Patterns Of Shape Variation Research Articles

The Evolution of Climatic Niches and its Role in Shaping Diversity Patterns in Diprotodontid Marsupials

The interplay between niche conservatism and niche evolution has been suggested to play a key role in shaping the biogeographical history of a given clade. Here, we integrate climatic data associated with the distribution range of 86 diprotodontid species and their phylogenetic relationships in order to examine the evolutionary dynamics of ecological niches of Diprotodontia and explore the link between diversification, niche evolution, and trends in biodiversity over space in this iconic group. Both mean annual temperature (MAT) and annual precipitation (AP) best-fitted punctuated modes of evolution indicate that climatic niche evolution in diprotodonts is speciational. Among-clade variation in rates of climatic niche evolution was correlated with variation in rates of lineage diversification, which reinforces the view that rapid shifts in climatic niches promote speciation. We found that both climatic attributes, AP and MAT, exhibited a pattern according to which species richness progressively declined along a gradient from ancestral to derived climatic conditions and, in turn, it was negatively correlated to niche breadth. However, correlation between niche breadth and niche position was not similar for both climatic traits, as these differ with respect to the relative position of the zone colonized by the most recent common ancestor within its corresponding axis. Diprotodontia diversity decreased while phylogenetic clustering increased, suggesting that niche conservatism associated with ancestral climate probably drives most of variation in species richness in this region. Our study shows that the diversification of diprotodontid marsupials appears to have occurred against a background of moderate phylogenetic niche consevatism, which largely determines the current distribution of this group.

Nocturnal bird diversity in forest fragments in north-west Ecuador

Abstract:Habitat preferences and response to habitat conversion remain under-studied for many groups in the tropics, limiting our understanding of how environmental and anthropogenic factors may interact to shape patterns of diversity. To help fill this knowledge gap, we surveyed nocturnal birds such as owls, nightjars and potoos through auditory transect surveys in 22 forest fragments (2.7 to 33.6 ha) in north-west Ecuador. We assessed the relative effect of habitat characteristics (e.g. canopy height and openness, and density of large trees) and fragment attributes (e.g. area, altitude and proportion of surrounding forest cover) on species richness and community composition. Based on our previous work, we predicted that nocturnal bird richness would be highest in relatively larger fragments with more surrounding forest cover. We recorded 11 total species with an average ± SD of 3.4 ± 1.4 (range = 2–7) species per fragment, with higher richness in fragments that were larger, at lower altitudes, and characterized by more open canopies. Nocturnal bird community similarity was not significantly correlated with any measured environmental variable. These results indicate that both landscape (e.g. altitude) and fragment-specific (e.g. size, forest structure) attributes are likely to interact to shape patterns of diversity among this poorly known but ecologically important guild in fragmented tropical landscapes.

Revisiting size and scaling in the anthropoid temporomandibular joint

Masticatory morphology in primates is likely under strong selective pressure to maximize feeding efficiency while simultaneously minimizing the occurrence of injury or pathology. As a result, masticatory shape, including aspects of temporomandibular joint (TMJ) morphology, varies widely across primates in relation to feeding behavior and body size. This study examines patterns of allometry in the TMJ of anthropoid primates, with the specific goal of evaluating how allometric patterns may reflect variation in loading and/or range of motion at this joint. Phylogenetic reduced major axis regressions were employed to examine how specific aspects of TMJ morphology scale in relation to body mass and mandible length. Patterns of shape variation across the entire masticatory apparatus were examined by utilizing geometric morphometric techniques. Results reveal that most aspects of TMJ shape scale with either isometry or positive allometry relative to body mass and/or mandible length, though several departures from these patterns were observed. In particular, male cercopithecoids tend to show distinct scaling patterns in TMJ height above the occlusal plane and condylar area, likely reflecting known trade-offs between increased range of motion and force production in this clade, as has been linked to selection for increased male canine size. The geometric morphometric analyses indicate that craniofacial and masticatory shape are strongly allometric, but that glenoid shape variation is less consistently allometric. Notably, different patterns of allometric shape variation were observed in platyrrhines, cercopithecoids, and hominoids, perhaps related to different, and potentially competing, selective pressures in each of these clades.

