Population size estimation for the Warren root collar weevil, Hylobius warreni Wood (Coleoptera: Curculionidae), a pest of regenerating lodgepole pine plantations

The Warren root collar weevil, Hylobius warreni Wood (Coleoptera: Curculionidae), is an endemic pest species of conifers, particularly lodgepole pine (Pinus contorta var. latifolia) (Pinaceae), in British Columbia. Larvae feed on the roots and root collars of young trees, resulting in girdling damage and mortality or growth reductions. Population sizes of adult H. warreni have historically been difficult to assess due to a lack of operational sampling methods or chemical attractants for the species. Therefore, most previous population estimates have relied on indirect or incomplete measures of damage by immature individuals. In this study, we tested the Björklund funnel trap to assess its efficacy as a method to estimate H. warreni populations. Funnel traps were placed on all 182 trees in half of a small (~1 ha) lodgepole pine stand over four days and remained in place for 13 days after the last traps were installed. Adult weevils were captured, marked, and released on the bole of the tree on which they had been caught. It is likely that most of the adult weevils in the plot, which was isolated from any nearby lodgepole pine stands, were caught at least once and many were caught multiple times. Population sizes were estimated using both the Schnabel method and the Schumacher and Eschmeyer method, resulting in population estimates of 1.83-2.19 weevils/tree and 731-875 weevils/ha. These measures are within the range of population sizes estimated by previous studies. The results suggest the Björklund funnel trap may be an effective operational tool for population monitoring for this species and may also be an effective tactic in population reduction strategies

Population size estimation for the Warren root collar weevil, Hylobius warreni Wood (Coleoptera: Curculionidae), a pest of regenerating lodgepole pine plantations

The Warren root collar weevil, Hylobius warreni Wood (Coleoptera: Curculionidae), is an endemic pest species of conifers, particularly lodgepole pine (Pinus contorta var. latifolia) (Pinaceae), in British Columbia. Larvae feed on the roots and root collars of young trees, resulting in girdling damage and mortality or growth reductions. Population sizes of adult H. warreni have historically been difficult to assess due to a lack of operational sampling methods or chemical attractants for the species. Therefore, most previous population estimates have relied on indirect or incomplete measures of damage by immature individuals. In this study, we tested the Björklund funnel trap to assess its efficacy as a method to estimate H. warreni populations. Funnel traps were placed on all 182 trees in half of a small (~1 ha) lodgepole pine stand over four days and remained in place for 13 days after the last traps were installed. Adult weevils were captured, marked, and released on the bole of the tree on which they had been caught. It is likely that most of the adult weevils in the plot, which was isolated from any nearby lodgepole pine stands, were caught at least once and many were caught multiple times. Population sizes were estimated using both the Schnabel method and the Schumacher and Eschmeyer method, resulting in population estimates of 1.83-2.19 weevils/tree and 731-875 weevils/ha. These measures are within the range of population sizes estimated by previous studies. The results suggest the Björklund funnel trap may be an effective operational tool for population monitoring for this species and may also be an effective tactic in population reduction strategies

Meta-analysis of type 2 Diabetes in African Americans Consortium

Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR)  = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe

Limits on the production of scalar leptoquarks from Z (0) decays at LEP

A search has been made for pairs and for single production of scalar leptoquarks of the first and second generations using a data sample of 392000 Z0 decays from the DELPHI detector at LEP 1. No signal was found and limits on the leptoquark mass, production cross section and branching ratio were set. A mass limit at 95% confidence level of 45.5 GeV/c2 was obtained for leptoquark pair production. The search for the production of a single leptoquark probed the mass region above this limit and its results exclude first and second generation leptoquarks D0 with masses below 65 GeV/c2 and 73 GeV/c2 respectively, at 95% confidence level, assuming that the D0lq Yukawa coupling alpha(lambda) is equal to the electromagnetic one. An upper limit is also given on the coupling alpha(lambda) as a function of the leptoquark mass m(D0)

