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bioRxiv2018

Global cooling & the rise of modern grasslands: Revealing cause & effect of environmental change on insect diversification dynamics

Utilising geo-historical environmental data to disentangle cause and effect in complex natural systems is a major goal in our quest to better understand how climate change has shaped life on Earth. Global temperature is known to drive biotic change over macro-evolutionary time-scales but the mechanisms by which it acts are often unclear. Here, we model speciation rates for Orthoptera within a phylogenetic framework and use this to demonstrate that global cooling is strongly correlated with increased speciation rates. Transfer Entropy analyses reveal the presence of one or more additional processes that are required to explain the information transfer from global temperature to Orthoptera speciation. We identify the rise of C4 grasslands as one such mechanism operating from the Miocene onwards. We therefore demonstrate the value of the geological record in increasing our understanding of climate change on macro-evolutionary and macro-ecological processes.

ecology↗

bioRxiv2018

Quorums enable optimal pooling of independent judgements

Majority-voting and the Condorcet Jury Theorem pervade thinking about collective decision-making. Thus, it is typically assumed that majority-voting is the best possible decision mechanism, and that scenarios exist where individually-weak decision-makers should not pool information. Condorcet and its applications implicitly assume that only one kind of error can be made, yet signal detection theory shows two kinds of errors exist, false positives and false negatives. We apply signal detection theory to collective decision-making to show that majority voting is frequently sub-optimal, and can be optimally replaced by quorum decision-making. While quorums have been proposed to resolve within-group conflicts, or manage speed-accuracy trade-offs, our analysis applies to groups with aligned interests undertaking single-shot decisions. Our results help explain the ubiquity of quorum decision-making in nature, relate the use of sub- and super-majority quorums to decision ecology, and may inform the design of artificial decision-making systems.\n\nImpact StatementTheory typically assumes that majority voting is optimal; this is incorrect - majority voting is typically sub-optimal, and should be replaced by sub-majority or super-majority quorum voting. This helps explain the prevalence of quorum-sensing in even the simplest collective systems, such as bacterial communities.

ecology↗

bioRxiv2018

Development of an eDNA method for monitoring fish communities: ground truthing in diverse lakes with characterised fish faunas

O_LIAccurate, cost-effective monitoring of fish is required to assess the quality of lakes under the European Water Framework Directive (WFD). Recent studies have shown that environmental DNA (eDNA) metabarcoding is an effective and non-invasive method, which can provide semi-quantitative information on fish communities in large lakes.\nC_LIO_LIThis study further investigated the potential of eDNA metabarcoding as a tool for WFD status assessment by collecting and analysing water samples from eight Welsh lakes and six meres in Cheshire, England, with well described fish faunas. Water samples (N = 252) were assayed using two mitochondrial DNA regions (Cytb and 12S rRNA).\nC_LIO_LIeDNA sampling indicated the presence of very similar species in the lakes compared to those expected on the basis of existing and historical information. In total, 24 species were detected with a total of 111 species occurrences in the lakes studied using eDNA. Secondly, there was a significant positive correlation between expected faunas and eDNA data in terms of confidence of species occurrence (Spearmans r = 0.74, df = 109, p <; 0.001). Thirdly, eDNA data can estimate relative abundance with the standard five-level classification scale (\"DAFOR\"). Lastly, four ecological fish communities were characterised using eDNA data which agrees with the pre-defined lake types according to environmental characteristics.\nC_LIO_LISynthesis and applications. This study provides further evidence that eDNA metabarcoding could be a powerful and non-invasive monitoring tool for WFD purpose in a wide range of lake types, considerably outperforming other methods for community level analysis.\nC_LI

