Eastern tent caterpillars: an exploration of the preferred host tree.

Abstract

Eastern tent caterpillars (Malacosoma americanum) are specialist herbivores on the Rosaceae family, particularly on black cherry trees (Prunus serotina). However, variation in tent occurrence and defoliation exists within populations of black cherry trees. This variation was exemplified in Waldron's Fen in Emmet County, Michigan in the spring of 2010. Black cherry trees were surveyed at the fen to see whether tree size and relative isolation from other trees affected tent occurrence. Additionally, caterpillars from the fen were raised in the lab to track weight gain in three groups each receiving a different food type: leaves from favored black cherry trees, unfavored black cherry trees, and sweet cherry trees.It was found that defoliation was higher in densely populated cherry plots and was lower in a plot densely populated with other non-cherry tree species. There were also trends indicating that trees with smaller DBHs and those that were more isolated from other trees had higher tent occurrences. It was also found that the optimal range for height of tent to be between 2 and 2.5m in height. The caterpillars that were fed unfavored black cherry leaves in the first cohort collected had significantly higher growth than the other groups. The caterpillars fed both black cherry leaf types in second cohort collected grew significantly larger than those fed sweet cherry. However, there was not a significant difference between nitrogen and phosphorus levels between the three food categories. All of these results suggest that selection may favor female moths that choose host trees with these characteristics.