Postnatal mandible growth in wild and laboratory mice: Differences revealed from bone remodeling patterns and geometric morphometrics.

Comparative information on the variation in the temporospatial patterning of mandible growth in wild and laboratory mice during early postnatal ontogeny is scarce but important to understand variation among wild rodent populations. Here, we compare mandible growth between two ontogenetic series from the second to the eighth week of postnatal life, corresponding to two different groups of mice reared under the same conditions: the classical inbred strain C57BL/6J, and Mus musculus domesticus. We characterize the ontogenetic patterns of bone remodeling of the mandibles belonging to these laboratory and wild mice by analyzing bone surface, as well as examine their ontogenetic form changes and bimodular organization using geometric morphometrics. Through ontogeny, the two mouse groups display similar directions of mandible growth, according to the temporospatial distribution of bone remodeling fields. The allometric shape variation of the mandibles of these mice entails the relative enlargement of the ascending ramus. The organization of the mandible into two modules is confirmed in both groups during the last postnatal weeks. However, especially after weaning, the mandibles of wild and laboratory mice differ in the timing and localization of several remodeling fields, in addition to exhibiting different patterns of shape variation and differences in size. The stimulation of dentary bone growth derived from the harder post-weaning diet might account for some features of postnatal mandible growth common to both groups. Nonetheless, a large component of the postnatal growth of the mouse mandible appears to be driven by the inherent genetic programs, which might explain between-group differences.

Environmental drivers of α-diversity patterns in monsoonal tropical stream fish assemblages: a case study from tributaries of Narmada basin, India

Environmental factors, such as local physico-chemical water parameters, habitat-structural conditions, geography and human disturbances can have a profound impact on the structure and composition of biotic communities. This study investigates the relationship of these factors with fish diversity in medium to small streams in Central India and identifies the key determinants of species richness and diversity in habitats increasingly facing impacts of urban development. Data on fish diversity on eighteen sites, representative of undisturbed and disturbed aquatic habitats, located in the Narmada river basin were collected across different seasons over two years. Seasonal patterns of alpha diversity for this region were analysed and the effect of environmental drivers on seasonal patterns of alpha diversity were assessed. Analyses of species data revealed significant differences in diversity patterns across seasons for both species richness and Shannon diversity. Results of generalized linear mixed models showed that along with disturbance, altitude and substrate heterogeneity, dissolved oxygen, pH and stream width proved to be important environmental variables that predict species richness. Further, variations in pH, dissolved oxygen, temperature, stream width, stream depth and stream width heterogeneity were found to also predict Shannon diversity index. Our study revealed that seasonal changes across the year play a crucial role in shaping diversity patterns. This study is relevant as an important step in identifying roles of various ecological factors driving fish diversity in the region and towards developing long term management plans for critical catchment areas of major rivers in tropical systems.

Craniomandibular Variation in the Taxonomically Problematic Gerbil Genus Gerbillus (Gerbillinae, Rodentia): Assessing the Influence of Climate, Geography, Phylogeny, and Size

The taxonomy of Gerbillus, the most speciose gerbil genus, is highly debated. Of particular contention is the relationship of Dipodillus to Gerbillus; some consider it to be a closely related genus, while others synonymize it with Gerbillus—either with or without recognizing it as a subgenus. The main objective of this study is to test the validity of common taxonomic groupings within the Gerbillus-Dipodillus species complex, which was achieved by using geometric morphometrics to examine cranial and mandibular variation in 34 out of the 52 Gerbillus-Dipodillus species. Craniomandibular size and shape were highly correlated, indicating strong allometric patterns in shape variation. The common taxonomic groups were significantly different in craniomandibular size and shape, yet they did overlap considerably in morphospace. A notable exception was the extreme divergence of Monodia (G. mauritaniae) from all other species in the occlusal view of the mandible. Morphospace overlap is likely a consequence of both phylogenetic history and environmental adaptation. Only the ventral cranium was associated with climate, particularly in areas related to resource acquisition. Geographic distance was not significantly associated with craniomandibular morphometric distance, and the groups overlapped greatly in their geographic range. Cranial and mandibular regions differed in discrimination power—the ventral cranium had among the highest, while the dorsal cranium and the occlusal mandible had the lowest. Craniomandibular regions varied in association with climate, phylogeny, and size—previous studies suggest this difference may be a consequence of different genetic controls for shape variation.

