Winter decline of spiders and insects in spruce Picea abies and its relation to predation by birds

Insects and spiders were sampled on branches of spruce in a 5.5 km² area before and after each of six winters. Psocoptera, Aphidoidea and Lepidoptera larvae were the most common insects in autumn. In Feb–Mar only 1% remained, most of the decline occurring already early in the winter. Spiders were almost as common as Psocoptera in autumn but survived winter to 28–45%. Spiders therefore are potentially more important food for wintering birds than are insects. Through the first five winters there was a steady increase in density of small (but not large) spiders both in autumn (290%) and spring (390%). Spring densities of small but not large spiders were significantly correlated to autumn densities. Usually there was no added variability of spider abundance between trees and most of the variability was found within trees. In autumn spiders occurred at significantly higher densities in the lower half of the spruce trees than in the upper half. Much of the reduction of large spiders over winter is known to be caused by predation by birds. Over winter, this predation probably makes the distribution of spiders within trees more uniform. The autumn density of three tit species, the goldcrest and the treecreeper was significantly correlated with the density of large spiders at the same time, but not with small spiders (which they presumably do not eat). This might be caused by territorial behaviour being related to food density in autumn.     

Integrated treatment of hepatitis C virus infection among people who inject drugs: A multicenter randomized controlled trial (INTRO-HCV)

BackgroundThe standard pathways of testing and treatment for hepatitis C virus (HCV) infection in tertiary healthcare are not easily accessed by people who inject drugs (PWID). The aim of this study was to evaluate the efficacy of integrated treatment of chronic HCV infection among PWID.Methods and findingsINTRO-HCV is a multicenter, randomized controlled clinical trial. Participants recruited from opioid agonist therapy (OAT) and community care clinics in Norway over 2017 to 2019 were randomly 1:1 assigned to the 2 treatment approaches. Integrated treatment was delivered by multidisciplinary teams at opioid agonist treatment clinics or community care centers (CCCs) for people with substance use disorders. This included on-site testing for HCV, liver fibrosis assessment, counseling, treatment, and posttreatment follow-up. Standard treatment was delivered in hospital outpatient clinics. Oral direct-acting antiviral (DAA) medications were administered in both arms. The study was not completely blinded. The primary outcomes were time-to-treatment initiation and sustained virologic response (SVR), defined as undetectable HCV RNA 12 weeks after treatment completion, analyzed with intention to treat, and presented as hazard ratio (HR) and odds ratio (OR) with 95% confidence intervals.Among 298 included participants, 150 were randomized to standard treatment, of which 116/150 (77%) initiated treatment, with 108/150 (72%) initiating within 1 year of referral. Among those 148 randomized to integrated care, 145/148 (98%) initiated treatment, with 141/148 (95%) initiating within 1 year of referral. The HR for the time to initiating treatment in the integrated arm was 2.2 (1.7 to 2.9) compared to standard treatment. SVR was confirmed in 123 (85% of initiated/83% of all) for integrated treatment compared to 96 (83% of initiated/64% of all) for the standard treatment (OR among treated: 1.5 [0.8 to 2.9], among all: 2.8 [1.6 to 4.8]). No severe adverse events were linked to the treatment.ConclusionsIntegrated treatment for HCV in PWID was superior to standard treatment in terms of time-to-treatment initiation, and subsequently, more people achieved SVR. Among those who initiated treatment, the SVR rates were comparable. Scaling up of integrated treatment models could be an important tool for elimination of HCV.Trial registrationClinicalTrials.gov.no {"type":"clinical-trial","attrs":{"text":"NCT03155906","term_id":"NCT03155906"}}NCT03155906

Dr. Fadnes and colleagues conducted a randomized controlled trial to compare the efficacy of integrated treatment using multidisciplinary teams to standard treatment of Hepatitis C virus infection among people who currently inject or formerly injected drugs.     

Indirect effects of fish community structure on submerged vegetation in shallow,eutrophic lakes: an alternative mechanism

The loss of submerged macrophytes during eutrophication of shallow lakes is a commonly observed phenomenon. The proximate reason for this decline is a reduction of available light due to increasing phytoplankton and/or epiphyton biomass. Here we argue that the ultimate cause for the transition from a macrophyte-dominated state to a phytoplankton-dominated state is a change in fish community structure. A catastrophic disturbance event (e.g. winterkill) acting selectively on piscivores, cascades down food chains, eventually reducing macrophyte growth through shading by epiphyton, an effect that is reinforced by increasing phytoplankton biomass. The transition back from the phytoplankton to the macrophyte state depends on an increase in piscivore standing stock and a reduction of planktivores. A conceptual model of these mechanisms is presented and supported by literature data and preliminary observations from a field experiment.     

