Areas Of Sympatry Research Articles

Biotic interactions vary across species' ranges and are likely conserved through geological time

AbstractAimThe evolutionary interactions between western spadefoot toads (genus Spea) represent a textbook example of character displacement, facilitated by dietary specialization of one Spea species on fairy shrimp (Anostraca) when all three co‐occur. The aim of this study is to understand the covariation between predator (Spea) and prey (Anostraca) range shifts in response to climate change oscillations, and whether biotic interactions can be used to project species distribution models on different time scales when studying species with dietary specialization. Taxon: Amphibia: Spea spp. and Crustacea: Anostraca.LocationNorth America.MethodsUsing multiple modelling techniques, we first estimated the potential distribution of central and western North American fairy shrimp species (Crustacea: Anostraca) and two western spadefoot toad species (Spea bombifrons and Spea multiplicata). We then created a shrimp species richness map by aggregating individual species estimates. Third, we studied the relationship between the probability of spadefoot toad presence and fairy shrimp species richness during the present and Last Glacial Maximum conditions. Finally, we estimated the strength and direction of the co‐occurrence between spadefoot toads and fairy shrimp sampled at the level of entire predicted range and at the regional level (allopatric and sympatric).ResultsFirst, the same abiotic environmental variables shape spadefoot toad and fairy shrimp species' distributions in central and western North America across time. Second, areas of sympatry of Spea bombifrons and Spea multiplicata correspond with dry conditions and higher shrimp richness. Finally, the spatial patterns of predator–prey co‐occurrence are highly variable across geography, forming a spatial mosaic over the species' ranges.Main ConclusionPredator–prey relationships form a spatial mosaic across geography and species ranges. Including biotic interactions into species distribution estimates for organisms with dietary specialization is highly recommended. Biotic interactions can be projected across different time frames for organisms with dietary specialization as they are likely conserved.

Influence of abiotic factors on habitat selection of sympatric ocelots and bobcats: testing the interactive range-limit theory

AimMitigating the effects of extreme conditions is a mechanism that can structure the activity patterns and habitat selection of a species and may particularly impact species at the extremes of their geographic distribution. Furthermore, changing climate patterns have the potential to influence biotic interactions between species in novel ways. As two species at the edges of their northern and southern distributions, respectively, ocelots and bobcats may face unique pressure compared to individuals in more central portions of their range. Our objective was to describe the selection of thermal cover by ocelots and bobcats to examine whether partitioning of thermal resources was occurring or if this was a source of potential interspecific competition.LocationWe monitored eight ocelots and 13 bobcats in South Texas, USA.MethodsWe compared selection within, above, and below their estimated thermoneutral zones to examine the effect of varying temperature on habitat selection. Additionally, we stationed 130 black globe thermal sensors to describe the thermal properties of the various cover types.ResultsWe observed variation in habitat selection across temperatures and species. Ocelots and bobcats selected for shrub cover and vertical canopy cover when cold stressed. When heat stressed, both species avoided bare ground and selected for higher vertical canopy cover and were located closer to dense cover. Black globe measurements revealed differences in environmental temperature across cover types, with forest and shrub cover significantly lower than herbaceous or bare ground.Main conclusionsChanging climates may influence interspecific competition and alter areas of sympatry through range shifts. Our results stress the importance of dense shrub cover and forested canopy as thermal refuge for ocelots and bobcats and suggest that abundant vegetation may mitigate the effects of interspecific competition during lower temperatures and niche partitioning may reduce interspecific competition during upper temperature limits, providing support for the interactive range-limit theory.