ecology↗

bioRxiv2018

Empirical analysis and modelling of Argos Doppler location errors in Romania

BackgroundAdvances in wildlife tracking technology have allowed researchers to understand the spatial ecology of many terrestrial and aquatic animal species. Argos Doppler is a technology that is widely used for wildlife tracking owing to the small size and low weight of the Argos transmitters. This allows them to be fitted to small-bodied species. The longer lifespan of the Argos units in comparison to units outfitted with miniaturized global positioning system (GPS) technology has also recommended their use. In practice, large Argos location errors often occur due to communication conditions such as transmitter settings, local environment, and the behavior of the tracked individual.\n\nMethodsConsidering the geographic specificity of errors and the lack of benchmark studies in Eastern Europe, the research objectives were: (1) to evaluate the accuracy of Argos Doppler technology under various environmental conditions in Romania, (2) to investigate the effectiveness of straightforward destructive filters for improving Argos Doppler data quality, and (3) to provide guidelines for processing Argos Doppler wildlife monitoring data. The errors associated with Argos locations in four geographic locations in Romania were assessed during static, low-speed and high-speed tests. The effectiveness of the Douglas Argos distance angle filter algorithm was then evaluated to ascertain its effect on the minimization of localization errors.\n\nResultsArgos locations received in the tests had larger associated horizontal errors than those indicated by the operator of the Argos system, including under ideal reception conditions. Positional errors were similar to those obtained in other studies outside of Europe. The errors were anisotropic, with larger longitudinal errors for the vast majority of the data. Errors were mostly related to speed of the Argos transmitter at the time of reception, but other factors such as topographical conditions and orientation of antenna at the time of the transmission also contributed to receiving low-quality data. The Douglas-Argos filter successfully excluded the largest errors while retaining a large amount of data when the threshold was set to the local scale (2 km).\n\nDiscussionFilter selection requires knowledge about the movement patterns and behavior of the species of interest, and the parametrization of the selected filter typically requires a trial and error approach. Selecting the proper filter reduces the errors while retaining a large amount of data. However, the post-processed data typically includes large positional errors; thus, we recommend incorporating Argos error metrics such as error ellipse or use complex modeling approaches when working with filtered data.

ecology↗

bioRxiv2018

Pollinator size and its consequences: Predictive allometry for pollinating insects

O_LIBody size is an integral functional trait that underlies pollination-related ecological processes, yet it is often impractical to measure directly. Allometric scaling laws have been used to overcome this problem. However, most existing models rely upon small sample sizes, geographically restricted sampling and have limited applicability for non-bee taxa. Predictive allometric models that consider biogeography, phylogenetic relatedness and intraspecific variation are urgently required to ensure greater accuracy.\nC_LIO_LIHere, we measured body size, as dry weight, and intertegular distance (ITD) of 391 bee species (4035 specimens) and 103 hoverfly species (399 specimens) across four biogeographic regions: Australia, Europe, North America and South America. We updated existing models within a Bayesian mixed-model framework to test the power of ITD to predict interspecific variation in pollinator dry weight in interaction with different co-variates: phylogeny or taxonomy, sexual dimorphism and biogeographic region. In addition, we used ordinary least squares (OLS) regression to assess intraspecific dry weight - ITD relationships for 10 bee and five hoverfly species.\nC_LIO_LIIncluding co-variates led to more robust interspecific body size predictions for both bees (Bayesian R2: 0.946; {Delta}R2 0.047) and hoverflies (Bayesian R2: 0.821; {Delta}R2 0.058) relative to models with ITD alone. In contrast, at the intraspecific level, our results demonstrate that ITD is an inconsistent predictor of body size for bees (R2: 0.02 - 0.66) and hoverflies (R2: -0.11 - 0.44).\nC_LIO_LITherefore, predictive allometry is more suitable for interspecific comparative analyses than assessing intraspecific variation. Collectively, these models form the basis of the dynamic R package, pollimetry, which provides a comprehensive resource for allometric research concerning insect pollinators worldwide.\nC_LI

ecology↗

bioRxiv2018

Effect of cadmium accumulation on the performance of plants and of herbivores that cope differently with organic defences

Some plants can accumulate in their shoots metals that are toxic to most other organisms. This ability may serve as a defence against herbivores. Although both metal accumulation and the production of organic defences may be costly to the plant, the two mechanisms may interact on their effect on herbivores. However, this interplay between metal-based and classical organic defences remains overlooked.\n\nTo fill this gap, we studied the interactions between tomato (Solanum lycopersicum), a plant that accumulates cadmium, and two spider-mites, Tetranychus urticae and T. evansi that respectively induce and suppress organic plant defences, measurable via the activity of trypsin inhibitors. We exposed plants to different concentrations of cadmium and measured their effect on mites and plants. The oviposition of both spider-mite species was higher on plants exposed to low concentrations of Cd than on control plants but decreased at concentrations above 0.5 mM. Therefore, herbivores with contrasting responses to organic defences responded similarly to metal accumulation by the plants. On the plant, despite clear evidence for Cd accumulation, we did not detect any effect of Cd on traits that reflect the general response of the plant, such as biomass, water content and carbon/nitrogen ratio. Still, we found an effect of Cd supply upon the quantity of soluble sugars and leaf reflectance changes that may reflect structural modifications in the cells. In turn, these changes in plant traits interfered with the performance of spider mites feeding on those plants.\n\nAdditionally, we show that the induction and suppression of plant defences by spider mites was not affected by Cd supply to the plants. Furthermore, the effect of metal supply on spider-mite performance was not affected by previous infestation. Together, our results suggest no interaction between metal-based and organic plant defences, on our system. This may be useful for plants living in heterogeneous environments, as they may use one or the other defence mechanism, depending on their relative performance in each environment. This may be relevant to studies on the interactions between herbivores and plants, from physiology to ecology.

