title: Host plant phenology affects performance of an invasive weevil, Phyllobius oblongus (Coleoptera: Curculionidae), in a northern hardwood forest.
abstract: We investigated how host plant phenology and plant species affected longevity, reproduction, and feeding behavior of an invasive weevil. Phyllobius oblongus L. (Coleoptera: Curculionidae) is common in northern hardwood forests of the Great Lakes Region. Adults emerge in spring, feed  on foliage of woody understory plants, and oviposit in the soil. Preliminary data indicate that adults often feed on sugar maple, Acer saccharum Marshall, foliage early in the season, then feed on other species such as raspberry, Rubus spp. Whether this behavior reflects temporal changes in  the quality of A. saccharum tissue or merely subsequent availability of later-season plants is unknown. We tested adult P. oblongus in laboratory assays using young (newly flushed) sugar maple foliage, old (2-3 wk postflush) sugar maple foliage, and raspberry foliage. Raspberry has  indeterminate growth, thus always has young foliage available for herbivores. Survival, oviposition, and leaf consumption were recorded. In performance assays under no-choice conditions, mated pairs were provided one type of host foliage for the duration of their lives. In behavioral choice  tests, all three host plants were provided simultaneously and leaf area consumption was compared. Adults survived longer on and consumed greater amounts of young maple and raspberry foliage than old maple foliage. P. oblongus preferred young maple foliage to old maple foliage early in the  season, however, later in the growing season weevils showed less pronounced feeding preferences. These results suggest how leaf phenology, plant species composition, and feeding plasticity in host utilization may interact to affect P. oblongus population dynamics.
authors.affiliation: University of Wisconsin, Department of Entomology, Madison, WI 53706, USA. drcoyle@wisc.edu
authors.forename: David R
authors.initials: DR
authors.lastname: Coyle
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Jordan
authors.forename: Kenneth F
authors.initials: KF
authors.lastname: Raffa
mesh_terms: D031002:Acer / Q000254:growth & development*; D017677:Age Distribution; D000818:Animals; D017753:Ecosystem; D005260:Female; D005518:Food Preferences; D060434:Herbivory; D008136:Longevity; D008297:Male; D008824:Michigan; D010058:Oviposition; D010571:Pest Control; D018515:Plant Leaves / Q000254:growth & development; D027824:Rosaceae / Q000254:growth & development*; D048889:Weevils / Q000502:physiology*