Can the intake of antiparasitic secondary metabolites explain the low prevalence of hemoparasites among wild Psittaciformes?

Background: Parasites can exert selection pressure on their hosts through effects on survival, on reproductive success, on sexually selected ornament, with important ecological and evolutionary consequences, such as changes in population viability. Consequently, hemoparasites have become the focus of recent avian studies. Infection varies significantly among taxa. Various factors might explain the differences in infection among taxa, including habitat, climate, host density, the presence of vectors, life history and immune defence. Feeding behaviour can also be relevant both through increased exposure to vectors and consumption of secondary metabolites with preventative or therapeutic effects that can reduce parasite load. However, the latter has been little investigated. Psittaciformes (parrots and cockatoos) are a good model to investigate these topics, as they are known to use biological control against ectoparasites and to feed on toxic food. We investigated the presence of avian malaria parasites (Plasmodium), intracellular haemosporidians (Haemoproteus, Leucocytozoon), unicellular flagellate protozoans (Trypanosoma) and microfilariae in 19 Psittaciformes species from a range of habitats in the Indo-Malayan, Australasian and Neotropical regions. We gathered additional data on hemoparasites in wild Psittaciformes from the literature. We considered factors that may control the presence of hemoparasites in the Psittaciformes, compiling information on diet, habitat, and climate. Furthermore, we investigated the role of diet in providing antiparasitic secondary metabolites that could be used as self-medication to reduce parasite load. Results: We found hemoparasites in only two of 19 species sampled. Among them, all species that consume at least one food item known for its secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, were free from hemoparasites. In contrast, the infected parrots do not consume food items with antimalarial or even general antiparasitic properties. We found that the two infected species in this study consumed omnivorous diets. When we combined our data with data from studies previously investigating blood parasites in wild parrots, the positive relationship between omnivorous diets and hemoparasite infestation was confirmed. Individuals from open habitats were less infected than those from forests. Conclusions: The consumption of food items known for their secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, as well as the higher proportion of infected species among omnivorous parrots, could explain the low prevalence of hemoparasites reported in many vertebrates

Untangling the relationship between fear of crime and perceived disorder: Evidence from a longitudinal study of young people in England and Wales

Over the last 40 years and more, a growing number of researchers have explored the links between perceptions of disorder and fear of criminal victimization. Many of these studies have posited a causal link from perceptions of disorder to subsequent fear, with disorderly cues in the environment signalling to individuals that an area is in decline and unable to control deviant behaviour. But a growing body of evidence approaches this question from the opposite direction, emphasizing the socially constructed nature of perceived disorder and the potential role that fear may have in giving meaning to ambiguous disorderly cues present in the environment. This conceptual uncertainty stems, in part, from the reliance of existing research on cross-sectional data, making it impossible to say whether it is perceptions of disorder that shape fear or whether fear drives perceived disorder. A cross-lagged panel design is applied to longitudinal data from the Offending Crime and Justice Survey to more carefully explore the causal links between fear and disorder

Do Neighbourhoods Generate Fear of Crime?

For a long time, criminologists have contended that neighborhoods are important determinants of how individuals perceive their risk of criminal victimization. Yet, despite the theoretical importance and policy relevance of these claims, the empirical evidence base is surprisingly thin and inconsistent. The current study's large sample size, analytical approach, and the independence of the empirical measures enabled researchers to overcome some of the limitations that have hampered much previous research into this question. The study found that neighborhood structural characteristics, visual signs of disorder, and recorded crime all have direct and independent effects on individual-level fear of crime. Additionally, the study demonstrates that individual differences in fear of crime are strongly moderated by neighborhood socioeconomic characteristics; between-group differences in expressed fear of crime are both exacerbated and ameliorated by the characteristics of the areas in which people live. Paper published as Brunton-Smith IR, & Sturgis P (2011). Do Neighborhoods Generate Fear of Crime?: An Empirical Test Using the British Crime Survey. Criminology 49(2):331-369 30 May 2011 Available at: http://onlinelibrary.wiley.com/doi/10.1111/j.1745-9125.2011.00228.x/abstrac

Do Neighbourhoods Generate Fear of Crime?

For a long time, criminologists have contended that neighborhoods are important determinants of how individuals perceive their risk of criminal victimization. Yet, despite the theoretical importance and policy relevance of these claims, the empirical evidence base is surprisingly thin and inconsistent. The current study's large sample size, analytical approach, and the independence of the empirical measures enabled researchers to overcome some of the limitations that have hampered much previous research into this question. The study found that neighborhood structural characteristics, visual signs of disorder, and recorded crime all have direct and independent effects on individual-level fear of crime. Additionally, the study demonstrates that individual differences in fear of crime are strongly moderated by neighborhood socioeconomic characteristics; between-group differences in expressed fear of crime are both exacerbated and ameliorated by the characteristics of the areas in which people live. Paper published as Brunton-Smith IR, & Sturgis P (2011). Do Neighborhoods Generate Fear of Crime?: An Empirical Test Using the British Crime Survey. Criminology 49(2):331-369 30 May 2011 Available at: http://onlinelibrary.wiley.com/doi/10.1111/j.1745-9125.2011.00228.x/abstrac

Untangling the relationship between fear of crime and perceived disorder: Evidence from a longitudinal study of young people in England and Wales

Over the last 40 years and more, a growing number of researchers have explored the links between perceptions of disorder and fear of criminal victimization. Many of these studies have posited a causal link from perceptions of disorder to subsequent fear, with disorderly cues in the environment signalling to individuals that an area is in decline and unable to control deviant behaviour. But a growing body of evidence approaches this question from the opposite direction, emphasizing the socially constructed nature of perceived disorder and the potential role that fear may have in giving meaning to ambiguous disorderly cues present in the environment. This conceptual uncertainty stems, in part, from the reliance of existing research on cross-sectional data, making it impossible to say whether it is perceptions of disorder that shape fear or whether fear drives perceived disorder. A cross-lagged panel design is applied to longitudinal data from the Offending Crime and Justice Survey to more carefully explore the causal links between fear and disorder