Does the Genetic Code Have A Eukaryotic Origin?

In the RNA world, RNA is assumed to be the dominant macromolecule performing most, if not all, core "house-keeping" functions. The ribo-cell hypothesis suggests that the genetic code and the translation machinery may both be born of the RNA world, and the introduction of DNA to ribo-cells may take over the informational role of RNA gradually, such as a mature set of genetic code and mechanism enabling stable inheritance of sequence and its variation. In this context, we modeled the genetic code in two content variables-GC and purine contents-of protein-coding sequences and measured the purine content sensitivities for each codon when the sensitivity (% usage) is plotted as a function of GC content variation. The analysis leads to a new pattern-the symmetric pattern-where the sensitivity of purine content variation shows diagonally symmetry in the codon table more significantly in the two GC content invariable quarters in addition to the two existing patterns where the table is divided into either four GC content sensitivity quarters or two amino acid diversity halves. The most insensitive codon sets are GUN (valine) and CAN (CAR for asparagine and CAY for aspartic acid) and the most biased amino acid is valine (always over-estimated) followed by alanine (always under-estimated). The unique position of valine and its codons suggests its key roles in the final recruitment of the complete codon set of the canonical table. The distinct choice may only be attributable to sequence signatures or signals of splice sites for spliceosomal introns shared by all extant eukaryotes.     

Does the Chemotherapy Backbone Impact on the Efficacy of Targeted Agents in Metastatic Colorectal Cancer? A Systematic Review and Meta-Analysis of the Literature

ImportanceThe EGFR inhibitors (EGFR-I) cetuximab and panitumumab and the angiogenesis inhibitors (AIs) bevacizumab and aflibercept have demonstrated varying efficacy in mCRC.ObjectiveTo document the overall impact of specific chemotherapy regimens on the efficacy of targeted agents in treating patients with mCRC. Data sources: MEDLINE, EMBASE and Cochrane databases were searched to 2014, supplemented by hand-searching ASCO/ESMO conference abstracts.ResultsEGFR-I added to irinotecan-based chemotherapy modestly improved OS with HR 0.90 (95% CI 0.81–1.00, p = 0.04), but more so PFS with HR 0.77 (95% CI 0.69–0.86, p<0.00001). No benefit was evident for EGFR-I added to oxaliplatin-based chemotherapy (OS HR 0.97 (95% CI 0.87–1.09) and PFS HR 0.92 (95% CI 0.83–1.02)). Significant oxaliplatin-irinotecan subgroup interactions were present for PFS with I² = 82%, p = 0.02. Further analyses of oxaliplatin+EGFR-I trials showed greater efficacy with infusional 5FU regimens (PFS HR 0.82, 95% CI 0.72–0.94) compared to capecitabine (HR 1.09; 95% CI 0.91–1.30) and bolus 5FU (HR 1.07; 95% CI 0.79–1.45); subgroup interaction was present with I² = 72%, p = 0.03. The oxaliplatin-irinotecan interaction was not evident for infusional 5FU regimens. For AIs, OS benefit was observed with both oxaliplatin-based (HR 0.83) and irinotecan-based (HR 0.77) regimens without significant subgroup interactions. Oxaliplatin+AI trials showed no subgroup interactions by type of FP, whilst an interaction was present for irinotecan+AI trials although aflibercept was only used with infusional FP (I² = 89.7%, p = 0.002).

Conclusion and Relevance

The addition of EGFR-I to irinotecan-based chemotherapy has consistent efficacy, regardless of FP regimen, whereas EGFR-I and oxaliplatin-based regimens were most active with infusional 5FU. No such differential activity was observed with the varying chemotherapy schedules when combined with AIs.     

Does Collocation Inform the Impact of Collaboration?

Background

It has been shown that large interdisciplinary teams working across geography are more likely to be impactful. We asked whether the physical proximity of collaborators remained a strong predictor of the scientific impact of their research as measured by citations of the resulting publications.

Methodology/Principal Findings

Articles published by Harvard investigators from 1993 to 2003 with at least two authors were identified in the domain of biomedical science. Each collaboration was geocoded to the precise three-dimensional location of its authors. Physical distances between any two coauthors were calculated and associated with corresponding citations. Relationship between distance of coauthors and citations for four author relationships (first-last, first-middle, last-middle, and middle-middle) were investigated at different spatial scales. At all sizes of collaborations (from two authors to dozens of authors), geographical proximity between first and last author is highly informative of impact at the microscale (i.e. within building) and beyond. The mean citation for first-last author relationship decreased as the distance between them increased in less than one km range as well as in the three categorized ranges (in the same building, same city, or different city). Such a trend was not seen in other three author relationships.

