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3,655 results for “Structural data”
Data from: Life-history characteristics and landscape attributes as drivers of genetic variation, gene flow and fine-scale population structure in Northern Dolly Varden (Salvelinus malma malma) in Canada
The Northern Dolly Varden (Salvelinus malma malma) displays variable life-history types and occupies freshwater habitats with varying levels of connectivity. Here, we assayed microsatellite DNA variation in Northern Dolly Varden from the western Canadian Arctic to resolve landscape and life history variables driving variation in genetic diversity and population structure. Overall, genetic variation was highest in anadromous populations and lowest in those isolated above waterfalls with stream-resident forms intermediate between the two. Anadromous and isolated populations were genetically divergent from each other while no genetic differentiation was detectable between sympatric anadromous and stream-resident forms. Population structure was stable over 25 years, hierarchically organized and conformed to an isolation-by-distance pattern, but stream-isolated forms often deviated from these patterns. Gene flow occurred primarily among Yukon North Slope populations and between sympatric anadromous and resident forms. These results were sex-dependent to some extent, but were influenced more by reproductive status and life history. Our study provides novel insights into the life history, population demographic and habitat variables that shape the distribution of genetic variation and population structure in Arctic fluvial habitats while providing a spatial context for management and conservation.
Data from: Genetic structure and the history of chub in the Alvord Basin
Knowledge of the distribution of genetic resources within and among taxa is prerequisite for development of management strategies which facilitate conservation of those resources. We used restriction-site associated DNA (RAD) sequencing to survey genetic variation in Alvord Chub and Borax Lake Chub from the Alvord Basin in southeastern Oregon and northern Nevada, USA. Our specific goals were to gain an understanding of the population genetic structure of Alvord Chub and the relationship between this species and Borax Lake Chub. Despite the fact that our collections were taken from ponds and streams, isolated from one another by kilometers of desert, our results revealed that diversity in Alvord Chub was primarily distributed among two regional groupings, which we hypothesize to be related to habitat changes following the end of the most recent glaciation event, approximately 10 thousand years ago. Our results further revealed that Alvord Chub and Borax Lake Chub shared common ancestors during that glaciation event, and that divergence between the two may have been sympatric. Finally, we observed evidence that the clade containing Alvord Chub and Borax Lake Chub was isolated from its closest extant relative, the Tui chub, during the Miocene Epoch, when volcanic flows were forming the mountains surrounding what became the Alvord Basin. These results will be useful for informing conservation strategies for Alvord Chub, and provide new insights regarding the role of these species in the evolutionary legacy of the region.
Data from: Nuclear microsatellite and mitochondrial DNA analyses reveal the regional genetic structure and phylogeographical history of a sanguivorous land leech, Haemadipsa japonica, in Japan
Recent molecular studies have indicated that phylogeographical history of Japanese biota is likely shaped by geohistory along with biological events, such as distribution shifts, isolation, and divergence of populations. However, the genetic structure and phylogeographical history of terrestrial Annelida species, including leech species, are poorly understood. Therefore, we aimed to understand the genetic structure and phylogeographical history across the natural range of Haemadipsa japonica, a sanguivorous land leech species endemic to Japan, by using nine polymorphic nuclear microsatellites (nSSR) and cytochrome oxidase subunit one (COI) sequences of mitochondrial DNA (mtDNA). Analyses using nSSR revealed that H. japonica exhibited a stronger regional genetic differentiation among populations (G'ST = 0.77) than other animal species, probably because of the low mobility of land leech. Analyses using mtDNA indicated that H. japonica exhibited two distinct lineages (A and B), which were estimated to have diverged in the middle Pleistocene and probably because of range fragmentation resulting from climatic change and glacial and interglacial cycles. Lineage A was widely distributed across Japan, and lineage B was found in southwestern Japan. Analyses using nSSR revealed that lineage A was roughly divided into two population groups (i.e., northeastern and southwestern Japan); these analyses also revealed a gradual decrease in genetic diversity with increasing latitude in lineage A and a strong genetic drift in populations of northeastern Japan. Combined with the largely unresolved shallow polytomies from the mtDNA phylogeny, these results implied that lineage A may have undergone a rapid northward migration, probably during the Holocene. Then, the regional genetic structure with local unique gene pools may have been formed within each lineage because of the low mobility of this leech species.