Population Genomics of Domesticated Cucurbita ficifolia Reveals a Recent Bottleneck and Low Gene Flow with Wild Relatives

Cucurbita ficifolia is a squash grown from Mexico to Bolivia. Its ancestor is unknown, but it has limited compatibility with wild xerophytic Cucurbita from Mexico’s highlands. We assembled the reference genome of C. ficifolia and assessed the genetic diversity and historical demography of the crop in Mexico with 2524 nuclear single nucleotide polymorphisms (SNPs). We also evaluated the gene flow between C. ficifolia and xerophytic taxa with 6292 nuclear and 440 plastome SNPs from 142 individuals sampled in 58 sites across their area of sympatry. Demographic modelling of C. ficifolia supports an eight-fold decrease in effective population size at about 2409 generations ago (95% CI = 464–12,393), whereas plastome SNPs support the expansion of maternal lineages ca. 1906–3635 years ago. Our results suggest a recent spread of C. ficifolia in Mexico, with high genetic diversity (π = 0.225, FST = 0.074) and inbreeding (FIS = 0.233). Coalescent models suggest low rates of gene flow with C. radicans and C. pedatifolia, whereas ABBA-BABA tests did not detect significant gene flow with wild taxa. Despite the ecogeographic proximity of C. ficifolia and its relatives, this crop persists as a highly isolated lineage of puzzling origin.

Genetic analysis of two species of Mnomen in the Kalamazoo Watershed reveal panmixia in Z. Aquatica, structure among Z. Palustris, and hybridization in areas of sympatry.

Mnomen or wild rice of the genus Zizania is an important part of Native American culture, especially in Michigan for the Ojibwe nation. An oil spill in 2010 along the Kalamazoo River and the subsequent clean-up lead to renewed interest in management of Mnomen within the Kalamazoo watershed. The affected water bodies were surveyed for Zizania species to map existing populations, determine the existing genetic diversity and species present, and to identify potential hybridization. Using Traditional Ecological Knowledge of rice beds and opportunistic sampling of encountered plants, 28 rice beds were sampled. Two species of Zizania were identified Z. palustris and Z. aquatica. Genetic diversity was measured using 11 microsatellite loci and was moderately high for both species (Z. aquatica HE = 0.669, H0 = 0.672, n=26 and Z. palustris HE = 0.697, H0 = 0.636, n=57). No evidence of population bottle-necking was found. Z. palustris was found to have k=3 populations on the landscape, while Z. aquatica was found to be a single panmictic population. Several individual hybrids were confirmed using genotyping and they were all found in areas where the two species co-occurred. Additionally, Z. aquatica was found to have expanded into areas historically with only Z. palustris downstream of the oil spill, potentially due to dredging and sediment relocation as part of the clean-up effort.

Host-specificity of biocontrol agents in the field – The significance of sampling sympatric relatives of target weeds (Acacia holosericea versus A. auriculiformis)

Acacia auriculiformis is an invasive weed that causes significant environmental damage across Florida, USA. Previous native range surveys in Australia identified a number of herbivores that are commonly associated with this plant, including several species of leaf-tying moths (Macrobathra spp.) and a chrysomelid beetle (Calomela intemerata). These herbivores are considered strong candidates as biological control agents, but the range of host species they use has not been determined. We therefore conducted a transect survey of herbivorous insects on A. holosericea, a closely-related sympatric relative of A. auriculiformis. These species share areas of sympatry and the latter was sampled simultaneously (in sympatry and allopatry). DNA barcoding approach identified an array of herbivorous insects feeding on A. holosericea, but few were found on both the Acacia species sampled. A literature survey suggested this pattern of host specificity may be consistent across Australian acacias, to the extent that each Acacia species may largely host its own suite of herbivores. These results do not negate the need for host testing procedures in biological control, but they do increase our confidence substantially that several promising potential biological control agents of A. auriculiformis (Macrobathra moths and Calomela beetles) have a restricted host species range. Our study illustrates how exploring the herbivore diversity of plant species closely related to the target weed can provide crucial information for biological control researchers.

Is there evidence of convergent displacement of characters in the release calls of Cuban species of the genus Peltophryne (Anura: Bufonidae)?

Abstract Anuran release calls are produced by females and males in response to mating attempts by other males. The efficiency of the release signal to initiate dismount ensures that amplexus is not prolonged, avoiding exposure to predation and increasing the time available for breeding opportunities. Convergent character displacement of release calls may facilitate interspecific communication. In this contribution, we described and compared the release calls of sexually active males of four endemic species of Cuban toads of the genus Peltophryne in allopatric and sympatric conditions, exploring possible evidence of convergent displacement in areas of sympatry. One of these species, Peltophryne peltocephala, is widely distributed in the Cuban archipelago, with contact areas with two other species of large toads. Convergent character displacement requires that the allopatric character states of the species are significantly different from each other, and the sympatric character states are not significantly different. Although significant differences were detected between pairs of different species, in terms of duration of call sequence, call duration, interval between calls and dominant frequency, we did not find a robust pattern consistent with the expected pattern of convergent displacement of acoustic characters. Almost all call variability of allopatric populations fell inside the variability of sympatric populations.

