Historical patterns of niche dynamics in Neotropical species of the <Emphasis Type="Italic">Drosophila</Emphasis> subgenus (Drosophilidae,Diptera)

Niche conservatism (NC) presence is a controversial question in evolutionary ecology. In Drosophila, little is known about which is the preponderant evolutionary pattern, since the adaptive radiation hypothesis first proposed by Throckmorton assumed niche divergence (ND) according to a niche occupancy scenario. Nevertheless, this hypothesis has not yet been straightforwardly tested. Our aim here was to test the role of NC patterns across evolution of American drosophilids belonging to the tripunctata and virilis-repleta lineages of the Drosophila subgenus, through measures of geographical, abiotic and biotic niche overlap and evaluations regarding the presence of phylogenetic signal or niche identity. We recovered phylogenetic signal attributable to phylogenetic niche conservatism when all species were analyzed together, but not in more restricted groups. Identity tests showed that niche equivalency was seldom rejected for the tripunctata lineage species. So, in general, neither the results for the Drosophila subgenus nor those for the tripunctata lineage support the hypothesis of an adaptive radiation. Notwithstanding, there were also several isolated cases supporting a scenario of ND, and ecological speciation was evident in some of the evaluated sister species pairs.     

Climatic Similarity of Extant and Extinct <Emphasis Type="Italic">Dasypus</Emphasis> Armadillos

The similar geographic distributions of an extinct (Dasypus bellus) and an extant (D. novemcinctus) armadillo species have long been of interest to scholars because of the unresolved phylogeny. The relationship between the two species has been investigated through morphological and phylogenetic studies, whereas the ecological perspective has been overlooked, the importance of which is more and more acknowledged in speciation events. Here, we used ecological niche models to study the climatic niche similarity of three species of Dasypus (D. bellus, D. novemcinctus, and D. kappleri) and provide new insights on the relationship among them. The climatic niche similarity was compared in two ways: hindcast of ecological niche models based on occurrences and climatic layers, and direct niche boundary comparison along bioclimatic axes. The fossil records of D. bellus were not predicted suitable by the ecological niche models of the two extant armadillos. The direct comparison of niche boundary showed that D. bellus lived in colder and relative dryer climates, with high temperature variation and low precipitation variation. Our results did not support the previously assumed ecological similarity of D. bellus and D. novemcinctus based on their geographic distributions and emphasized the possibility of a cold adapted characteristic of the life history of D. bellus.     

Ants of the tribe Formicini (Hymenoptera,Formicidae) from Late Eocene amber of Europe

The tribe Formicini (Formicinae) from the Late Eocene Baltic, Bitterfeld, Rovno, and Scandinavian ambers is revised. Ants are recorded for the first time from the Bitterfeld and Scandinavian ambers. Two new genera (Cataglyphoides gen. nov. and Conoformica gen. nov.) and six new species (Cataglyphoides intermedius sp. nov., Conoformica bitterfeldiana sp. nov., Formica kutscheri sp. nov., F. palaeopolonica sp. nov., F. radchenkoi sp. nov., F. zherikhini sp. nov.) are described. A new combination, Cataglyphoides constrictus (Mayr, 1868), comb. nov., is established. A lectotype of Camponotus constrictus Mayr, 1868 and a neotype of Formica phaethusa Wheeler, 1915 are designated. Formica clymene Wheeler, 1915 is recognized as a new synonym of F. phaethusa Wheeler, 1915. An identification key for workers of Formicini species from Late Eocene European ambers is provided.     

Genetic variability and population structure of grey wolf (<Emphasis Type="Italic">Canis lupus</Emphasis>) in Serbia

Results of previous morphometric and genetic analyses of grey wolf (Canis lupus L.) population from Serbia indicated different patterns of population subdivision. In order to explore population structure, level of genetic variability, genetic drift, inbreeding and signals of bottleneck for grey wolves from Serbia, we applied highly polymorphic genetic markers (microsatellites). Obtained data are valuable in determination of conservation units and creation of appropriate management plans. We have amplified 18 highly polymorphic microsatellites, in a total sample of 75 grey wolves, from different localities across Serbia and multilocus genotypes were analyzed using appropriate software. Observed values of the basic genetic parameters (H_O = 0.69; H_E = 0.75) indicated moderate level of genetic variability, similar to genetic variability in other populations belonging to the Dinaric-Balkan population of grey wolf. In STRUCTURE analysis, although ΔK was estimated to be at first peak K = 2, and second peak K = 4, CLUMPAK analyses showed that there’s no structuring for any of assumed K, and therefore the population of grey wolf from Serbia may be considered as one continuous population and treated as one conservation unit in future management plans. Signals of bottleneck haven’t been observed (Wilcoxon test two phase mutation model p = 0.247; and stepwise mutation model p = 0.815).     

