Population genetic structure of the red fox (Vulpes vulpes) in the UK

The red fox (Vulpes vulpes) is common and widely distributed within the UK. It is a carrier or potential carrier of numerous zoonotic diseases. Despite this, there are no published reports on the population genetics of foxes in Britain. In this study, we aim to provide an insight into recent historical movement of foxes within Britain, as well as a current assessment of the genetic diversity and gene flow within British populations. We used 14 microsatellite markers to analyse 501 red fox samples originating from England, southern Scotland and northern France. High genetic diversity was evident within the sample set as a whole and limited population genetic structure was present in British samples analysed. Notably, STRUCTURE analysis found support of four population clusters, one of which grouped two southern England sampling areas with the nearby French samples from Calais, indicating recent (post-formation of the Channel) mixing of British and French populations. This may coincide with reports of large-scale translocations of foxes into Britain during the nineteenth century for sport hunting. Other STRUCTURE populations may be related to geographic features or to cultural practices such as fox hunting. In addition, the two British urban populations analysed showed some degree of differentiation from their local rural counterparts.

Biotic effects of climate change in urban environments: The case of the grey-headed flying-fox (Pteropus poliocephalus) in Melbourne, Australia

Urban climates are known to differ from those of the surrounding rural areas, as human activities in cities lead to changes in temperature, humidity and wind regimes. These changes can in turn affect the geographic distribution of species, the behaviour of animals and the phenology of plants. The grey-headed flying-fox (Pteropus poliocephalus) is a large, nomadic bat from eastern Australia that roosts in large colonies known as camps. Historically a warm temperate to tropical species, P. poliocephalus recently established a year-round camp in the Royal Botanic Gardens Melbourne. Using a bioclimatic analysis, we demonstrated that on the basis of long-term data, Melbourne does not fall within the climatic range of other P. poliocephalus camp sites in Australia. Melbourne is drier than other summer camps, and cooler and drier than other winter camps. The city also receives less radiation, in winter and annually, than the other summer and winter camps of P. poliocephalus. However, we found that temperatures in central Melbourne have been increasing since the 1950s, leading to warmer conditions and a reduction in the number of frosts. In addition, artificial watering of parks and gardens in the city may contribute the equivalent of 590 mm (95% CI: 450–720 mm) of extra rainfall per year. It appears that human activities have increased temperatures and effective precipitation in central Melbourne, creating a more suitable climate for camps of the grey-headed flying-fox. As demonstrated by this example, anthropogenic climate change is likely to complicate further the task of conserving biological diversity in urban environments.

Hunting the unobservables for optimal social security a general equilibrium approach

We study the optimal size of a pay-as-you-go social security program for an economy composed of both permanent-income and hand-to-mouth consumers. While previous work on this topic is framed within a two-period partial equilibrium setup, we study this issue in a life-cycle general equilibrium model. Because this type of welfare analysis depends critically on unobservable preference parameters, we methodically consider all parameterizations of the unobservables that are both feasible and reasonable—all parameterizations that can mimic key features of macro data (feasible) while still being consistent with micro evidence and convention (reasonable). The baseline model predicts that the optimal tax rate is between 6 percent and 15 percent of wage income.

Multi-robot hunting in dynamic environments

This paper is concerned with multi-robot hunting in dynamic environments. A BCSLA approach is proposed to allow mobile robots to capture an intelligent evader. During the process of hunting, four states including dispersion-random-search, surrounding, catch and prediction are employed. In order to ensure each robot appropriate movement in each state, a series of strategies are developed in this paper. The dispersion-search strategy enables the robots to find the evader effectively. The leader-adjusting strategy aims to improve the hunting robots’ response to environmental changes and the outflank strategy is proposed for the hunting robots to force the evader to enter a besieging circle. The catch strategy is designed for shrinking the besieging circle to catch the evader. The predict strategy allows the robots to predict the evader’s position when they lose the tracking information about the evader. A novel collision-free motion strategy is also presented in this paper, which is called the direction-optimization strategy. To test the effect of cooperative hunting, the target to be captured owns a safety-motion strategy, which helps it to escape being captured. The computer simulations support the rationality of the approach.