Genomic and environmental insights and conservation challenges for two hybridizing iconic crocodile species across Mexico: Crocodylus acutus and C. moreletii

AbstractHybridization is of key relevance for conservation of wild species, and yet it is still one of the most controversial issues in conservation. Identifying historical and contemporary factors promoting the formation and maintenance of hybrids is crucial for the management of endangered species, as well as characterizing the environmental factors and patterns of habitat use among parental species and their hybrids. Crocodiles are a conservation priority group since all 23 species recognized worldwide are in a protected category and hybridization occurs between many of their species, particularly between Crocodylus acutus and C. moreletii. Their hybridization system encompasses a geographically extensive hybrid zone, where two distinct hybrids and two C. acutus lineages have diverged and only a few geographically isolated populations of both parental species remain. We used a combined approach of genome‐wide sequencing and ecological niche modeling to discern the geographic and temporal patterns of introgression, migration, and demography, and to assess the ecological niches of the distinct lineages. Our approach enabled us to determine the spatial and temporal components of the divergence and admixture events of hybrids and non‐admixed lineages, to describe the environmental characteristics and geographic extent of areas of sympatry, and to confirm human‐mediated hybridization events. Our findings also showed overall distinct ranges and ecological niches among lineages, where hybrids presented a different set of environmental requirements from both parental species. This approach can be readily applied to different taxa and ecological contexts, providing species information on genetics and the environment with direct conservation relevance. We additionally describe the various conservation challenges that C. acutus and C. moreletii currently face, highlighting that these distinct crocodile species and hybrid lineages warrant recognition and need urgent conservation effort.

Genome-wide phylogeography reveals cryptic speciation in the circumglobal planktonic calcifier Limacina bulimoides.

Little is known about when and how planktonic species arise and persist in the open ocean without apparent dispersal barriers. Pteropods are planktonic snails with thin shells susceptible to dissolution that are used as bio-indicators of ocean acidification. However, distinct evolutionary units respond to acidification differently, and defining species boundaries is therefore crucial for predicting the impact of changing ocean conditions. In this global population genomic study of the shelled pteropod Limacina bulimoides, we combined genetic (759,000 single nucleotide polymorphisms) and morphometric data from 161 individuals, revealing three major genetic lineages (FST = 0.29-0.41): an "Atlantic lineage" sampled across the Atlantic, an "Indo-Pacific lineage" sampled in the North Pacific and Indian Ocean, and a "Pacific lineage" sampled in the North and South Pacific. A time-calibrated phylogeny suggests that the lineages diverged about 1 million years ago, with estimated effective population size remaining high (~10 million) throughout Pleistocene glacial cycles. We do not observe any signatures of recent hybridization, even in areas of sympatry in the North Pacific. While the lineages are reproductively isolated, they are morphologically cryptic, with overlapping shell shape and shell colour distributions. Despite showing that the circumglobal L. bulimoides consists of multiple species with smaller ranges than initially thought, we found that these pteropods still possess high levels of genetic variability. Our study adds to the growing evidence that speciation is often overlooked in the open ocean, and suggests the presence of distinct biological species within many other currently defined circumglobal planktonic species.

