882 research outputs found

    High Antipredatory Efficiency of Insular Lizards: A Warning Signal of Excessive Specimen Collection?

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    We live-captured lizards on islands in the Gulf of California and the Baja California peninsula mainland, and compared their ability to escape predation. Contrary to expectations, endemic lizard species from uninhabited islands fled from humans earlier and more efficiently than those from peninsular mainland areas. In fact, 58.2% (n = 146) of the lizards we tried to capture on the various islands escaped successfully, while this percentage was only 14.4% (n = 160) on the peninsular mainland. Separate evidence (e.g., proportion of regenerated tails, low human population at the collection areas, etc.) challenges several potential explanations for the higher antipredatory efficiency of insular lizards (e.g., more predation pressure on islands, habituation to humans on the peninsula, etc.). Instead, we suggest that the ability of insular lizards to avoid predators may be related to harvesting by humans, perhaps due to the value of endemic species as rare taxonomic entities. If this hypothesis is correct, predation-related behavioral changes in rare species could provide early warning signals of their over-exploitation, thus encouraging the adoption of conservation measures

    Ventilatory frequency as a measure of the response of tammar wallabies (Macropus eugenii) to the odour of potential predators

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    This study uses changes in ventilatory frequency to quantify the physiological response of an Australian terrestrial herbivore, the tammar wallaby (Macropus eugenii), to olfactory cues suggesting the presence of potential predators. Ventilatory frequency proved to be a quantifiable measure to assess the response of this macropod marsupial to olfactory cues. Ventilatory frequency increased from mean resting levels of 45 ± 5.1 breaths min–1 to 137 ± 11.2 breaths min–1 during the first minute of exposure to all odours. These physiological responses diminished over time, with ventilatory frequency in the first minute after introduction of the scents greater than that during the subsequent four, suggesting that the initial reaction was due to disturbance and was investigative in nature. However, the ratio of ventilatory frequency in the remaining 4 min after introduction of the odours compared with before was greater for fox (3.58 ± 0.918) and cat (2.44 ± 0.272) odours than for snake (2.27 ± 0.370), distilled water (1.81 ± 0.463) and quoll (1.71 ± 0.245) odours, suggesting that fox and cat odour provoked a greater response. However, the wallabies’ response to the odour of these introduced predators and to horse odour (2.40 ± 0.492) did not differ. Our study indicates that a long period of co-history with particular predators is not a prerequisite for detection of potentially threatening species. We do not find any support for the hypothesis that an inability to interpret olfactory cues to detect and respond to potential predation by introduced predators is responsible for the decline of these macropod marsupials

    Chaos, containment and change: responding to persistent offending by young people

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    This article reviews policy developments in Scotland concerning 'persistent young offenders' and then describes the design of a study intended to assist a local planning group in developing its response. The key findings of a review of casefiles of young people involved in persistent offending are reported. It emerges that youth crime and young people involved in offending are more complex and heterogeneous than is sometimes assumed. This, along with a review of some literature about desistance from offending, reaffirms the need for properly individualised interventions. Studies of 'desisters' suggest the centrality of effective and engaging working relationships in this process. However, these studies also re-assert the significance of the social contexts of workers’ efforts to bring 'change' out of 'chaos'. We conclude therefore that the 'new correctionalism' must be tempered with appreciation of the social exclusion of young people who offend

    The relationship work of sexual intimacy in long-term heterosexual and LGBTQ partnerships

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    Sex is perceived as crucial to relationship success. This article reveals how sexual intimacy is part of the relationship work that couples ordinarily complete to sustain their partnerships over time. It problematizes the binary logics of good–bad sex, female–male desire, and homo–heterosexual difference and shows how fluctuations of desire and/or sexual capacity are managed by couples through intimate knowledge. Findings presented here derive from a multiple methods study with 50 long-term heterosexual and LGBTQ partnerships. I demonstrate how the absence of normative sexual scripts enables queer couples to more readily manage sexual discrepancies. Gendered differences and inequalities persist within many heterosexual relationships while reflexivity and increased openness characterizes queer coupledom. Women and LGBTQ couples are more inclined to deploy humour to diffuse difficult situations and in this context gay men are akin to women more so than heterosexual men

    Production and perception of situationally variable alarm calls in wild tufted capuchin monkeys (Cebus apella nigritus)

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    Many mammalian and avian species produce conspicuous vocalizations upon encountering a predator, but vary their calling based on risk urgency and/or predator type. Calls falling into the latter category are termed “functionally referential” if they also elicit predator-appropriate reactions in listeners. Functionally referential alarm calling has been well documented in a number of Old World monkeys and lemurs, but evidence among Neotropical primates is limited. This study investigates the alarm call system of tufted capuchin monkeys (Cebus apella nigritus) by examining responses to predator and snake decoys encountered at various distances (reflecting differences in risk urgency). Observations in natural situations were conducted to determine if predator-associated calls were given in additional contexts. Results indicate the use of three call types. “Barks” are elicited exclusively by aerial threats, but the call most commonly given to terrestrial threats (the “hiccup”) is given in nonpredatory contexts. The rate in which this latter call is produced reflects risk urgency. Playbacks of these two call types indicate that each elicits appropriate antipredator behaviors. The third call type, the “peep,” seems to be specific to terrestrial threats, but it is unknown if the call elicits predator-specific responses. “Barks” are thus functionally referential aerial predator calls, while “hiccups” are better seen as generalized disturbance calls which reflect risk urgency. Further evidence is needed to draw conclusions regarding the “peep.” These results add to the evidence that functionally referential aerial predator alarm calls are ubiquitous in primates, but that noncatarrhine primates use generalized disturbance calls in response to terrestrial threats

