Suitability of Eucalyptus and Corymbia for Mnesampela privata (Guenée) (Lepidoptera: Geometridae) larvae
1 Mnesampela privata (Guenée) has a host list of 40 Eucalyptus and at least one Corymbia species. Larval survival and performance was studied on 19 species to investigate how certain leaf traits influence the suitability of different species.
2 After 7 days, survival on Eucalyptus aggregata and Eucalyptus camphora is greater than 70% even though the toughness of leaves is 0.15–0.19 mg/mm2. However, after the same time, survival on genotypes of Eucalyptus melliodora and Eucalyptus sideroxylon was less than 60%, or even 0%, even though the toughness of some leaves was as low as 0.11 mg/mm2. An unmeasured allelochemical, rather than toughness, may reduce survival on these species.
3 Dry weights of first-instar larvae were negatively correlated with leaf toughness for 13 of the species studied. Species that produced the heaviest first-instar larvae were not the same hosts that produced the heaviest second-instar larvae.
4 Dry weights of female pupae were negatively correlated with total oil content for five of the species studied.
5 Larvae exhibit age-related changes in feeding behaviour. Neonates skeletonize leaves (avoid leaf veins and oil glands) and post-third-instar larvae ingest whole leaf fragments (consume small leaf veins and oil glands). These findings suggest that neonates are sensitive to high leaf toughness and non-oil plant secondary metabolites whereas older larvae are less sensitive to high leaf toughness and are likely to become larger adults on hosts with lower oil contents.
Document Type: Research Article
Affiliations: 1: Co-operative Research Centre for Sustainable Production Forestry, 2: C/– Department of Agriculture–Western Australia, 444 Albany Highway, Albany, WA 6330, Australia and CSIRO Entomology, GPO 1700, Canberra, ACT 2601, Australia
Publication date: November 1, 2004