The effect of fire history in shaping diversity patterns of flower-visiting insects in post-fire Mediterranean pine forests

Fire affects diversity and structure of flower-visitor communities. We explored the effect of fire history on the diversity patterns and structure of the flower-visitor guilds (bees, beetles, flies, sawflies, and wasps), across a post-fire regeneration sequence of pine forests in Rhodes Island, Greece. Fire history was defined by fire frequency and post-fire age of sites. We did not find significant differences in species richness and abundance per guild between fire-history regimes except for the abundance of flies, sawflies and the entire flower-visitor community. Fire strongly affected the community structure of bees, beetles, and sawflies. Some of the most abundant and common species responded significantly to fire in terms of abundance; yet, we observed no significant variation in the abundance of the common species of bees, the most prominent pollinator group, implying that provision of pollination services may not be considerably affected by fire. Long-unburnt sites displayed higher heterogeneity in species composition compared to recently-burnt sites (either burnt once or twice). This pattern deviated significantly from null expectations when analyzing the abundance-based metric of β-diversity and was obscure in the case of the presence/absence-based metric, indicating that fire affected mainly the spatial distribution of individuals, i.e. the main change is not due to species turnover but to changes in relative abundance. Furthermore, the species composition in recently-burnt sites (burnt once in 2008) were more similar than in twice-burnt sites (including areas burnt once between 1984 and 1992, and in 2008), indicating that fire frequency affected post-fire heterogeneity of species composition.

Glaciations, deciduous forests, water availability and current geographical patterns in the diversity of European Carabus species

AbstractAimCurrent climate, biotic habitat provision and historical events are known drivers of diversity patterns. However, these three factors are seldom evaluated together. Here, we study the influence of climate, the distribution of deciduous forests and Pleistocene climate changes on the species diversity of Carabus ground beetles in Europe.LocationContinental Europe.MethodsWe used geographically weighted regressions (GWR) to explore geographical variation in the relationship between species richness and current climate in a spatially explicit context. Further, we analysed simultaneously the network of relationships among current temperature, climatic variability since the Last Glacial Maximum (LGM) and the distribution of deciduous forests through structural equation models (SEM). Also, we assessed dissimilarity in the composition of European faunas by means of beta diversity metrics related with true spatial replacement and nestedness.ResultsWe find that Carabus richness patterns are, at least in part, influenced by water–energy dynamics. However, the effects of current climate are also shaped by Pleistocene glaciations, as water and energy variables change in importance at the southern limits of the ice sheet during the LGM. Accordingly, this border results in abrupt shifts in the relative importance of both (1) current and past climate correlates on Carabus richness, and (2) nestedness and true turnover on the compositional changes among their assemblages. Moreover, we also detect a direct effect of the geographical distribution of deciduous forests on Carabus species richness in both northern and southern regions.Main conclusionsOur results confirm that the processes shaping diversity patterns may depend on the history of particular regions. While Carabus richness seems to be largely driven by current climate in southern Europe, in the north it appears to be more affected by the imprint of past climates. Our findings also suggest that the areas of influence of Pleistocene glaciations may depend on the idiosyncratic characteristics of particular taxa.

