Which peer reviewers voluntarily reveal their identity to authors? Insights into the consequences of open-identities peer review.

Identifying reviewers is argued to improve the quality and fairness of peer review, but is generally disfavoured by reviewers. To gain some insight into the factors that influence when reviewers are willing to have their identity revealed, I examined which reviewers voluntarily reveal their identities to authors at the journal Functional Ecology, at which reviewer identities are confidential unless reviewers sign their comments to authors. I found that 5.6% of reviewers signed their comments to authors. This proportion increased slightly over time, from 4.4% in 2003-2005 to 6.7% in 2013-2015. Male reviewers were 1.8 times more likely to sign their comments to authors than were female reviewers, and this difference persisted over time. Few reviewers signed all of their reviews; reviewers were more likely to sign their reviews when their rating of the manuscript was more positive, and papers that had at least one signed review were more likely to be invited for revision. Signed reviews were, on average, longer and recommended more references to authors. My analyses cannot distinguish cause and effect for the patterns observed, but my results suggest that 'open-identities' review, in which reviewers are not permitted to be anonymous, will probably reduce the degree to which reviewers are critical in their assessment of manuscripts and will differentially affect recruitment of male and female reviewers, negatively affecting the diversity of reviewers recruited by journals.

Gender differences in peer review outcomes and manuscript impact at six journals of ecology and evolution.

The productivity and performance of men is generally rated more highly than that of women in controlled experiments, suggesting conscious or unconscious gender biases in assessment. The degree to which editors and reviewers of scholarly journals exhibit gender biases that influence outcomes of the peer-review process remains uncertain due to substantial variation among studies. We test whether gender predicts the outcomes of editorial and peer review for >23,000 research manuscripts submitted to six journals in ecology and evolution from 2010 to 2015. Papers with female and male first authors were equally likely to be sent for peer review. However, papers with female first authors obtained, on average, slightly worse peer-review scores and were more likely to be rejected after peer review, though the difference varied among journals. These gender differences appear to be partly due to differences in authorial roles. Papers for the which the first author deferred corresponding authorship to a coauthor (which women do more often than men) obtained significantly worse peer-review scores and were less likely to get positive editorial decisions. Gender differences in corresponding authorship explained some of the gender differences in peer-review scores and positive editorial decisions. In contrast to these observations on submitted manuscripts, gender differences in peer-review outcomes were observed in a survey of >12,000 published manuscripts; women reported similar rates of rejection (from a prior journal) before eventual publication. After publication, papers with female authors were cited less often than those with male authors, though the differences are very small (~2%). Our data do not allow us to test hypotheses about mechanisms underlying the gender discrepancies we observed, but strongly support the conclusion that papers authored by women have lower acceptance rates and are less well cited than are papers authored by men in ecology.

The effectiveness of journals as arbiters of scientific impact.

Academic publishers purport to be arbiters of knowledge, aiming to publish studies that advance the frontiers of their research domain. Yet the effectiveness of journal editors at identifying novel and important research is generally unknown, in part because of the confidential nature of the editorial and peer review process. Using questionnaires, we evaluated the degree to which journals are effective arbiters of scientific impact on the domain of Ecology, quantified by three key criteria. First, journals discriminated against low-impact manuscripts: The probability of rejection increased as the number of citations gained by the published paper decreased. Second, journals were more likely to publish high-impact manuscripts (those that obtained citations in 90th percentile for their journal) than run-of-the-mill manuscripts; editors were only 23% and 41% as likely to reject an eventual high-impact paper (pre- versus postreview rejection) compared to a run-of-the-mill paper. Third, editors did occasionally reject papers that went on to be highly cited. Error rates were low, however: Only 3.8% of rejected papers gained more citations than the median article in the journal that rejected them, and only 9.2% of rejected manuscripts went on to be high-impact papers in the (generally lower impact factor) publishing journal. The effectiveness of scientific arbitration increased with journal prominence, although some highly prominent journals were no more effective than much less prominent ones. We conclude that the academic publishing system, founded on peer review, appropriately recognizes the significance of research contained in manuscripts, as measured by the number of citations that manuscripts obtain after publication, even though some errors are made. We therefore recommend that authors reduce publication delays by choosing journals appropriate to the significance of their research.

