scholarly journals Myxomatosis on the Western Plains of Victoria

1977 ◽  
Vol 79 (2) ◽  
pp. 209-217 ◽  
Author(s):  
F. G. Tighe ◽  
J. W. Edmonds ◽  
I. F. Nolan ◽  
Rosamond C. H. Shepherd ◽  
A. Gocs
Keyword(s):  
Myxoma Virus ◽  
Eastern Australia ◽  
Selection For

SUMMARYMyxomatosis on the Western Plains is an enzootic disease in contrast with the epizootic pattern which is general in eastern Australia. The most unusual aspects are the presence of significant numbers of diseased rabbits throughout the winter and the continuously low percentage of rabbits with antibodies to myxoma virus.Climatic and topographic conditions are unsuited to the production of the high densities of mosquitoes necessary for widespread epizootics. Under these conditions the effects of less efficient methods of myxomatosis transmission are apparent. The unusual epidemiology of myxomatosis has resulted in selection for virulence of the virus similar to that which has occurred under summer epizootic conditions. All field strains are now in the mid range of virulence.

Nest-tree selection by the threatened brush-tailed phascogale (Phascogale tapoatafa) (Marsupialia:Dasyuridae) in a highly fragmented agricultural landscape

2006 ◽  
Vol 33 (2) ◽  
pp. 113 ◽  
Author(s):  
Rodney van der Ree ◽  
Andrew F. Bennett ◽  
Todd R. Soderquist
Keyword(s):  
Wildlife Conservation ◽  
Agricultural Landscape ◽  
Intensive Study ◽  
Spatial And Temporal Patterns ◽  
Canopy Tree ◽  
Roadside Vegetation ◽  
Eastern Australia ◽  
Standing Trees ◽  
Scattered Trees ◽  
Selection For

The conservation of roosting and nesting resources is of critical concern for many hollow-dependent species around the world. We investigated the nest-tree requirements of the threatened brush-tailed phascogale (Phascogale tapoatafa) in a highly cleared agricultural landscape in south-eastern Australia. We documented the physical characteristics of selected nest trees and describe the spatial and temporal patterns of nest-tree use as revealed by radio-tracking. Nine phascogales (seven females, two males) were radio-tracked between March and July 1999 in an area where most woodland habitat is confined to linear strips along roads and streams or small patches and scattered trees in cleared farmland. Female phascogales were monitored for 13–35 days over periods of 5–15 weeks and two males were monitored for 2 and 9 days respectively. A total of 185 nest-tree fixes was collected and all nests occupied by phascogales were in standing trees. Eighty-three nest trees were identified, ranging in diameter at breast height (dbh) from 25 to 171 cm, with a mean dbh for the trees used by each individual phascogale of >80 cm. Phascogales did not discriminate between canopy tree species in selecting nest trees, but showed highly significant selection for trees in the largest size class. All individuals used multiple nest trees, with the seven females occupying an average of 11.4 nest trees from a mean of 25 diurnal locations. The number of nest trees continued to increase throughout the study, suggesting that more would be identified during a longer or more intensive study. Occupied nest trees were located throughout each individual’s home range, highlighting the importance of a continuous spatial distribution of suitable nest trees across the landscape. Nest trees were also located in adjacent farmland up to 225 m from roadside vegetation, demonstrating the value that scattered clumps and even single trees in farmland can have for wildlife conservation.

Communal Nesting in the Digger Wasp Cerceris australis (Hymenoptera : Sphecidae)

1982 ◽  
Vol 30 (4) ◽  
pp. 557 ◽  
Author(s):  
HE Evans ◽  
AW Hook
Keyword(s):  
Body Size ◽  
Ovarian Development ◽  
Egg Laying ◽  
Nest Construction ◽  
Digger Wasp ◽  
Short Period ◽  
Eastern Australia ◽  
A Cell ◽  
Selection For ◽  
Successive Generations