Hunting Plato's Agalmata

In this essay I argue that to understand Plato's philosophy, we must understand why Plato presented this philosophy as dialogues: namely, works of literature. Plato's writing of philosophy corresponds to his understanding of philosophy as a transformative way of life, which must nevertheless present itself politically, to different types of people. As a model, I examine Lacan's famous reading of Plato's Symposium in his seminar of transference love in psychoanalysis. Unlike many other readings, Lacan focuses on Alcibiades' famous description of what caused his desire for Socrates: the supposition that beneath Socrates' Silenus-like language and appearance, there were agalmata, treasures, hidden in his belly. I argue that this image of Socrates can also stand as an image for how we ought to read and to teach Plato's philosophy: as harbouring different levels of insight, couched in Plato's philosophy as literature.

Field metabolic rate and body water turnover of the red fox (Vulpes vulpes) in Australia

We measured the daily energy expenditure of free-living red foxes Vulpes vulpes occupying a temperate region of New South Wales, Australia. Field metabolic rate (FMR) and body water turnover were estimated using doubly labelled water. In autumn, male body mass ranged from 5 to 6.1 kg (mean 5.6 kg) and their FMRs averaged 2328 kJ/day. Female body mass in autumn ranged from 4.9 to 6.6 kg (mean 5.4 kg) and their FMRs averaged 1681 kJ/day. Body water influx for males and females was 314 and 251 mL/day, respectively. Body composition of each fox was analysed after the field measurements and revealed a significant correlation between body water content, as estimated from tritiated water space, and body lipids (r² = 0.72). This supports the use of body water determination as a potentially non-destructive method to gauge body condition.

Cooperative hunting by distributed mobile robots based on local interaction

This paper proposes a distributed control approach called local interactions with local coordinate systems (LILCS)to multirobot hunting tasks in unknown environments, where a team of mobile robots hunts a target called evader, which will actively try to escape with a safety strategy. This robust approach can cope with accumulative errors of wheels and imperfect communication networks. Computer simulations show the validity of the proposed approach.

Effects of a fox removal program on small and medium-sized mammal population dynamics within the Anglesea Heathlands, Victoria

This thesis assessed the diet of foxes within the ALCOA lease area of Anglesea to determine which native and introduced species foxes were eating. Results showed that Swamp Wallaby was regularly eaten but many other mammals, birds, insects and reptiles were also consumed. The response of native mammals to seasonal fox removal was also determined.

Conditioned taste aversion reduces fox depredation on model eggs on beaches

Context:  Conditioned taste aversion (CTA) is induced by an association of a food item with a negative experience, such as illness, which causes animals to avoid subsequent consumption of that particular food item. Inducing CTA may help reduce depredation rates of threatened fauna where predator population control is undesirable, impractical or unsuccessful.

Aims:  We investigated whether CTA could be induced among foxes (Vulpes vulpes) to model eggs which mimicked those of the threatened hooded plover (Thinornis rubricollis).

Methods:   Model eggs treated with a potential CTA-inducing chemical (sodium carbonate) and control eggs free of the agent were exposed to fox depredation for 28 days to simulate a hooded plover incubation period. To investigate whether CTA would persist in wild foxes, we implemented a part-time agent treatment (an initial 14 day exposure period of model eggs with the CTA agent followed by a second 14 day period when model eggs were free of the agent).

Key results:  Similar intervals to the first depredation event were found for all model eggs regardless of treatment. After the first depredation event by foxes, the rate and likelihood of fox depredation was significantly lower in treated eggs than in control eggs. The likelihood or rate of depredation across the three treatments did not differ between the first and second periods.

Conclusions: Our results suggest that during an exposure period of at least 28 days, CTA can be induced in wild foxes to eggs on beaches. Our results also suggest that 14 days may be insufficient time for wild foxes to develop a lasting CTA to familiar food items such as eggs.

Implications:  Treatment of eggs with a CTA-inducing chemical may present a viable alternative to traditional predator control techniques for hooded plovers, as well as other ground-nesting birds, provided that an extended exposure to the CTAinducing agent occurs.

Piggyback hunting-browsing the internet in Australia via unsecured wireless networks : virtual theft or acceptable behaviour in an online world?