Data from: Population structure of two rabies hosts relative to the known distribution of rabies virus variants in Alaska
For pathogens that infect multiple species the distinction between reservoir hosts and spillover hosts is often difficult. In Alaska, three variants of the arctic rabies virus exist with distinct spatial distributions. We test the hypothesis that rabies virus variant distribution corresponds to the population structure of the primary rabies hosts in Alaska, arctic foxes (Vulpes lagopus) and red foxes (V. vulpes) in order to possibly distinguish reservoir and spill over hosts. We used mitochondrial DNA (mtDNA) sequence and nine microsatellites to assess population structure in those two species. mtDNA structure did not correspond to rabies virus variant structure in either species. Microsatellite analyses gave varying results. Bayesian clustering found 2 groups of arctic foxes in the coastal tundra region, but for red foxes it identified tundra and boreal types. Spatial Bayesian clustering and spatial principal components analysis identified 3 and 4 groups of arctic foxes, respectively, closely matching the distribution of rabies virus variants in the state. Red foxes, conversely, showed eight clusters comprising 2 regions (boreal and tundra) with much admixture. These results run contrary to previous beliefs that arctic fox show no fine-scale spatial population structure. While we cannot rule out that the red fox is part of the maintenance host community for rabies in Alaska, the distribution of virus variants appears to be driven primarily by the artic fox Therefore we show that host population genetics can be utilized to distinguish between maintenance and spillover hosts when used in conjunction with other approaches.
Data from: Joint effects of habitat, zooplankton, host stage structure and diversity on amphibian chytrid
Why does the severity of parasite infection differ dramatically across habitats? This question remains challenging to answer because multiple correlated pathways drive disease. Here, we examined habitat–disease links through direct effects on parasites and indirect effects on parasite predators (zooplankton), host diversity and key life stages of hosts. We used a case study of amphibian hosts and the chytrid fungus, Batrachochytrium dendrobatidis, in a set of permanent and ephemeral alpine ponds. A field experiment showed that ultraviolet radiation (UVR) killed the free-living infectious stage of the parasite. Yet, permanent ponds with more UVR exposure had higher infection prevalence. Two habitat-related indirect effects worked together to counteract parasite losses from UVR: (i) UVR reduced the density of parasite predators and (ii) permanent sites fostered multi-season host larvae that fuelled parasite production. Host diversity was unlinked to hydroperiod or UVR but counteracted parasite gains; sites with higher diversity of host species had lower prevalence of infection. Thus, while habitat structure explained considerable variation in infection prevalence through two indirect pathways, it could not account for everything. This study demonstrates the importance of creating mechanistic, food web-based links between multiple habitat dimensions and disease.
Data from: Drivers of phylogenetic assemblage structure of the Furnariides, a widespread clade of lowland Neotropical birds
Species co-occurrence in local assemblages is shaped by different processes at different spatial and temporal scales. Here we focus on historical explanations and examine the phylogenetic structure of local assemblages of the Furnariides clade (Aves: Passeriformes), assessing the influence of diversification rates on the assembly and species co-occurrence within those assemblages. Using 120 local assemblages across Bolivia and Argentina and a nearly complete phylogeny for the clade, we analyzed assemblage phylogenetic structure applying a recently developed model (DAMOCLES) accounting for the historical processes of speciation, colonization and local extinction. We also evaluated how diversification rates determine species co-occurrence. We found that the assembly of Furnariides assemblages can largely be explained by speciation, colonization and local extinction without invoking current local species interactions. Phylogenetic structure of open habitat assemblages mainly showed clustering, characterized by faster rates of colonization and local extinction than in forest habitats, whereas forest habitat assemblages were congruent with the model's equal rates expectation, thus highlighting the influence of habitat preferences on assembly and co-occurrence patterns. Our results suggest that historical processes are sufficient to explain local assemblage phylogenetic structure, while there is little evidence for species ecological interactions in avian assemblage diversity and composition.
