Consumption of Foliage of Juvenile and Mature Red Oak Trees by Late Instar Gypsy Moth Larvae12

Abstract

By using sleeve cages, daily consumption of red oak foliage, Quercus rubra L., by 4th, 5th, and 6th larval instars of Lymantria dispar (L.) was found to average 3.5, 7,6, and 9.5 cm2, respectively. Older larvae consumed more foliage, although consumption differences between 5th and 6th instars were not significant. A regression describing sleeve-cage consumption was developed: Y = −8.20 + 3.00X, when Y = mean daily consumption of a larva in cm2 of foliage, and X = the larval instar (R2 = 0.61). A 2nd regression that also considered precipitation during the feeding trial was developed: Y1 = −12,22 + 3.97X, −270X2 when Y1 = the mean daily consumption of a larva, X1 = the larval instal, and X2 = the amount of precipitation (R2 =0.71). Addition of the precipitation term explained an additional 10% of the observed variation; this suggests that less feeding occurs during rainy weather.