The survival of platypuses in captivity

Data are presented on the duration of survival of 228 platypuses at six Australian zoos between 1934 and 1988. Only 22.4% of all platypuses survived more than 1 year in captivity. Of 15 living platypuses, 3 had been held in captivity for less than 1 year, 5 for between 1 and 5 years, 6 for between 5 and 10 years and 1 for 21 years. Of 213 platypuses that died in captivity, 81.7% had died within 1 year; most within the first month. The duration of survival was unrelated to the age of animals at acquisition or to sex. The survival rate of animals donated to zoos, including "refugees", was similar to that of purpose-caught animals. Clearly, only a small proportion of platypuses adapted to captive husbandry. The cause of death of most platypuses was not established. However, infectious disease did not appear to be significant. Approximately 28% of deaths were related to inadequate husbandry. Recommendations are made to improve the survival of platypuses in captivity. Research has commenced in zoos to facilitate this goal.     

Epizootics of sudden death in tammar wallabies (Macropus eugenii) associated with an orbivirus infection

Epizootics of sudden death in tammar wallabies (Macropus eugenii) occurred at six research facilities and zoological gardens in New South Wales, Australia, in late 1998 and at one Queensland research facility in March 1999. There were 120 confirmed tammar wallaby deaths during this period; however, population censuses indicated that up to 230 tammar wallabies may have died. The majority of animals died without premonitory signs. A small proportion of wallabies exhibited increased respiratory rate, sat with a lowered head shortly before death or were discovered in lateral recumbency, moribund and with muscle fasciculations. Gross postmortem findings consistently included massive pulmonary congestion, mottled hepatic parenchyma and subcutaneous oedema throughout the hindlimbs and inguinal region. Approximately 30% of the animals examined also had extensive haemorrhage within the fascial planes and skeletal muscle of the hindlimb adductors, inguinal region, ventral thorax, dorsal cervical region and perirenal retroperitoneal area. The tissues of affected animals became autolytic within a short period after death. Bacteriological examination of tissues from 14 animals did not provide any significant findings. Toxicological examination of the gastric and colonic contents of four animals did not reveal evidence of brodifacoume or other rodenticides. Viruses from the Eubenangee serogroup of the Orbivirus genus were isolated from the cerebral cortex of nine, and the myocardium of two, tammar wallabies and the liver and intestine of another tammar wallaby. A similar orbivirus was also isolated from the cerebrospinal fluid of another tammar wallaby that died suddenly. The disease agent appears to be a previously unrecognised orbivirus in the Eubenangee serogroup. This is the first report of epizootics of sudden deaths in tammar wallabies apparently associated with an orbivirus infection.     

Comparison of light- and temperature-based index models for potato (Solanum tuberosum L.) growth and development

Robust and simple methods of normalizing for the weather of particular growing seasons enable improved in-season decisions, such as supplemental fertilizer timing. Common methods involve expressing the progress of the season in terms of degree-days or cumulative incident solar radiation, in contrast to days after planting or emergence. This study compared a newly introduced temperature-derived variable, “relative thermal index” (RTI) based on a modified beta distribution model, with growing degree day (GDD), physiological day (Pday), and cumulative photosynthetically active radiation (PAR), for their ability in normalizing for seasonal differences in growth and development of well-managed commercial potato fields of cvs Russet Burbank and Russet Norkotah in humid, temperate central Wisconsin. The proposed RTI was superior to all other investigated variables in reducing the standard deviation of crop mass among field-years through full canopy development, after which PAR became the more powerful normalization. Values of 15, 27, and 30 RTI corresponded to tuber initiation onset, canopy full interception of light, and tuber-bulking onset, respectively, for both varieties; RTI values were more consistent across the two varieties for these stages than were other variables. Presumably RTI was superior to other thermal time indices because it more appropriately reflected the dependence of potato growth rate on relatively cool temperatures.     

Investigations into the toxicity of Echium plantagineum in sheep: 2. Pen feeding experiments

In a pen feeding trial fresh Echium plantagineum was fed as the sole diet to crossbred sheep with or without a history of previous access to the plant. Control groups received a diet of lucerne chaff and oats. During the trial, sheep on the Echium diet lost weight and deaths occurred with histological evidence of excessive copper accumulation, usually accompanied by pyrrolizidine alkaloid damage, in the liver and biochemical evidence of liver toxicity. It is concluded that E. plantagineum alone is not a suitable fodder for sheep and can be toxic due to its pyrrolizidine alkaloid content and high copper to molybdenum ratio.     

Lithospheric Contributions to Arc Magmatism: Isotope Variations Along Strike in Volcanoes of Honshu, Japan

Major chemical exchange between the crust and mantle occurs in subduction zone environments, profoundly affecting the chemical evolution of Earth. The relative contributions of the subducting slab, mantle wedge, and arc lithosphere to the generation of island arc magmas, and ultimately new continental crust, are controversial. Isotopic data for lavas from a transect of volcanoes in a single arc segment of northern Honshu, Japan, have distinct variations coincident with changes in crustal lithology. These data imply that the relatively thin crustal lithosphere is an active geochemical filter for all traversing magmas and is responsible for significant modification of primary mantle melts.     

For the public good: weaving a multifunctional landscape in the Corn Belt

Critics of modern agriculture decry the dominance of monocultural landscapes and look to multifunctionality as a desirable alternative that facilitates the production of public goods. In this study, we explored opportunities for multifunctional Midwestern agriculture through participatory research led by farmers, landowners, and other local actors. We suggest that agriculture typically fosters some degree of multifunctionality that arises from the divergent intentions of actors. The result is a scattered arrangement of what we term patchwork multifunctionality, a ubiquitous status quo in which individuals provide public goods without coordination. In contrast, interwoven multifunctionality describes deliberate collaboration to provide public goods, especially those cases where landowners work across fence lines to weave a synergistic landscape. Using examples from two case studies, we demonstrate the spectrum of patchwork and interwoven multifunctionality that currently exists in the Corn Belt, and present underutilized opportunities for public good creation.     

The Anatomy and Chemistry Of “Rubbery” Wood in Apple Var. Lord Lambourne

The anatomy of a one-year-old vertical normal stem of apple var. Lord Lamboume was compared with that of a comparable stem infected with rubbery wood virus and with that of a normal stem caused to undergo an anatomical georeaction by bending it at right angles to the vertical. The stem anatomy of 5-year-old orchard trees showing rubbery wood symptoms was compared with that of comparable normal trees. Staining reactions and investigations using light, polarizing and ultra-violet microscopes, and X-ray diffraction techniques established the anatomical identity of rubbery and georeaction wood.

Rubbery wood resembled georeaction wood in having a lignin content less than that of normal wood. It differed from georeaction wood in that oxidation of its lignin produced a molar ratio of syringaldehyde to vanillin which was less than that from normal wood lignin. Rubbery wood gave a yield of milled wood lignin greater than that of normal wood. This suggests that the lignin of rubbery wood is less firmly bound to the polysaccharide framework. This could account for the greater flexibility of rubbery wood.