ecology↗

bioRxiv2018

What we (don’t) know about global plant diversity

RationaleThe era of big biodiversity data has led to rapid, exciting advances in theoretical and applied biological, ecological and conservation sciences. While large genetic, geographic and trait databases are available, these are neither complete nor random samples of the globe. Biases in species absence in these databases create problems, reducing our inferential and predictive power.\n\nMethodsWe performed a comprehensive examination of the taxonomic and spatial sampling in the most complete current databases for plant genes, locations, and traits.\n\nResultsOnly 17.7% of the worlds described land plants feature in all three databases, meaning that more than 82% of plant biodiversity lacks representation in at least one database. Species coverage is highest for location data and lowest for genetic data. Bryophytes and orchids stand out taxonomically and the equatorial region stands out spatially as poorly represented in all databases.\n\nConclusionWe have highlighted a number of clades and regions about which we know little functionally, spatially and genetically, on which we should set research targets. The scientific community should recognize and reward the significant value, both for biodiversity science and conservation, of filling in these gaps in our knowledge of the plant tree of life.

ecology↗

bioRxiv2018

Impending regeneration failure of the IUCN Vulnerable Borneo ironwood (Eusideroxylon zwageri)

The regeneration of many climax species in tropical forest critically depends on adequate seed dispersal and seedling establishment. Here we report the decreased abundance and increased spatial aggregation of younger trees of the Borneo ironwood (Eusideroxylon zwageri) in a protected forest in Sabah Malaysia. We observed a high level of seedling herbivory with strong density dependence, likely exacerbated by local aggregation and contributing to the progressively shrinking size-distribution. We also note the largely undocumented selective herbivory by sambar deer on E. zwageri seedlings. This study highlights the combined impact of altered megafauna community on a tree population through interlinked ecological processes and the need for targeted conservation intervention for this iconic tropical tree species.

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bioRxiv2018

Competition for hosts modulates vast antigenic diversity to generate persistent strain structure in Plasmodium falciparum

In their competition for hosts, parasites with antigens that are novel to host immunity will be at a competitive advantage. The resulting frequency-dependent selection can structure parasite populations into strains of limited genetic overlap. For Plasmodium falciparum-the causative agent of malaria-in endemic regions, the high recombination rates and associated vast diversity of its highly antigenic and multicopy var genes preclude such clear clustering; this undermines the definition of strains as specific, temporally-persisting gene variant combinations. We use temporal multilayer networks to analyze the genetic similarity of parasites in both simulated data and in an extensively and longitudinally sampled population in Ghana. When viewed over time, populations are structured into modules (i.e., groups) of parasite genomes whose var gene combinations are more similar within, than between, the modules, and whose persistence is much longer than that of the individual genomes that compose them. Comparison to neutral models that retain parasite population dynamics but lack competition reveals that the selection imposed by host immunity promotes the persistence of these modules. The modular structure is in turn associated with a slower acquisition of immunity by individual hosts. Modules thus represent dynamically generated niches in host immune space, which can be interpreted as strains. Negative frequency-dependent selection therefore shapes the organization of the var diversity into parasite genomes, leaving a persistence signature over ecological time scales. Multilayer networks extend the scope of phylodynamics analyses by allowing quantification of temporal genetic structure in organisms that generate variation via recombination or other non-bifurcating processes. A strain structure similar to the one described here should apply to other pathogens with large antigenic spaces that evolve via recombination. For malaria, the temporal modular structure should enable the formulation of tractable epidemiological models that account for parasite antigenic diversity and its influence on intervention outcomes.\n\nSignificanceMany pathogens, including the causative agent of malaria Plasmodium falciparum, use antigenic variation, obtained via recombination, as a strategy to evade the human immune system. The vast diversity and multiplicity of genes encoding antigenic variation in high transmission regions challenge the notion of the existence of distinct strains: temporally-persistent and specific combinations of genes relevant to epidemiology. We examine the role of human immune selection in generating such genetic population structure in the major blood-stage antigen of Plasmodium falciparum. We show, using simulated and empirical data, that immune selection generates and maintains modules of genomes with higher genetic similarity within, than between, these groups. Selection further promotes the persistence of these modules for much longer times than those of their constituent genomes. Simulations show that the temporal modular structure reduces the speed at which hosts acquire immunity to the parasite. We argue that in P. falciparum modules can be viewed as dynamic strains occupying different niches in human immune space; they are thus relevant to formulating transmission models that encompass the antigenic diversity of the parasite. Our analyses may prove useful to understand the interplay between temporal genetic structure and epidemiology in other pathogens of human and wildlife importance.

