USE OF A SECONDARY HOST BY NON-OUTBREAK POPULATIONS OF THE GYPSY MOTH'

摘要: Oak species are the favored host of gypsy moth populations in north- eastern United States, although herbivore expands its range dramatically during an outbreak. Pitch pine, a secondary because unacceptability for early devel- opment, was found to be frequently used oviposition oak-pitch pine forests with non-outbreak populations. This observation led study ecological and behavioral factors that can contribute use under low-density conditions by irruptive species. A series manipulative field laboratory experiments plus natural history provided data on pattern pitch life cycle moth, effect larval growth, differential impact enemies depending use. I (1) egg masses occurred far more than expected based frequency populations; (2) laboratory, early-instar larvae could not survive while late-instar grew well; (3) field, began feed rest after onset fourth instar. Compared oak, (4) experienced less parasitism; (5) microhabitat held nuclear polyhedrosis virus (NPV), major mortality agent moth; (6) individuals hatching from eggs laid were infected NPV; (7) dosed known amount NPV survived longer when feeding foliage. The appeared beneficial may have important population dynamics. mobility associated switching dispersal first-instar oviposited unacceptable food represent mechanism host-range extension.