Induction of diapause in a migratory seed bug,Neacoryphus bicrucis (Say) (Heteroptera: Lygaeidae)

Summary Neacoryphus bicrucis hibernates in the adult stage and exhibits a facultative reproductive diapause. Constant photoperiods of the durations encountered in the field do not evoke the diapause response but Shortening of the photoperiods does, providing the decrease in daylength is of a certain length and occurs within a certain photoperiodic interval. The sensitive stages are larval instars II to V. The percentage of diapausing bugs increases as temperature is lowered.It is suggested that the response to daylength shortening in N. bicrucis is an adaptation to ensure seasonal synchronization in a highly migratory species where successive generations may breed at different latitudes.     

Two aberrant Tubificidae (Oligochaeta) from Pearl River in the People's Republic of China

The enigmaticIlyodrilus mastix Brinkhurst, 1978, andTectidrilus achaetus sp.nov. are described from the Guangzhou Reach of Pearl River, southern China. The first species is characterized by its greatly enlarged, eversible, feeding apparatus, and was previously known only from British Columbia, Canada.Tectidrilus achaetus is unique within the Tubificidae by lacking setae. A slightly modified definition of the, otherwise marine, genusTectidrilus Erséus, 1982 is provided.     

Dynamics and structure of a Velia caprai (Heteroptera) population in a South Swedish stream

Population density was estimated monthly by means of direct counts for 16 consecutive months. Capture-recapture experiments revealed that 9–22% of the population was observed by this technique. Most nymphs appeared in June, and the presence of nymphs in September suggests a second generation. There was a strong positive correlation between summer surface drift and mean annual population density for five out of six sections studied. In July-August the sex ratio was near equal, while in September females began to dominate. The bias towards females was strong until new imagines emerged in July. From September a marked weight dimorphism was observed between the sexes. Food limitation, and skewed sex and weight ratios implied intersexual competition in this population. Brown trout possibly affected the population density in one section with less shelter. Wing dimorphism was observed in July and August. Macropterous individuals represented a low percentage (<17%) and were only observed in sections with high densities.     

GTP and IAP Shifts Adenosine A1-Agonist Binding in Smooth Muscle Membranes to the Low Affinity State,Similar to the one Found in Intact Cells

Abstract

Adenosine A₁ receptors in the smooth muscle cell line DDT₁ MF-2 were characterized by radioligand binding using the antagonist [³H]-8-cyclopentyl-1,3-dipropylxanthine ([³H]DPCPX) as the ligand. Binding properties of adenosine agonists and antagonists to both intact cells and membranes were investigated.     

Activation of Protein Kinase C in Permeabilized Human Neuroblastoma SH-SY5Y Cells

The activation of protein kinase C was investigated in digitonin-permeabilized human neuroblastoma SH-SY5Y cells by measuring the phosphorylation of the specific protein kinase C substrate myelin basic protein4-14. The phosphorylation was inhibited by the protein kinase C inhibitory peptide PKC19-36 and was associated to a translocation of the enzyme to the membrane fractions of the SH-SY5Y cells. 1,2-Dioctanoyl-sn-glycerol had no effect on protein kinase C activity unless the calcium concentration was raised to concentrations found in stimulated cells (above 100 nM). Calcium in the absence of other activators did not stimulate protein kinase C. Phorbol 12-myristate 13-acetate was not dependent on calcium for the activation or the translocation of protein kinase C. The induced activation was sustained for 10 min, and thereafter only a small net phosphorylation of the substrate could be detected. Calcium or dioctanoylglycerol, when applied alone, only caused a minor translocation, whereas in combination a marked translocation was observed. Arachidonic acid (10 microM) enhanced protein kinase C activity in the presence of submaximal concentrations of calcium and dioctanoylglycerol. Quinacrine and p-bromophenacyl bromide did not inhibit calcium- and dioctanoylglycerol-induced protein kinase C activity at concentrations which are considered to be sufficient for phospholipase A2 inhibition.     

The ecology and evolution of partial migration

Partial migration, where populations of animals are composed of a mixture of resident and migratory individuals, is a widespread phenomenon in nature. It has been reported to occur in all major vertebrate groups, and can have significant ecological consequences. Here we give an overview of the ecology and evolution of partial migration in animals. We firstly review the different types of partial migration, and assess the ecological drivers responsible for driving individual differences in migratory tendency within populations. A variety of factors can be important in promoting the evolution of partial migration, including competition for resources or breeding opportunities, predation risk and intraspecific niche diversity. Often various factors act synergistically to create complex patterns of movement polymorphism within populations. The question of how partial migration is maintained over evolutionary timescales is also addressed. Whilst many theoretical considerations of partial migration utilise an evolutionary stable state (ESS) paradigm, empirical evidence for this is lacking. Rather the evidence suggests that partial migration is mostly condition dependent, and the optimum outcome for an individual is dependent upon its phenotype. What determines whether an individual follows a migratory or resident strategy is discussed in light of new theory and empirical data which supports the idea that environmentally responsive genetic thresholds are important across a range of species, from birds to fish, in proximately shaping migratory tendency. Finally we espouse our vision of how partial migration research will develop in the future, and suggest a number of exciting directions that studies into migratory dimorphism may take in the coming years.