided by winds. These characteristics make it a key pest for cotton. Probable overwintering «hot spots» for the boll weevil were identifi ed in Misiones-Argentina, where large numbers of prediapausing weevils concentrate after arrival from newly harvested cotton fi elds in Paraguay, probably attracted by citrus orchards volatiles. The boll weevils facultative quiescence is always relative to environmental adverse conditions. This suggests that overwintering in the boll weevil can be defi ned as «oligopause», an intermediate form of diapause. Since its introduction to Brazil in 1983, until 2006, it has spread southwest at an average of 61 km year-1 towards Argentina. However, it took the boll weevil approximately ten years to move 250 km between Paraguay and the main cotton growing area in Argentina. This slower progress is probably due to the actions taken by the Argentine government through the boll weevil eradication program. The arrival of the boll weevil at the cotton cropping areas in Paraguay and Argentina reinforces the fact that the boll weevil should fi nally be included in an integrated cotton pest management program jointly with other major cotton pests. KEY WORDS. Cotton boll weevil. Integrated Pest Management. Cotton key pest.