Exploring stream communities in a tropical biodiversity hotspot: biodiversity,regional occupancy,niche characteristics and environmental correlates

Exploring and describing biodiversity and the mechanisms structuring it is fundamental to advancing ecology. This is particularly pertinent in understudied biogeographical regions, such as the Afrotropics, that are characterised by strong seasonal climatic shifts. We investigated the characteristics of stream biodiversity in the Niger Delta region of Nigeria, a tropical biodiversity hotspot, by examining patterns in 20 stream invertebrate communities across both the wet and dry seasons. For this, we took a multi-faceted approach accounting for the three levels of biodiversity (α, β and γ), including partitioning the nestedness and turnover components of β diversity, regional occupancy-abundance patterns, niche characteristics, and the environmental drivers of community structure. α diversity was low in these streams, with strong turnover between sites leading to high β diversity contributing to regional biodiversity, but there was little variation in communities between seasons. The proportion of sites occupied by taxa declined with increasing niche position, and decreasing niche breadth. Occupancy was predicted well by a combination of these two factors (niche position and breadth), but not mean local abundance, as the abundance-occupancy link was an upper-limit unimodal relationship. On average, community structure was linked more strongly to environmental variables in the wet season. Our findings demonstrate the clear role of spatial, but not temporal, turnover in assemblages, which likely reflects the environmental heterogeneity of this region. This is further supported by the fact that regional occupancy was mostly related to niche characteristics, particularly niche position. We emphasise the importance of continued basic and applied ecological work in this important biogeographic region to enable better protection of its biodiversity.     

Tree community structure reflects niche segregation of three parapatric squirrel monkey species (<Emphasis Type="Italic">Saimiri</Emphasis> spp.)

Integration between ecology and biogeography provides insights into how niche specialization affects the geographical distribution of species. Given that rivers are not effective barriers to dispersal in three parapatric species of squirrel monkeys (Saimiri vanzolinii, S. cassiquiarensis and S. macrodon) inhabiting floodplain forests of Central Amazonia, we tested whether forest structure and tree diversity may explain species differences in niche specialization and spatial segregation. We sampled 6617 trees of 326 species in three habitats (high várzea, low várzea and chavascal) used by three Saimiri species, and estimated tree species richness in each of them. For each tree, we measured variables known to influence habitat use in primates, such as crown area and presence of lianas, epiphytes and hemi-epiphytes. We used ANOVA to compare these variables and performed multivariate analyses (NMDS, ANOSIM and SIMPER) to evaluate dissimilarities in forest structure among each habitat inhabited by the three Saimiri species. We identified differences in the tree species richness, crown area and presence of lianas, epiphytes and hemi-epiphytes between the three habitats for all Saimiri species. NMDS demonstrated that areas of high and low várzeas occupied by S. vanzolinii were clearly separated from the other species. We also found that different plant species contributed to dissimilarity among Saimiri ranges. Our findings support the hypothesis that tree community structure may promote niche specialization and spatial segregation among primates. We discuss how these patterns could have been favored by historical changes in forest flood patterns, the evolutionary history of Saimiri spp., and past competition.     

Ecogeographical Variation in Skull Shape of South-American Canids: Abiotic or Biotic Processes?

Species morphological changes can be mutually influenced by environmental or biotic factors, such as competition. South American canids represent a quite recent radiation of taxa that evolved forms very disparate in phenotype, ecology and behaviour. Today, in the central part of South America there is one dominant large species (the maned wolf, Chrysocyon brachyurus) that directly influence sympatric smaller taxa via interspecific killing. Further south, three species of similar sized foxes (Lycalopex spp.) share the same habitats. Such unique combination of taxa and geographic distribution makes South American dogs an ideal group to test for the simultaneous impact of climate and competition on phenotypic variation. Using geometric morphometrics, we quantified skull size and shape of 431 specimens belonging to the eight extant South American canid species: Atelocynus microtis, Cerdocyon thous, Ch. brachyurus, Lycalopex culpaeus, L. griseus, L. gymnocercus, L. vetulus and Speothos venaticus. South American canids are significantly different in both skull size and shape. The hypercarnivorous bush dog is mostly distinct in shape from all the other taxa while a degree of overlap in shape—but not size—occurs between species of the genus Lycalopex. Both climate and competition impacts interspecific morphological variation. We identified climatic adaptations as the main driving force of diversification for the South American canids. Competition has a lower degree of impact on their skull morphology although it might have played a role in the past, when canid community was richer in morphotypes.     