Local conditionsvsregional context: variation in composition of bird communities along the Middle Paraná River, an extensive river-floodplain system of South America

We studied spatial changes in species composition (i.e., beta diversity) of local assemblages of birds along ∼450 km of the Middle Paraná River, an extensive fluvial system of South America. Point counts were used to survey birds at 60 plots located in shrub swamps and marshes of the floodplain within four sites (15 plots per site). Two sites were surrounded by each of the two upland ecoregions. Beta diversity of bird assemblages was high and was more important than alpha diversity in shaping regional diversity (i.e., gamma diversity) of the fluvial system. Compositional changes were related to species turnover among plots, while nestedness dissimilarity was not important for shaping diversity patterns. Variation-partitioning analysis showed that local conditions (i.e., landscape composition within a radius of 200 m from the center of each plot) accounted for more spatial variation in assemblage composition than did location along the fluvial system. Adjacent upland ecoregions did not account for spatial changes in bird composition within the fluvial system. In conclusion, environmental heterogeneity created by flood pulses is an important factor for sustaining regional diversity of birds within the fluvial system through effects on beta diversity.

Climatic niche conservatism and ecological opportunity in the explosive radiation of arvicoline rodents (Arvicolinae, Cricetidae).

Climatic niche conservatism shapes patterns of diversity in many taxonomic groups, while ecological opportunity (EO) can trigger rapid speciation that is less constrained by the amount of time a lineage has occupied a given habitat. These two processes are well studied, but limited research has considered their joint and relative roles in shaping diversity patterns. We characterized climatic and biogeographic variables for 102 species of arvicoline rodents (Arvicolinae, Cricetidae), testing the effects of climatic niche conservatism and EO on arvicoline diversification as lineages transitioned between biogeographic regions. We found that the amount of time a lineage has occupied a precipitation niche is positively correlated with diversity along a precipitation gradient, suggesting climatic niche conservatism. In contrast, shift in diversification rate explained diversity patterns along a temperature gradient. Our results suggest that an indirect relationship exists between temperature and diversification that is associated with EO as arvicoline rodents colonized warm Palearctic environments. Climatic niche conservatism alone did not fully explain diversity patterns under density-dependence, highlighting the additional importance of EO-related processes in promoting the explosive radiation in arvicoline rodents and shaping diversity pattern among biogeographic regions and along climatic gradients.

Re-evaluation of batoid pectoral morphology reveals novel patterns of diversity among major lineages.

Batoids (Chondrichthyes: Batoidea) are a diverse group of cartilaginous fishes which comprise a monophyletic sister lineage to all neoselachians or modern sharks. All species in this group possess anteroposteriorly expanded-pectoral fins, giving them a unique disc-like body form. Reliance on pectoral fins for propulsion ranges from minimal (sawfish) to almost complete dependence (skates and rays). A recent study on the diversity of planform pectoral fin shape in batoids compared overall patterns of morphological variation within the group. However, inconsistent pectoral homology prevented the study from accurately representing relationships within and among major batoid taxa. With previous work in mind, we undertook an independent investigation of pectoral form in batoids and evaluated the implications of shape diversity on locomotion and lifestyle, particularly in the skates (Rajoidei) and rays (Myliobatoidei). We used geometric morphometrics with sliding semilandmarks to analyze pectoral fin outlines and also calculate fin aspect ratios (AR), a functional trait linked to locomotion. In agreement with previous work, our results indicated that much of the evolution of batoid pectoral shape has occurred along a morphological axis that is closely related to AR. For species where kinematic data were available, both shape and AR were associated with swimming mode. This work further revealed novel patterns of shape variation among batoids, including strong bimodality of shape in rays, an intermediate location of skate species in the morphospace between benthic/demersal and pelagic rays, and approximately parallel shape trajectories in the benthic/demersal rays and skates. Finally, manipulation of landmarks verified the need for a consistent and accurate definition of homology for the outcome and efficacy of analyses of pectoral form and function in batoids.

Parasite species richness and intensity of interspecific interactions increase with latitude in two wide-ranging hosts.

