Transactions of the Royal Society of South Australia

Mode of access: Internet.

Ecology of Leptocoris Hahn (Hemiptera: Rhopalidae) Soapberry Bugs in Australia

Soapberry bugs are worldwide seed predators of plants in the family Sapindaceae. Australian sapinds are diverse and widespread, consisting of about 200 native trees and shrubs. This flora also includes two introduced environmental weeds, plus cultivated lychee (Litchi chinensis Sonn.), longan (Dimocarpus longan Lour.) and rambutan (Nephelium lappaceum L.). Accordingly, Australian soapberry bugs may be significant in ecology, conservation and agriculture. Here we provide the first account of their ecology. We find five species of Leptocoris Hahn in Australia, and list sapinds that do and do not serve as reproductive hosts. From museum and field records we map the continental distributions of the insects and primary hosts. Frequency of occupation varies among host species, and the number of hosts varies among the insects. In addition, differences in body size and beak length are related to host use. For example, the long-beaked Leptocoris tagalicus Burmeister is highly polyphagous in eastern rainforests, where it occurs on at least 10 native and non-native hosts. It aggregates on hosts with immature fruit and commences feeding before fruits dehisce. Most of its continental range, however, matches that of a single dryland tree, Atalaya hemiglauca F. Muell., which has comparatively unprotected seeds. The taxon includes a smaller and shorter-beaked form that is closely associated with Atalaya, and appears to be taxonomically distinct. The other widespread soapberry bug is the endemic Leptocoris mitellatus Bergroth. It too is short-beaked, and colonises hosts phenologically later than L. tagalicus, as seeds become more accessible in open capsules. Continentally its distribution is more southerly and corresponds mainly to that of Alectryon oleifolius Desf. Among all host species, the non-native environmental weeds Cardiospermum L. and Koelreuteria Laxm. are most consistently attacked, principally by L. tagalicus. These recent host shifts have biocontrol implications. In contrast, the sapinds planted as fruit crops appear to be less frequently used at present and mainly by the longer-beaked species.

The ecology and evolution of invasive Potamopyrgus antipodarum in Australia

The spread of invasive organisms is one of the greatest threats to ecosystems and biodiversity worldwide. Understanding the evolutionary and ecological factors responsible for the transport, introduction, establishment and spread of invasive species will assist the development of control strategies. The New Zealand mudsnail, Potamopyrgus antipodarum (Gray 1843) (Gastropoda: Hydrobiidae), is a global freshwater invader, with populations established in Europe, Asia, the Americas and Australia. While sexual and asexual P. antipodarum coexist in the native range, invasive populations reproduce by parthenogenesis, producing dense populations that compete for resources with native species. Potamopyrgus antipodarum is a natural model system for the study of evolutionary and ecological processes underlying invasion. This thesis assesses the invasion history, genetic diversity and ecology of P. antipodarum in Australia, with particular focus on: a) potential source populations, b) distribution and structure of populations, and c) species traits related to the establishment, persistence and spread of invasive P. antipodarum. Genetic analyses were carried out on specimens collected for this study from New Zealand and Australia, along with existing museum samples. In combination with published data, the analyses revealed low genetic diversity among and within invasive populations in south-eastern Australia, relative to New Zealand populations. Phylogenetic relationships inferred from mitochondrial sequences indicated that the Australian populations belong to clades dominated by parthenogenetic haplotypes that are known to be present in Europe and the US. These ‘invasive clades’ are likely to originate from the North Island of New Zealand, and suggest a role for selection in determining genetic composition of invasive populations. The genotypic diversity of Australian P. antipodarum was low, with few, closely related clones distributed across south-eastern Australia. The pattern of clone distribution was not consistent with any assessed geographical or abiotic factors; instead a few, widely-distributed clones were present in high frequencies at most sites. Differences in clone frequencies were found, which may indicate differential success of clonal lineages. A range of traits have been proposed as facilitators of invasion success, and within-species variation in these traits can promote differential success of genotypes. Using laboratory-based experiments, the performance of the three most common Australian clones was tested across a suite of invasion-relevant traits. Ecologically-relevant variation in traits was found among the clones. These differences may have determined the spatial distribution of clones, and may continue to do so into the future. This thesis found that the P. antipodarum invasion of Australia is the result of few introductions of a small number of globally-invasive genotypes that vary in ecologically-relevant traits. From a source of considerable genetic diversity in the native range, very few genotypes have become invasive. Those that are invasive appear to be very successful at continental scales. These findings highlight a capacity in asexual invaders to successfully invade, and potentially adapt to, a broad range of ecosystems. The P. antipodarum invasion system is amenable to research using combinations of field-based studies, molecular and laboratory approaches, and is likely to yield significant, broadly-applicable insights into invasion.