Data from: Dynamic pore structure evolution of the ion adsorbed rare earth ore during the ion exchange process
<p><span>During the leaching process of the ion adsorbed rare earth ore, the pore structure evolution of the ore body plays a vital role in the seepage of the leaching solution. To investigate the evolution of the pore structure during the leaching process, experiments have been carried out with remodeled rare earth ore samples based on physical characteristics of in-situ ores. The seepage rate difference between deionized water leaching solution and 2% NH<sub>4</sub>Cl leaching solution during the active leaching period are analyzed. The porosity and the dynamic pore size evolution of pore structures in the ore body are discussed. Results indicate that along with ion exchange between the rare earth ore and the leaching solution, the porosity of the sample remains constant and the pore structure shows a decreasing trend in the first part and an increasing trend in the second part. Specifically, during the ion exchange process, the number of minimal pores (0~5μm), small pores (5~10μm), and medium pores (10~25μm) increases significantly and the number of medium-large pores (25~60μm), large pores (60~120μm), and mega pores (>120μm) decreases dramatically. Along with the completion of the ion exchange process, the evolution of porous structure shows an opposite trend. The mechanism study reveals that the evolution of pore structure is induced by the difference of ionic strength in the leaching solution during the ion exchange process, where the rare earth ore microparticles will be absorbed or desorbed on to the solid phase.</span></p>
Data from: Population structure of a widespread bat (Tadarida brasiliensis) in an island system
Dispersal is a driving factor in the creation and maintenance of biodiversity, yet little is known about the effects of habitat variation and geography on dispersal and population connectivity in most mammalian groups. Bats of the family Molossidae are fast-flying mammals thought to have potentially high dispersal ability, and recent studies have indicated gene flow across hundreds of kilometers in continental North American populations of the Brazilian free-tailed bat, Tadarida brasiliensis. We examined the population genetics, phylogeography, and morphology of this species in Florida and across islands of The Bahamas, which are part of an island archipelago in the West Indies. Previous studies indicate that bats in the family Phyllostomidae, which are possibly less mobile than members of the family Molossidae, exhibit population structuring across The Bahamas. We hypothesized that T. brasiliensis would show high population connectivity throughout the islands and that T. brasiliensis would show higher connectivity than two species of phyllostomid bats that have been previously examined in The Bahamas. Contrary to our predictions, T. brasiliensis shows high population structure between two groups of islands in The Bahamas, similar to the structure exhibited by one species of phyllostomid bat. Phylogenetic and morphological analyses suggest that this structure may be the result of ancient divergence between two populations of T. brasiliensis that subsequently came into contact in The Bahamas. Our findings additionally suggest that there may be cryptic species within T. brasiliensis in The Bahamas and the West Indies more broadly.
Data from: Killer whales (Orcinus orca) in Iceland show weak genetic structure among diverse isotopic signatures and observed movement patterns
Local adaption through ecological niche specialization can lead to genetic structure between and within populations. In the Northeast Pacific, killer whales (Orcinus orca) of the same population have uniform specialized diets that are non-overlapping with other sympatric, genetically divergent and socially isolated killer whale ecotypes. However, killer whales in Iceland show intra-population variation of isotopic niches and observed movement patterns: some individuals appear to specialise on herring and follow it year-round while others feed upon herring only seasonally or opportunistically. We investigated genetic differentiation among Icelandic killer whales with different isotopic signatures and observed movement patterns. This information is key for management and conservation purposes but also for better understanding how niche specialization drives genetic differentiation. Photo-identified individuals (N = 61) were genotyped for 22 microsatellites and a 611 bp portion of the mitochondrial control region. Photo-identification of individuals allowed linkage of genetic data to existing data on individual isotopic niche, observed movement patterns and social associations. Population subdivision into three genetic units was supported by a Discriminant Analysis of Principal Components (DAPC). Genetic clustering corresponded to the distribution of isotopic signatures, mtDNA haplotypes and observed movement patterns, but genetic units were not socially segregated. Genetic differentiation was weak (FST <0.1), suggesting ongoing gene flow or recent separation of the genetic units. Our results show that killer whales in Iceland are not as genetically differentiated, ecologically discrete or socially isolated as the Northeast Pacific prey-specialized killer whales. If any process of ecological divergence and niche specialization is taking place among killer whales in Iceland it is likely at a very early stage and has not led to the patterns observed in the Northeast Pacific.
