Physiological Activity of the Boll Weevil During the Fall and Winter in Subtropical Areas of the Rio Grande Valley of Texas12

Abstract

Results of laboratory and field studies showed that adults of Anthonomus grandis grandis Boheman, captured in Leggett traps baited with grandlure or collected from surface leaf litter and duff during the non-cotton season (September to April) of 1978–1979 and 1979–1980 in a subtropical area near Brownsville, Tex., were unique in that they remained physiologically active throughout the winter. Boll weevils were trapped even on days when minimum temperatures were as low as 1.5°C. Females caught during the fall remained sexually mature, mated, and stored viable sperm in their spermatheca, but egg hatch was not observed under laboratory conditions (artificial diet) during ca. 2 months in the winter. However, these females oviposited fertile eggs when fed for at least 10 days with fresh cotton squares. Catches of teneral weevils were very common throughout the winter, an indication that weevils could remain reproductive through the winter when proper nourishment was available from cotton regrowths or seedling plants in unattended or abandoned fields.