Ant Predation on Eggs and Larvae of the Black Cutworm (Lepidoptera: Noctuidae) and Japanese Beetle (Coleoptera: Scarabaeidae) in Turfgrass

Abstract

We studied ant predation on eggs and larvae of the black cutworm, Agrotis ipsilon (Hufnagel), and on eggs of the Japanese beetle, Popillia japonica Newman, on golf courses and lawns in central Kentucky. Lasius neoniger Emery accounted for >99% of the ant mounds on golf putting greens and collars. Although often regarded as a nuisance pest, L. neoniger preyed heavily upon A. ipsilon eggs on turfgrass cores implanted into putting greens, collars, fairways, and roughs. Predation on eggs was lower in fairways than in roughs, and in plots where ant populations were reduced by insecticides. When 1,600 individual 1st-instar cutworms were placed near L. neoniger nests on putting greens, 62% were attacked and killed upon their 1st encounter with the ants. Third- and 4th-instar cutworms generally fended off attacks by L. neoniger and Formica pallidifulva nitiventris Emery, but were invariably killed during encounters with Formica schaufussi Mayr and Formica subsericea Say, larger ants that are common in lawns and golf roughs. Predation on implanted Japanese beetle eggs also tended to be greater in roughs than in fairways, and fewer grubs were found in areas of golf roughs where ants were abundant than where ants had been controlled. This study suggests that predation by indigenous ants provides an important buffer against pest outbreaks on lawns and golf courses.