Study of 39 nests of Cerceris australis at nine localities in eastern Australia has demonstrated that most nests are occupied by two or three successive generations of wasps and may ultimately contain well over 100 cells. Nests are dug deep in the soil and are provisioned with scarab beetles, which are allowed to accumulate in the burrow before from two to six are placed in a cell. Nests are usually occupied by several females, some of which are provisioners, bringing in beetles day after day and each time leaving the nest usually after only a few seconds, and others are non-provisioners, leaving the nest for a short period once a day and returning without prey. During the day, nest entrances are occupied by females (believed to be usually non-provisioners) stationed facing out; they are effective in deterring the entry of ants and mutillids. The factors that determine what role a female will play remain obscure. Both provisioners and non-provisioners show progressive mandibular wear as well as essentially similar ovarian development; there are no consistent differences in body size between members of the two groups. In any one nest, considerable variation in the appearance of the ovaries is apparent, and oosorption appears to be common. More than one female often appears to be in egg-laying condition, and the fact that cooperating provisioners bring in enough beetles each day to provision several cells suggests that more than one female lays an egg each day. However, the presence of oocytes in various stages of resorption suggests that in some individuals oviposition is suppressed. No correlation was found between extent of oosorption and the provisioner-nonprovisioner dichotomy. The necessity to guard these large, multicellular nests from parasitoids and predators has evidently brought about selection for the development of a caste of guards which, however, continue to play a role in nest construction and presumably in laying eggs on beetles provided by other females.

scholarly journals Selection for resistance to myxomatosis in domestic rabbits (Oryctolagus cuniculus)

1969 ◽  
Vol 67 (4) ◽  
pp. 743-754 ◽  
Author(s):  
W. R. Sobey
Keyword(s):  
Data Analysis ◽  
Survival Time ◽  
Oryctolagus Cuniculus ◽  
Probit Analysis ◽  
Myxoma Virus ◽  
Response To Selection ◽  
Selection For ◽  
Domestic Rabbits

SUMMARY1. Response to selection was achieved with all strains of Myxoma virus used.2. Heritability of resistance to myxomatosis was determined by intra-sire correlation using survival time as an index and by an all-or-none probit analysis. Both resulted in an estimate of heritability of about 35–40%.3. The ability of animals to survive myxomatosis varied widely with environ mental variation in time.I am indebted to W. Menzies for his very able assistance in all aspects of the work; to Dorothy Conolly for her critical assistance with data analysis, and to Dr J. M. Rendel for suggesting the probit analysis for determining heritability.

A winter epizootic of myxomatosis in subalpine south-eastern Australia

1971 ◽  
Vol 19 (3) ◽  
pp. 275 ◽  
Author(s):  
JD Dunsmore ◽  
RT Williams ◽  
WJ Price
Keyword(s):  
Social Contact ◽  
Myxoma Virus ◽  
Infection Transmission ◽  
South Eastern ◽  
Rabbit Population ◽  
Slow Progression ◽  
Eastern Australia ◽  
The Common ◽  
Case Mortality ◽  
Established Population

An epizootic of myxomatosis in rabbits that occurred during the winter months (March-August) of 1969 is described in detail. Virus of virulence grade 111, the common virulence of field strains of myxoma virus presently in Australia, was isolated during the epizootic. The estimated case mortality was 86% over the 5 months during which the epizootic was active. Only 41228 of the original susceptible and established population completely avoided infection. Transmission through the population was relatively slow and apparently depended on social contact between individual rabbits. The seasonal conditions and the slow progression of the disease through the population make it most unlikely that mosquitoes were involved in transmitting the virus. The origin of the virus that initiated the epizootic is discussed, including the possibility that it was not a reintroduction of myxoma virus to the population. This implies that the virus may have remained latent in the rabbit population for several years.

Recurrent selection for grazing tolerance in winter-active populations of the perennial grass, Phalaris aquatica L.

2006 ◽  
Vol 12 ◽  
pp. 89-92
Author(s):  
Richard Culvenor ◽  
Suzanne Boschma ◽  
Kevin Reed
Keyword(s):  
Recurrent Selection ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Soil Conditions ◽  
Environment Interaction ◽  
Response To Selection ◽  
North West ◽  
Phalaris Aquatica ◽  
Eastern Australia ◽  
Selection For

Phalaris (Phalaris aquatica L.) is a perennial grass of Mediterranean origin used widely by the sheep and cattle industries of south-eastern Australia. Winter-active cultivars released since the 1970's have the potential for higher herbage productivity than the earlier, semi-winter dormant cultivars but have been reported to be less persistent under sub-optimal grazing management and soil conditions. To improve genetic potential for persistence in winter-active phalaris, a program of recurrent selection was conducted by subjecting three populations of half-sib families to two cycles of selection for persistence under heavy, largely continuous grazing pressure. Cycle 2 progeny families and bulked seedlots of each generation were grown in separate grazed plot trials in Western Victoria and the Southern Tablelands and North-West Slopes of New South Wales from 1999-2003 to assess response to selection. Positive linear response to selection was observed in all populations at the Western Victorian and Southern Tablelands sites. Response to selection was absent and persistence was very low under higher temperature and drought stress on the North-West Slopes. This high level of genotype × environment interaction for persistence was also observed among final generation families. Families with better persistence than current winteractive cultivars at the two southern sites were identified in each population and a new cultivar is being formed from the parents.