Data from: Novel concordance between geographic, environmental and genetic structure in the ecological generalist prickly sculpin (Cottus asper) in California
Ecological generalists may contain a wealth of information concerning diversity, ecology, and geographic connectivity throughout their range. We explored these ideas in prickly sculpin (Cottus asper), a small generalist freshwater fish species where coastal forms have potentially undergone radiations into inland lacustrine and riverine environments. Using a 962bp cytochrome b mtDNA marker and 11 microsatellites, we estimated diversity, divergence times, gene flow, and structure among populations at 43 locations throughout California. We then incorporated genetic and GIS data into ecological niche models to assess ecological conditions within identified groups. Though not reciprocally monophyletic, unique mtDNA haplotypes, microsatellite clustering, and measures of isolation by distance (Coastal: r = 0.960, P < 0.001; Inland: r = 0.277, P = 0.148) suggest 2 novel taxonomic groups, Coastal and Inland (constrained to Great Central Valley). Divergence estimates of 41–191 kya combined with the regional biogeographic history suggest geographic barriers are absent between groups since divergence, but ecological niche modeling revealed significant environmental differences (t = 10.84, P < 0.001). Introgressed individuals were also discovered between groups in an ecologically and geographically intermediate region. Population structure was limited, predominately found in tributaries of the San Joaquin basin in the Inland group. Overall, C. asper exhibited substantial genetic diversity, despite its ecological generality, reflecting California's historically unique and complex hydrology. More broadly, this study illustrates variable environments within the range of a generalist species may mask genetic divergences and should not be overlooked in biodiversity assessments.
Data from: Spatial and ecological population genetic structures within two island-endemic Aeonium species of different niche width
The Crassulacean genus Aeonium is a well-known example for plant species radiation on oceanic archipelagos. However, while allopatric speciation among islands is documented for this genus, the role of intra-island speciation due to population divergence by topographical isolation or ecological heterogeneity has not yet been addressed. The aim of this study was to investigate intraspecific genetic structures and to identify spatial and ecological drivers of genetic population differentiation on the island scale. We analyzed inter simple sequence repeat variation within two island-endemic Aeonium species of La Palma: one widespread generalist that covers a large variety of different habitat types (Ae. davidbramwellii) and one narrow ecological specialist (Ae. nobile), in order to assess evolutionary potentials on this island. Gene pool differentiation and genetic diversity patterns were associated with major landscape structures in both species, with phylogeographic implications. However, overall levels of genetic differentiation were low. For the generalist species, outlier loci detection and loci–environment correlation approaches indicated moderate signatures of divergent selection pressures linked to temperature and precipitation variables, while the specialist species missed such patterns. Our data point to incipient differentiation among populations, emphasizing that ecological heterogeneity and topographical structuring within the small scales of an island can foster evolutionary processes. Very likely, such processes have contributed to the radiation of Aeonium on the Canary Islands. There is also support for different evolutionary mechanisms between generalist and specialist species.
Data from: Congruent population structure across paralogous and non-paralogous loci in Salish Sea chum salmon (Oncorhynchus keta)
Whole genome duplications are major evolutionary events with a lasting impact on genome structure. Duplication events complicate genetic analyses as paralogous sequences are difficult to distinguish; consequently paralogs are often excluded from studies. The effects of an ancient whole genome duplication (approximately 88MYA) are still evident in salmonids through the persistence of numerous paralogous gene sequences and partial tetrasomic inheritance. We use restriction site-associated DNA sequencing (RADseq) on ten collections of chum salmon from the Salish Sea in the USA and Canada to investigate genetic diversity and population structure in both tetrasomic and re-diploidized regions of the genome. We use a pedigree and high-density linkage map to identify paralogous loci and to investigate genetic variation across the genome. By applying multivariate statistical methods, we show that it is possible to characterize paralogous genetic loci and that they display similar patterns of population structure as the diploidized portion of the genome. We find genetic associations with the adaptively important trait of run timing in both sets of loci. By including paralogous loci in genome scans, we can observe evolutionary signals in genomic regions that have routinely been excluded from population genetic studies in other polyploid-derived species.
