Anthonomus grandis Boheman (Coleoptera: Curculionidae) en la Zona Central y Sur Oeste de Misiones, Argentina: Polen como fuente alimenticia y su relacion con el estado fisiologico en insectos adultos | Anthonomus grandis Boheman (Coleoptera: Curculionidae) in Central and South West Area of Misiones, Argentina: Pollen as feeding source and their relationship with the physiologic state in adult insects

Host feeding plants of adult boll weevils (Anthonomus grandis Boheman) were determined within the period: January 1997-December 1999. This took place through the identification of pollen grains, isolated from the digestive tracts of boll weevils captured in pheromone traps placed in a transect line which passes through the localities of Montecarlo, San Ignacio, Candelaria and the Capital in the province of Misiones. Cotton has not been cultivated for five years in that province, nevertheless important populations of weevils still remain during the whole year. About 1,360 weevils were dissected and 5,325 pollen grains were found; these were assigned to 28 species. Only those that presented percentages above 1%, which were 20 (4,183 pollen grains), were used. They belonged to five botanical families: Malvaceae, Compositae, Solanaceae, Euphorbiaceae and Leguminosae. Pollen of alternative plants provides the necessary energy for the survival of adult weevil in the absence of cotton pollen. The variation in the levels of relative abundance of pollen was analyzed with the study of the time of capture, sex, color, type of corporal fat, and reproductive status, using a log linear model (P<0.01).The following third order significant interactions were observed: time of capture x sex x reproductive status; color x corporal fat x reproductive status; levels of pollinic abundance x corporal fat x reproductive status. The ingesta level varied significantly with the corporal fat and the reproductive status, which are some determinants of the physiologic status of adult weevils. The grouping and ordering analyses showed the period of time, selectivity and use of the availability of pollen, since gender and species varied in the different seasons of the year, but they always belonged to the five mentioned families.