Apparent acquired resistance by a weevil to its parasitoid is influenced by host plant

Field parasitism rates of the Argentine stem weevil Listronotus bonariensis (Kuschel; Coleoptera: Curculionidae) by Microctonus hyperodae Loan (Hymenoptera: Braconidae) are known to vary according to different host Lolium species that also differ in ploidy. To further investigate this, a laboratory study was conducted to examine parasitism rates on tetraploid Italian Lolium multiflorum, diploid Lolium perenne and diploid hybrid L. perenne x L. multiflorum; none of which were infected by Epichloë endophyte. At the same time, the opportunity was taken to compare the results of this study with observations made during extensive laboratory-based research and parasitoid-rearing in the 1990s using the same host plant species. This made it possible to determine whether there has been any change in weevil susceptibility to the parasitoid over a 20 year period when in the presence of the tetraploid Italian, diploid perennial and hybrid host grasses that were commonly in use in the 1990’s. The incidence of parasitism in cages, in the presence of these three grasses mirrored what has recently been observed in the field. When caged, weevil parasitism rates in the presence of a tetraploid Italian ryegrass host were significantly higher (75%) than rates that occurred in the presence of either the diploid perennial (46%) or the diploid hybrid (52%) grass, which were not significantly different from each other. This is very different to laboratory parasitism rates in the 1990s when in the presence of both of the latter grasses high rates of parasitism (c. 75%) were recorded. These high rates are typical of those still found in weevils in the presence of both field and caged tetraploid Italian grasses. In contrast, the abrupt decline in weevil parasitism rates points to the possibility of evolved resistance by the weevil to the parasitoid in the diploid and hybrid grasses, but not so in the tetraploid. The orientation of plants in the laboratory cages had no significant effect on parasitism rates under any treatment conditions suggesting that plant architecture may not be contributing to the underlying mechanism resulting in different rates of parasitism. The evolutionary implications of what appears to be plant-mediated resistance of L. bonariensis to parasitism by M. hyperodae are discussed.The work was funded jointly by the Bio-Protection Research Center, Lincoln University and as part of an AGMARDT Postdoctoral Fellowship (Grant P15018 to F.T.)

Juvenile Justice, Young People and Human Rights in Australia

This article identifies the key human rights issues that emerge for young people in juvenile justice in Australia. While there is a clear framework for respecting the human rights of children within juvenile justice, the article poses the question: To what extent does Australia actually operationalise and comply with these rights in law, policy and practice? In answering, it discusses various national and international reports, legislation, academic and other research and litigation on behalf of children. It identifies substantive and procedural human rights violations affecting young people in juvenile justice, many of which fall disproportionately on two over-represented groups: Indigenous young people, and those with mental health disorders and cognitive disability. While there are review and compliance mechanisms in place, respect for young people's rights within the broad area of juvenile justice remains problematic

Concurrent Program Design in the Extended Theory of Owicki and Gries

Feijen and van Gasteren have shown how to use the theory of Owicki and Gries to design concurrent programs, however, the lack of a formal theory of progress has meant that these designs are driven entirely by safety requirements. Proof of progress requirements are made post-hoc to the derivation and are operational in nature. In this paper, we describe the use of an extended theory of Owicki and Gries in concurrent program design. The extended theory incorporates a logic of progress, which provides opportunity to develop a program in a manner that gives proper consideration to progress requirements. Dekker's algorithm for two process mutual exclusion is chosen to illustrate the use of the extended theory

Human rights and youth justice reform in England and Wales: A systemic analysis

This article examines critically the persistently antagonistic relationship – across the past quarter-century – between the provisions of international human rights instruments and the nature and direction of youth justice reform in England and Wales. It introduces the core provisions of the human rights framework that pertain to youth justice and it sketches the nature and direction of policy reform over the 25-year period under scrutiny (1991–2016). To obtain a comprehensive sense of the relationship between human rights and youth justice reform in the jurisdiction, it applies a detailed systemic analysis; beginning at the point at which criminal responsibility is formally imputed and progressing through each stage of the youth justice system, up to the point where the child might ultimately be deprived of her/his liberty. By taking a ‘long-view’ of youth justice reform and by adopting a systemic end-to-end analysis of the human rights–youth justice interface, the article presents an analytical account of both change (policy reforms) and continuity (the enduring nature of human rights violations)

Extending the theory of Owicki and Gries with a logic of progress

This paper describes a logic of progress for concurrent programs. The logic is based on that of UNITY, molded to fit a sequential programming model. Integration of the two is achieved by using auxiliary variables in a systematic way that incorporates program counters into the program text. The rules for progress in UNITY are then modified to suit this new system. This modification is however subtle enough to allow the theory of Owicki and Gries to be used without change

