Relationship between vulnerability of willow plants and preferences of ladybeetles to willow plant volatiles.

<p>Leaf areas damaged by five larvae of leaf beetle <i>Plagiodera versicolora</i> until pupation was defined as an index of vulnerability of willow plants (mean ± S.E., N = 10). The relative residence time of predatory ladybeetles <i>Aiolocaria hexaspilota</i>, attracted by willow plant volatiles was defined as an index of the preferences of the ladybeetles (mean ± S.E., N = 30). Odour source: (A) infested plants and (B) uninfested plants. Erio: <i>Salix eriocarpa</i>; Chae: <i>S. chaenomeloides</i>; Inte: <i>S. integra</i>; Miya: <i>S. miyabeana</i>; Jess: <i>S. jessoensis</i>; Grac: <i>S. gracilistyla</i> and Tria: <i>S. triandra</i>.