Variation in some floral, seed, and growth characteristics of Acacia harpophylla (Brigalow)

1971 ◽  
Vol 19 (3) ◽  
pp. 335 ◽  
Author(s):  
JE Coaldrake
Keyword(s):  
Numerical Methods ◽  
Seed Size ◽  
Geographic Range ◽  
Growth Characteristics ◽  
Substantial Variation ◽  
Australian Species ◽  
Eastern Australia ◽  
North Eastern ◽  
Selection For ◽  
Increasing Temperature

Statistical and other numerical methods of analysis were used to examine variation in Acacia harpophylla (brigalow), a species of wide occurrence in north-eastern Australia. Experiment indicated that the species is largely cross-pollinated. From material collected in the field floret counts, seed size, longevity, and imbibition and germination rates all revealed substantial variation, possibly of a clinal type, within the species. In a glasshouse experiment with 255 seedlings measurement of 19 characters revealed wide differences in morphology, growth, and ontogeny. Over the geographic range sampled, much of the variation found would be consistent with selection for adaptation to increasing temperature and aridity. It is suggested that analogous variation may occur in other Australian species of Acacia.

Relationships among leaf flammability attributes and identifying low-leaf-flammability species at the wildland–urban interface

2019 ◽  
Vol 28 (4) ◽  
pp. 295 ◽  
Author(s):  
Daniel W. Krix ◽  
Megan L. Phillips ◽  
Brad R. Murray
Keyword(s):  
Risk Management ◽  
Functional Trait ◽  
Species Selection ◽  
Emergent Properties ◽  
Leaf Water Content ◽  
Leaf Mass Per Area ◽  
Wildland Urban Interface ◽  
Plant Functional Trait ◽  
Eastern Australia ◽  
Selection For

Leaf flammability is a multidimensional plant functional trait with emerging importance for wildfire risk management. Understanding relationships among leaf flammability attributes not only provides information about the properties of leaves as fuels in the wildland–urban interface (WUI), it can also offer an effective way to identify low-leaf-flammability species. We examined relationships between leaf ignitibility, sustainability and combustibility among 60 plant species of the WUI of eastern Australia. We found that leaf ignitibility and sustainability worked in opposition to each other as dimensions of flammability. Species with leaves that were slow to ignite were those with leaves that sustained burning for the longest, whereas species with leaves that were fast to ignite had leaves that burned for the shortest periods of time. Low leaf combustibility was related to short leaf burning sustainability but not to ignitibility. We created an overall leaf flammability index (OLFI) to rank species on emergent properties of ignitibility, sustainability and combustibility attributes in combination. We found that low-leaf-flammability species with low OLFI values had small leaf area, high leaf mass per area and high leaf water content. Our findings have implications for species selection for green firebreaks in the WUI.

The Litoria ewingi complex (Anura : Hylidae) in south-eastern Australia III. Blood protein variation across a narrow hybrid zone betweeen L. ewingi and L. Paraewingi

1972 ◽  
Vol 20 (4) ◽  
pp. 435 ◽  
Author(s):  
DF Gartside
Keyword(s):  
Hybrid Zone ◽  
Molecular Forms ◽  
Direct Selection ◽  
Blood Protein ◽  
Electrophoretic Study ◽  
Genetic Incompatibility ◽  
Protein Variation ◽  
Eastern Australia ◽  
Selection For ◽  
High Level

An electrophoretic study of transferrin distribution across a narrow hybrid zone between L. ewingi and L. paraewingi revealed seven molecular forms of transferrin. The transferrin frequencies and distribution may be an incidental product of the high level of genetic incompatibility between the taxa, or the result of direct selection for different transferrin types, or both. Haemoglobin variation was found only in L. ewingi samples. In most cases haemoglobins of L. ewingi and L. paraewingi were electrophoretically identical. The position and width of the hybrid zone, based on the biochemical data, generally agree with dimensions based on other criteria, although one transferrin cline is wider than those for other characteristics.

scholarly journals Studies in the epidemiology of infectious myxomatosis of rabbits: I. Recovery of Australian wild rabbits (Oryctolagus Cuniculus) from myxomatosis under field conditions