Although the latitudinal diversity gradient is a well-known and general pattern, the mechanisms structuring it remain elusive. Two key issues limit differentiating these. First, habitat type usually varies with latitude, precluding a standardized evaluation of species richness. Second, broad-scale and local factors hypothesized to shape diversity patterns covary with one another, making it difficult to tease apart independent effects. Examining communities of parasites in widely distributed hosts can eliminate some of these confounding factors. We quantified diversity and interspecific interactions for trematode parasites infecting two similar snail species across 27 degrees of latitude from 43 locations in tropical and temperate oceans. Counter to typical patterns, we found that species richness, levels of parasitism, and intensity of intraguild predation increased with latitude. Because speciation rates are precluded from driving diversity gradients in this particular system, the reversed gradients are likely due to local ecological factors, specifically, increased productivity and stability. We highlight how this system may serve as a useful tool to provide insight into what processes drive diversity gradients in general.

Stochastic distribution of small soil eukaryotes resulting from high dispersal and drift in a local environment.

A central challenge in ecology is to understand the relative importance of processes that shape diversity patterns. Compared with aboveground biota, little is known about spatial patterns and processes in soil organisms. Here we examine the spatial structure of communities of small soil eukaryotes to elucidate the underlying stochastic and deterministic processes in the absence of environmental gradients at a local scale. Specifically, we focus on the fine-scale spatial autocorrelation of prominent taxonomic and functional groups of eukaryotic microbes. We collected 123 soil samples in a nested design at distances ranging from 0.01 to 64 m from three boreal forest sites and used 454 pyrosequencing analysis of Internal Transcribed Spacer for detecting Operational Taxonomic Units of major eukaryotic groups simultaneously. Among the main taxonomic groups, we found significant but weak spatial variability only in the communities of Fungi and Rhizaria. Within Fungi, ectomycorrhizas and pathogens exhibited stronger spatial structure compared with saprotrophs and corresponded to vegetation. For the groups with significant spatial structure, autocorrelation occurred at a very fine scale (<2 m). Both dispersal limitation and environmental selection had a weak effect on communities as reflected in negative or null deviation of communities, which was also supported by multivariate analysis, that is, environment, spatial processes and their shared effects explained on average <10% of variance. Taken together, these results indicate a random distribution of soil eukaryotes with respect to space and environment in the absence of environmental gradients at the local scale, reflecting the dominant role of drift and homogenizing dispersal.

Traits of collembolan life-form indicate land use types and soil properties across an European transect

Land use changes are among the main factors shaping diversity patterns of soil fauna in European ecosystems. However, current knowledge on soil fauna biodiversity levels across land use types to establish baseline values with monitoring purposes are still lacking. Also, only few initiatives have been including functional components of soil fauna on biodiversity monitoring, despite the noticeable link between soil organisms and aboveground ecosystem services. Here, we analyzed the differences of collembolan taxonomic and functional diversity across an European transect with sites comprising different land use types (forests, grasslands and arable lands) and characteristics in terms of habitat conditions and soil properties. No clear relation was found between collembolan species richness and the site typology established in this study. However, community traits of life-forms responded to the gradient of site properties and indicated different land use types based on the higher proportion of eu-edaphic species in forested sites, in comparison to grasslands and arable lands. Among the environmental variables, pH was the main soil parameter influencing both collembolan richness and community weighted mean of life-forms, and was negatively correlated to both biodiversity components.The effects of pH may also reflect the influence of land use history and management practices in different European ecosystems and more suitable traits related to pH preferences, and tolerance should be further investigated for collembolan species. Our results suggest that functional diversity may provide a clearer picture on soil fauna diversity changes across different land use types and site properties. So components of functional diversity based on community traits should be included in the ‘indicator shopping basket’ of soil biodiversity monitoring studies across European ecosystems.

A virtual geometric morphometric approach to the quantification of long bone bilateral asymmetry and cross-sectional shape.