Conclusions/Significance

Despite the positive impact of emerging communication technologies on scientific research, our results provide striking evidence for the role of physical proximity as a predictor of the impact of collaborations.     

Does Invasion of Exotic Plants Promote Invasion of Exotic Flower Visitors? A Case Study from the Temperate Forests of the Southern Andes

Habitat disturbance, particularly of human origin, promotes the invasion of exotic plants, which in turn might foster the invasion of alien-interacting animals. Here we assess whether the invasion of exotic plants – mostly mediated by habitat disturbance – facilitates the invasion of exotic flower visitors in temperate forests of the southern Andes, Argentina. We recorded visit frequencies and the identity of visitors to the flowers of 15 native and 15 exotic plant species occurring in different highly disturbed and less disturbed habitats. We identified three alien flower visitors, the hymenopterans Apis mellifera, Bombus ruderatus, and Vespula germanica. We found significantly more visitation by exotic insects in disturbed habitats. This pattern was explained, at least in part, by the association between alien flower visitors and flowers of exotic plants, which occurred more frequently in disturbed habitats. However, this general pattern masked different responses between the two main alien flower visitors. Apis mellifera exploited almost exclusively the flowers of a subset of herbaceous exotic plants that thrive under disturbance, whereas B. ruderatus visited equally flowers of both exotic and native plants in both disturbed and undisturbed habitats. We did not find any strong evidence that flowers of exotic plants were more generalist than those of native plants, or that exotic flower visitors were more generalist than their native counterparts. Our results suggest that alien plant species could facilitate the invasion of at least some exotic flower visitors to disturbed habitats. Because flowering plants as well as flower visitors benefit from this mutualism, this association may enhance, through a positive feedback, successful establishment of both exotic partners.     

Does Drug-Eluting Bead Transcatheter Arterial Chemoembolization Improve the Management of Patients with Hepatocellular Carcinoma? A Meta-Analysis

Background

Drug eluting beads (DEB) are relatively new embolic agents that allow sustained release of chemotherapeutic agents in a localized fashion to the tumor. This technique is associated with reduced systemic side effects relative to systemic chemotherapy and an increase in the dose of antineoplastic agent delivered to the lesion. The meta-analysis was undertaken to assess the effectiveness of DEB-transcatheter arterial chemoembolization (TACE) in the management of hepatocellular cancer.

Methods

We searched the Web of Science, PubMed, EBSCO, EMBASE, the Wiley Library and Google Scholar for studies on DEB-TACE in the management of hepatocellular cancer from 1979 to April 2013. The risk of bias was assessed using RevMan 5·1. Random and fixed-effects meta-analytical models were used where indicated, and between-study heterogeneity was assessed. Disease control, complications and severe complications were recorded.

Results

Five studies met the selection criteria, three RCTs and two case-control studies, published from 2010 to 2012, included 217 patients in the DEB-TACE group and 237 in the conventional-TACE group. There was no significance over disease control (OR 2.27, 95% CI 0.78–6.63) with moderate between-study heterogeneity (χ² = 6.83, degrees of freedom [df] = 3; p<0.08; I² = 56%). Complications in both groups were assessed and no significant difference was observed (χ² = 6.34, degrees of freedom [df] = 4; p<0.18; I² = 37%). Severe complications were also assessed and no significant difference was observed (χ² = 6.47, degrees of freedom [df] = 4; p<0.17; I² = 38%). No publication bias relating to the above outcomes was detected by funnel plot. DEB-TACE benefited disease control without an increase in complications and severe complications.     

Does the Mode of Plastid Inheritance Influence Plastid Genome Architecture?