Geographic clines in wing morphology relate to colonization history in New World but not Old World populations of yellow dung flies.

Geographic clines offer insights about putative targets and agents of natural selection as well as tempo and mode of adaptation. However, demographic processes can lead to clines that are indistinguishable from adaptive divergence. Using the widespread yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae), we examine quantitative genetic differentiation (QST ) of wing shape across North America, Europe, and Japan, and compare this differentiation with that of ten microsatellites (FST ). Morphometric analyses of 28 populations reared at three temperatures revealed significant thermal plasticity, sexual dimorphism, and geographic differentiation in wing shape. In North America morphological differentiation followed the decline in microsatellite variability along the presumed route of recent colonization from the southeast to the northwest. Across Europe, where S. stercoraria presumably existed for much longer time and where no molecular pattern of isolation by distance was evident, clinal variation was less pronounced despite significant morphological differentiation (QST >FST ). Shape vector comparisons further indicate that thermal plasticity (hot-to-cold) does not mirror patterns of latitudinal divergence (south-to-north), as might have been expected under a scenario with temperature as the major agent of selection. Our findings illustrate the importance of detailed phylogeographic information when interpreting geographic clines of dispersal traits in an adaptive evolutionary framework.

Patterns of authorship in ecology and evolution: First, last, and corresponding authorship vary with gender and geography.

The position of an author on the byline of a paper affects the inferences readers make about their contributions to the research. We examine gender differences in authorship in the ecology literature using two datasets: submissions to six journals between 2010 and 2015 (regardless of whether they were accepted), and manuscripts published by 151 journals between 2009 and 2015. Women were less likely to be last (i.e., "senior") authors (averaging ~23% across journals, years, and datasets) and sole authors (~24%), but more likely to be first author (~38%), relative to their overall frequency of authorship (~31%). However, the proportion of women in all authorship roles, except sole authorship, has increased year-on-year. Women were less likely to be authors on papers with male last authors, and all-male papers were more abundant than expected given the overall gender ratio. Women were equally well represented on papers published in higher versus lower impact factor journals at all authorship positions. Female first authors were less likely to serve as corresponding author of their papers; this difference increased with the degree of gender inequality in the author's home country, but did not depend on the gender of the last author. First authors from non-English-speaking countries were less likely to serve as corresponding author of their papers, especially if the last author was from an English-speaking country. That women more often delegate corresponding authorship to one of their coauthors may increase the likelihood that readers undervalue their role in the research by shifting credit for their contributions to coauthors. We suggest that author contribution statements be more universally adopted and that these statements declare how and/or why the corresponding author was selected for this role.

Recruitment of reviewers is becoming harder at some journals: a test of the influence of reviewer fatigue at six journals in ecology and evolution.

BACKGROUND: It is commonly reported by editors that it has become harder to recruit reviewers for peer review and that this is because individuals are being asked to review too often and are experiencing reviewer fatigue. However, evidence supporting these arguments is largely anecdotal. MAIN BODY: We examine responses of individuals to review invitations for six journals in ecology and evolution. The proportion of invitations that lead to a submitted review has been decreasing steadily over 13 years (2003-2015) for four of the six journals examined, with a cumulative effect that has been quite substantial (average decline from 56% of review invitations generating a review in 2003 to just 37% in 2015). The likelihood that an invitee agrees to review declines significantly with the number of invitations they receive in a year. However, the average number of invitations being sent to prospective reviewers and the proportion of individuals being invited more than once per year has not changed much over these 13 years, despite substantial increases in the total number of review invitations being sent by these journals-the reviewer base has expanded concomitant with this growth in review requests. CONCLUSIONS: The proportion of review invitations that lead to a review being submitted has been declining steadily for four of the six journals examined here, but reviewer fatigue is not likely the primary explanation for this decline.