37° Sur a 19° Norte: Fotografía contemporánea de Australia

Curatorial considerations, aims and objectives:The title for this exhibition (37 ° South to 19 ° North) refers to the Latitude of Melbourne, Australia and Cuernavaca, Mexico.My curatorial objective for making such a reference to the geographical was to invoke a sense of both distance and connection between the two locations of Australia and Mexico and to also create a sense of sharing, not only between our distant landscapes and cultures but also between the feelings and emotions that we all experience in response to the places in which we live out the moments which make up our daily lives.In developing this project I considered the work of more than 35 contemporary Australian photographers and finally selected 15 photographers (including myself). Most of these artists have or have had close connection to Melbourne and to the southern/eastern line of Australian continent. The final selection ranged from Hobart to Maroochydore and one artist who had lived in Melbourne for many years but was now living in Mexico. These photographers (and the specific works) were selected because their long term creative practice captures a sense of location (place and space) with a deep introspective sensibility which I feel offers a viewer a personal and softly spoken vision of some particular aspect of an Australian location, be that exterior landscape or interior place and a sense of unique connection to such places. These images are not documents but rather representations of feelings, stories, memories and dreams which emerge in the milieu of our inhabitants.In selecting the works, careful consideration was also given to diversity of approaches to photographic practice in conjunction to thematic content. Formats and media included black and white, pin hole photography, toy camera, large format (both 4” x 5” and 10”x 8”), phone camera, various digital camera images and other experimental approaches. The local art scene in Cuernavaca is very strong and there is a strong interest in photography. This is partially due to the number of local arts schools and universities which offer studies in photography as well as the political dimension regarding Mexican art in general - as a tool of both political media, reportage and documentary work, photography is a significant medium for many of the people who would be visiting the exhibition. I therefore felt it was important to address the diversity of approaches to the medium which are currently being explored by Australian practitioners.The City Museum of Cuernavaca provided two large walls and some smaller sections of side walls on both the grounds level and the upper level of the main museum galleries for exhibition.The works were arranged with a simple thematic structure. Top level, left to right, then bottom level, left to right starting with images which presented a sense of wilderness and landscape (which were also quite abstract and reductive) to more representational landscape images moving to landscape with small figures (people) emerging within the images (Ash Kerr) to landscapes with larger figures and the emerging presence of man-made elements to urban landscapes and then to interior urban scapes and finally to interior locations with people and finally finishing on the metaphorical image by Harry Nankin of Bogong Moths and the politics of climate change. (It is also interesting to note that the migration path of the Bongong moth matches well the distribution of the artists selected for this project)Broadly speaking the images started outside with broad landscape to intimate interior locations. With these works a great deal of personal content from each photographer was presented. Most artists chose to present 3 large format images while some only presented 2 images. Other graphic and visual elements were considered in the final placement of the images.It must also be noted that the artists selected ranged broadly from very highly established and significant local artists to mid-career/younger establishing artist to some lesser known and emerging artists. From a curatorial perspective I feel this is offers the possibility of what I shall term, a more balanced representation of the local Australian practice and it provides a context in which both established and emerging artists / works must engage on a dialogue, within the exhibition. I believe it also placing the curatorial premise on the strength of the work rather than on whom the artists are and their status. It also supports the younger emerging artists and provides a less formal and predictable outcome for the established artists and for as a collective presentation as a whole.