Gypsy moth preference and performance was assessed for a number of oak species important in eastern forest and urban landscapes. Preference of second instar caterpillars was assessed using leaf disks in a series of two-choice tests for eight oak species, including black (Quercus velutina), burr (Q. macrocarpa), cherrybark (Q. pagodifolia), pin (Q. palustris), northern red (Q. rubra), swamp white (Q. bicolor), white (Q. alba), and willow (Q. phellos) oaks. Burr, cherrybark, and black oak were most preferred, and willow and northern red were the least preferred of the species tested. Performance tests were run using fourth instar larvae fed foliage from burr, cherrybark, northern red, pin, and willow oaks, and relative growth rate (RGR), relative consumption rate (RCR), and development time (length of larval stadium) were measured. There were significant differences among the five oak species in gypsy moth larval growth, consumption, and development (P=0.0005, P=0.002, and P<0.001 respectively). Caterpillars reared on pin oak foliage had the greatest growth and consumption rates and the shortest development time. Although caterpillar performance was greatest on pin oak, pin oak was only intermediate in caterpillar preference. Caterpillars fed willow oak foliage had similar growth and consumption rates, but developed more slowly and were among the least preferred. Burr oak, the most preferred of the species tested, ranked poorly with respect to caterpillar growth, consumption, and development time. We also measured leaf toughness and calculated leaf density. Leaf toughness and density were not consistently correlated with gypsy moth larval preference or performance, suggesting physical leaf characteristics play a minor role influencing gypsy moth success on oak.
Species 1: Lepidoptera Lymantriidae Lymantria dispar (L.) (gypsy moth)
Species 2: Fagales Fagaceae Quercus palustris (pin oak)
Species 3: Fagales Fagaceae Quercus phellos (willow oak)
Keywords: preference, performance
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA