346 research outputs found

    Fear Of Predators Compromises Parental Care And Juvenile Survival In A Songbird

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    Predators kill, but the risk of being killed is also a powerful force affecting survival because scared prey eat less, thereby increasing the likelihood of starvation. Young of most animals are extremely vulnerable to predators and may alter their behaviour to limit detection. I investigated the previously unexplored effects that predation risk has on the behaviour of newly fledged offspring and their parents, and the impact this has on offspring survival. I manipulated predation risk using sound and found that parent song sparrows reduced their feedings, providing 60% less food overall. Critically, not only did this parental response estimate survival of individual offspring, it allowed me to project that the number of surviving fledglings decreased by ~24%, and fear overall reduced the number of offspring produced per year by ~54%. Counter to my expectation, song sparrow fledglings actually appear to be increasing their auditory detectability in response to reduced provisioning due to their parents’ response

    The behavioural ecology and predator-prey interactions of leopards (Panthera pardus) and chacma baboons (Papio ursinus) in an Afromontane environment

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    The interactions between predators and prey have long been considered to play an important role in behaviour, physiology, and evolution. Both predators and prey can influence one another’s spatial and temporal patterns in activity and space use. To understand such dynamic processes, one must simultaneously assess the behavioural ecology of both predator and prey within the same environment. Such analyses have been rare in primatology. With the aid of behavioural, telemetry, and environmental data collected between the years 2012 and 2017, a combination of methods including home range analyses, resource selection functions, activity pattern analyses and spatial regression models were used to independently test hypotheses relating to space use and activity patterns in chacma baboons (Papio ursinus) and their main predator, the leopard (Panthera pardus) within the western Soutpansberg Mountains, South Africa. Collectively, the results allowed me to test hypotheses about how baboons spatially and behaviourally respond to the threat posed by predation. The utilisation of spatial-temporal data deriving from two sympatric species provides not only a detailed assessment on how such animals independently use their environment yet is a novel approach for understanding the complex dynamics of predator-prey interactions. My results showed that leopards established home ranges in topographically complex and highly vegetated areas while avoiding humans and also preferentially used areas of dense vegetation. Leopards were also less active in these areas, preferentially resting in areas of cover and away from human activity. Although primarily crepuscular, leopards shifted their behaviour when in proximity to humans with an increase in nocturnal activity, with day length and weather also influencing their activity scheduling. Despite the presence of leopards on the landscape, baboons primarily avoided areas that were perceived to be risky from the threat imposed by other baboon groups rather than leopards. In contrast, the probability of encountering leopards had the biggest influence on spatial variation in vigilance. In confirmation of previous studies, risk effects exceeded the importance of food availability in determining range use, although baboons selected areas of greater food availability during winter when food was shortest suggesting that they trade off an increase in risk for foraging opportunities at these times. Despite clear seasonal constraints on behaviour in winter, however, the baboons did not appear to compensate with increased nocturnal activity at these times. This study highlights the value of integrating information on both predators and prey into studies of primate-predator interactions and suggests potential avenues for future research

    Learning Strategies in Coopetitive Environments

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    The objective of this chapter is to explore the learning strategies that can be deployed by firms in coopetitive configurations with no other choice than deploying an “adverse learning” mechanism to reach their customers through cooperation with their competitors. After exploring the mechanisms of asymmetric learning in a first section, the chapter adopts an ecological perspective (Hawley, 1950) in drawing parallels between animal organization and groups of firms in gaining a strategic advantage through asymmetric learning.coopetition; Learning Behavior; Learning Strategy.

    Learning Strategies in Coopetitive Environments

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    The objective of this chapter is to explore the learning strategies that can be deployed by firms in coopetitive configurations with no other choice than deploying an “adverse learning” mechanism to reach their customers through cooperation with their competitors. After exploring the mechanisms of asymmetric learning in a first section, the chapter adopts an ecological perspective (Hawley, 1950) in drawing parallels between animal organization and groups of firms in gaining a strategic advantage through asymmetric learning

    Proceedings, MSVSCC 2012

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    Proceedings of the 6th Annual Modeling, Simulation & Visualization Student Capstone Conference held on April 19, 2012 at VMASC in Suffolk, Virginia

    A Cross-Disciplinary Approach to the Maritime Security Risk of Piracy and Lessons Learned From Agent-Based Modeling

