LATE-SEASON MIGRATION OF THE BOLL-WEEVIL (COLEOPTERA, CURCULIONDAE) IN THE TEXAS ROLLING PLAINS

Late season migration of the boll weevil, Anthonomus grandis Boheman, from isolated cotton fields was studied by marking weevil populations in the fields and recovering migrants with pheromone traps and also th rough examination of leaf litter in overwinter habitats. A high percen tage of the resident boll weevil population was marked when the test f ields were sprayed with a dye impregnated, cotton seed oil bait. The m ajority of marked migratory boll weevils were recovered within 2 miles of the test fields. However, some marked boll weevils were captured u p to 10 miles from their point of origin. Pheromone trap studies indic ated that the percentage of diapausing boll weevils in the migratory p opulation decreased as the distance of migration increased. During the late summer and early fall, the majority of the migrating boll weevil population was composed of reproductive individuals, with peak migrat ion of diapausing individuals occurring approximately 45 days later. T hese data indicate that a portion of the diapausing boll weevil popula tion may be progeny of earlier reproductive migrants.