ecology↗

bioRxiv2018

A tale of two species: Human perception influences outcome of human-wild life interactions

Wild life is increasingly coming in contact with humans in many parts of the world. Human perception of wild life may be an important factor in population management and conservation practices in urban and semi-urban areas. Human attitude towards bird species may vary from non-violent coexistence to a perception of birds as pests. Based on the data collected from survey interviews, we studied the perceptions of local communities in Rajasthan, India towards Indian Peafowl. Local communities in Rajasthan reported Indian Peafowl as crop pest and this perception varied across seasons. The crop loss incurred due to Indian Peafowl also varied across seasons according to the respondents. Despite reporting peafowls as a crop pest, locals regularly offered grains for them as a traditional practice. Thus, at our study sites locals have mostly positive perception about Indian peafowl around them.\n\nFood provisioning by local human population influenced diet composition and time-budget of Indian Peafowls at food provision and non-provision sites. Sites at which food provisioning was less or absent, peafowl spent more time in walking in search of food and more than half of their diet consisted of natural food. In contrast, the sites at which plenty of grains were available, time spent in walking was significantly less, while time spent in feeding was significantly more; and over 70% of their diet consisted of carbohydrate and protein-rich provisioned grains. Food provisioning changed the benefit: cost ratio (measured as time spent in feeding to time spent in all other behaviours) between provision and non-provision sites. Thus, food provisioning by humans can change feeding ecology of native Indian peafowl populations, while the presence of peafowl in human dominated landscape changes how humans interact with wild life around them.

ecology↗

bioRxiv2018

Metabolic adaptations underlying genome flexibility in prokaryotes

Even across genomes of the same species, prokaryotes exhibit remarkable flexibility in gene content. We do not know whether this flexible or \"accessory\" content is mostly neutral or adaptive, largely due to the lack of explicit analyses of accessory gene function. Here, across 96 diverse prokaryotic species, I show that a considerable fraction (~40%) of accessory genomes harbours beneficial metabolic functions. These functions take two forms: (1) they significantly expand the biosynthetic potential of individual strains, and (2) they help reduce strain-specific metabolic auxotrophies via intra-species metabolic exchanges. I find that the potential of both these functions increases with increasing genome flexibility. Together, these results are consistent with a significant adaptive role for prokaryotic pangenomes.\n\nAuthor SummaryRecent and rapid advancements in genome sequencing technologies have revealed key insights into the world of bacteria and archaea. One puzzling aspect uncovered by these studies is the following: genomes of the same species can often look very different. Specifically, some \"core\" genes are maintained across all intraspecies genomes, but many \"accessory\" genes differ between strains. A major ongoing debate thus asks: do most of these accessory genes provide a benefit to different strains, and if so, in what form? In this study, I suggest that the answer is \"yes, through metabolic interactions\". I show that many accessory genes provide significant metabolic advantages to different strains in different conditions. I achieve this by explicitly conducting a large-scale systematic analysis of 1,339 genomes across 96 diverse species of bacteria and archaea. A surprising prediction of this study that in many ecological niches, co-occurring strains of the same species may help each other survive by exchanging metabolites exclusively produced by these different accessory genes. More pronounced gene differences lead to more underlying metabolic advantages.

ecology↗

bioRxiv2018

High dispersal levels and lake warming are emergent drivers of cyanobacterial community assembly over the Anthropocene