Shifting range in a stingless bee leads to pre-mating reproductive interference between species

Human-induced shifts in species’ ranges can increase contact between closely related species and lead to reproductive interference. In Australia, climate change and trade in stingless bee colonies is increasing the range overlap of two cryptic species: Tetragonula carbonaria and T. hockingsi. To investigate reproductive interactions between these species, we validated a diagnostic-PCR test based on the mitochondrial gene COI to ID field specimens to species. We then assessed the likelihood of reproductive interference in four ways. First, we imaged the male genitalia of each species and found no evidence of reproductive character displacement. Second, we assessed species composition of mating aggregations in an area of sympatry (Southeast Queensland) and confirmed that some males join the mating aggregations of interspecific colonies. Third, we translocated T. hockingsi colonies into the southern range of T. carbonaria (Sydney) and tracked their ability to requeen. These translocated colonies attracted mating aggregations comprised almost entirely of interspecific males, but never formed hybrid colonies; instead, queens either mated with their brothers, or the colony failed to requeen at all. Finally, we presented T. carbonaria males with either conspecific or interspecific virgin queens and found that males attempted to mate only with their own species’ queens. In all, we conclude that reproductive barriers between these species are complete with respect to “short-range” mating cues, but not for “long-range” mate attraction cues. Our study highlights that hive movements can increase some forms of pre-mating reproductive interference between managed bee species, even where the species do not actually mate or hybridize.

Anisakis infection in anchovies (Engraulis encrasicolus) from Iberian waters, southwestern Europe: Post-mortem larval migration

The Anisakis larvae presence in fish for human consumption is a health risk that needs to be monitored. The anchovy is a fish that is highly appreciated by consumers and that can harbour Anisakis. It is thus necessary to periodically evaluate the presence of anisakid larvae in them. So, anchovies from Iberian Peninsula coasts were analysed. Fish examination for macroscopic nematodes showed L3s of both Anisakis type I and Hysterothylacium aduncum. The Anisakis prevalence varies with the catching area and the fish size. The muscle prevalence was 7.45% (mean intensity 1.75; range 1-5). Molecular analysis showed 110 A. simplex s.s. (17 in muscle), 22 A. pegreffii (3) and 7 hybrid genotype individuals (1). Considering that most of the Iberian Peninsula coasts are a sympatry area between these two Anisakis species, it has been observed that A. simplex s.s./A. pegreffii ratio increases from south to north in a clockwise direction. Also, 19 larvae were detected on the fish surface from the Bay of Biscay, indicating the ability of these larvae to migrate after the fish death. The A. simplex s.s./A. pegreffii larvae proportion found on the anchovy surface is similar to the found in viscera and lower than in muscle, suggesting that most of the larvae migrating to the surface must have come from the visceral package. This confirms the importance of removing fish viscera immediately after capture, for those fish species where this is possible. As both species cause anisakiasis/anisakidosis, these data show a real risk to human health, especially in dishes highly prized in Mediterranean countries prepared with raw or semi-raw anchovies.

Hybrids of Ixodes ricinus and Ixodes persulcatus ticks effectively acquire and transmit tick-borne encephalitis virus.

Ixodes rici nus and Ixodes persulcatus ticks are the main vectors of tick-borne encephalitis virus (TBEV), which has three main subtypes connected with certain tick species: the European subtype, associated with I. ricinus, and the Siberian and Far-Eastern subtypes, associated with I. persulcatus. Distribution ranges of these species overlap and form large sympatric areas in the East European Plain and Baltic countries. It has previously been shown that crossing of I. ricinus and I. persulcatus is possible, with the appearance of sterile hybrids. Hybridization of ticks can affect not only the spread of ticks but also the properties of natural foci of arbovirus infections, in particular TBEV. In the present study, we analyzed the effectiveness of virus transmission from infected mice to larvae and nymphs and trans-stadial transmission (from larvae to nymph and adult) in I. ricinus, I. persulcatus, and hybrids. For this purpose, we bred a hybrid generation from the crossing of I. persulcatus females and I. ricinus males, and we used the Siberian and European subtypes of TBEV. We showed that after feeding on infected mice, virus prevalence in engorged ticks decreased over time, and after molting, the opposite was true. In hybrids we observed the highest acquisition effectiveness and RNA copy numbers during Siberian TBEV subtype transmission. The efficiency of trans-stadial transmission of both TBEV subtypes was similar in hybrids and parental species. After the second trans-stadial TBEV transmission, a significant increase in ticks' infection rates was observed only in specific subtype-tick combination. Our data demonstrate the possible features of TBEV circulation in the I. ricinus and I. persulcatus sympatry area.