Citations increase with manuscript length, author number, and references cited in ecology journals.

Most top impact factor ecology journals indicate a preference or requirement for short manuscripts; some state clearly defined word limits, whereas others indicate a preference for more concise papers. Yet evidence from a variety of academic fields indicates that within journals longer papers are both more positively reviewed by referees and more highly cited. We examine the relationship between citations received and manuscript length, number of authors, and number of references cited for papers published in 32 ecology journals between 2009 and 2012. We find that longer papers, those with more authors, and those that cite more references are cited more. Although paper length, author count, and references cited all positively covary, an increase in each independently predicts an increase in citations received, with estimated relationships positive for all the journals we examined. That all three variables covary positively with citations suggests that papers presenting more and a greater diversity of data and ideas are more impactful. We suggest that the imposition of arbitrary manuscript length limits discourages the publication of more impactful studies. We propose that journals abolish arbitrary word or page limits, avoid declining papers (or requiring shortening) on the basis of length alone (irrespective of content), and adopt the philosophy that papers should be as long as they need to be.

The relationship between manuscript title structure and success: editorial decisions and citation performance for an ecological journal.

A poorly chosen article title may make a paper difficult to discover or discourage readership when discovered, reducing an article's impact. Yet, it is unclear how the structure of a manuscript's title influences readership and impact. We used manuscript tracking data for all manuscripts submitted to the journal Functional Ecology from 2004 to 2013 and citation data for papers published in this journal from 1987 to 2011 to examine how title features changed and whether a manuscript's title structure was predictive of success during the manuscript review process and/or impact (citation) after publication. Titles of manuscripts submitted to Functional Ecology became marginally longer (after controlling for other variables), broader in focus (less frequent inclusion of genus and species names), and included more humor and subtitles over the period of the study. Papers with subtitles were less likely to be rejected by editors both pre- and post-peer review, although both effects were small and the presence of subtitles in published papers was not predictive of citations. Papers with specific names of study organisms in their titles fared poorly during editorial (but not peer) review and, if published, were less well cited than papers whose titles did not include specific names. Papers with intermediate length titles were more successful during editorial review, although the effect was small and title word count was not predictive of citations. No features of titles were predictive of reviewer willingness to review papers or the length of time a paper was in peer review. We conclude that titles have changed in structure over time, but features of title structure have only small or no relationship with success during editorial review and post-publication impact. The title feature that was most predictive of manuscript success: papers whose titles emphasize broader conceptual or comparative issues fare better both pre- and post-publication than do papers with organism-specific titles.

Comparison of life history and genetic properties of cowpea bruchid strains and their response to hypoxia.

The cowpea bruchid (Callosobruchus maculatus) is the most important storage pest of grain legumes and comprises geographically distinct strains. Storage under a modified atmosphere with decreased O2 content represents an alternative to chemical fumigants for pest control of stored grains. In this study, we compared reproduction, development and survival, as well as genome size of bruchid strains from South India (SI), Burkina Faso (BF), Niger (CmNnC) and the United States (OH), reared on mung bean (Vigna radiata). Fecundity and egg-to-adult duration varied significantly among these strains. Notably, strain BF had the highest fecundity, and strain SI displayed the fastest development whereas strain OH was the slowest. Differences in adult lifespan among strains were only detected in unmated but not in the mated group. Genome size of SI females was significantly larger than that of OH females, and for all four strains, the female genomes were larger than those of their corresponding males. Furthermore, we studied effects of exposure to 1% O2+99% N2 on strains SI and BF. Mortality caused by hypoxia was influenced by not only developmental stage but also by insect strain. Eggs were most sensitive, particularly at the early stage, whereas the 3rd and 4th instar larvae were most tolerant and could survive up to 15 days of low O2. Strain SI was slightly more resistant than BF in egg and larval stages. Proteolytic activity prior to, during and after hypoxia treatment revealed remarkable metabolic plasticity of cowpea bruchids in response to modified atmosphere.

Intraoperative neuromonitoring: can the results of direct stimulation of titanium-alloy pedicle screws in the thoracic spine be trusted?