Plastid genomes show an impressive array of sizes and compactnesses, but the forces responsible for this variation are unknown. It has been argued that species with small effective genetic population sizes are less efficient at purging excess DNA from their genomes than those with large effective population sizes. If true, one may expect the primary mode of plastid inheritance to influence plastid DNA (ptDNA) architecture. All else being equal, biparentally inherited ptDNAs should have a two-fold greater effective population size than those that are uniparentally inherited, and thus should also be more compact. Here, we explore the relationship between plastid inheritance pattern and ptDNA architecture, and consider the role of phylogeny in shaping our observations. Contrary to our expectations, we found no significant difference in plastid genome size or compactness between ptDNAs that are biparentally inherited relative to those that are uniparentally inherited. However, we also found that there was significant phylogenetic signal for the trait of mode of plastid inheritance. We also found that paternally inherited ptDNAs are significantly smaller (n = 19, p = 0.000001) than those that are maternally, uniparentally (when isogamous), or biparentally inherited. Potential explanations for this observation are discussed.     

Does Fire Influence the Landscape-Scale Distribution of an Invasive Mesopredator?

Predation and fire shape the structure and function of ecosystems globally. However, studies exploring interactions between these two processes are rare, especially at large spatial scales. This knowledge gap is significant not only for ecological theory, but also in an applied context, because it limits the ability of landscape managers to predict the outcomes of manipulating fire and predators. We examined the influence of fire on the occurrence of an introduced and widespread mesopredator, the red fox (Vulpes vulpes), in semi-arid Australia. We used two extensive and complimentary datasets collected at two spatial scales. At the landscape-scale, we surveyed red foxes using sand-plots within 28 study landscapes – which incorporated variation in the diversity and proportional extent of fire-age classes – located across a 104 000 km² study area. At the site-scale, we surveyed red foxes using camera traps at 108 sites stratified along a century-long post-fire chronosequence (0–105 years) within a 6630 km² study area. Red foxes were widespread both at the landscape and site-scale. Fire did not influence fox distribution at either spatial scale, nor did other environmental variables that we measured. Our results show that red foxes exploit a broad range of environmental conditions within semi-arid Australia. The presence of red foxes throughout much of the landscape is likely to have significant implications for native fauna, particularly in recently burnt habitats where reduced cover may increase prey species’ predation risk.     

A Comparison of the Performance of the I-gel? vs. the LMA-S?during Anesthesia: A Meta-Analysis of Randomized Controlled Trials

Background and Objective

Conflicting results were found between the I-gel™ and the LMA-Supreme™ during anesthesia, so we conducted a meta-analysis of randomized controlled trials (RCTs) to compare the effectiveness and safety of the I-gel™ vs. the LMA-Supreme™during anesthesia.

Methods

A comprehensive search was conducted using Pubmed, EMbase, ISI Web of Knowledge, the Cochrane Library, China Journal Full-text Database, Chinese Biomedical Database, Chinese Scientific Journals Full-text Database, CMA Digital Periodicals, and Google scholar to find RCTs that compare the LMA-S™ with the i-gel™during anesthesia. Two reviewers independently selected trials, extracted data, and assessed the methodological qualities and evidence levels. Data were analyzed by RevMan 5.0 and comprehensive meta-analysis software.

Results

Ten RCTs were included. There were no significant differences in oropharyngeal leak pressures (mean difference [MD] 0.72, 95% confidence interval [CI] –1.10 2.53), device placement time (MD –1.3, 95%CI –4.07 1.44), first attempt insertion success (risk ratio [RR] 1.01, 95% CI 0.9 1.14), grade 3 and 4 fiberoptic view (RR 0.89, 95%CI 0.65 1.21), and blood on removal (RR 0.62, 95%CI 0.32 1.22) between the i-gel™ and the LMA-Supreme™, respectively. However, the LMA-Supreme™was associated with easier gastric tube insertion (RR 1.17, 95%CI 1.07 1.29), and more sore throat (RR 2.56, 95%CI 1.60 4.12) than the i-gel™ group.

Conclusions

The LMA-Supreme™ and i-gel™ were similarly successful and rapidly inserted. However, the LMA-Supreme™ was shown to be easier for gastric tube insertion and associated with more sore throat compared with the i-gel™.     

Does Glass Size and Shape Influence Judgements of the Volume of Wine?

Background

Judgements of volume may influence the rate of consumption of alcohol and, in turn, the amount consumed. The aim of the current study was to examine the impact of the size and shape of wine glasses on perceptions of wine volume.