Where has all the youth crime gone? youth justice in an age of austerity

Youth justice under the Coalition government in England and Wales has been characterised by considerable gains — falling youth crime, increased diversion and substantial reductions in child imprisonment — that would generally be associated with a progressive agenda. Focusing on youth justice policy in England and Wales, this article suggests that the tensions implicit in a government of the new right delivering outcomes that demonstrate an increased tolerance to children who offend can be explained by the logic of austerity. That same logic brings with it other policy measures that are potentially less compatible with children's well-being

Children, family and the state : revisiting public and private realms

The state is often viewed as part of the impersonal public sphere in opposition to the private family as a locus of warmth and intimacy. In recent years this modernist dichotomy has been challenged by theoretical and institutional trends which have altered the relationship between state and family. This paper explores changes to both elements of the dichotomy that challenge this relationship: a more fragmented family structure and more individualised and networked support for children. It will also examine two new elements that further disrupt any clear mapping between state/family and public/private dichotomies: the third party role of the child in family/state affairs and children's application of virtual technology that locates the private within new cultural and social spaces. The paper concludes by examining the rise of the 'individual child' hitherto hidden within the family/state dichotomy and the implications this has for intergenerational relations at personal and institutional levels

Who are these youths? Language in the service of policy

In the 1990s policy relating to children and young people who offend developed as a result of the interplay of political imperatives and populist demands. The ‘responsibilisation’ of young offenders and the ‘no excuses’ culture of youth justice have been ‘marketed’ through a discourse which evidences linguistic changes. This article focuses on one particular area of policy change, that relating to the prosecutorial decision, to show how particular images of children were both reflected and constructed through a changing selection of words to describe the non-adult suspect and offender. In such minutiae of discourse can be found not only the signifiers of public attitudinal and policy change but also the means by which undesirable policy developments can be challenged

We make the road by walking: challenging conceptualisations of leisure time for children in poverty

In this article, we discuss a research project focusing on the ways in which children in poverty spend and experience their leisure time. We argue that the dominant conceptualisation of leisure time participation reduces poverty to a lack of social and cultural capital, marginalising poor children as passive objects of socialisation. Inspired by the interpretative paradigm of lifeworld orientation, three insights are identified throughout poor children’s experiences, which include the following: (1) challenging taken-for-granted divisions of time; (2) giving meaning to regimes of time as an on-going learning process; and (3) imagining a socially just future

Above–belowground herbivore interactions in mixed plant communities are influenced by altered precipitation patterns

Root- and shoot-feeding herbivores have the capacity to influence one another by modifying the chemistry of the shared host plant. This can alter rates of nutrient mineralization and uptake by neighboring plants and influence plant–plant competition, particularly in mixtures combining grasses and legumes. Root herbivory-induced exudation of nitrogen (N) from legume roots, for example, may increase N acquisition by co-occurring grasses, with knock-on effects on grassland community composition. Little is known about how climate change may affect these interactions, but an important and timely question is how will grass–legume mixtures respond in a future with an increasing reliance on legume N mineralization in terrestrial ecosystems. Using a model grass–legume mixture, this study investigated how simultaneous attack on lucerne (Medicago sativa) by belowground weevils (Sitona discoideus) and aboveground aphids (Acyrthosiphon pisum) affected a neighboring grass (Phalaris aquatica) when subjected to drought, ambient, and elevated precipitation. Feeding on rhizobial nodules by weevil larvae enhanced soil water retention under ambient and elevated precipitation, but only when aphids were absent. While drought decreased nodulation and root N content in lucerne, grass root and shoot chemistry were unaffected by changes in precipitation. However, plant communities containing weevils but not aphids showed increased grass height and N concentrations, most likely associated with the transfer of N from weevil-attacked lucerne plants containing more nodules and higher root N concentrations compared with insect-free plants. Drought decreased aphid abundance by 54% but increased total and some specific amino acid concentrations (glycine, lysine, methionine, tyrosine, cysteine, histidine, arginine, aspartate, and glutamate), suggesting that aphid declines were being driven by other facets of drought (e.g., reduced phloem hydraulics). The presence of weevil larvae belowground decreased aphid numbers by 30%, likely associated with a significant reduction in proline in weevil-treated lucerne plants. This study demonstrates how predicted changes to precipitation patterns and indirect interactions between herbivores can alter the outcome of competition between N-fixing legumes and non-N-fixing grasses, with important implications for plant community structure and productivity