1953 ◽  
Vol 51 (2) ◽  
pp. 225-244 ◽  
Author(s):  
Frank Fenner ◽  
I. D. Marshall ◽  
Gwendolyn M. Woodroofe
Keyword(s):  
Mortality Rate ◽  
Neutralizing Antibodies ◽  
Complement Fixation ◽  
Small Population ◽  
Myxoma Virus ◽  
Rabbit Population ◽  
Eastern Australia ◽  
Before And After ◽  
Grade Ii ◽  
Case Mortality

1. Australian wild rabbits which had recovered from myxomatosis acquired in the field contained in their serum antibodies which could be detected by complement-fixation or neutralization tests for a long period (more than 18 months) after their recovery. The titre of complement-fixing antibody fell fairly rapidly during the first few months, and remained at a steady level thereafter. No change could be detected in the titre of neutralizing antibodies throughout the observation period.2. Inoculation of such rabbits with myxoma virus was sometimes followed by the development of a local lesion at the inoculation site, and in these rabbits the titre of complement-fixing antibody rose, but there was no alteration in the neutralizing power of the serum. In other animals no lesion developed and there was no change in the antibody titre.3. Serum was collected from a total of 824 wild rabbits from seventeen localities in eastern Australia with varying histories of myxomatosis since December 1950. Examination of 135 of these sera by both neutralization and complement-fixation tests showed that the results obtained by the two methods were in close agreement.4. In many areas in which the disease was absent in the summer of 1950–1 and produced a violent epizootic in 1951–2, the majority (70–90 %) of the sera collected from rabbits 2–5 months after the height of the epizootic contained antibody to myxoma virus, i.e. the majority of the survivors had recovered from the disease.5. Counts of the rabbit population before and after a violent epizootic in the summer of 1951–2, and the proportion of immune animals amongst the survivors in these areas showed that the case-mortality rate was between 99·4 and 99·8%.6. Consideration of the results obtained in the serological surveys showed that the case-mortality rate was probably of this order (about 99·5%) in all areas in which there had been no disease or a negligible outbreak in 1950–1, whether they had a grade I or grade II kill in 1951–2.7. In certain other areas, in which a grade I outbreak in 1950–1 was followed by a grade II or poorer kill in 1951–2, the observed immune rate was considerably higher than would be expected if the case-mortality rate (assuming that the whole rabbit population was susceptible) was 99·5%. The possible causes of this are discussed. Survival of immune survivors from the first epizootic through the second may be a factor of some importance, but it is probably not the only factor involved.8. The areas just mentioned were exceptional. In most places there was either no build-up of population after the 1950–1 epizootic, or a second effective epizootic destroyed the majority of rabbits in the small population which had developed by reproduction of the survivors of the first outbreak.

Selection for seed retention in Phalaris tuberosa L.

1963 ◽  
Vol 14 (6) ◽  
pp. 755 ◽  
Author(s):  
JR McWilliam
Keyword(s):  
Genetic Variation ◽  
Perennial Grass ◽  
Economic Problem ◽  
Base Population ◽  
Response To Selection ◽  
Seed Shattering ◽  
Commercial Strain ◽  
Seed Retention ◽  
Eastern Australia ◽  
Selection For

Loss of seed from the maturing inflorescence (seed shattering) is common in grasses and constitutes a serious economic problem in many species. This paper reports the results of artificial selection to improve seed retention in Phalaris tuberosa, an important perennial grass in south-eastern Australia. A study of the factors controlling the loss of seed in this species has revealed that the seed lies free within the inflorescence at maturity, and its loss is promoted by the opening of the glumes. This in turn is influenced by the structure of the inflorescence. The highest seed retention has been found in plants with a short rigid inflorescence containing a large number of densely packed spikelets. Wide variation for seed retention exists between strains of P. tuberosa. The lowest value (25%) was found for natural ecotypes from Algeria and Morocco, and the highest for a selection from a strain of the Australian commercial type obtained from Argentina (81%). An estimate of the heritability for seed retention was high (0.92 ± 0.11), and most of the genetic variation appeared to be additive. There was a marked response to selection for high seed retention. With the Argentine variety as the base population, an increase of 29% in the average level of seed retention was achieved from the first cycle of selection. This level represents an increase of 60% by comparison with the widely grown commercial strain. The importance of high seed retention in relation to the economics of Phalaris seed production is briefly discussed.

Sign in / Sign up

Export Citation Format

Share Document