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NT Naturalist - Number 25, Published March 2014

ISSN: 0155-4093

Editor: Richard Willan

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1. First report of a lacaziosis-like disease (LLD) observed in the Australian Snubfin Dolphin (Orcaella heinsohni) in Darwin Harbour, Northern Territory, Australia

AuthorsCarol Palmer and Amanda Peterson
AbstractA lacaziosis-like disease (LLD) was photographed on the skin of three Australian Snubfin Dolphins (Orcaella heinsohni) in Darwin Harbour in 2008 and 2010, and this represents the first report of the skin disease recorded in Australia on this species of dolphin. Lacaziosis-like disease is considered non-lethal, but it could be indicative of decreasing water quality and/or exposure to potentially immunosuppressive anthropogenic or environmental pressures. Photo-identification data provides an efficient and cost-effective approach for documenting the occurrence of LLD and monitoring for the prevalence and incidence of skin lesions in a dolphin population.
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2. A bird in the hand is not always easily identified: Description of downy chicks of Chestnut-backed Button-quail (Turnix castanotus) from Cobourg Peninsula, Northern Territory, Australia

AuthorsSimon J. Ward and Stuart Young
AbstractA clutch of four downy button-quail chicks was captured in a pitfall trap on Cobourg Peninsula, without an adult bird to aid identification. We believe they were Chestnutbreasted Button-quail and provide a description and reasons for this identification.
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3.

AuthorsAmanda Lilleyman and Bastiaan J. Hensen
AbstractThe Asian subspecies Gelochelidon nilotica affinis of Gull-billed Tern breeds in Asia and migrates to northern Australia during its non-breeding season, which is the Australian wet season/summer. A substantial non-breeding population of this tern occurs in northwestern Australia and it is also an uncommon but regular visitor to the northern coasts of Queensland. However, G. nilotica affinis remains infrequently reported in the Top End. This fact has prompted us formally to report its occurrence in the Darwin region. Interestingly, our own and other recent reports fall outside its normal wet season/summer visiting period in northern Australia. We comment on the importance of recognising and recording this migratory tern, which is separable from the Australian-breeding subspecies (G. affinis macrotarsa) with some care in the field, and include some guidelines to identification of these terns in the field.
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4. Management of Brazilian Joyweed (Alternanthera brasiliana) in the Casuarina Coastal Reserve, Darwin, Australia

AuthorsRichard C. Willan
AbstractFor the past 20 years, the only locality in the Darwin region in which Brazilian Joyweed (Alternanthera brasiliana) has been recorded outside cultivation is the Casuarina Coastal Reserve. This article documents its recent proliferation as ‘spot fires’ in disturbed and undisturbed woodland habitats in the central western section of the Coastal Reserve, as well as its spread to woodland at Charles Darwin University’s Brinkin campus on the southern extremity of the Coastal Reserve. Both are probably marginal or sub-optimal locations in terms of the species’ full range of habitats. This article also profiles Brazilian Joyweed’s identifying characteristics and ecology, in particular those aspects that make it an opportunistic invader, and management options in the Coastal Reserve. There, Brazilian Joyweed is spreading, outcompeting native species thereby threatening the ecosystem, and contravening the visual aesthetics of the Reserve. Brazilian Joyweed causes dermatitis and asthma in some people, and is not consumed by – that is, not controlled by – any vertebrate or invertebrate herbivore. These undesirable characteristics, when taken together, render its eradication in the Coastal Reserve and the University campus highly desirable. The populations in both localities should be, and indeed can successfully be, eliminated at the present time. However, the more wet seasons these populations remain unchecked, the harder eradication will become.
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5. Remarks on the spatial distribution of some butterflies and diurnal moths (Lepidoptera) in the Top End of the Northern Territory, Australia

AuthorsMichael F. Braby
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6. A review of the diet of flower wasps (Hymenoptera: Thynnidae: Thynninae)

AuthorsGraham R. Brown and Ryan D. Phillips
AbstractThe feeding preferences of Australian flower wasps (Thynnidae: Thynninae) are reviewed based on the available literature, a search of a specimen database of almost 8,000 records and an examination of selected representatives of all described genera for the presence of pollen. The vast majority of records of feeding by flower wasps are on nectar, but they also feed on the exudates of scale insects, leafhoppers and aphids. The plants visited most frequently are from the family Myrtaceae, with most other families represented by only a small number of records. Interestingly, there are almost no records from several of Australia’s most diverse plant families. It remains to be tested if members of the Myrtaceae show specific adaptations to pollination by flower wasps or if there is variation in wasp morphology in response to variation in diet. Future dietary studies of flower wasps should aim to quantify both floral and other food sources to aid in understanding the ecological requirements of these wasps and how they co-exist in such diverse communities.
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7. Changes in dominance of dipteran families on Coral Sea cays over ten years during a period of substantial vegetation change

AuthorsDeborah Rich, Penelope Greenslade and Dan Bickel
AbstractThe habitat on the Coringa-Herald group of coral cays within the northern Coral Sea underwent profound change after about 2000 because of extensive dieback of the dominant forest trees. This work summarises surveys on these cays in 1995, 1996, 1997 and 2007, in order to understand the effect on the native insect fauna of the introduced biological control agent, the non-specific predatory ladybird beetle Cryptolaemus montrouzieri (Coleoptera: Coccinellidae), that was liberated to control scale insects (Hemiptera: Coccidae) whose infestation was responsible for the dieback of the forest trees. This paper documents the families of Diptera (flies) collected on the surveys and it records changes in presence and abundance of Chloropidae, Phoridae, Sarcophagidae, Canacidae, Lonchaeidae and Chironomidae sampled in pitfall traps and yellow pans. Despite some differences in collecting methods and seasons between surveys, there is evidence of substantial changes in the presence and relative abundance of these families. The decline of several families on Coringa Cay and on North East Herald Cay between 1995/96 and 2007 could be the result of a trophic cascade of species loss following tree dieback. One of the most conspicuous changes was that Chloropidae increased on North East Herald Cay between 1997 and 2007 following increases in populations of scale insects, but chloropids are not thought to have had a direct role in the control of scale insects.
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