Humble beginnings of the Australian giant wood moth ( Endoxyla cinereus ): A century‐old mystery solved

Abstract

The Australian giant wood moth, Endoxyla cinereus (Cossidae), is a major forestry pest whose later instars bore into the trunks and branches of Eucalyptus , but the early larval stages have remained unknown for over a century. Using DNA analysis, we identified larvae collected from galls formed by scale insects (Apiomorpha spp.), as En. cinereus . This relationship was tested by rearing over 100 000 neonate larvae on alternative potential food resources including active galls of scale insects ( Apiomorpha munita and A. crispa). Only larvae assigned to galls fed and developed into later instars. The complete life cycle of this moth was also confirmed by rearing a gall‐fed larvae to adulthood over 2 years after establishment in a tree (Eu. tereticornis). This two‐phase developmental strategy explains how larvae bridge the large size gap between hatching and tree establishment and provides a mechanism for the high reproductive output and dispersal bottlenecks of this species.