UNLABELLED: OBJECTVIE: Intraoperative neuromonitoring of thoracic-level pedicle screw implantation for detecting breaches in the pedicle cortex has adopted methods originally developed in the early 1990s for stainless steel (SS) alloy screws used at lumbosacral levels. In our recent attempts to monitor thoracic-level pedicle screw placement, we were surprised to find that these widely used stimulation parameters were largely ineffectual when stimulating directly through titanium alloy (Ti-alloy) pedicle screws. The objectives of this study, then, were twofold: (1) to report the number of episodes in which intraoperative neuromonitoring of thoracic screw position failed to detect a medially directed breach (or malplacement) in a previously described and limited sample set; and (2) to compare the frequency-specific impedance of a sample of Ti-alloy pedicle screws to comparably sized screws made of SS alloys. We predicted that Ti-alloy screws would demonstrate impairment in conduction properties that could help explain the difficulties we, and others, have recently experienced with neuromonitoring of thoracic pedicle screw placement. METHODS: Based on threshold values for train-of-four stimulation of spinal motor pathways, we quantified the incidence of medial breaches of thoracic-level pedicles in a small cohort of subjects. We also evaluated the conductive properties of Ti-alloy pedicle screws and compared these with SS screws. Eleven pedicle screws were examined using energy-dispersive x-ray spectroscopy to identify their alloys, after which DC resistance and AC impedance for each screw was measured. Furthermore, a subset of five screws was used to investigate the current delivery under dynamic testing conditions. RESULTS: Postoperative computed tomography of 6 subjects revealed 10 instances of significant medial screw malpositioning, out of a total of 88 screws placed. In each of these 10 instances, direct stimulation of thoracic pedicle screws at intensities considered in the literature to be clinically significant (i.e., ≤11 mA) failed to predict these medial pedicle breaches, yet each breach was reliably identified with low-intensity stimulation applied via a ball-tipped probe. For in vitro studies, most screws made of titanium alloys had higher resistance and impedance at tested frequencies compared with their SS counterparts. Moreover, there was widespread variability in conduction properties between Ti-alloy screws, whereas SS screws behaved in a more homogeneous manner. CONCLUSIONS: When compared with screws made of SS, most Ti-alloy pedicle screws behaved more like semiconductors, showing conduction properties that were highly frequency dependent. These properties likely contributed to the difficulties we encountered in interpreting thoracic screw placements based on stimulus-evoked electromyography from direct screw stimulation.

Inbreeding-stress interactions: evolutionary and conservation consequences.

The effect of environmental stress on the magnitude of inbreeding depression has a long history of intensive study. Inbreeding-stress interactions are of great importance to the viability of populations of conservation concern and have numerous evolutionary ramifications. However, such interactions are controversial. Several meta-analyses over the last decade, combined with omic studies, have provided considerable insight into the generality of inbreeding-stress interactions, its physiological basis, and have provided the foundation for future studies. In this review, we examine the genetic and physiological mechanisms proposed to explain why inbreeding-stress interactions occur. We specifically examine whether the increase in inbreeding depression with increasing stress could be due to a concomitant increase in phenotypic variation, using a larger data set than any previous study. Phenotypic variation does usually increase with stress, and this increase can explain some of the inbreeding-stress interaction, but it cannot explain all of it. Overall, research suggests that inbreeding-stress interactions can occur via multiple independent channels, though the relative contribution of each of the mechanisms is unknown. To better understand the causes and consequences of inbreeding-stress interactions in natural populations, future research should focus on elucidating the genetic architecture of such interactions and quantifying naturally occurring levels of stress in the wild.

Optimal decision-making in mammals: insights from a robot study of rodent texture discrimination.

