Diel patterns of insect herbivory and plant secondary metabolites in understory shrubs on Barro Colorado Island

Plants produce a broad diversity of secondary metabolites as defenses against herbivory. In response, herbivorous insects have evolved a diversity of behavioral and biochemical counter-adaptations to these defenses. Despite that a significant portion of leaf area removal by insects in the tropics occurs at night, virtually all studies of chemically mediated interactions between herbivorous insects and their host plants have been conducted primarily or entirely during the daytime. Accordingly, I set out to quantify if rates of herbivory differ between the day and night. I used leaf photographs and single plant herbivore exclosures on 126 individual plants of four species in the genera Piper and Psychotria on Barro Colorado Island, Panama, to quantify the timing of herbivory over the course of 56 diel cycles. I found that on young leaves, protecting plants from herbivores during the night causes significantly fewer leaves to be damaged than if plants are protected only during the day but are exposed at night. I then characterized qualitative differences in the secondary metabolite profiles of the leaves of these plant species during daytime and nighttime hours using ultra high-performance liquid chromatography (UHPLC), electrospray ionization and molecular fragmentation, and tandem mass spectrometry (MS/MS). Network analyses show that plant secondary metabolites varied greatly in their presence in leaves over the course of several hours, suggesting that ecologically significant differences exist in the overall chemical profile that herbivores would encounter in leaves during different times of a day. Whether these variations in putative defense compounds may affect the foraging times and behaviors of herbivorous insects remains unresolved. Most larval herbivores lack an effective means for dispersing to new hostplants. Therefore, feeding strategies that maximize assimilation and growth, and minimize time to pupation, are expected to be most advantageous. However, larval lepidopterans exhibit numerous behaviors that appear to interfere with maximizing the rate of foliage consumption. Caterpillars may limit their foraging times to specific periods of the diel due to uneven predation risk, to predictably variable abiotic (especially temperature and humidity) conditions, or to short-term variation in forage quality. While daily variation in forage nutrient levels and secondary metabolite concentrations has been well-studied in numerous systems, the influence of such variation on the daily rhythms of herbivore feeding activity has not yet been determined. I propose that the highly sensitive and specialized senses of olfaction and gustation in herbivores suit them well for limiting their feeding bouts to times of the day when plants are less well-defended (which I propose is the night). Such behavior is especially likely to occur in environments where there is relatively low variation between daytime and nighttime temperatures and humidity and where predation risk is always relatively high, or even higher during the nighttime than the day, as is likely the case in many tropical forests

In search of legitimacy: Restorative youth conferencing in Northern Ireland

Restorative justice principles often feature prominently in peace agreements and initiatives to foster reconciliation and peace-building. As part of its own transitional process, Northern Ireland has undertaken a wide-ranging programme of criminal justice reform, whereby restorative practices have become a central response to juvenile offending. Drawing on a major evaluation of the Northern Ireland Youth Conferencing Scheme, this paper suggests that restorative conferencing holds the potential not only to promote reconciliation between victims and offenders, but it may even bolster the legitimacy deficit suffered by criminal justice institutions. Whilst is vital that such schemes continue to foster their engagement with civil society and the wider community, the broader potential of restorative processes to contribute to post-conflict peace-building is considerable, especially in relation to fostering a sense of legitimacy necessary for the operation of society and the institutions of the state

Contesting the ‘national interest’ and maintaining ‘our lifestyle’: A discursive analysis of political rhetoric around climate change

The release of the fourth United Nations Intergovernmental Panel on Climate Change (IPCC) report in February 2007 prompted a flood of responses from political leaders around the globe. Perhaps nowhere was this more apparent than in Australia, where its release coincided with the first sitting week of the Australian Parliament, in an election year. The current study involves a discursive analysis of climate change rhetoric produced by politicians from the major Australian political parties in the period following the release of the IPCC leading up to the national election. Data include both transcripts of parliamentary debate and statements directly broadcast in the media. The analysis focuses on the various ways in which the issue of climate change was invoked and rhetorically managed by each of the two parties in the lead up to the election. In particular, it focuses on the ways in which appeals to the 'national interest' and 'lifestyle maintenance', both regular features of political rhetoric, were mobilized by both parties to discursively manage their positions on the climate change issue. Implications of the ways in which such appeals were constructed are discussed in relation to the discursive limits of the ways in which the issue of climate change is constructed in public debate