Invasion of winter moth in New England: Effects of defoliation and site quality on tree mortality.

Abstract Widespread and prolonged defoliation by the European winter moth, Operophtera brumata L., has occurred in forests of eastern Massachusetts for more than a decade and populations of winter moth continue to invade new areas of New England. This study characterized the forests of eastern Massachusetts invaded by winter moth and related the duration of winter moth defoliation estimated using dendrochronology to observed levels of tree mortality and understory woody plant density. Quercus basal area mortality in mixed Quercus and mixed Quercus-Pinus strobus forests in eastern Massachusetts ranged from 0-30%; mortality of Quercus in these forests was related to site quality and the number of winter moth defoliation events. In addition, winter moth defoliation events lead to a subsequent increase in understory woody plant density. Our results indicate that winter moth defoliation has been an important disturbance in New England forests that may have lasting impacts

Douglas-fir beetle lipid levels in relation to tree physical characteristics

The relationship of Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, brood adult lipid levels and position of development along infested tree boles was investigated. In addition, the effects of phloem and bark thickness on brood adult lipid levels were also tested. There were no significant differences (P > 0.05) in brood adult lipid levels in relation to bole position, phloem thickness, or bark thickness found in this study. Numbers of attacks, larval mines, brood adults, and parasitoid cocoons did not differ significantly by tree bole position. Results from this study suggest Douglas-fir beetle does not benefit, in the form of increased lipid levels, from oviposition at different bole positions

Basic and applied studies on Douglas-fir beetle : spatial relationships of infestations, lipids and host habitat, and attraction distances of pheromone-baited traps

Three studies on Douglas-fir beetle (DFB), Dendroctonuspseudotsuae, were conducted to investigate its basic and applied biology. Studies included investigations into the spatial relationship of DFB infestations over multiple years and multiple landscapes, relationships between DFB brood adult lipid levels and position of development along the length of tree boles, and determination of the attraction distances of DFB pheromone-baited traps. Distances between infestations varied, but in general as DFB populations increased, distance to nearest infestation declined. When DFB populations were epidemic, 88% of within-year infestations were < 1,000 m from other infestations. Between-year average nearest neighbor distances followed a similar pattern to within-year distances. During periods of endemic populations, there was a wide range in distances between infestations. Risk ratings were developed for each ranger district studied as well as an overall average risk rating for the region.There were no significant differences in brood adult lipid levels in relation to bole position, phloem width, or bark width found in the study on brood position and lipid levels. Numbers of attacks, larval galleries, brood adults, and parasitoids did not differ significantly by tree bole position. Results from this study suggest Douglas-fir beetle does not benefit, in the form of increased lipid levels, from oviposition at different bole positions. The study on attraction distances of DFB pheromone-baited traps determined distances helpful for management of this bark beetle. Two mark-recapture and one trap interference study were conducted to determine the sampling range and range of attraction of DFB pheromone-baited traps. Mark-recapture studies indicated that most D. pseudotsugae were recaptured from distances < 200 m from the pheromone-baited trap. Results of the trap interference experiment provided no insight into the range of attraction of D. pseudotsugue pheromones

Statistical description of inhomogeneous samples by scanning microwave microscopy

A quantitative analysis of the dielectric properties of a multiphase sample using a scanning microwave microscope (SMM) is proposed. The method is demonstrated using inhomogeneous samples composed of a resin containing micrometric inclusions of a known ceramic material. The SMM suitable for this task employs relatively large tips (tens of micrometers in diameter). Additionally, in order to make the instrument more suitable for high-throughput analysis, an original design for rapid tip changes is implemented. Single-point measurements of dielectric constant at random locations on the sample were performed, leading to histograms of dielectric constant values. These are related to the dielectric constants of the two phases using Maxwell–Garnett effective medium theory, taking into account the volume-of-interaction in the sample beneath the tip

Effects of Invasive Winter Moth Defoliation on Tree Radial Growth in Eastern Massachusetts, USA

