The influence of leaf age on the oviposition preference of Chrysophtharta bimaculata (Olivier) and the establishment of neonates

<b>Summary</b>\ud \ud 1 The degree of discrimination shown by a herbivore when selecting oviposition sites has been suggested as a key factor to understanding herbivore population dynamics. Chrysophtharta bimaculata (Coleoptera: Chrysomelidae) is a primary pest of Tasmanian eucalypt forests and can cause severe defoliation. Previous work suggests that females show discrimination when selecting oviposition sites. Our aim was to test the degree of oviposition discrimination exhibited by C. bimaculata with regards to leaf toughness, a character that is critical to neonate survival.\ud \ud 2 We conducted an experiment examining the leaf toughness critical for neonate survival and found that significant larval mortality occurs above a toughness of 46.9 g. We also determined that the maximum toughness of leaves upon which larvae established in the field was 48.2 g, supporting the laboratory result.\ud \ud 3 Field surveys showed that although the majority of eggs were laid on leaves suitable for larval establishment, many eggs were laid on unsuitable, tougher leaves. However, all eggs were normally placed within 20 cm of suitable leaves and glasshouse trials demonstrated the neonates could move this distance without mortality occurring.\ud \ud 4 We conclude that egg batch distribution and larval performance of C. bimaculata will influence the population dynamics of C. bimaculata in two ways. Firstly, the availability of expanding/newly expanding leaves of eucalypt hosts will determine larval carrying capacity. Secondly, at a more localized level, the deposition of large numbers of egg batches on both suitable and unsuitable leaves followed by successful neonate migration increases the risk of resource depletion and poor larval development

Can insect body pollen counts be used to estimate pollen deposition on pak choi stigmas?

Measuring pollen deposition onto stigmas by insects is one technique used to assess pollinator effectiveness, but it can be unpredictable and time-consuming as insects must visit test flowers. This study examined whether a measurement of pollen grains from flower-visiting insects could be used to predict pollen deposited on stigmas. Individuals were collected from four bee and six fly species as they visited pak choi flowers in commercial and trial seed fields to assess their body pollen. Pollen was removed from insects by pressing their bodies (excluding actively-collected pollen on bees\' hind legs) with a cube of gelatinefuchsin. In this study, there appears to be a strong correlation between mean estimated pollen counts for each insect species and previously published data recording mean number of pollen grains deposited on stigmas for the same species. Therefore, the measurement of pollen grains directly from flower-visiting insects shows potential as a quicker and easier technique to assess pollinator effectiveness as insects can be directly collected from flowers

Assessing Instrument Mixes through Program- and Agency-Level Data: Methodological Issues in Contemporary Implementation Research

Theories of policy instrument choice have gone through several "generations" as theorists have moved from the analysis of individual instruments to comparative studies of instrument selection and the development of theories of instrument choice within implementation "mixes" or "governance strategies." Current "next generation" theory on policy instruments centers on the question of the optimality of instrument choices. However, empirically assessing the nature of instrument mixes is quite a complex affair, involving considerable methodological difficulties and conceptual ambiguities related to the definition and measurement of policy sector and instruments and their interrelationships. Using materials generated by Canadian governments, this article examines the practical utility and drawbacks of three techniques used in the literature to inventory instruments and identify instrument ecologies and mixes: the conventional "policy domain" approach suggested by Burstein (1991); the "program" approach developed by Rose (1988a); and the "legislative" approach used by Hosseus and Pal (1997). This article suggests that all three approaches must be used in order to develop even a modest inventory of policy instruments, but that additional problems exist with availability and accessibility of data, both in general and in terms of reconciling materials developed using these different approaches, which makes the analysis of instrument mixes a time-consuming and expensive affair. Copyright 2006 by The Policy Studies Organization.

Hotspot activating PRKD1 somatic mutations in polymorphous low-grade adenocarcinomas of the salivary glands

Polymorphous low-grade adenocarcinoma (PLGA) is the second most frequent type of malignant tumor of the minor salivary glands. We identified PRKD1 hotspot mutations encoding p.Glu710Asp in 72.9% of PLGAs but not in other salivary gland tumors. Functional studies demonstrated that this kinase-activating alteration likely constitutes a driver of PLGA