Destructive Forest Cockchafers: Gut Microbes Help Beetles Digest Wood

Dec. 19, 2012 — Apart from the common European cockchafer (Melolontha melolontha), the European forest cockchafer (Melolontha hippocastani) is the most common species of the Melolontha genus. These insects can damage huge areas of broadleaf trees and conifers in woodlands and on heaths. Cockchafers house microbes in their guts that help them to digest their woody food, such as lignocelluloses and xylans. Scientists of the Max Planck Institute for Chemical Ecology in Jena, Germany, have now performed comprehensive RNA analyses and identified the microbiota of cockchafer larvae feeding on roots and of the adult beetles feeding on leaves.

Surprisingly, the guts of adult beetles house the same microbial species that were present in the larval midgut − despite having metamorphosized from larva to beetle. These microbes include clostridia as well as other bacterial species that are as yet unknown. Moreover, only a small percentage of the microbes living in the gut originated from the roots or leaves the larvae or beetles were feeding on. These microbes seem to be characteristic bacterial symbionts with which the forest cockchafer has long been associated.

Continued:  http://www.sciencedaily.com/releases/2012/12/121219133427.htm