The widespread use of three-dimensional digitization means that models of whole bone geometry are routinely captured for many applications in virtual anthropology. In this article, we test whether a geometric morphometric (GMM) approach can be used to accurately quantify directional bilateral asymmetry in cross-sectional shape using virtual bone models. We introduce a method to (1) orient virtual long bone models and extract cross sections and (2) collect GMM landmarks to analyze cross-sectional shape. Landmark data, captured using polar radii, were analyzed for an example study set of paired humeri from Andaman Islanders sampled at 35%, 50%, and 65% locations. The GMM method can (1) detect significant differences in left and right cross-sectional shape and (2) allow the directionality of shape change (distribution of bone from centroid) to be evaluated in the context of whole outline shape and in relation to the axis of maximum bending rigidity. The protocol may be used with models created from laser (surface) scan or computed tomography (CT) scan data, and applied to cross-sectional images that were collected using periosteal molding techniques. The results demonstrate directional bilateral asymmetry in shape, but do not recover the same signal for size measurements. Our method offers a pathway to quantify both the pattern of variation in shape and the relationship between size and shape variation, opening new questions about how those patterns manifest over ontogeny, change temporally or differ in relation to the nature and intensity of the activity, and bone loading conditions.

Speciation dynamics during the global radiation of extant bats.

Species richness varies widely across extant clades, but the causes of this variation remain poorly understood. We investigate the role of diversification rate heterogeneity in shaping patterns of diversity across families of extant bats. To provide a robust framework for macroevolutionary inference, we assemble a time-calibrated, species-level phylogeny using a supermatrix of mitochondrial and nuclear sequence data. We analyze the phylogeny using a Bayesian method for modeling complex evolutionary dynamics. Surprisingly, we find that variation in family richness can largely be explained without invoking heterogeneous diversification dynamics. We document only a single well-supported shift in diversification dynamics across bats, occurring at the base of the subfamily Stenodermatinae. Bat diversity is phylogenetically imbalanced, but-contrary to previous hypotheses-this pattern is unexplained by any simple patterns of diversification rate heterogeneity. This discordance may indicate that diversification dynamics are more complex than can be captured using the statistical tools available for modeling data at this scale. We infer that bats as a whole are almost entirely united into one macroevolutionary cohort, with decelerating speciation through time. There is also a significant relationship between clade age and richness, suggesting that global bat diversity may still be expanding.

Metacommunity versus Biogeography: A Case Study of Two Groups of Neotropical Vegetation-Dwelling Arthropods

Biogeography and metacommunity ecology provide two different perspectives on species diversity. Both are spatial in nature but their spatial scales do not necessarily match. With recent boom of metacommunity studies, we see an increasing need for clear discrimination of spatial scales relevant for both perspectives. This discrimination is a necessary prerequisite for improved understanding of ecological phenomena across scales. Here we provide a case study to illustrate some spatial scale-dependent concepts in recent metacommunity studies and identify potential pitfalls. We presented here the diversity patterns of Neotropical lepidopterans and spiders viewed both from metacommunity and biogeographical perspectives. Specifically, we investigated how the relative importance of niche- and dispersal-based processes for community assembly change at two spatial scales: metacommunity scale, i.e. within a locality, and biogeographical scale, i.e. among localities widely scattered along a macroclimatic gradient. As expected, niche-based processes dominated the community assembly at metacommunity scale, while dispersal-based processes played a major role at biogeographical scale for both taxonomical groups. However, we also observed small but significant spatial effects at metacommunity scale and environmental effects at biogeographical scale. We also observed differences in diversity patterns between the two taxonomical groups corresponding to differences in their dispersal modes. Our results thus support the idea of continuity of processes interactively shaping diversity patterns across scales and emphasize the necessity of integration of metacommunity and biogeographical perspectives.

Evolution at a different pace: distinctive phylogenetic patterns of cone snails from two ancient oceanic archipelagos.