Texture perception is studied here in a physical model of the rat whisker system consisting of a robot equipped with a biomimetic vibrissal sensor. Investigations of whisker motion in rodents have led to several explanations for texture discrimination, such as resonance or stick-slips. Meanwhile, electrophysiological studies of decision-making in monkeys have suggested a neural mechanism of evidence accumulation to threshold for competing percepts, described by a probabilistic model of Bayesian sequential analysis. For our robot whisker data, we find that variable reaction-time decision-making with sequential analysis performs better than the fixed response-time maximum-likelihood estimation. These probabilistic classifiers also use whatever available features of the whisker signals aid the discrimination, giving improved performance over a single-feature strategy, such as matching the peak power spectra of whisker vibrations. These results cast new light on how the various proposals for texture discrimination in rodents depend on the whisker contact mechanics and suggest the possibility of a common account of decision-making across mammalian species.

The effect of whisker movement on radial distance estimation: a case study in comparative robotics.

Whisker movement has been shown to be under active control in certain specialist animals such as rats and mice. Though this whisker movement is well characterized, the role and effect of this movement on subsequent sensing is poorly understood. One method for investigating this phenomena is to generate artificial whisker deflections with robotic hardware under different movement conditions. A limitation of this approach is that assumptions must be made in the design of any artificial whisker actuators, which will impose certain restrictions on the whisker-object interaction. In this paper we present three robotic whisker platforms, each with different mechanical whisker properties and actuation mechanisms. A feature-based classifier is used to simultaneously discriminate radial distance to contact and contact speed for the first time. We show that whisker-object contact speed predictably affects deflection magnitudes, invariant of whisker material or whisker movement trajectory. We propose that rodent whisker control allows the animal to improve sensing accuracy by regulating contact speed induced touch-to-touch variability.

Male inbreeding status affects female fitness in a seed-feeding beetle.

Inbreeding generally reduces male mating activity such that inbred males are less successful in male-male competition. Inbred males can also have smaller accessory glands, transfer less sperm and produce sperm that are less motile, less viable or have a greater frequency of abnormalities, all of which can reduce the fertilization success and fitness of inbred males relative to outbred males. However, few studies have examined how male inbreeding status affects the fitness of females with whom they mate. In this study, we examine the effect of male inbreeding status (inbreeding coefficient f = 0.25 vs. f = 0) on the fecundity, adult longevity and the fate of eggs produced by outbred females in the seed-feeding beetle, Callosobruchus maculatus. Females mated to inbred males were less likely to lay eggs. Of those that laid eggs, females mated to inbred males laid 6-12% fewer eggs. Females mated to inbred males lived on average 5.4% longer than did females mated to outbred males, but this effect disappeared when lifetime fecundity was used as a covariate in the analysis. There was no effect of male inbreeding status on the proportion of a female's eggs that developed or hatched, and no evidence that inbred males produced smaller nuptial gifts. However, ejaculates of inbred males contained 17-33% fewer sperm, on average, than did ejaculates of outbred males. Our study demonstrates that mating with inbred males has significant direct consequences for the fitness of female C. maculatus, likely mediated by effects of inbreeding status on the number of sperm in male ejaculates. Direct effects of male inbreeding status on female fitness should be more widely considered in theoretical models and empirical studies of mate choice.

Inclusive fitness theory and eusociality.

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Nowak et al. argue that inclusive fitness theory has been of little value in explaining the natural world, and that it has led to negligible progress in explaining the evolution of eusociality. However, we believe that their arguments are based upon a misunderstanding of evolutionary theory and a misrepresentation of the empirical literature. We will focus our comments on three general issues.

Inbreeding depression increases with environmental stress: an experimental study and meta-analysis.