Methods

Online experiment: Participants (n = 360; recruited via Mechanical Turk) were asked to match the volume of wine in two wine glasses, specifically: 1. the Reference glass holding a fixed reference volume, and 2. the Comparison glass, for which the volume could be altered until participants perceived it matched the reference volume. One of three comparison glasses was shown in each trial: ‘wider’ (20% wider but same capacity); ‘larger’ (same width but 25% greater capacity); or ‘wider-and-larger’ (20% wider and 25% greater capacity). Reference volumes were 125ml, 175ml and 250ml, in a fully factorial within-subjects design: 3 (comparison glass) x 3 (reference volume). Non-zero differences between the volumes with which participants filled comparison glasses and the corresponding reference volumes were identified using sign-rank tests.

Results

Participants under-filled the wider glass relative to the reference glass for larger reference volumes, and over-filled the larger glass relative to the reference glass for all reference volumes. Results for the wider-and-larger glass showed a mixed pattern across reference volume. For all comparison glasses, in trials with larger reference volumes participants tended to fill the comparison glass less, relative to trials with smaller reference volumes for the same comparison glass.

Conclusions

These results are broadly consistent with people using the relative fullness of glasses to judge volume, and suggest both the shape and capacity of wine glasses may influence perceived volume. Perceptions that smaller glasses contain more than larger ones (despite containing the same volume), could slow drinking speed and overall consumption by serving standard portions in smaller glasses. This hypothesis awaits testing.     

Does Temporal Variation in Predation Risk Influence the Intensity of Antipredator Responses? A Test of the Risk Allocation Hypothesis

Temporal variation in predation risk may fundamentally influence antipredator responses of prey animals. To maximize lifetime fitness, prey must be able to optimize energy gain and minimize predation risk, and responses to current levels of risk may be influenced by background levels of risk. A ‘risk allocation’ model has recently been proposed to predict the intensity of antipredator responses that should occur as predation risk varies over time. Prey animals from high‐risk environments should respond to predators with relatively low intensities of antipredator behaviour because long periods of antipredator behaviour may result in unacceptable decreases in levels of foraging activity. Moreover, animals that are under frequent risk should devote more energy to foraging during brief pulses of safety compared with animals under infrequent attack. In this study, we experimentally tested the risk allocation hypothesis. We exposed juvenile rainbow trout, Oncorhynchus mykiss, to three levels of risk (high, moderate and low) crossed with two levels of temporal variation (exposed to risk three times a day and once a day). In accordance with the model, we found that trout exposed to risky situations more frequently responded with significantly less intense antipredator behaviour than trout exposed to risk infrequently. The intensity of response of trout exposed to moderate risk three times a day decreased to levels similar to situations of no risk. However, in contrast to the second prediction of the model, animals under frequent risk were not more active during periods of safety compared with animals under infrequent risk. Although behaviour in the face of predation risk was dependent on the broader temporal context in which risk varied, the specific predictions of the risk allocation model were only partly supported.     

Does Plant Species Richness Guarantee the Resilience of Local Medical Systems? A Perspective from Utilitarian Redundancy

Resilience is related to the ability of a system to adjust to disturbances. The Utilitarian Redundancy Model has emerged as a tool for investigating the resilience of local medical systems. The model determines the use of species richness for the same therapeutic function as a facilitator of the maintenance of these systems. However, predictions generated from this model have not yet been tested, and a lack of variables exists for deeper analyses of resilience. This study aims to address gaps in the Utilitarian Redundancy Model and to investigate the resilience of two medical systems in the Brazilian semi-arid zone. As a local illness is not always perceived in the same way that biomedicine recognizes, the term “therapeutic targets” is used for perceived illnesses. Semi-structured interviews with local experts were conducted using the free-listing technique to collect data on known medicinal plants, usage preferences, use of redundant species, characteristics of therapeutic targets, and the perceived severity for each target. Additionally, participatory workshops were conducted to determine the frequency of targets. The medical systems showed high species richness but low levels of species redundancy. However, if redundancy was present, it was the primary factor responsible for the maintenance of system functions. Species richness was positively associated with therapeutic target frequencies and negatively related to target severity. Moreover, information about redundant species seems to be largely idiosyncratic; this finding raises questions about the importance of redundancy for resilience. We stress the Utilitarian Redundancy Model as an interesting tool to be used in studies of resilience, but we emphasize that it must consider the distribution of redundancy in terms of the treatment of important illnesses and the sharing of information. This study has identified aspects of the higher and lower vulnerabilities of medical systems, adding variables that should be considered along with richness and redundancy.     

