FEEDING PATTERNS AND ATTACHMENT ABILITY OF ALTICA-SUBPLICATA (COLEOPTERA, CHRYSOMELIDAE) ON SAND-DUNE WILLOW

To investigate feeding patterns of a specialist herbivore, Altica subp licata, larvae and adults were caged separately on host plants, Salix cordata, and leaf damage was estimated. Young, relatively more pubesce nt leaves near the tops of the shoots were consumed more than older le aves. Larvae clearly preferred the young, pubescent leaves and avoided the oldest leaves. Adults showed a stronger preference for the first five young leaves, but amount of consumption did not differ among the older leaves. Attachment ability on smooth and pubescent leaves was ex amined as a possible factor influencing feeding patterns. Scanning ele ctron microscopy of tarsal adhesive structures and leaf surfaces was c onducted to investigate how A. subplicata attaches to its host. Adhesi ve setae on the tarsi of adults may be effective for attachment on the older, smooth leaves and their tarsal claws are likely used to cling to trichomes of pubescent leaves. Larvae have fleshy adhesive pads for attachment. Laboratory experiments on attachment of larvae and adults to smooth and pubescent leaves under various wind conditions showed t hat wind caused difficulty in attachment and movement, but leaf pubesc ence did not affect the number of beetles that fell off leaves. Howeve r, larvae fell off more quickly when placed on pubescent leaves. Thus, other factors such as nutritional quality and microclimate provided b y trichomes may be responsible for the preference for pubescent leaves exhibited by A. subplicata.