Data from: Genetic structure of introduced American mink (Neovison vison) in Patagonia: colonisation insights and implications for control and management strategies
Context: Biological invasions have caused dramatic changes in native biodiversity and ecosystem function. Studies of genetic variation and evolutionary changes are useful for understanding population dynamics during biological invasions, and shed light on management, prevention and restoration strategies. Aims: This study aimed to investigate the structure and genetic variability of American mink (Neovison vison), an invasive species in southern South America, introduced for fur farming in the 1930s. Methods: Samples from 153 mink were obtained from 12 locations in southern Chile to sequence the mitochondrial DNA (mtDNA) control region and to genotype 11 polymorphic microsatellite loci. Key results: The highest mtDNA diversity was detected in Puerto Cisnes, suggesting multiple introductions and/or the most probable area where mink was first introduced. The latter is also supported by microsatellite data, because a high percentage of individuals from different locations were assigned to this location. All other locations showed low or no mtDNA diversity, possibly due to founder effect. The results also indicate marked population structure, with three genetic clusters coincident with the main historical introduction points, with low dispersal among them. Conclusions: The results suggest that control strategies for American mink in southern Chile should be concentrated on these three genetically differentiated management units, and particularly on source populations and locations with low effective population size and restricted connectivity. Implications: Genetic approaches have been used for the management of numerous alien species worldwide. Recommendations delivered here for American mink control could also be implemented in other regions and for other invasive species with similar genetic diversity distribution and connectivity.
Data from: RAD sequencing resolves fine-scale population structure in a benthic invertebrate: implications for understanding phenotypic plasticity
The field of molecular ecology is transitioning from the use of small panels of classical genetic markers such as microsatellites to much larger panels of single nucleotide polymorphisms (SNPs) generated by approaches like RAD sequencing. However, few empirical studies have directly compared the ability of these methods to resolve population structure. This could have implications for understanding phenotypic plasticity, as many previous studies of natural populations may have lacked the power to detect genetic differences, especially over micro-geographic scales. We therefore compared the ability of microsatellites and RAD sequencing to resolve fine-scale population structure in a commercially important benthic invertebrate by genotyping great scallops (Pecten maximus) from nine populations around Northern Ireland at 13 microsatellites and 10 539 SNPs. The shells were then subjected to morphometric and colour analysis in order to compare patterns of phenotypic and genetic variation. We found that RAD sequencing was superior at resolving population structure, yielding higher Fst values and support for two distinct genetic clusters, whereas only one cluster could be detected in a Bayesian analysis of the microsatellite dataset. Furthermore, appreciable phenotypic variation was observed in size-independent shell shape and coloration, including among localities that could not be distinguished from one another genetically, providing support for the notion that these traits are phenotypically plastic. Taken together, our results suggest that RAD sequencing is a powerful approach for studying population structure and phenotypic plasticity in natural populations.
Data from: Genetic diversity and population structure of the Pelagic Thresher Shark (Alopias pelagicus) in the Pacific Ocean: evidence for two evolutionarily significant units
There has been an increasing concern about shark overexploitation in the last decade, especially for open ocean shark species, where there is a paucity of data about their life histories and population dynamics. Little is known regarding the population structure of the pelagic thresher shark, Alopias pelagicus. Though an earlier study using mtDNA control region data, showed evidence for differences between eastern and western Pacific populations, the study was hampered by low sample size and sparse geographic coverage, particularly a lack of samples from the central Pacific. Here, we present the population structure of Alopias pelagicus analyzing 351 samples from six different locations across the Pacific Ocean. Using data from mitochondrial DNA COI sequences and seven microsatellite loci we found evidence of strong population differentiation between western and eastern Pacific populations and evidence for reciprocally monophyly for organelle haplotypes and significant divergence of allele frequencies at nuclear loci, suggesting the existence of two Evolutionarily Significant Units (ESU) in the Pacific Ocean. Interestingly, the population in Hawaii appears to be composed of both ESUs in what seems to be clear sympatry with reproductive isolation. These results may indicate the existence of a new cryptic species in the Pacific Ocean. The presence of these distinct ESUs highlights the need for revised management plans for this highly exploited shark throughout its range.