Resource use divergence facilitates the evolution of secondary syntopy in a continental radiation of songbirds (Meliphagoidea): insights from unbiased co‐occurrence analyses

Allopatric speciation followed by the evolution of range overlap (sympatry) allows the build‐up of regional diversity. However, local species richness requires that species co‐occur locally (syntopy). Importantly, correct estimates of syntopy must be available to identify ecological traits facilitating it. We thus provide a method to correctly estimate local co‐occurrence and demonstrate it on the evolution of secondary syntopy. First, we performed probabilistic co‐occurrence analyses on simulated data across a sympatry gradient from 0 to 100%. Second, we extracted 116 species pairs younger than 10 My from a dated phylogeny of Meliphagoidea songbirds. We constructed a presence–absence matrix of 58 species across 470 sites based on 37 250 censuses in Australia and Tasmania from 1989 to 1995. We also constructed a spatial mask based on species ranges, identifying sites within versus outside the area of sympatry. We ran both unconstrained and range mask‐constrained co‐occurrence analyses. We compared the resulting syntopy and predicted it by species ecology. Simulations and exact analyses showed that co‐occurrence analyses must be limited to sites in the area of sympatry between species. Without this spatial limit, syntopy was negatively biased, especially in common species. Accordingly, syntopy was negatively biased in Meliphagoidea when data from all sites were used, but this bias decreased with increasing sympatry, in agreement with numerical and exact analyses. When using correct estimates, syntopy increased with increasing divergence in the use of foraging stratum (ground, shrub, subcanopy and canopy) and with decreasing divergence in diet. In conclusion, we introduced a general method for calculating local species co‐occurrence and confirmed its validity by simulations. We illustrated its use by analyzing the evolution of secondary syntopy in a phylogenetic framework. We found support for both niche divergence (foraging stratum) and niche conservatism (diet) in facilitating evolutionary transitions to secondary syntopy, allowing the build‐up of local species richness.

Diverse data sources and new statistical models offer prospects for improving the predictability of anthropogenic hybridization.

Human disturbance can theoretically influence the rates of hybridization, but few studies have convincingly identified a causal link. Grabenstein et al. (2022) used a genomic and phenotypic study of chickadees to associate hybridization with human disturbance. Additionally, this is consistent with citizen science reports of chickadee hybrids across the range. We highlight the exciting aspects of this work and make suggestions about a role for broad geographic and genomic sampling, and new statistical methods to better connect hybridization outcomes to anthropogenic disturbance in diverse study systems.

Sequential hybridization may have facilitated ecological transitions in the Southwestern pinyon pine syngameon.

Multispecies interbreeding networks, or syngameons, have been increasingly reported in natural systems. However, the formation, structure, and maintenance of syngameons have received little attention. Through gene flow, syngameons can increase genetic diversity, facilitate the colonization of new environments, and contribute to hybrid speciation. In this study, we evaluated the history, patterns, and consequences of hybridization in a pinyon pine syngameon using morphological and genomic data to assess genetic structure, demographic history, and geographic and climatic data to determine niche differentiation. We demonstrated that Pinus edulis, a dominant species in the Southwestern US and a barometer of climate change, is a core participant in the syngameon, involved in the formation of two drought-adapted hybrid lineages including the parapatric and taxonomically controversial fallax-type. We found that species remain morphologically and genetically distinct at range cores, maintaining species boundaries while undergoing extensive gene flow in areas of sympatry at range peripheries. Our study shows that sequential hybridization may have caused relatively rapid speciation and facilitated the colonization of different niches, resulting in the rapid formation of two new lineages. Participation in the syngameon may allow adaptive traits to be introgressed across species barriers and provide the changes needed to survive future climate scenarios.