Notes on the abundance and host preference of Dendroctonus punctatus (Coleoptera: Scolytidae) in spruce forests near Prince George, B.C.

info:eu-repo/semantics/publishe

Natural History and Ecology of Bark Beetles

Scolytine beetles show enormous diversity in their mating behaviors, host plant associations, chemical and acoustic signaling, symbiotic relationships, and other critical aspects of their life histories. They can be monogamous or polygamous, solitary or gregarious, and employ levels of parental care that range from gallery maintenance in many tribes to eusociality in some ambrosia beetles. Within this complexity, however, scolytines display some generalities that arise from reproducing within plants, such as sophisticated host location systems, morphological adaptations that facilitate tunneling, advanced communication systems that provide very specific information about plants, and close associations with microbial symbionts. Bark beetles produce pheromones that both attract mates and serve additional functions that vary with the beetles' host-plant relationships. Some species use aggregation pheromones to coordinate cooperative resource procurement, a behavior needed to overcome the sophisticated defenses of live trees. A broad array of microbial symbionts is associated with bark beetles, and these fungi and bacteria vary in their degrees of association, impacts, mechanisms, and functional substitutabilities. Some symbionts contribute to acquisition, utilization, and defense of the host plant resource, and some provide a direct food base. A wide array of predators, competitors, and parasites exploit bark beetles. Many of these natural enemies utilize chemical signals emanating from the beetles or their symbionts in host location, depending on the stage they attack. The habitat in which bark beetles reside poses significant challenges to predators and parasites, so their effects on population dynamics are often limited. Some behavioral, reproductive, and landscape patterns emerge when bark beetle species are functionally categorized by the physiological condition of host plants they colonize. Bark beetles play important and varied roles in ecosystem processes, contributing to biodiversity, nutrient cycling, and heterogeneity. They also pose challenges to resource management in both native and commercial ecosystems. The scale at which beetles exert impacts varies markedly among functional groups, with most species having very localized effects. A few species exert landscape-scale effects, and these ecosystem engineers are among the most pronounced disturbance agents of the biomes they help shape. Their population dynamics are characterized by cross-scale interactions, density-dependent feedbacks, plasticity in host selection decisions, critical thresholds at multiple levels of interaction, and multi-equilibria. A variety of anthropogenic inputs, specifically transport into new regions, habitat manipulations that homogenize forest structure or impede predators, and climatic changes such as elevated temperature and increased drought, increase the socioeconomic losses caused by both eruptive and historically noneruptive species.SCOPUS: ch.binfo:eu-repo/semantics/publishe

Economics and Politics of Bark Beetles

Large bark beetle outbreaks are regarded as major forest disturbances, ranking first in the USA before hurricanes, tornadoes, and fire, with a 20,400,000ha average annual impact area and annual average costs (shared with pathogens) above US$2 billion per year. In Europe, over the period 1950-2000, insect damage (which equates mostly to bark beetles) ranked third, with 8% of the total damage due to forest disturbances. The damage amounted to 2.88 million m3 per year between 1958 and 2001. The major direct economic consequences of these outbreaks have been widely analyzed, various mitigation methods have been designed and implemented, and diverse political, industrial, and commercial initiatives have been developed to salvage the remains of the devastated forests. However, the many other environmental and sociological consequences of these disturbances are still largely unexplored. Significant progress has been made in analyzing the multi-scale positive influence of bark beetle activity, from the landscape to the stand level, as well as the various socioeconomic changes brought by bark beetle outbreaks. Silvicultural, environmental, and social consequences of bark beetle outbreaks are described and discussed, as well as the different issues related to the salvage of damaged forests. The wider context of management policies, including risk management and exotic species management, is discussed. Five case studies are presented to illustrate how biological features of specific systems lead to particular sociopolitical issues: Ips typographus in Europe; secondary ambrosia beetles attacking living beech in Europe; Dendroctonus rufipennis in Alaska; Dendroctonus ponderosae in British Columbia; and Ips pini in North America.SCOPUS: ch.binfo:eu-repo/semantics/publishe