Data from: Impact of population expansion on genetic diversity and structure of river otters (Lontra canadensis) in central North America
Populations of North American river otters (Lontra canadensis) declined throughout large portions of the continent during the early 1900s due to habitat degradation and unregulated trapping. River otters had been extirpated in North Dakota (ND), but the Red River Valley has since been recolonized, with potential source populations including the neighboring states of Minnesota or South Dakota, or the Canadian province of Manitoba (MB). We genotyped 9 microsatellite loci in 121 samples to determine the source population of river otters in the Red River Valley of ND, as well as to assess population structure and diversity of river otters in central North America. Overall, genetic diversity was high, with an average observed heterozygosity of 0.58. Genetic differentiation was low (F ST < 0.05) between river otters in ND and those of Minnesota, suggesting that eastern ND was recolonized by river otters from Minnesota. River otters from MB were genetically distinct from all other sampled populations. Low genetic differentiation (F ST = 0.044) between South Dakota and Louisiana (LA) suggested that reintroductions using LA stock were successful. The genetic distinctiveness of river otters from different geographic regions should be considered when deciding on source populations for future translocations.
Data from: Rehabilitating the cyanobacteria – niche partitioning, resource use efficiency, and phytoplankton community structure during diazotrophic cyanobacterial blooms
1. Blooms of nitrogen-fixing cyanobacteria are recurrent phenomena in marine and freshwater habitats, and their supplying role in aquatic biogeochemical cycles is generally considered vital. The objective of this study is to analyze if an increasing proportion of nitrogen-fixing cyanobacteria affects (i) the composition of the non-diazotrophic component of ambient phytoplankton communities, and (ii) resource use efficiency (RUE; ratio of chl a to total nutrients) – an important ecosystem function. We hypothesize that diazotrophs increase community P use, and decrease N use efficiencies, as new N is brought into the system, relaxing N, and concomitantly aggravating P limitation. We test this by analyzing an extensive dataset from the Baltic Sea (> 3700 quantitative phytoplankton samples), known to harbor conspicuous and recurrent blooms of Nodularia spumigena and Aphanizomenon sp. 2. System-level phosphorus use efficiency (RUEP) was positively related with high proportion of diazotrophic cyanobacteria, suggesting aggravation of phosphorus limitation. However, concomitant decrease of nitrogen use efficiency (RUEN) was not observed. Nodularia spumigena, a dominant diazotroph and a notorious toxin producer, had a significantly stronger relationship with RUEP, compared to the competing non-toxic Aphanizomenon sp., confirming niche differentiation in P acquisition strategies between the major bloom-forming cyanobacterial species in the Baltic Sea. Nodularia occurrences were associated with stronger temperature stratification in more offshore environments, indicating higher reliance on in situ P regeneration. 3. By using constrained and unconstrained ordination, permutational multivariate analysis of variance, and local similarity analysis, we show that diazotrophic cyanobacteria explained no more than a few percent of the ambient phytoplankton community variation. The analyses furthermore yielded rather evenly distributed negative and positive effects on individual co-occurring phytoplankton taxa, with no obvious phylogenetic or functional trait-based patterns. 4. Synthesis. Our study reveals that despite the widely acknowledged noxious impacts of cyanobacterial blooms, the overall effect on phytoplankton community structure is minor. There are no predominantly positive or negative associations with ambient phytoplankton species. Species-specific niche differences in cyanobacterial resource acquisition affect important ecosystem functions, like biomass production per unit limiting resource.