Saguinus mystax(Primates: Callitrichidae)

AbstractSaguinus mystax (Spix, 1823), a callitrichid (tamarin and marmoset family) commonly called the mustached tamarin, is 1 of 12 species in the genus Saguinus. In this large callitrichid (450–650 g), females are slightly heavier than males. It occurs in Brazil and Peru, south of Rio Amazonas from Río Ucayali in the west to Rio Purus in the east, in primary and secondary tierra firma rainforests. The diet consists of fruit pulp, insects, gums, nectar, and small vertebrates. It lives in groups of 3–10 individuals with a male-biased adult sex ratio and has a cooperative breeding system. In areas of sympatry, S. mystax forms mixed-species groups with saddle-back tamarins, Leontocebus. Although captured for the pet trade and sporadically hunted, it is considered “Least Concern” (LC) by the International Union for Conservation of Nature.

A comparison of nest-site characteristics for two sympatric Estrildid finches (Uraeginthus spp.) in Tanzania.

It is well known that birds have great diversity in nesting strategies, but we still have limited knowledge of the variation among species that share the habitat. Here, I will report and compare the nesting strategies between the two sympatric songbirds. Blue‐capped (Uraeginthus cyanocephalus) and red‐cheeked cordon‐bleus (Uraeginthus bengalus) are socially monogamous, biparental songbirds (family Estrildidae) that sympatrically inhabit arid landscapes with trees and bushes in East Africa. Both species build domed nests with grasses that are often located near wasp nests. They also sometimes take over old weaver (family Ploceidae) nests. While these nesting strategies are already described as common behavioral traits in both species in the literature, interspecies variation in these nesting strategies in areas of sympatry is not reported. My initial field observation during their breeding season suggested that whether these nesting strategies were adopted or not varied somewhat between the sympatric cordon‐bleus. Thus, I carried out a more formal investigation to test these differences. I found that red‐cheeked cordon‐bleus built their nests near wasp nests more frequently than blue‐capped cordon‐bleus, while I did not find any other significant differences between the nesting sites of the two species, such as the use of weaver nests, the types of nesting plants, or nest heights. These results suggest that the sympatric cordon‐bleus share several nest‐site characteristics, but that red‐cheeked cordon‐bleus have an affinity for nesting near wasp nests. Further studies will be required to elucidate the costs and benefits of these nesting strategies or the role that adjacency to wasp nests might play in the sympatry of the two species.

Distributional overlap and potential competition between a threatened habitat specialist and generalist frog species in coastal wallum habitats ofSouth EastQueensland, Australia

AbstractCoastal wallum wetlands inhabited by the vulnerable wallum sedgefrog (Litoria olongburensis) are highly susceptible to habitat degradation owing to their unusual hydrology and water chemistry. Anthropogenic impacts on wallum wetland environs pose a significant threat to the wallum sedgefrog by allowing the eastern sedgefrog (Litoria fallax), a habitat generalist and closely related competitor species, to colonise and displace the wallum sedgefrog from disturbed wallum habitat. To identify ‘at risk’ areas, overlapping species distribution models were utilised to highlight areas of sympatry between these species in south east Queensland, where competition with the eastern sedgefrog poses a particular threat to the wallum sedgefrog. Significant areas of distributional overlap (including 47% of the wallum sedgefrog's modelled distribution) were identified, primarily in mainland areas where anthropogenic disturbance is highest. When overlayed with the boundaries of protected areas, 84% of the area exclusively inhabited by the wallum sedgefrog occurs within the bounds of protected lands. In contrast, 74% of overlapping distribution of the two species occurred outside of these parks, highlighting the importance of protected areas in the conservation of the wallum sedgefrog. This study highlights areas where competition with the eastern sedgefrog presents a particular threat to the wallum sedgefrog, helping inform effective conservation initiatives for this species.

Sharing the Space: Variation in Morphometric, Ecoregional, Migratory and Reproductive Patterns of Three Sympatric Artibeus Species

