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

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

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 Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. The larvae are a serious pest of ''

Eucalyptus ''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as euca ...

'' 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 other wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingspan of ...

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 (pronounced ) ( mi, Tāmaki Makaurau) is a large metropolitan city in the North Island of New Zealand. The List of New Zealand urban areas by population, most populous urban area in the country and the List of cities in Oceania by po ...

. 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 ''Meteorus'' is a genus of parasitoid wasps in the family Braconidae. It comprises over 330 species worldwide. ''Meteorus'' wasps are distinguished from other braconid wasps by the presence of a second submarginal cell in the forewing and a pet ...

'' 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