Effects of dietary moisture content and cut wood of different species on survival and weight of Asian longhorned beetle larvae (Coleoptera: Cerambycidae)

The wood-boring cerambycid Anoplophora glabripennis (Motschulsky), Asian longhorned beetle, is a highly destructive invasive pest that feeds on healthy hardwoods by tunneling under the bark and then within the sapwood as larvae mature. Larval weight gain and survival can be affected by the nutritional content, moisture content, and physical traits of the available food source. In this study, we experimentally manipulated the larval resource quality by controlling the moisture content of artificial diet (70% and 40% moisture) and by inserting larvae into cut wood of 2 different hosts (sugar maple [Acer saccharum Marshall] and gray birch [Betula populifolia Marshall]). First and/or fifth instars from a Chicago, Illinois laboratory colony were used to follow larval survival, weight, and pupation. Artificial diet moisture content did not affect larvae survival; however, larvae reared on a diet containing 70% moisture weighed more on average than those reared on a diet containing 40% moisture for all time intervals weights were taken. First instars reared in cut gray birch were more likely to survive, grow larger, and molt than first instars reared on cut sugar maple (only one larva survived). The species of cut wood did not have a significant impact on the survival, weight gain, or adult emergence of fifth instars. Our findings suggest that this insect's tolerance of highly variable host quality provides it with ample capacity to survive, disperse, and reproduce even when dietary moisture content is low or declining, as might be expected in trees in the late stages of infestation.