ALMOND, MELON, AND PIGWEED POLLEN RETENTION IN THE BOLL WEEVIL (COLEOPTERA; CURCULIONIDAE)

The boll weevil (Anthonomus grandis Boheman) remains a devastating insect pest on cotton (Gossypium hirsutum C. Linnaeus), particularly where it has not been eradicated. Identifying and understanding the survival of overwintered boll weevils, when cotton is not available, is important in designing mitigation programs and controlling this insect pest, especially in areas where boll weevils are active all year. Many non-malvaceous taxa have been listed as possible overwintering adult food sources. The purpose of this research was to determine if pollen from three non-malvaceous taxa could be used as food sources for overwintering boll weevils in the Lower Rio Grande Valley of Texas, where weevils are active year-round and during cotton-free periods. The taxa are almond [Prunus dulcis (Mill.) D.A. Webb], melon (Cucumis melo C. Linnaeus subsp. melo), and pigweed (Amaranthus sp.), Furthermore, it was intended to determine the retention of these pollen types in the boll weevil gut. More weevils (84%) contained almond pollen when they had additional water than those (30%) that did not have additional water. Almond pollen was found in 100% of the examined weevils after 72 hours, and in 80% after 96 hours. Pigweed and melon pollen were never found after 48 hours. Overall, almond pollen was found in more weevils (96%) than pigweed (40%), or melon (12%). In addition, a greater number of almond pollen grains (539) were found than pigweed (41), or melon (21). This shows that these types of pollen were consumed, and could play a part in the survival of overwintering weevils. However, more research is needed to examine the nutritional value of these, and other, pollen grains for overwintering boll weevil survival, and to determine the length of time weevils can survive feeding on these pollen types.