In a world that is increasingly dominated by the Internet, there is a growing demand for low cost access at the users convenience. The expansion of wireless Internet networks, in particular unsecured wireless Internet networks, gives rise to novel challenges for the regulation of Internet access. The ability to access unsecured wireless Internet networks with ease and with very little impact upon the owner of the network suggests that such 'piggybacking' may be criminal behaviour or may amount to an actionable civil wrong. This paper will explore the legal ramifications of piggybacking an unsecured wireless network with knowledge that there is no entitlement to the use of the network and will consider what Australian authorities should do about this situation. This paper will look at the position in Australia and juxtapose this with that of the United Kingdom and the United States of America. In both the United Kingdom and the United States of America prosecutions have taken place of individuals who knowingly accessed unsecured wireless
networks for their own personal use.

Hoarding of pulsed resources : temporal variations in egg-caching by arctic fox

Resource pulses are common in various ecosystems and often have large impacts on ecosystem functioning. Many animals hoard food during resource pulses, yet how this behaviour affects pulse diffusion through trophic levels is poorly known because of a lack of individual-based studies. Our objective was to examine how the hoarding behaviour of arctic foxes (Alopex lagopus) preying on a seasonal pulsed resource (goose eggs) was affected by annual and seasonal changes in resource availability. We monitored foraging behaviour of foxes in a greater snow goose (Chen caerulescens atlanticus) colony during 8 nesting seasons that covered 2 lemming cycles. The number of goose eggs taken and cached per hour by foxes declined 6-fold from laying to hatching, while the proportion of eggs cached remained constant. In contrast, the proportion of eggs cached by foxes fluctuated in response to the annual lemming cycle independently of the seasonal pulse of goose eggs. Foxes cached the majority of eggs taken (> 90%) when lemming abundance was high or moderate but only 40% during the low phase of the cycle. This likely occurred because foxes consumed a greater proportion of goose eggs to fulfill their energy requirement at low lemming abundance. Our study clearly illustrates a behavioural mechanism that extends the energetic benefits of a resource pulse. The hoarding behaviour of the main predator enhances the allochthonous nutrients input brought by migrating birds from the south into the arctic terrestrial ecosystem. This could increase average predator density and promote indirect interactions among prey.

Predator behaviour and predation risk in the heterogeneous Arctic environment

1. Habitat heterogeneity and predator behaviour can strongly affect predator–prey interactions but these factors are rarely considered simultaneously, especially when systems encompass multiple predators and prey.

2. In the Arctic, greater snow geese Anser caerulescens atlanticus L. nest in two structurally different habitats: wetlands that form intricate networks of water channels, and mesic tundra where such obstacles are absent. In this heterogeneous environment, goose eggs are exposed to two types of predators: the arctic fox Vulpes lagopus L. and a diversity of avian predators. We hypothesized that, contrary to birds, the hunting ability of foxes would be impaired by the structurally complex wetland habitat, resulting in a lower predation risk for goose eggs.

3. In addition, lemmings, the main prey of foxes, show strong population cycles. We thus further examined how their fluctuations influenced the interaction between habitat heterogeneity and fox predation on goose eggs.

4. An experimental approach with artificial nests suggested that foxes were faster than avian predators to find unattended goose nests in mesic tundra whereas the reverse was true in wetlands. Foxes spent 3·5 times more time between consecutive attacks on real goose nests in wetlands than in mesic tundra. Their attacks on goose nests were also half as successful in wetlands than in mesic tundra whereas no difference was found for avian predators.

5. Nesting success in wetlands (65%) was higher than in mesic tundra (56%) but the difference between habitats increased during lemming crashes (15%) compared to other phases of the cycle (5%). Nests located at the edge of wetland patches were also less successful than central ones, suggesting a gradient in accessibility of goose nests in wetlands for foxes.

6. Our study shows that the structural complexity of wetlands decreases predation risk from foxes but not avian predators in arctic-nesting birds. Our results also demonstrate that cyclic lemming populations indirectly alter the spatial distribution of productive nests due to a complex interaction between habitat structure, prey-switching and foraging success of foxes.