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    This dissertation takes a cross-disciplinary approach to understanding pirate activity. Maritime piracy presents a dynamic ever-evolving problem. In today’s globalized world, contemporary maritime piracy presents a transnational threat. It is a complex socio-economic and political problem which the modern world considers to be criminal activity. Like all complex problems it must be deconstructed to fully comprehend it. All criminal activity, maritime piracy included, has certain elements of supply and demand. For the activity to occur there must be a certain level, or supply, of targets. At the same time, we can posit that there must be a lack of other opportunities for the pirates, who calculate that the risk of engaging in piracy is worthwhile. This risk calculation is a function of the potential rewards minus the sum of the risks. An increase in pirate attacks creates a demand for better maritime security. An increase in maritime security causes an increase in risk to pirates. Improved pirate capabilities may decrease this risk. The result is a constantly evolving complex problem. This study proposes a parsimonious agent-based model, focused on the socio-economic and political variables that encourage piracy, with utility across many specific regional domains. By simplifying the details of certain aspects of the model, the focus is placed on the issues at the heart of the problem. This allows for new insights into the dynamic relationship between these factors

    Group Living, Parental Care, Age Structure, and Genetic Relatedness in Liolaemus leopardinus, a High-elevation Lizard from the Andes of Chile

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    Social behavior refers to any interactions between two or more conspecifics. A relatively common social behavior in the animal kingdom is group living, which provides benefits to group members (e.g., enhanced vigilance and predation avoidance). Predation risk is an important force that selects for behavioral traits, and promotes the evolution of sociality favored by kin selection. Most studies of sociality have focused on animal groups in which interactions are overtly obvious. Although interactions differ among the various vertebrate lineages, taxa are often categorized as social or non-social, ignoring the diversity and complexity of social behavior. Reptiles have been usually labeled as non-social; however, the degree of sociality can vary among species as shown in the genus Egernia. Liolaemus leopardinus is a high-elevation lizard species endemic to the Chilean Andes. It is viviparous, lives in large colonies, and adults and juveniles are highly social, but little is known about the natural history of the species. Our findings over two field seasons suggest that bird predation causes mothers of L. leopardinus to engage in parental behavior, and that predation by birds forces newborns of the species to behave secretively and to seek solitary refuge underneath rocks partially covered by bushes. Skeletochronology revealed the formation of annual growth rings in the phalangeal bones of subjects of L. leopardinus; however, the method was poorly suited for aging individuals. However, when body size of various free-ranging subjects repeatedly captured and measured was plotted against activity periods of three years, we could assign individuals to four age groups, and estimated the age when female lizards became sexually mature. We provide spatial, behavioral, and genetic evidence that supports the conclusion that L. leopardinus forms social groups of closely related individuals with non-relatives mixed in. Genetically related juveniles and adults spend time in close association, share home ranges and communal refuges during the day and night, and overwinter together in deep rock crevices. As a whole, our study revealed fine details regarding the gregarious behavior of L. leopardinus, a social but highly secretive species. We suggest that predation, kin recognition, and roosting drive the evolution of sociality in L. leopardinus, and not thermoregulation, refuge availability, or food.Zoolog

    Urban fox squirrel ecology and management

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    I studied the habitat selection, survival, and anti-predator behaviors of the fox squirrel (Siurus niger) across the urban-rural gradient in College Station, Texas. From two years of tracking the radio locations of 82 fox squirrels, my data suggested that fox squirrels in urban areas selected for use large mast bearing trees that mimicked the habitat features they prefer in non-urban areas and avoided conifer and ornamental tree species. Urban fox squirrels selected to use buildings and non-native grass during certain seasons and showed a tolerance for pavement, including it proportionally in their core-areas. Analysis of radio-telemetry data of urban and rural fox squirrels suggested that the rates of survival and causes of mortality differed between the two populations. At least 60% of the mortalities on the rural site were caused by predation, while 60%) were cause by vehicular collisions. Observations of anti-predator behaviors supported my hypothesis that squirrels decrease their anti-predator behaviors as the human presence increases. Observational data also supported my hypothesis that this phenomenon was caused by habituation. I also found that the time dedicated to anti-predator behaviors differed among urban, rural, and suburban fox squirrel populations in response to coyote and hawk vocalizations. The mean responses to both vocalizations on the rural site (coyote = 45%, hawk = 55%) were at least twice that of those found on the urban sites (coyote = 11%, hawk = 20%). I also used survey responses to questions about squirrel management to test theoretical frameworks linking attitudes to behaviors. My data suggests that beliefs and attitudes that are modified by variables shown to increase accessibility generally correspond better to behaviors. My data also suggests that the inclusion of a measure of previous behaviors will increase the predictive ability of models within different theoretical frameworks. Most importantly for the advancement of a comprehensive theoretical framework, my study showed that composite models combining components of the theory of reasoned action and attitude to behavioral process models out-performed other models
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