Re-Defining <Emphasis Type="Italic">Canis etruscus</Emphasis> (Canidae,Mammalia): A New Look into the Evolutionary History of Early Pleistocene Dogs Resulting from the Outstanding Fossil Record from Pantalla (Italy)

An outstanding sample of Canis etruscus has been found within the faunal assemblage from the early Pleistocene site of Pantalla (Italy), which is referred to the early late Villafranchian. Canis etruscus appeared in Europe about 2 Ma ago. It is regarded as an important taxon for biochronology, as its first occurrence (the “wolf event”) has been used to define one of the Villafranchian faunal turnovers. The discovery of four crania from Pantalla prompted a revision of C. etruscus, in order to better describe its cranial morphology. Since early studies, the distinction between C. etruscus and the coeval C. arnensis has been based mainly on mandibular traits. For this reason, our study is aimed at highlighting differences in craniodental characters between the two species. Canis arnensis has been conventionally considered a jackal-like dog, while C. etruscus is regarded as a wolf-like dog. Consequently, we decided to use jackals for comparison, in addition to C. lupus. Although the jackal group has been traditionally considered as quite homogenous (different species are partially sympatric and similar in both size and ecology), recent genetic studies demonstrate that jackals are not monophyletic. Considering the model offered by extant species, our goal is to delineate the degree of intra- and interspecific variability among the basal forms of the genus Canis.     

Evidence of adaptation,niche separation and microevolution within the genus <Emphasis Type="Italic">Polaromonas</Emphasis> on Arctic and Antarctic glacial surfaces

Polaromonas is one of the most abundant genera found on glacier surfaces, yet its ecology remains poorly described. Investigations made to date point towards a uniform distribution of Polaromonas phylotypes across the globe. We compared 43 Polaromonas isolates obtained from surfaces of Arctic and Antarctic glaciers to address this issue. 16S rRNA gene sequences, intergenic transcribed spacers (ITS) and metabolic fingerprinting showed great differences between hemispheres but also between neighboring glaciers. Phylogenetic distance between Arctic and Antarctic isolates indicated separate species. The Arctic group clustered similarly, when constructing dendrograms based on 16S rRNA gene and ITS sequences, as well as metabolic traits. The Antarctic strains, although almost identical considering 16S rRNA genes, diverged into 2 groups based on the ITS sequences and metabolic traits, suggesting recent niche separation. Certain phenotypic traits pointed towards cell adaptation to specific conditions on a particular glacier, like varying pH levels. Collected data suggest, that seeding of glacial surfaces with Polaromonas cells transported by various means, is of greater efficiency on local than global scales. Selection mechanisms present of glacial surfaces reduce the deposited Polaromonas diversity, causing subsequent adaptation to prevailing environmental conditions. Furthermore, interactions with other supraglacial microbiota, like algae cells may drive postselectional niche separation and microevolution within the Polaromonas genus.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> outer membrane protein,HomC, shows geographic dependent polymorphism that is influenced by the Bab family

The array of outer membrane proteins (OMPs) found in Helicobacter pylori provides a crucial component for persistent colonization within the gastric niche. Not only does H. pylori harbor a wide number of OMPs, but these OMPs often vary across strains; this likely contributes to immune evasion, adaptation during long term colonization, and potentially differential disease progression. Previous work from our group described OMP differences among the Bab family (babA, babB, and babC) and Hom family (homA and homB) from 80 American H. pylori clinical isolates (AH) and 80 South Korean H. pylori clinical isolates (KH). In the current study, we expanded our investigation to include the less well characterized Hom family member, HomC.     

Food resource partitioning of the <Emphasis Type="Italic">Mustelus lunulatus</Emphasis> and <Emphasis Type="Italic">Mustelus henlei</Emphasis> (Elasmobranchii: Carcharhiniformes)

The feeding habits and trophic ecology of Mustelus lunulatus and Mustelus henlei in the central coast of the Colombian Pacific were evaluated and compared to determine whether there was trophic niche overlap or resource partitioning between these two sympatric shark species. A total of 59 prey items were identified and grouped into 10 taxonomic categories. Mustelus lunulatus fed in large proportion on Stomatopoda and Brachyura, whereas M. henlei fed almost exclusively on Teleostei. Dendrobranchiata, Cephalopoda, Anomura and Polychaeta complemented the diets of both species. There were significant differences in diet between the two species, and there was an ontogenetic diet shift in Mustelus lunulatus, with Stomatopoda being the main prey item of juveniles and Brachyura the main prey item of adults. Dietary overlap (by sex and size) was low between species, but it was high for each species, with significant overlap between juveniles and adults of M. lunulatus and M. henlei, and between males and females of M. henlei. There were differences in the trophic levels of the species, sexes and sizes. This study suggests there is food resource partitioning, and differing ecological function of the two Mustelus species in the food web of the study area.     