Does the Arthropod Microbiota Impact the Establishment of Vector-Borne Diseases in Mammalian Hosts?

The impact of the microbiota on the immune status of its host is a source of intense research and publicity. In comparison, the effect of arthropod microbiota on vector-borne infectious diseases has received little attention. A better understanding of the vector microbiota in relation to mammalian host immune responses is vital, as it can lead to strategies that affect transmission and improve vaccine design in a field of research where few vaccines exist and effective treatment is rare. Recent demonstrations of how microbiota decrease pathogen development in arthropods, and thus alter vector permissiveness to vector-borne diseases (VBDs), have led to renewed interest. However, hypotheses on the interactions between the arthropod-derived microbiota and the mammalian hosts have yet to be addressed. Advances in DNA sequencing technology, increased yield and falling costs, mean that these studies are now feasible for many microbiologists and entomologists. Here, we distill current knowledge and put forward key questions and experimental designs to shed light on this burgeoning research topic.     

Does Endophyte Influence Regrowth of Tall Fescue?

The influence of ecological and environmental factors on theresponse of the mutualistic symbionts Acremonium coenophialum(Morgan-Jones and Gams), and tall fescue ( Festuca arundinacea,Schreb.) has received substantial attention. However, much ofwhat is known about developmental and physiological responseshas been obtained from static or mature canopies and the influenceof defoliation on the symbiota has not been considered in detail.A controlled environment experiment was conducted to assessthe influence of defoliation and endophyte on the regrowth anddevelopment of two tall fescue genotypes and their respectiveendophytes, known to differ in morphology and alkaloid productioncapacity. The response of endophyte infected relative to non-infectedplants was evaluated for measured and calculated parametersfor each defoliation. While the influence of genotype was substantialon virtually all parameters, endophyte interacted with genotypeand defoliation resulting in enhanced plasticity of mutualistsas a response to varying conditions. Endophyte infection influencedleaf mass depending upon genotype, while the relative benefitof endophyte on pseudostem mass was affected by defoliation.Endophyte interacted with genotype to influence relative growthrate and productivity relative to nitrogen concentration whencanopies were clipped, but was less important when canopiesremained uncut. In some instances endophyte gave growth andsize advantage to the host and did not in others. Generalitiesregarding symbiont response to extrinsic factors may be misleading,since responses depend upon the specific mutualism consideredand conditions imposed. Acremonium coenophialum ; Festuca arundinacea ; non-structural carbohydrate; relative growth rate     

Does Methyl Salicylate, A Component of Herbivore-induced Plant Odour, Promote Sporulation of the Mite-pathogenic Fungus Neozygites tanajoae?

Blends of volatile chemicals emanating from cassava leaves infested by the cassava green mite were found to promote conidiation of Neozygites tanajoae, an entomopathogenic fungus specific to this mite. Methyl salicylate (MeSA) is one compound frequently present in blends of herbivore-induced plant volatiles (HIPV) as well as that of mite-infested cassava. Here, we investigated the effect of methyl salicylate in its pure form on the production of pre-infective spores (conidia), and the germination of these spores into infective spores (capilliconidia), by a Brazilian isolate and a Beninese isolate of N. tanajoae. Mummified mites previously infected by the fungal isolates were screened under optimal abiotic conditions for sporulation inside tightly closed boxes with or without methyl salicylate diffusing from a capillary tube. Production of conidia was consistently higher (37%) when the Beninese isolate was exposed to MeSA than when not exposed to it (305.5 ± 52.62 and 223.2 ± 38.13 conidia per mummy with and without MeSA, respectively). MeSA, however, did not promote conidia production by the Brazilian isolate (387.4 ± 44.74 and 415.8 ± 57.95 conidia per mummy with and without MeSA, respectively). Germination of the conidia into capilliconidia was not affected by MeSA for either isolate (0.2%, 252.6 ± 31.80 vs. 253.0 ± 36.65 for the Beninese isolate and 4.2%, 268.5 ± 37.90 vs. 280.2 ± 29.43 for the Brazilian isolate). The effects of MeSA on the production of conidia were similar to those obtained under exposure to the complete blends of HIPV for the case of the Beninese isolate, but dissimilar (no promoting effect of MeSA) for the case of the Brazilian isolate. This shows that MeSA, being one compound out of many HIPV, can be a factor promoting sporulation of N. tanajoae, but it may not be the only factor as its effect varies with the fungal isolate under study.     

