Oviposition Preferences of the Polyphagous Moth Choristoneura parallela (Lepidoptera: Tortricidae): Effects of Plant Species, Leaf Size, and Experimental Design

Abstract

The fireworm Choristoneura parallela (Robinson) is a major pest of cranberry in New Jersey. Eggs typically are laid on the leaves of various weed species, and larvae disperse onto cranberry by ballooning. We used laboratory-reared moths and greenhouse experiments to investigate oviposition preferences among 3 weed species: greenbrier, Smilax rotundifolia L.; leatherleaf, Chamaedaphne calyculata (L.); and sheep laurel, Kalmia angustifolia L. In no-choice tests conducted in screen cages using cuttings, leatherleaf received the most egg masses whereas the other species did not differ. In this test there were no differences among species in the latency to the 1st egg mass; and the latency between the 1st and 2nd egg masses did not differ for greenbrier compared with the other species but was shorter for leatherleaf than for sheep laurel. The results were similar in 3-way choice tests conducted in screen cages using cuttings with leatherleaf receiving the highest percentage of egg masses and the other species not differing. However, a different preference hierarchy was found in 3-way choice tests conducted in plastic boxes using a single leaf of each species: greenbrier received the highest percentage of egg masses, leatherleaf received more than sheep laurel, and sheep laurel received no egg masses. Two-way choice tests using paired leaves in plastic boxes showed that larger greenbrier and leatherleaf leaves were preferred over smaller ones of the same species, but that leatherleaf was preferred over sheep laurel even when sheep laurel leaves were larger. These results demonstrate that this moth exhibits oviposition preferences among plant species but that the preference hierarchy depends on the experimental situation, and that both the species and the size of individual leaves can be factors.