Disentangling the relative importance of deterministic and stochastic processes in shaping natural communities is central to ecology. Studies on community assembly over broad temporal and spatial scales in aquatic microorganisms are scarce. Here, we used 16S rDNA sequence data from lake sediments to test for community assembly patterns in cyanobacterial phylogenies across ten European peri-Alpine lakes and over a century of eutrophication and climate warming. We studied phylogenetic similarity in cyanobacterial assemblages over spatial and temporal distance, and environmental gradients, comparing detected patterns with theoretical expectations from deterministic and stochastic processes. We found limited evidence for deviation of lake communities from a random assembly model and no significant effects of geographic distance on phylogenetic similarity, suggesting no dispersal limitation and high levels of stochastic assembly. We did not detect a significant effect of phosphorus and nitrogen levels on deviation of community phylogenies from random. We found however a significant decay of phylogenetic similarity for non-random communities over a gradient of air temperature and water column stability. We show how phylogenetic data from sedimentary archives can improve our understanding of microbial community assembly processes, and support previous evidence that climate warming has been the strongest environmental driver of cyanobacterial community assembly over the Anthropocene.

ecology↗

bioRxiv2018

Spatial patterns of species richness and nestedness in ant assemblages along an elevational gradient in a Mediterranean mountain range

The study of biodiversity spatial patterns along ecological gradients can serve to elucidate factors shaping biological community structure and predict ecosystem responses to global change. Ant assemblages are particularly interesting as study cases, because ant species play a key role in many ecosystem processes and have frequently been identified as useful bioindicators. Here we analyzed the response of ant species richness and assemblage composition to elevational gradients in Mediterranean grasslands and subsequently tested whether these responses were stable spatially and temporally. We sampled ant assemblages in two years (2014, 2015) in two mountain ranges (Guadarrama, Serrota) in Central Spain, along an elevational gradient ranging from 685 to 2390 m a.s.l.\n\nJackknife estimates of ant species richness ranged from three to 18.5 species and exhibited a hump-shaped relationship with elevation that peaked at mid range values (1100 - 1400 m). This pattern was transferable temporally and spatially. Elevation was significantly related to ant assemblage composition and facilitated separation of higher elevation assemblages (> 1700 m) from the remaining lower elevation species groups. Ant assemblages were nested; therefore species assemblages with a decreased number of species were a subset of the richer assemblages, although species turnover was more important than pure nestedness in all surveys. The degree of nestedness changed non-linearly as a cubic polynomial with elevation. These assembly patterns were observed over time but not between the two study regions.\n\nWe concluded double environmental stressors typical of Mediterranean mountains explained species richness patterns: drought at low elevations and cold temperatures at high elevations likely constrained richness at both extremes of elevational gradients. The fact that species turnover showed a dominant role over pure nestedness suggested current ant assemblages were context-dependent (spatio-temporal factors) and highly vulnerable to global change, which threatens the conservation of present day native ant communities, particularly at high elevations.

ecology↗

bioRxiv2018

Interspecific plant competition mediates impact of climate change on the ecophysiology of a plant-herbivore interaction.

O_LIBiotic interactions shape community evolution, but we lack mechanistic insights on how metabolic and ecological processes under climate change are altered by biotic interactions.\nC_LIO_LIWe used a two-trophic model community consisting of the aphid Dysaphis plantaginea feeding on the forb Plantago lanceolata, and a grass competitor Lolium perenne that does not experience herbivory by the aphid. Monocultures and mixtures were exposed to the herbivory treatment and to three relevant simulated environmental changes as prevalent under current climate change (increased temperature, CO2, and increased temperature and CO2)\nC_LIO_LIElevated CO2 reduced the nitrogen content of P. lanceolata, while simultaneous increases of CO2 and temperature modified the plant metabolic component and the magnitude of these responses in different directions. Elevated CO2 enhanced defence systems in P. lanceolata, but these effects were not altered by warming. Interspecific plant competition did, however, neutralise these responses. There were no indirect effects of climate change on aphid population growth despite changes in plant defense, nutritional quality and biomass induced by our environmental change scenarios.\nC_LIO_LIWe thus demonstrate interactions between abiotic and biotic processes on plant metabolite profiles, but more importantly, that climate change effect on a selection of the metabolic pathways are altered by herbivory and competition. Our experiment under semi-natural conditions thus demonstrates the non-additive and often neutralizing effects of biotic interactions on plant metabolism and species performance under climate-associated environmental change.\nC_LI

ecology↗

bioRxiv2018

Policy lessons from spatiotemporal enrollment patterns of Payment for Ecosystem Service Programs in Argentina