Does Minimally-Invasive Pancreaticoduodenectomy Have Advantages over Its Open Method? A Meta-Analysis of Retrospective Studies

Background

While more and more open procedures now routinely performed using laparoscopy, minimally invasive pancreaticoduodenectomy (MIPD) remains one of the most challenging abdominal procedures. Therefore, we carried out this meta-analysis to evaluate whether MIPD is safe, feasible and worthwhile.

Methods

PubMed, EMBASE, and Cochrane Library were searched to identify studies published between January 1994 and November 2013 comparing MIPD with open pancreaticoduodenectomy (OPD). Intraoperative outcomes, oncologic safety, postoperative complications, and postoperative recovery were evaluated.

Results

11 retrospective studies representing 869 patients (327 MIPDs, 542 OPDs) were included. MIPD was associated with a reduction in estimated blood loss (MD −361.93 ml, 95% CI −519.22 to −204.63 ml, p<0.001, I² = 94%), wound infection (OR 0.41, 95% CI 0.22 to 0.78, p = 0.007, I² = 0%), and hospital stay (MD −2.64 d, 95% CI −4.23 to −1.05 d, p = 0.001, I² = 78%). However, it brings longer operative time (MD 105 min, 95% CI 49.73 to 160.26 min, p<0.001, I² = 93%). There were no significant differences between the two procedures in likelihood of overall complications (p = 0.05), pancreatic fistula (PF) (p = 0.86), delayed gastric empting (DGE) (p = 0.96), positive surgical margins (p = 0.07), retrieval of lymph nodes (p = 0.48), reoperation (p = 0.16) and mortality (p = 0.64).

Conclusions

Our results suggest that MIPD is currently safe, feasible and worthwhile. But considering the selection bias, complexity of MIPD and lack of long-term oncologic outcomes, we suggest it be performed in a high-volume pancreatic surgery center in selected patients.     

Does the type of matrix matter? A quantitative review of the evidence

It has been increasingly recognized that the type of matrix surrounding habitat patches can affect biodiversity in landscapes, but there were only qualitative reviews of the subject focused on particular taxonomic groups. We present a quantitative review of studies from 1985 to 2008 that compared effects of different matrix types on individuals, populations and communities. We compiled 104 studies, most on animals, covering a broad range of landscape types and spatial scales. Most studies were empirical, focused on individuals and communities, and evaluated abundance/richness in the patch as the dependent variable. The type of matrix surrounding habitat patches influenced the studied parameters in 95% of the studies, but such effects were overall smaller compared to patch size or isolation effects. Matrix type effects were strongly species-specific, with different species responding differently to matrix type in 96% of studies comparing species or group of species. In 88% of studies, matrix types more similar in structure to the patch had higher quality for the studied organisms from the point of view of functional connectivity. Overall, the type of matrix is important, but patch size and isolation are the main determinants of ecological parameters in landscapes. Matrix quality generally increases with increasing structural similarity with habitat patches, a pattern that could be used as a general guideline for management of the matrix in fragmented landscapes.     

Does the Refuge Availability Influence the Spawning Behavior of Mature Male Parr in Salmonids? A Test in the Miyabe Charr

In many salmon and charr, both 'migratory males' and 'precocious males' are maintained as alternative life-histories within a population. During breeding, precocious males gather around the mating pair of migratory fish and attempt to sneak in the spawning between larger male and female charr. Refuges such as debris and shallow areas may provide shelter from aggressive attacks and allow precocious males to hold positions closer to the pair (nest) and/or sneak more easily during the mating. Here we examine whether the availability of refuges influences the breeding behavior of precocious male parr of the Miyabe charr under experimental and natural conditions. Aggressive attacks directed toward precocious parr by the mating pair or other parr was not influenced by the refuge availability either under experimental conditions or in the wild. We did not find the effect of high refuge availability on the proximity of parr to the nest beyond the experimental conditions where the density of refuges was probably higher than in the natural stream. There were no effects of high refuge availability either on parr's attempts at sneak mating or on their success in spawning. Thus, our results provide little evidence that the refuge availability influences parr sneaking behavior. Other possible effects of high refuge availability, for example, the increase of fertilization success and the decrease of energy expenditure and risk taking, remain to be considered.