T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Beetle (Eucalyptus tortoise) Paropsis charybdis

Kingdom: Animalia

Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Chrysomelidae
Subfamily: Chrysomelinae
Genus: Paropsis
Species: P. charybdis
Binominial name: Paropsis charybdis
Common name: Eucalyptus tortoise beetle

Paropsis charybdis is a small (6-8mm long) beetle that is native to Australia. The beetle is stout and is strongly convex. Its back looks like a tiny tortoise, hence its common name ‘Eucalyptus tortoise beetle’. The beetle colour can vary from a straw-colour to reddish-brown, with darker marks on the back.

Throughout New Zealand it a pest and is responsible for a decline in planting the Eucalyptus nitens tree, a species widely favoured for wood fibre. Other species of Eucalyptus grown in New Zealand can be defoliated to some extent by this tortoise beetle and this has virtually curtailed the planting of the Eucalyptus species as a commercial crop. Both the larvae and adults feed on the leaves leaving the margins heavily scalloped. In time a tree can loose most of its leaves. Heavy and repeated defoliations will kill the tree. Paropsis charybdis nymphs and adults hide during the day under loose bark and feed at night.

The adult beetles over winter under leaf litter or under loose bark, emerging in spring before feeding and beginning oviposition. Through studies done in laboratories it is though that female are capable of laying 1500-2000 eggs in batches of 10-30 over several months. Because mating usually occurs after the beginning of oviposition there can be a large number of infertile eggs at the beginning of laying. There are two generations of Paropsis charybdis per year. Eggs take about 14-21 days to hatch. After the eggs hatch the larvae go through four larval stages (instars). The late instar larvae drop to the leaf litter on the ground below to pupate. They emerge as second generation adults.

Full grown larvae are usually yellowish but sometimes they are pinkish. They are covered with black spots and there is a dark stripe running down each side. When disturbed or alarmed the larva extrudes a pair of horn-like processes from near the rear end and ejects a strong-smelling spray.

A larva of the eucalyptus tortoise beetle.