Inbreeding-environment interactions occur when inbreeding leads to differential fitness loss in different environments. Inbred individuals are often more sensitive to environmental stress than are outbred individuals, presumably because stress increases the expression of deleterious recessive alleles or cellular safeguards against stress are pushed beyond the organism's physiological limits. We examined inbreeding-environment interactions, along two environmental axes (temperature and rearing host) that differ in the amount of developmental stress they impose, in the seed-feeding beetle Callosobruchus maculatus. We found that inbreeding depression (inbreeding load, L) increased with the stressfulness of the environment, with the magnitude of stress explaining as much as 66% of the variation in inbreeding depression. This relationship between L and developmental stress was not explainable by an increase in phenotypic variation in more stressful environments. To examine the generality of this experimental result, we conducted a meta-analysis of the available data from published studies looking at stress and inbreeding depression. The meta-analysis confirmed that the effect of the environment on inbreeding depression scales linearly with the magnitude of stress; a population suffers one additional lethal equivalent, on average, for each 30% reduction in fitness induced by the stressful environment. Studies using less-stressful environments may lack statistical power to detect the small changes in inbreeding depression. That the magnitude of inbreeding depression scales with the magnitude of the stress applied has numerous repercussions for evolutionary and conservation genetics and may invigorate research aimed at finding the causal mechanism involved in such a relationship.

Natural selection on body size is mediated by multiple interacting factors: a comparison of beetle populations varying naturally and experimentally in body size.

Body size varies considerably among species and among populations within species, exhibiting many repeatable patterns. However, which sources of selection generate geographic patterns, and which components of fitness mediate evolution of body size, are not well understood. For many animals, resource quality and intraspecific competition may mediate selection on body size producing large-scale geographic patterns. In two sequential experiments, we examine how variation in larval competition and resource quality (seed size) affects the fitness consequences of variation in body size in a scramble-competing seed-feeding beetle, Stator limbatus. Specifically, we compared fitness components among three natural populations of S. limbatus that vary in body size, and then among three lineages of beetles derived from a single base population artificially selected to vary in size, all reared on three sizes of seeds at variable larval density. The effects of larval competition and seed size on larval survival and development time were similar for larger versus smaller beetles. However, larger-bodied beetles suffered a greater reduction in adult body mass with decreasing seed size and increasing larval density; the relative advantage of being large decreased with decreasing seed size and increasing larval density. There were highly significant interactions between the effects of seed size and larval density on body size, and a significant three-way interaction (population-by-density-by-seed size), indicating that environmental effects on the fitness consequences of being large are nonadditive. Our study demonstrates how multiple ecological variables (resource availability and resource competition) interact to affect organismal fitness components, and that such interactions can mediate natural selection on body size. Studying individual factors influencing selection on body size may lead to misleading results given the potential for nonlinear interactions among selective agents.

Sex differences in phenotypic plasticity affect variation in sexual size dimorphism in insects: from physiology to evolution.

Males and females of nearly all animals differ in their body size, a phenomenon called sexual size dimorphism (SSD). The degree and direction of SSD vary considerably among taxa, including among populations within species. A considerable amount of this variation is due to sex differences in body size plasticity. We examine how variation in these sex differences is generated by exploring sex differences in plasticity in growth rate and development time and the physiological regulation of these differences (e.g., sex differences in regulation by the endocrine system). We explore adaptive hypotheses proposed to explain sex differences in plasticity, including those that predict that plasticity will be lowest for traits under strong selection (adaptive canalization) or greatest for traits under strong directional selection (condition dependence), but few studies have tested these hypotheses. Studies that combine proximate and ultimate mechanisms offer great promise for understanding variation in SSD and sex differences in body size plasticity in insects.

Genetic architecture underlying convergent evolution of egg-laying behavior in a seed-feeding beetle.

Independent populations subjected to similar environments often exhibit convergent evolution. An unresolved question is the frequency with which such convergence reflects parallel genetic mechanisms. We examined the convergent evolution of egg-laying behavior in the seed-feeding beetle Callosobruchus maculatus. Females avoid ovipositing on seeds bearing conspecific eggs, but the degree of host discrimination varies among geographic populations. In a previous experiment, replicate lines switched from a small host to a large one evolved reduced discrimination after 40 generations. We used line crosses to determine the genetic architecture underlying this rapid response. The most parsimonious genetic models included dominance and/or epistasis for all crosses. The genetic architecture underlying reduced discrimination in two lines was not significantly different from the architecture underlying differences between geographic populations, but the architecture underlying the divergence of a third line differed from all others. We conclude that convergence of this complex trait may in some cases involve parallel genetic mechanisms.