Asian longhorned beetle phenology: evaluating the effects of host wood moisture on time to pupation and adult eclosion

The Asian longhorned beetle (ALB), Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), is a high risk alien invasive species in the U.S., considered to have been introduced in larval form within solid wood packing material entering U.S. ports across the past 10 years. Alterations to environmental conditions have been found to constrain the lifecycle development of ALB. Early studies by Keena (2002) found correlations between ambient temperature and the timing of pupation. We report results from experimental manipulations of host wood quality, as measured by the moisture content of artificial diet, on metrics of lifecycle development. Declining host wood moisture content is seen to be correlated with decreased time to pupation and adult eclosion.

Three populations of Asian longhorned beetles were reared from egg hatch through adult eclosion under controlled laboratory conditions. Experimental treatments comprised artificial diet for which the moisture content was manipulated to replicate a range of naturally occurring conditions within host trees.

Results of this study support the hypothesis that host wood moisture content influences lifecycle development in the Asian longhorned beetle, revealing statistically significant differences in mean time to pupation and adult eclosion between treatment groups, as well as lower mean body mass across development in treatment groups reared with artificial diet with lower moisture content. Declining host wood quality may cue later-instar larvae developing within the sapwood to complete pupation and adult eclosion sooner than would occur within unstressed host trees.