Population study of Malacosoma americanum in Prunus serotina.

Abstract

Eastern tent caterpillars (Malacosoma americanum) are a pest species, which aggregate in silk tents constructed in the crotches of a variety of different host trees. Adult tent caterpillars oviposit egg masses on the thin outward branches of trees during early spring. I investigated whether or not the tent caterpillar population on a plot of black cherry trees (Prunus serotina) is increasing or decreasing based on the current number of tents and egg masses. I took a variety of measurements including: the coordinates of the tree, DGH, canopy area, height, number of egg masses per tree, height of each egg mass, distance from the end of the branch for each egg mass, direction of the egg mass (N or S), number of tents per tree, direction of the tents (N or S). I also examined where females chose to oviposit and looked at where the tents were located. I expected to find the oviposition sites towards the ends of the cherry tree branches. I predicted that the tents and the egg masses would be found predominantly on the southern sides of the cherry trees, since tent caterpillars are thermoregulated. I found that egg masses were positively correlated with DGH of the cherry trees. Egg masses were a mean distance of 9.89 cm away from the end of the branches and there were an average of 124 eggs/egg mass. There was no significant difference in the number of egg masses and tents on the North versus South side of the cherry trees. Also, the cherry trees showed a clumped distribution and the tent caterpillars were randomly distributed. Our results also showed that the tent caterpillar population is stable, with a predicted caterpillar population of 3782 caterpillars.