''Uraba lugens'', the gum-leaf skeletoniser, is a

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

of the family

Nolidae Nolidae is a family of moths with about 1,700 described species worldwide. They are mostly small with dull coloration, the main distinguishing feature being a silk cocoon with a vertical exit slit. The group is sometimes known as tuft moths, aft ...

. It is found in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. The larvae are a serious pest of ''

Eucalyptus ''Eucalyptus'' () is a genus of more than 700 species of flowering plants in the family Myrtaceae. Most species of ''Eucalyptus'' are trees, often Mallee (habit), mallees, and a few are shrubs. Along with several other genera in the tribe Eucalyp ...

'' species and their close relatives. The

wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingsp ...

is 25–30 mm. In Australia there are about one or two generations per year.Mansfield S, Kriticos DJ, Potter KJB, Watson MC (2005) Parasitism of gum leaf skeletoniser ( Uraba lugens) in New Zealand. New Zealand Plant Protection 58, 191–196.Berndt LA, Mansfield S, Withers TM (2007) A method for host range testing of a biological control agent for Uraba lugens. New Zealand Plant Protection 60, 286–290.

General

''Uraba lugens'' is nicknamed the mad hatterpillar because of its distinctive exoskeletal feature. Every time it sheds the head portion of its exoskeleton, the exoskeleton stays attached to its body. Over time, developing through its life span, the head grows bigger and sheds increasingly larger exoskeleton shells, which build upon each other. ''Uraba lugens'' develops as a typical moth. The life cycles occur twice a year: once in the summer and once in the winter. Eggs are laid in groups of 100–200 and are about 1 mm in diameter. Caterpillars are mostly yellow with some black markings. After hatching from a cocoon, the resulting moths are grey in colour. During the larval stage, ''Uraba lugens'' can cause damage to trees by chewing.

Pest

In 2001, an infestation of ''U. lugens'' was discovered in south-west

Auckland Auckland ( ; ) is a large metropolitan city in the North Island of New Zealand. It has an urban population of about It is located in the greater Auckland Region, the area governed by Auckland Council, which includes outlying rural areas and ...

. By 2007, the population had established throughout the greater Auckland area and was still spreading. Management programmes were created and potential biological control agents were tested. Because the ''U. lugens'' is also found in Australia, and extensive

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

networks already exist there, four Australian parasitoids were quarantined in New Zealand and tested for their efficiency in controlling the New Zealand population. These species were larvae parasitoids '' Cotesia urabae'', '' Dolichogenidea eucalypti'', '' Euplectrus'' species and larvae/pupal parasitoid '' Eriborus'' species. Native New Zealand species were also tested for biological control, as it would be preferable to use native species rather than imported species if there was enough parasitism to suppress the pest population. The two native species assessed were '' Meteorus pulchricornis'' and '' Xanthopimpla rhopaloceros'', both being pupal parasitoids. Both were unsuccessful for biological control. ''M. pulchricornis'' had a higher parasitism rate of alternative hosts than that of the target host, and ''X. rhopaloceros'' failed to recognise the target host when they did not have cocoons. Of the four species imported, ''D. eucalypti'' did not survive transport, the ''Eriborus'' species did not reproduce in captivity, and ''Euplectrus'' species were lost after one generation. Parasitism rates and non-target effects including negative and positive effects were assessed. ''C. urabae'' was considered the most successful, as it successfully attacked ''U. lugens'', survived multiple generations and had preferred to attack ''U. lugens'' when choice of hosts was present.

References

{{Taxonbar, from=Q7899534 Nolinae Moths of Australia Moths of New Zealand Moths described in 1866