Evidence for limited dispersal of larval gypsy moth, Lymantria dispar L (Lepidoptera: Lymantriidae)

From 1985 through 1995, burlap flaps were stapled to 100 trees in a 10 by 10 grid in a 4-ha forest plot. Each year, the number of fourth- to six-instar larvae of gypsy moth, Lymantria dispar L., under each burlap flap was recorded at least weekly in June and into July. From 1987 through 1990, 100 000 - 120 000 hatching gypsy moth larvae were released near the center of this plot in early May at the time of natural hatch. Tn the 4 years that releases occurred, there was a distinct, single cluster of large larvae under the burlap flaps near the center of the plot. This pattern did not occur in other years. Results are interpreted to mean that total dispersal of larvae from first to ultimate instar is limited, even though first instars are readily dispersed by wind.