    Inmate Recidivism as a Measure of Private Prison Performance

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    The growth of the private corrections industry has elicited interest in the comparative performance of state and private prisons. One way to measure the service quality of private prisons is to examine inmates' postrelease performance. Current empirical evidence is limited to four studies, all conducted in Florida. This analysis replicates and adds to the Florida measures in a different state and enhances previous methods. It uses data for a large cohort of Oklahoma state prison inmates released between 1997 and 2001. Controlling for known covariates, multivariate survival analysis revealed comparative rates of reincarceration for inmates in multiple exposure and comparison groups. These results are unique among prior studies on this topic; private prison inmates had a greater hazard of recidivism in all eight models tested, six of which were statistically significant. Finding no empirical support for claims of superior service from private corrections, the authors discuss policy implications and prospects for future research.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Demand-side approaches for limiting global warming to 1.5 °C

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    The Paris Climate Agreement defined an ambition of limiting global warming to 1.5 °C above preindustrial levels. This has triggered research on stringent emission reduction targets and corresponding mitigation pathways across energy economy and societal systems. Driven by methodological considerations, supply side and carbon dioxide removal options feature prominently in the emerging pathway literature, while much less attention has been given to the role of demand-side approaches. This special issue addresses this gap, and aims to broaden and strengthen the knowledge base in this key research and policy area. This editorial paper synthesizes the special issue’s contributions horizontally through three shared themes we identify: policy interventions, demand-side measures, and methodological approaches. The review of articles is supplemented by insights from other relevant literature. Overall, our paper underlines that stringent demand-side policy portfolios are required to drive the pace and direction of deep decarbonization pathways and keep the 1.5 °C target within reach. It confirms that insufficient attention has been paid to demand-side measures, which are found to be inextricably linked to supply-side decarbonization and able to complement supply-side measures. The paper also shows that there is an abundance of demand-side measures to limit warming to 1.5 °C, but it warns that not all of these options are “seen” or captured by current quantitative tools or progress indicators, and some remain insufficiently represented in the current policy discourse. Based on the set of papers presented in the special issue, we conclude that demand-side mitigation in line with the 1.5 °C goal is possible; however, it remains enormously challenging and dependent on both innovative technologies and policies, and behavioral change. Limiting warming to 1.5 °C requires, more than ever, a plurality of methods and integrated behavioral and technology approaches to better support policymaking and resulting policy interventions

    Captive-born collared peccary (Pecari tajacu, Tayassuidae) fails to discriminate between predator and non-predator models

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    Captive animals may lose the ability to recognize their natural predators, making conservation programs more susceptible to failure if such animals are released into the wild. Collared peccaries are American tayassuids that are vulnerable to local extinction in certain areas, and conservation programs are being conducted. Captive-born peccaries are intended for release into the wild in Minas Gerais state, southeastern Brazil. In this study, we tested the ability of two groups of captive-born collared peccaries to recognize their predators and if they were habituated to humans. Recognition tests were performed using models of predators (canids and felids) and non-predators animals, as well as control objects, such as a plastic chair; a human was also presented to the peccaries, and tested as a separate stimulus. Anti-predator defensive responses such as fleeing and threatening displayswere not observed in response to predator models. Predator detection behaviors both from visual and olfactory cues were displayed, although they were not specifically targeted at predator models. These results indicate that collared peccaries were unable to recognize model predators. Habituation effects, particularly on anti-predator behaviors, were observed both with a 1-h model presentation and across testing days. Behavioral responses to humans did not differ from those to other models. Thus, if these animals were to be released into the wild, they should undergo anti-predator training sessions to enhance their chances of survival

    Exploratory behavior, but not aggressiveness, is correlated with breeding dispersal propensity in the highly philopatric thorn-tailed rayadito

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    Studies on the relationship between behavioral traits and dispersal are necessary to understand the evolution of dispersal syndromes. Empirical studies have mainly focused on natal dispersal, even though behavioral differences between dispersers and philopatric individuals are suspected to hold through the whole life cycle, potentially affecting breeding dispersal propensity. Using capture–mark–recapture data and behavioral trials in a forest passerine, the thorn-tailed rayadito Aphrastura spinicauda, we describe inter-individual differences in exploratory behavior and aggressiveness, and investigate the relationship between those traits and breeding dispersal. Our study took place in Fray Jorge National Park, north-central Chile, where a relatively isolated population of rayaditos inhabits a naturally fragmented environment. We found that scores for behavioral traits were consistent between years. Exploratory behavior was similar between sexes, while males showed higher levels of aggression towards a conspecific male intruder. Only exploratory behavior was related to breeding dispersal propensity, with fast-exploring rayaditos being more likely to have dispersed between seasons. This finding provides indirect evidence for the existence of a dispersal strategy that could reduce dispersal costs in the fragmented landscape of Fray Jorge. To our knowledge, this is the first study documenting an association between breeding dispersal and exploratory behavior in a wild bird population. A longitudinal individual-based study will help determining whether this association constitutes a behavioral syndrome.Indexación: Scopu
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