Parasites and predators of Dendroctonus ponderosae Hopkins (Coleoptera : Scolytidae) in ponderosa pine

The bark beetle Dendroctonus ponderosae Hopkins (Coleoptera: Scolytidae) has caused severe mortality in recent decades to young stands of ponderosa pine in the western United States. Insect parasites and predators, believed to be of importance in the population dynamics of the beetle, were the subject of the thesis research, conducted in eastern Oregon. An annotated catalog of parasites and predators of D. ponderosae found in ponderosa pine is given. Parasites encountered were few both in number of species and relative abundance, and generally were limited in distribution to the upper boles of infested trees. As a result, they were considered of little importance as mortality factors. Medetera aldrichii Wheeler (Diptera: Dolichopodida) was the most abundant and widely distributed predator collected from infested ponderosa pine. The coleopteran predators Enoclerus sphegeus Fabricius, E. lecontei (Wolcott) (Coleoptera: Cleridae) and Temnochila virescens Mannerheim (Coleoptera: Ostomidae) were found in relatively low numbers. Other insect species present in sufficient numbers to Influence bark beetle brood survival, if predaceous, included Lonchaea sp. (Diptera: Lonchaeidae); Rhizophagus sculpturatus Mannerheim (Coleoptera: Rhizophagidae); Aulonium longum LeConte (Coleoptera: Colyiidae); Othnius sp. (Coleoptera: Othniidae); Corticeus sp. (Coleoptera: Tenebrionidae) and species of Staphylinidae (order Coleoptera). Five infestations, representing three distinct levels in a bark beetle gradation (enzootic, epizootic, decline from epizootic), were sampled to determine if differences in species composition and abundance of natural enemies existed among infestation levels. No differences in species composition of known predators nor of the more common associated insects possibly predaceous in habit were found. M. aldrichii was the only predatory species to exhibit a significant numerical (density dependent) response to increasing bark beetle infestation level. On basis of this attribute and its relative abundance, this species was considered by far the most important insect enemy of D. ponderosae in young ponderosa pine. Results suggest that M. aldrichii, as a natural regulatory agent of D. ponderosae, exerts little influence in preventing bark beetle outbreaks in ponderosa pine but may significantly accelerate population decline. Since all other predatory insects showed no evident response to host density increases, their combined influence on bark beetle broods would be greatest at low population levels. The spatial distribution of the more common predators within a given infestation was determined. Density of M. aldrichii was found to be positively correlated with tree diameter. Analysis of predator and bark beetle abundance in relation to subcortical moisture of host trees revealed that M. aldrichii was more susceptible to low moisture extremes than either the prey or common coleopteran predators. Larvae of M. aldrichii were not encountered in trees, sampled just prior to beetle emergence, in which subcortical tissues had dried below the fiber saturation point. As a result, survival of N. aldrichii and its effectiveness as a predator would be reduced in individual trees that dry rapidly and excessivly after bark beetle attack. Although mature larvae of E. sphegeus, E. lecontei and T. virescens appeared able to withstand low subcortical moisture extremes, early instar larvae may be susceptible. In epizootic bark beetle infestations M. aldrchii occurred in greatest numbers, shortly after bark beetle attack, in trees with high prey densities. At the relatively low predator to prey ratios present in study areas, predation in trees of high prey density could have done little more than reduce intraspecific competition of bark beetle brood

Impact of Minimum Winter Temperatures on the Population Dynamics of Dendroctonus Frontalis

Predicting population dynamics is a fundamental problem in applied ecology. Temperature is a potential driver of short-term population dynamics, and temperature data are widely available, but we generally lack validated models to predict dynamics based upon temperatures. A generalized approach involves estimating the temperatures experienced by a population, characterizing the demographic consequences of physiological responses to temperature, and testing for predicted effects on abundance. We employed this approach to test whether minimum winter temperatures are a meaningful driver of pestilence from Dendroctonus frontalis (the southern pine beetle) across the southeastern United States. A distance-weighted interpolation model provided good, spatially explicit, predictions of minimum winter air temperatures (a putative driver of beetle survival). A Newtonian heat transfer model with empirical cooling constants indicated that beetles within host trees are buffered from the lowest air temperatures by approximately 1-4 degrees C (depending on tree diameter and duration of cold bout). The life stage structure of beetles in the most northerly outbreak in recent times (New Jersey) were dominated by prepupae, which were more cold tolerant (by \u3e3 degrees C) than other life stages. Analyses of beetle abundance data from 1987 to 2005 showed that minimum winter air temperature only explained 1.5% of the variance in interannual growth rates of beetle populations, indicating that it is but a weak driver of population dynamics in the southeastern United States as a whole. However, average population growth rate matched theoretical predictions of a process-based model of winter mortality from low temperatures; apparently our knowledge of population effects from winter temperatures is satisfactory, and may help to predict dynamics of northern populations, even while adding little to population predictions in southern forests. Recent episodes of D. frontalis outbreaks in northern forests may have been allowed by a warming trend from 1960 to 2004 of 3.3 degrees C in minimum winter air temperatures in the southeastern United States. Studies that combine climatic analyses, physiological experiments, and spatially replicated time series of population abundance can improve population predictions, contribute to a synthesis of population and physiological ecology, and aid in assessing the ecological consequences of climatic trends

Association of vitamin D status with arterial blood pressure and hypertension risk : a mendelian randomisation study

Peer reviewe

Common Genetic Polymorphisms Influence Blood Biomarker Measurements in COPD

Implementing precision medicine for complex diseases such as chronic obstructive lung disease (COPD) will require extensive use of biomarkers and an in-depth understanding of how genetic, epigenetic, and environmental variations contribute to phenotypic diversity and disease progression. A meta-analysis from two large cohorts of current and former smokers with and without COPD [SPIROMICS (N = 750); COPDGene (N = 590)] was used to identify single nucleotide polymorphisms (SNPs) associated with measurement of 88 blood proteins (protein quantitative trait loci; pQTLs). PQTLs consistently replicated between the two cohorts. Features of pQTLs were compared to previously reported expression QTLs (eQTLs). Inference of causal relations of pQTL genotypes, biomarker measurements, and four clinical COPD phenotypes (airflow obstruction, emphysema, exacerbation history, and chronic bronchitis) were explored using conditional independence tests. We identified 527 highly significant (p 10% of measured variation in 13 protein biomarkers, with a single SNP (rs7041; p = 10−392) explaining 71%-75% of the measured variation in vitamin D binding protein (gene = GC). Some of these pQTLs [e.g., pQTLs for VDBP, sRAGE (gene = AGER), surfactant protein D (gene = SFTPD), and TNFRSF10C] have been previously associated with COPD phenotypes. Most pQTLs were local (cis), but distant (trans) pQTL SNPs in the ABO blood group locus were the top pQTL SNPs for five proteins. The inclusion of pQTL SNPs improved the clinical predictive value for the established association of sRAGE and emphysema, and the explanation of variance (R2) for emphysema improved from 0.3 to 0.4 when the pQTL SNP was included in the model along with clinical covariates. Causal modeling provided insight into specific pQTL-disease relationships for airflow obstruction and emphysema. In conclusion, given the frequency of highly significant local pQTLs, the large amount of variance potentially explained by pQTL, and the differences observed between pQTLs and eQTLs SNPs, we recommend that protein biomarker-disease association studies take into account the potential effect of common local SNPs and that pQTLs be integrated along with eQTLs to uncover disease mechanisms. Large-scale blood biomarker studies would also benefit from close attention to the ABO blood group

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)