Winter moth, Operophtera brumata L. (Lepidoptera: Geometridae), has been defoliating hardwood trees in eastern Massachusetts since the 1990s. Native to Europe, winter moth has also been detected in Rhode Island, Connecticut, eastern Long Island (NY), New Hampshire, and Maine. Individual tree impacts of winter moth defoliation in New England are currently unknown. Using dendroecological techniques, this study related annual radial growth of individual host (Quercus spp. and Acer spp.) trees to detailed defoliation estimates. Winter moth defoliation was associated with up to a 47% reduction in annual radial growth of Quercus trees. Latewood production of Quercus was reduced by up to 67% in the same year as defoliation, while earlywood production was reduced by up to 24% in the year following defoliation. Winter moth defoliation was not a strong predictor of radial growth in Acer species. This study is the first to document impacts of novel invasions of winter moth into New England

Selective molecular annealing:in situ small angle X-ray scattering study of microwave-assisted annealing of block copolymers

Microwave annealing has emerged as an alternative to traditional thermal annealing approaches for optimising block copolymer self-assembly. A novel sample environment enabling small angle X-ray scattering to be performed in situ during microwave annealing is demonstrated, which has enabled, for the first time, the direct study of the effects of microwave annealing upon the self-assembly behavior of a model, commercial triblock copolymer system [polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene]. Results show that the block copolymer is a poor microwave absorber, resulting in no change in the block copolymer morphology upon application of microwave energy. The block copolymer species may only indirectly interact with the microwave energy when a small molecule microwave-interactive species [diethylene glycol dibenzoate (DEGDB)] is incorporated directly into the polymer matrix. Then significant morphological development is observed at DEGDB loadings ≥6 wt%. Through spatial localisation of the microwave-interactive species, we demonstrate targeted annealing of specific regions of a multi-component system, opening routes for the development of "smart" manufacturing methodologies

Discovery of quantitative trait loci for resistance to parasitic nematode infection in sheep: I. Analysis of outcross pedigrees

BACKGROUND: Currently most pastoral farmers rely on anthelmintic drenches to control gastrointestinal parasitic nematodes in sheep. Resistance to anthelmintics is rapidly increasing in nematode populations such that on some farms none of the drench families are now completely effective. It is well established that host resistance to nematode infection is a moderately heritable trait. This study was undertaken to identify regions of the genome, quantitative trait loci (QTL) that contain genes affecting resistance to parasitic nematodes. RESULTS: Rams obtained from crossing nematode parasite resistant and susceptible selection lines were used to derive five large half-sib families comprising between 348 and 101 offspring per sire. Total offspring comprised 940 lambs. Extensive measurements for a range of parasite burden and immune function traits in all offspring allowed each lamb in each pedigree to be ranked for relative resistance to nematode parasites. Initially the 22 most resistant and 22 most susceptible progeny from each pedigree were used in a genome scan that used 203 microsatellite markers spread across all sheep autosomes. This study identified 9 chromosomes with regions showing sufficient linkage to warrant the genotyping of all offspring. After genotyping all offspring with markers covering Chromosomes 1, 3, 4, 5, 8, 12, 13, 22 and 23, the telomeric end of chromosome 8 was identified as having a significant QTL for parasite resistance as measured by the number of Trichostrongylus spp. adults in the abomasum and small intestine at the end of the second parasite challenge. Two further QTL for associated immune function traits of total serum IgE and T. colubiformis specific serum IgG, at the end of the second parasite challenge, were identified on chromosome 23. CONCLUSION: Despite parasite resistance being a moderately heritable trait, this large study was able to identify only a single significant QTL associated with it. The QTL concerned adult parasite burdens at the end of the second parasite challenge when the lambs were approximately 6 months old. Our failure to discover more QTL suggests that most of the genes controlling this trait are of relatively small effect. The large number of suggestive QTL discovered (more than one per family per trait than would be expected by chance) also supports this conclusion