Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact email@example.com with any questions.
Body temperatures in ectotherms are strongly affected by their thermal environment. Ectotherms respond to variation in the thermal environment either by modification of behavioural thermoregulation to maintain their optimal body temperature or by shifting their optimal body temperature. In this study, the body temperatures of males of three populations of spotted snow skinks, Niveoscincus ocellatus, living along an altitudinal gradient (low, mid, and high altitude) were studied in the field and laboratory in spring, summer, and autumn, representing the full activity period of this species. The environmental variation across both sites and seasons affected their field active body temperatures. At the low and mid altitude, N. ocellatus had a higher mean body temperature than at the high altitude. Animals achieved their thermal preference at the low and mid altitude sites in all seasons. At the high altitude, however, N. ocellatus struggled to reach its preferred body temperatures, especially in autumn. The lower body temperature at the high-altitude site is likely due to limited thermal opportunity and/or an effect of avoiding the costs associated with increased intensity of basking.
The post-breeding migration of an adult male little eagle (Hieraaetus morphnoides) was followed from south-eastern Australia to the Northern Territory using a GPS satellite transmitter. The bird bred in open woodland habitat on the edge of the city of Canberra, Australian Capital Territory (ACT), before it flew more than 3300 km in 18 days, to winter in an area of eucalypt savannah in the Northern Territory. It remained there for 59 days, within a range of ∼30 km2, after which the last signal was transmitted. The bird was subsequently resighted back in its ACT territory at the end of winter, thus completing a return migration. This is the first confirmation of post-breeding migration for the species.
Exudivorous mammals exploit food items of high quality and high rates of renewal, offset by wide dispersion and variable availability. How this influences foraging effort and size-related foraging efficiency remains poorly described. We examined the time budget of 5–6 male and 5–6 female squirrel gliders (Petaurus norfolcensis) during 6–8 nights in each of three seasons that were stratified by moon phase. Radio-collared gliders were observed during a series of 1-h focal observations from dusk until dawn. Feeding dominated the time budget, accounting for 78% of observation time, or 85% of time when combined with behaviours associated with foraging. Females appear to maximise feeding rates before entering the energetically demanding phase of late lactation. Little time was spent resting while outside the den. Longer nights and the full moon were associated with later emergence and earlier retirement times. Animals re-entered their tree-hollow dens during the night, representing 2% of activity in late spring, 18% in winter and 9% in autumn (10% overall). This behaviour may relate to predation risk and lactation demands. We reviewed the percentage of the time budget that petaurid gliders devoted to feeding and found no clear relationship with body size.
Larval amphibians (tadpoles) are an important link in aquatic food webs, as they can be highly abundant consumers and prey for a wide variety of predators. Most tadpoles are considered omnivores, predominately grazing on algae, detritus and macrophytes, though recent work has identified greater plasticity and breadth in diet than previously considered. We used gut content and stable isotope analysis (SIA) in a baseline study to determine the important dietary items (ingested material) and food sources (assimilated material) for tadpoles of two abundant generalist frog species in regulated floodplain wetlands of the Murrumbidgee River, south-east Australia. We identified a wide variety of dietary items in the gut contents, including whole microcrustaceans, filamentous algae and macrophytes. The composition of several ingested food items was correlated with their availability in each wetland. However, SIA identified biofilm as the food source most consistently assimilated across several wetlands, though microcrustaceans and algae contributed when abundant. Biofilm is likely the most important basal food item for tadpoles in floodplain wetlands because it is ubiquitous and has a high nutritional quality. Identifying important food sources is a crucial step towards developing management strategies for promoting tadpole recruitment in regulated wetlands.
Short-tailed pythons (Python breitensteini, P. brongersmai and P. curtus) are exploited in large numbers for the international leather trade, but their ecology remains poorly known. We quantify sexual dimorphism and reproductive output in P. breitensteini from Kalimantan and P. brongersmai from sites in north and south Sumatra. Sexual dimorphism was more evident in P. breitensteini (males less heavy-bodied than females, and with longer heads relative to body length) than in either population of P. brongersmai. Although having a smaller average adult body size, P. breitensteini had a larger clutch size (mean of 17.2 eggs, versus 12.6 and 14.5 in the two brongersmai populations), and a higher reproductive frequency (92% of adult-size females reproductive, versus 38 and 50%). Female pythons from Kalimantan laid their eggs in September through November whereas female P. brongersmai from north Sumatra oviposited from March to May, in keeping with their geographic position either side of the equator. Paradoxically, however, P. brongersmai from south Sumatra apparently lay eggs at the same time as their northern conspecifics, despite their latitudinal position corresponding to our P. breitensteini study site. Reproductive traits within tropical snakes may be more diverse than is currently understood, even within clades of closely related taxa.
The small-eyed snake (Cryptophis nigrescens) is a common non-threatened species in eastern Australia. It coexists with the threatened broad-headed snake (Hoplocephalus bungaroides), a species adversely affected by habitat disturbance and subject to poaching. The small-eyed snake is a habitat generalist and not subject to poaching. It may prey on other snakes, including the broad-headed snake, and, like the broad-headed snake, may shelter under thermally favourable loose rocks during the cooler months of the year. This may lead to interactions between these species due to the limited availability of such rocks, and possibly exacerbate other threats to the broad-headed snake, such as poaching and the loss of thermally favourable rocks. I conducted repeat surveys for snakes at 64 rock outcrops in Royal National Park over a 16-year period. I predicted that site use by the small-eyed snake would not be influenced by a disturbance variable previously documented to influence site use by the broad-headed snake. Observations were consistent with this prediction, confirming the unique vulnerability of the broad-headed snake. I used my long-term data to analyse the co-occurrence of the two species. The broad-headed snake was detected as frequently at sites with and without the small-eyed snake, suggesting that these species occupy outcrops independently of each other. Therefore, interactions with the small-eyed snake will not reduce the effectiveness of habitat restoration for the broad-headed snake in Royal National Park.
Wildlife parasitology is a highly diverse area of research encompassing many fields including taxonomy, ecology, pathology and epidemiology, and with participants from extremely disparate scientific fields. In addition, the organisms studied are highly dissimilar, ranging from platyhelminths, nematodes and acanthocephalans to insects, arachnids, crustaceans and protists. This review of the parasites of wildlife in Australia highlights the advances made to date, focussing on the work, interests and major findings of researchers over the years and identifies current significant gaps that exist in our understanding. The review is divided into three sections covering protist, helminth and arthropod parasites. The challenge to document the diversity of parasites in Australia continues at a traditional level but the advent of molecular methods has heightened the significance of this issue. Modern methods are providing an avenue for major advances in documenting and restructuring the phylogeny of protistan parasites in particular, while facilitating the recognition of species complexes in helminth taxa previously defined by traditional morphological methods. The life cycles, ecology and general biology of most parasites of wildlife in Australia are extremely poorly understood. While the phylogenetic origins of the Australian vertebrate fauna are complex, so too are the likely origins of their parasites, which do not necessarily mirror those of their hosts. This aspect of parasite evolution is a continuing area for research in the case of helminths, but remains to be addressed for many other parasitic groups.