Over the last 50 years, payment for ecosystem services schemes (PES) have been lauded as a market-based solution to curtail deforestation and restore degraded ecosystems. However, PES programs often fail to conserve sites under strong long-term deforestation pressures and allocate financial resources without having a sizeable impact on long-term land use change. Underperformance, in part, is likely due to adverse selection as landowners with land at the lowest threat from conversion or loss may be most likely to enroll or enrollment may be for short time-periods. Improving program performance to overcome adverse selection requires understanding attributes of landowners and their land across large scales to identify spatial and temporal enrollment patterns that drive adverse selection. In this paper, we examine these patterns in Argentinas PES program in the endangered Chaco forest ecoregion, which was established in 2007 under the National Forest Law. Our study area covers 252,319 km2. Among our most important findings is that large parcels of enrolled land and land owned by absentee landowners show greater evidence of spatiotemporal adverse selection than smaller plots of land and land owned by local actors. Furthermore, lands managed for conservation and restoration are more likely to be associated with adverse selection than lands that provide financial returns such as harvest of non-timber forest products, silviculture, and silvopasture. However, prior to recommending that PES programs focus on land uses with higher potential earnings, a greater understanding is needed of the degree to which these land uses meet ecological and biodiversity goals of PES programs. Because of this, we posit that a PES incorporating a market-based compensation strategy that varies with commodity prices, along with approaches that provide incentives for conservation and restoration land uses and enrollment of local landowners, could promote long-term conservation of endangered lands.

ecology↗

bioRxiv2018

Urbanization plays a minor role in the flooding and surface water chemistry of Puerto Rico’s mangroves

Although hydrology and water chemistry are known to change in proximity to cities, there remains little empirical evidence connecting specific components of urban landscapes to mangrove flooding dynamics or surface water chemistry. This study constructs five-year water level models from tidal harmonics and precipitation inputs to characterize mangrove flooding across urban gradients in three watersheds of Puerto Rico. There was some evidence for an influence of urbanization on both flooding and water chemistry, but this depended on the definition of urbanness, and points instead to geomorphology as the primary culprit. Urban sites exhibited 46% longer hydroperiods and 450% lower depths than non-urban sites. Rainfall importance was explained more by geomorphology than by urbanization and suggested systems with limited tidal connectivity are four times more sensitive to rainfall than systems with full tidal connectivity. There was also evidence for changes in tidal amplitudes along the urban gradient, which may explain the observed differences in flooding. Relationships between surface water chemical metrics and land cover contradicted previous studies by suggesting lower nutrients and biochemical oxygen demand with increasing urbanization. These results reinforce the understanding that the most important drivers of urban mangrove hydrology and water quality in Puerto Rico are likely geomorphology and tidal connectivity, with little but not zero influence from surrounding land cover. Results should be considered alongside the reported errors stemming from inaccuracies in digital elevation and rainfall response models, and will be useful in understanding future ecological censuses on the island.

ecology↗

bioRxiv2018

Complex responses of global insect pests to climate change

Insect pests strongly affect the productivity and profitability of agriculture and forestry. Despite the well-known sensitivity of insects to abiotic effects such as temperature, their potential responses to ongoing climate change remain unclear. Here we compile and review documented climate change responses of 31 of the globally most impactful phytophagous insect pests, focussing on species for which long-term, high-quality data are available. Most of the selected species show at least one response affecting their severity as pests, including changes in geographic range, population dynamics, life-history traits, and/or trophic interactions. Of the studied pests, 41% only show responses that are linked to increased pest severity, 4% only show responses of decreased severity, whereas importantly 55%, the majority of studied pests, show mixed responses including both increased and decreased severity under ongoing climate change. Variability in impact is further supported by a thermal sensitivity analysis showing little benefit of climate warming in relation to the optimal developmental temperatures for the majority of these pests under both current climate and future projections. Overall the results show that calculating the net effect of climate change on phytophagous insect pest impact is far from straightforward. The documented variation in responses, e.g. between agricultural and forest pests, indicates that efforts to mitigate undesirable climate change effects must target individual species, taking into account the complex ecological and evolutionary mechanisms underlying their responses.

ecology↗

bioRxiv2018

Assessing precocious maturation in salmon using ultrasound imaging

AO_SCPLOWBSTRACTC_SCPLOWSalmonids are characterized by a large diversity of life histories, but their study is often limited by the imperfect observation of the true state of an individual in the wild. Challenged by the need to reduce uncertainty of empirical data, recent development in medical imaging techniques offered new opportunities to assess precocious maturation in Atlantic salmon parr. Traditional phenotypic (external) examination and ultrasound (internal) examination were compared and recommendations on fish handling and ultrasound image interpretation are provided. By allowing to see the unseen, portable ultrasound imaging offers great opportunities for ecological studies in the wild, such as the assessment of individual sexual maturation.

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