Foraging resources of adult Mexican corn rootworm (Coleoptera : Chrysomelidae) in Bell County, Texas

Pollen analyses were used to determine pollen foraging resources of adult M exican corn rootworms, Diabrotica virgifera zeae Krysan & Smith, captured n ear Temple, Bell County, TX, In 1996 and 1997. In 1996, adult Mexican corn rootworms were captured in a corn. Zea mays L., field. In 1997, nine locati ons outside of cornfields were added. Overall, 92% of the beetles (n = 1,32 3) contained pollen. More than 142,000 pollen grains were counted. represen ting 45 families, 63 genera, and 27 species. Overall, in 1996, noncorn gras s pollen (70%) occurred in the greatest percentage of total pollen followed by corn (17%), then nongrass pollen (13%). In 1997, noncorn grass pollen ( 76%) had the greatest percentage, then nongrass (18%), and finally corn pol len (6%). Corn pollen was found in 34% of the beetles in 1996 and 26% in 19 97. Fifteen Asteraceae taxa were encountered including sunflower, Helianthu s annuus L. Thirteen Fabaceae were found including soybean, Glycine max L. Mexican corn rootworm adults foraged mainly on noncorn grass pollen, but al so foraged on pollen from a large diversity of plant species, indicating th at noncorn pollen may play a role in the food habits of Mexican corn rootwo rm adults.