Data from: Strong coupling of plant and fungal community structure across western Amazonian rainforests
The Amazon basin harbors a diverse ecological community that has a critical role in the maintenance of the biosphere. Although plant and animal communities have received much attention, basic information is lacking for fungal or prokaryotic communities. This is despite the fact that recent ecological studies have suggested a prominent role for interactions with soil fungi in structuring the diversity and abundance of tropical rainforest trees. In this study, we characterize soil fungal communities across three major tropical forest types in the western Amazon basin (terra firme, seasonally flooded and white sand) using 454 pyrosequencing. Using these data, we examine the relationship between fungal diversity and tree species richness, and between fungal community composition and tree species composition, soil environment and spatial proximity. We find that the fungal community in these ecosystems is diverse, with high degrees of spatial variability related to forest type. We also find strong correlations between α- and β-diversity of soil fungi and trees. Both fungal and plant community β-diversity were also correlated with differences in environmental conditions. The correlation between plant and fungal richness was stronger in fungal lineages known for biotrophic strategies (for example, pathogens, mycorrhizas) compared with a lineage known primarily for saprotrophy (yeasts), suggesting that this coupling is, at least in part, due to direct plant–fungal interactions. These data provide a much-needed look at an understudied dimension of the biota in an important ecosystem and supports the hypothesis that fungal communities are involved in the regulation of tropical tree diversity.
Data from: Invariant antagonistic network structure despite high spatial and temporal turnover of interactions
Recent work has suggested that emergent ecological network structure exhibits very little spatial or temporal variance despite changes in community composition. However, the changes in network interactions associated with turnover in community composition have seldom been assessed. Here we examine whether changes in ecological networks are best detected by standard emergent network metrics or by assessing internal network changes (i.e. interaction and composition turnover). To eliminate possible spatial or phylogenetic effects, that in large-scale studies may obscure mechanisms structuring networks and interactions, we sampled multiple antagonistic (plant-herbivore) networks for a single diverse plant family (the Restionaceae) in the hyperdiverse Cape Floristic Region. These are the first plant-herbivore networks constructed for this global biodiversity hotspot. We found invariant emergent network structure despite considerable changes in insect and plant composition across communities over time and space. In contrast, there was high interaction turnover between networks. Seasonally, this was driven by turnover in insect species and insect host switching. Spatially, this was driven by simultaneous turnover in plant and insect species, suggesting that many insects are host specific or that both groups exhibit parallel responses to environmental gradients. Spatial interaction turnover was also driven by turnover in plants, showing that many insects can utilise multiple (possibly closely related) hosts and this may create divergent selection gradients that promote insect speciation. Thus we show highly variable interaction fidelity, despite invariant emergent network structure. We suggest that evaluating internal network changes may be more effective at elucidating the processes structuring networks, and many fine-scale changes may be obscured when only calculating emergent network metrics.
Data from: Stepping-stone expansion and habitat loss explain a peculiar genetic structure and distribution of a forest insect
It is challenging to unravel the history of organisms with highly scattered populations. Such species may have fragmented distributions because extant populations are remnants of a previously more continuous range, or because the species has narrow habitat requirements in combination with good dispersal capacity (naturally or vector borne). The northern pine processionary moth Thaumetopoea pinivora has a scattered distribution with fragmented populations in two separate regions, northern and south-western Europe. The aims of this study were to explore the glacial and postglacial history of T. pinivora, and add to the understanding of its current distribution and level of contemporary gene flow. We surveyed published records of its occurrence and analysed individuals from a representative subset of populations across the range. A 633 bp long fragment of the mtDNA COI gene was sequenced and nine polymorphic microsatellite loci were genotyped. Only nine nucleotide sites were polymorphic in the COI gene and 90% of the individuals from across its whole range shared the same haplotype. The microsatellite diversity gradually declined towards the north, and unique alleles were found in only three of the northern and three of southern sites. Genetic structuring did not indicate complete isolation among regions, but an increase of genetic isolation by geographic distance. Approximate Bayesian model choice suggested recent divergence during the postglacial period, but glacial refugia remain unidentified. The progressive reduction of suitable habitats is suggested to explain the genetic structure of the populations and we suggest that T. pinivora is a cold-tolerant relict species, with situation-dependent dispersal.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.