Ancient oceanic archipelagos of similar geological age are expected to accrue comparable numbers of endemic lineages with identical life history strategies, especially if the islands exhibit analogous habitats. We tested this hypothesis using marine snails of the genus Conus from the Atlantic archipelagos of Cape Verde and Canary Islands. Together with Azores and Madeira, these archipelagos comprise the Macaronesia biogeographic region and differ remarkably in the diversity of this group. More than 50 endemic Conus species have been described from Cape Verde, whereas prior to this study, only two nonendemic species, including a putative species complex, were thought to occur in the Canary Islands. We combined molecular phylogenetic data and geometric morphometrics with bathymetric and paleoclimatic reconstructions to understand the contrasting diversification patterns found in these regions. Our results suggest that species diversity is even lower than previously thought in the Canary Islands, with the putative species complex corresponding to a single species, Conus guanche. One explanation for the enormous disparity in Conus diversity is that the amount of available habitat may differ, or may have differed in the past due to eustatic (global) sea level changes. Historical bathymetric data, however, indicated that sea level fluctuations since the Miocene have had a similar impact on the available habitat area in both Cape Verde and Canary archipelagos and therefore do not explain this disparity. We suggest that recurrent gene flow between the Canary Islands and West Africa, habitat losses due to intense volcanic activity in combination with unsuccessful colonization of new Conus species from more diverse regions, were all determinant in shaping diversity patterns within the Canarian archipelago. Worldwide Conus species diversity follows the well-established pattern of latitudinal increase of species richness from the poles towards the tropics. However, the eastern Atlantic revealed a striking pattern with two main peaks of Conus species richness in the subtropical area and decreasing diversities toward the tropical western African coast. A Random Forests model using 12 oceanographic variables suggested that sea surface temperature is the main determinant of Conus diversity either at continental scales (eastern Atlantic coast) or in a broader context (worldwide). Other factors such as availability of suitable habitat and reduced salinity due to the influx of large rivers in the tropical area also play an important role in shaping Conus diversity patterns in the western coast of Africa.

Multispecies interactions across trophic levels at macroscales: retrospective and future directions

Trophic interactions among multiple species are ubiquitous in nature and their importance for structuring ecological communities has been extensively demonstrated at local spatial scales. However, how local species interactions scale‐up to large spatial scales and how they contribute to shape species distributions and diversity patterns at macroecological extents remains less clear. Here, we provide an overview of recent and potential future developments in macroecology that explore the role of antagonistic and mutualistic interactions among multiple species across trophic levels. Recent studies broadly represent two analytical methods (analyses of species richness and ecological networks) and provide evidence that plant–animal interactions (e.g. pollination, frugivory) and predator–prey interactions influence large‐scale richness patterns and that ecological network structure varies systematically at macroscales. Current methodological problems and challenges are related to defining the functional links in cross‐trophic richness analyses, understanding trait effects in multispecies interactions, and addressing sampling effects when analyzing multiple ecological networks across large spatial extents. Key topics for future research are 1) testing paleoclimatic imprints on interaction diversity, 2) understanding macroevolution and the phylogenetic structure of multispecies interactions, 3) quantifying contemporary spatial and temporal variability in complex ecological networks, and 4) predicting novel interactions under global change. Moreover, we see great potential for a deeper bidirectional integration of macroecology and network research, e.g. by analyses of trait complementarity and functional diversity of interacting groups and by employing species distribution modeling to predict changes in functional network structure. Addressing these key topics and achieving a better integration between these two research fields will significantly advance our understanding of the ecological and evolutionary drivers of multispecies interactions. This could also help to develop more realistic forecasts of changes in biodiversity under climate and land use change.

Morphological variation on isolated populations of Praocis (Praocis) spinolai.

In this study, the morphological variations of four geographically isolated populations of Praocis ( Praocis ) spinolai Gay & Solier (Coleoptera: Tenebrionidae) in the transitional coastal desert, Chile, were studied. The study was conducted in the coastal area of Punta de Choros and Los Choros-Archipelago, which includes three islands: Choros, Damas, and Gaviota. 113 specimens of the species P. ( P. ) spinolai belonging to the four locations sampled were collected analyzed with geometric morphometrics techniques to explore the pattern of shape variation on the different isolated environments. The principal component analysis revealed a well-defined pattern of variation between the populations analyzed. Moreover, differences between populations emerged also from the canonical variation analysis and were confirmed by the Procrustes ANOVA. All analyses performed confirmed the existence of a pattern of variation, due to the isolation of the populations and to environmental effects. The islands are subject to more arid pressures than the continent, where there is a more stable environment and the presence of coastal wetlands and the coastal range of mountains act together and enable fog condensation. This study indicates the existence of a clear pattern of variation, which indicates an evolutionary trend among the population examined.