Occurrence of Lepidoptera on selected host trees in two central Appalachian National Forests

In 1995 and 1906, Lepidoptera larvae of 13 families were sampled by pruning foliage from canopies of maple, hickory, red oak group, white oak, and che stnut oak. The families were Arctiidae, Geometridae, Hesperiidae, Lasiocamp idae, Lycaenidae, Lymantriidae, Noctuidae, Notodontidae, Nymphalidae, Papil ionidae, Saturniidae, Sphingidae, and Thyatiridae. Samples were collected f rom 18 plots (each 200 ha), nine in the George Washington National Forest i n Virginia and nine in the Monongahela National Forest in West Virginia. Sa mpling seasons were from May to mid-August; foliage samples were collected each week. The occurrence of Lepidoptera on host trees within the two fores ts was compared. A total of 131 species of caterpillars representing 13 fam ilies was collected. Most larvae were Noctuidae (47 species) and Geometrida e (44 species). Of 6,743 larvae collected over both years, 57% were gypsy m oth, Lymantria dispar (L.). The population of this species collapsed during the second year of the study because of the fungus Entomophaga maimaiga. O ther particularly abundant species in both forests were Acronicta ovata Gro te, Hyphantria cunea (Drury), Polia latex (Guenee), Melanolophia canadaria (Guenee), Alsophila pometaria (Harris), and Nadata gibbosa (J.E. Smith). So me species were found only in one forest. Larval richness and abundance wer e higher in May and. August and. the lowest numbers occurred in June and Ju ly. Abundance and richness were different for the 2 yr. Population shifts m ay be directly related to weather conditions or indirectly related through the effects of temperature or rainfall patterns on natural enemies, foliage chemistry, or other factors. The number of species of caterpillars collect ed from the host tree groups was 62 on maple,77 on hickory; 76 on the red o ak group, 75 on chestnut oak, and 66 on white oak. The abundance of larvae ranged. from 14.8% collected on maple to 25.4% collected on the red oak gro up.