Bats of the phyllostomid genus Artibeus are primarily frugivorous, and they often are captured carrying the fruits of figs (Ficus spp.) or Cecropia spp. Although two or three species of Artibeus (sensu stricto) are found sympatrically in many regions of the Neotropics, little is known about the potential competitive interactions of these congeners in areas of sympatry. Competition might occur for food, roost sites, or other resources, and might be expressed as spatial or temporal partitioning in feeding or reproduction, as increased displacement of feeding- or foraging-related characters, or as some combination of these factors. These effects might be more pronounced near the distributional limits of the species, where resources might be more limited (both in abundance and diversity), and more patchily distributed. Three species of Artibeus (A. fimbriatus, A. lituratus, and A. planirostris), are at or near their southern or south-western distributional limits in Paraguay. Previous analyses in Paraguay have determined that A. lituratus and A. planirostris are migratory, with A. lituratus being most abundant during the wet season (October–February), and A. planirostris in the variable season (March–May). Artibeus fimbriatus and A. lituratus are relatively more abundant in the Atlantic Forest ecoregion; and A. planirostris in the Cerrado. In this study we examined morphometric variation in wing and craniomandibular characters, as well as reproductive patterns, to further explore the potential niche partitioning along these dimensions that may reduce competition for resources. We tested for morphometric differences among the species, and for geographic and secondary sexual variation in each of the three species. Both wing and craniodental characters vary significantly among species. Artibeus fimbriatus exhibits sexual dimorphism in only one cranial character, and A. lituratus shows sexual dimorphism in three craniodental characters and in all wing characters, whereas A. planirostris is not sexually dimorphic in any character. Weak geographic variation was found in craniodental characters in A. planirostris, and in wing characters in the other two species. Differences were also encountered in the three species' morphometric responses to temperature and precipitation parameters. Evaluating these differences in morphometric patterns in the context of ecoregional and seasonal associations, migratory status and reproductive patterns, we conclude that the three species mitigate competitive pressure through a complex partitioning of available niche space.

Niche modelling and comparative morphology untangle taxonomy of the Dysschema eurocilia clade (Lepidoptera: Erebidae) and reveal a relictual Pleistocene Arc distribution

Dysschema is the largest genus in Pericopina, with 69 species. The highly polymorphic species D. eurocilia (Cramer, 1777) was recently united in a clade with three other species: D. aorsa (Boisduval, 1870) stat. rev., D. bivittata (Walker, 1854) stat. rev. and D. molesta (Hering, 1925) stat. rev. Typological taxonomic treatment and lack of understanding of geographic distributions contributed to a proliferation of publications and disputed validity of names. We analysed the genital morphology and wing patterns for the four putative species in the ‘D. eurocilia clade’ and estimated the ecological niche using Ecological Niche Modelling (ENM) to clarify taxonomic scenarios, delimit species and infer speciation mechanisms. We also used ENM to understand the distributions of phenotypes of D. eurocilia. The morphological data and ENM suggested an alternative hypothesis to previous taxonomic works on species within the ‘D. eurocilia clade’. The ENM also revealed distribution patterns supporting the northern Andes as a geographic barrier between Central and South America, while the interconnected Andean valleys might represent areas of sympatry. Additionally, the predicted distribution showed that certain phenotypes in D. eurocilia have distribution through the South American diagonal of open formations, which might represent a relictual distribution known as the Pleistocene Arc.

Distribution patterns of South American mustelids (Carnivora: Mustelidae)

AbstractClimate has long been recognized as one of the main determinants of the geographical distribution of species. Variations associated with primary productivity in temperature, rainfall, and photoperiod can affect survival and reproduction, affecting the peripheries of geographical distributions. The importance of graphical visualization of these distributions lies in conservation, management, and environmental research. With respect to the South American species of mustelids, 37% are threatened according to the IUCN Red List, and the limits of distributions and their determinants are poorly known for the majority of species. Here, complete and updated databases and maps of geographical and temporal distribution are presented for the 12 species of mustelids inhabiting South America. Museum specimens and recorded localities were gathered based on an online search. Geographic limits of distributions were assessed, as were environmental values for all localities. Comparison with IUCN maps was undertaken to determine the need for updating. Finally, sympatry and syntopy among species analyzed were examined using Geographic Information Systems. The most complete and updated database of geographic distributions of South American mustelids to date was assembled for all species, encompassing 9,826 localities. New areas with recorded localities not present in IUCN maps were documented in many species, indicating the need to update current maps for conservation efforts. Areas of sympatry and syntopy were found among many species, indicating that patterns of coexistence between them are not well known. This study will serve as a framework for ensuing efforts in species distribution modeling, conservation decisions, and field studies, among others.