title: Contrasting diets reveal metabolic plasticity in the tree-killing beetle, Anoplophora glabripennis (Cerambycidae: Lamiinae).
abstract: Wood-feeding insects encounter challenging diets containing low protein quantities, recalcitrant carbohydrate sources, and plant defensive compounds. The Asian longhorned beetle (Anoplophora glabripennis) is a wood-feeding insect that attacks and kills a diversity of hardwood tree species. We compared gene expression of midguts collected from larvae feeding in a preferred tree, sugar maple, to those consuming a nutrient-rich artificial diet, to identify genes putatively involved in host plant utilization. Anoplophora glabripennis larvae exhibited differential expression of ~3600 genes in response to different diets. Genes with predicted capacity for plant and microbial carbohydrate usage, detoxification, nutrient recycling, and immune-related genes relevant for facilitating interactions with microbial symbionts were upregulated in wood-feeding larvae compared to larvae feeding in artificial diet. Upregulation of genes involved in protein degradation and synthesis was also observed, suggesting that proteins incur more rapid turnover in insects consuming wood. Additionally, wood-feeding individuals exhibited elevated expression of several mitochondrial cytochrome C oxidase genes, suggesting increased aerobic respiration compared to diet-fed larvae. These results indicate that A. glabripennis modulates digestive and basal gene expression when larvae are feeding in a nutrient-poor, yet suitable host plant compared to a tractable and nutrient-rich diet that is free of plant defensive compounds.
authors.affiliation: Department of Entomology and Center for Chemical Ecology, The Pennsylvania State University, University Park, PA 16802 USA.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Mason
authors.affiliation: Stored Product Insect and Engineering Research Unit, USDA, Agricultural Research Service, Center for Grain and Animal Health Research, Manhattan, KS 66502 USA.
authors.forename: Erin D
authors.initials: ED
authors.lastname: Scully
authors.affiliation: Tropical Crop and Commodity Protection Research Unit, USDA, Agricultural Research Service, Daniel K. Inouye Pacific Basin Agricultural Research Center, Hilo, HI 96720 USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Geib
authors.affiliation: Department of Entomology and Center for Chemical Ecology, The Pennsylvania State University, University Park, PA 16802 USA.
authors.forename: Kelli
authors.initials: K
authors.lastname: Hoover