Contrasting the early life histories of sympatric Arctic gadids <Emphasis Type="Italic">Boreogadus saida</Emphasis> and <Emphasis Type="Italic">Arctogadus glacialis</Emphasis> in the Canadian Beaufort Sea

The early life stages of Boreogadus saida and Arctogadus glacialis are morphologically similar, making it difficult to assess differences in their ecological niche. The present study documented for the first time the early life stage ecology of A. glacialis, compared it to that of B. saida, and identified the factors separating the niches of the two sympatric species. The 10,565 larval gadids collected in the Beaufort Sea from April to August of 2004 and 2008 were identified to species either directly by genetics and/or otolith nucleus size, or indirectly with a redistribution procedure. Between 8.0 and 8.7 % of all gadids were assigned to A. glacialis. Larvae of A. glacialis were longer at hatch and experienced lower mortality rates than those of B. saida. The two species shared similar spatiotemporal and vertical distributions, hatching season, and growth rate. Under the ice, feeding incidence of B. saida was low (14 %) relative to A. glacialis (88 %). At lengths <15 mm, both species specialized on different prey. The diet of fish >15 mm overlapped (Schoener’s index = 0.7), with Calanus glacialis and C. hyperboreus providing >50 % of the carbon intake of both species. The higher mortality in B. saida may be explained by the smaller size at age from hatching to metamorphosis and a lower under-ice feeding incidence. The early larval stage appears to be the key period of niche divergence between the two species.     

Interspecific killing between wolves and golden jackals in Iran

Interspecific killing is a widespread phenomenon among mammalian carnivores; being common, for instance, within the canid guild. The canid guild in Hamadan province, west of Iran, comprises three species: the gray wolf Canis lupus pallipes, the golden jackal Canis aureus, and the red fox Vulpes vulpes. In this area, habitat transformation and agricultural land uses have significantly reduced wild prey populations. In search of food, members of the canid guild are often driven to human settlements. Due to inefficient waste management, the major source of food for canids here is anthropogenic food resources, such as livestock and pet carcasses, and domestic waste illegally dumped near poultry farms and rural areas. Here, we described one of the first reports in the literature of a case of interspecific killing between a wolf and a golden jackal. On June 13, 2016, a collared wolf (adult male) killed an adult jackal (adult male). Further studies are required to understand intraguild competition among red fox, golden jackals, and wolves in this area.     

No effect of round goby <Emphasis Type="Italic">Neogobius melanostomus</Emphasis> colonisation on young-of-the-year fish density or microhabitat use

The round goby Neogobius melanostomus has recently invaded several major freshwater systems in Europe and North America. Despite numerous studies predicting an impact on native fish assemblages, few have attempted to demonstrate it. In this case study, we monitored the effect of N. melanostomus colonisation on abundance and habitat utilisation of both young-of-the-year (YOY) native fish and YOY western tubenose goby Proterorhinus semilunaris in a typical, medium-sized European river. Colonisation by N. melanostomus had no apparent effect on either native fish abundance and species richness or P. semilunaris abundance. Moreover, after colonisation, both native fish and P. semilunaris occupied similar niches (i.e. microhabitats) to those occupied before colonisation. While niche use of YOY N. melanostomus and P. semilunaris overlapped significantly, YOY native fish utilised different habitats from the gobiids. We suggest that N. melanostomus did not compete for resources with YOY fish in our study area due to lack of niche overlap and/or surplus resources. As N. melanostomus rapidly dominated the fish assemblage at our site, we further suggest that utilisation of an empty niche, rather than competitive superiority, was the main factor facilitating its success.     

Trophic consequences of non-native pumpkinseed <Emphasis Type="Italic">Lepomis gibbosus</Emphasis> for native pond fishes

Introduced non-native fishes can cause considerable adverse impacts on freshwater ecosystems. The pumpkinseed Lepomis gibbosus, a North American centrarchid, is one of the most widely distributed non-native fishes in Europe, having established self-sustaining populations in at least 28 countries, including the U.K. where it is predicted to become invasive under warmer climate conditions. To predict the consequences of increased invasiveness, a field experiment was completed over a summer period using a Control comprising of an assemblage of native fishes of known starting abundance and a Treatment using the same assemblage but with elevated L. gibbosus densities. The trophic consequences of L. gibbosus invasion were assessed with stable isotope analysis and associated metrics including the isotopic niche, measured as standard ellipse area. The isotopic niches of native gudgeon Gobio gobio and roach Rutilus rutilus overlapped substantially with that of non-native L. gibbosus, and were also substantially reduced in size compared to ponds where L. gibbosus were absent. This suggests these native fishes shifted to a more specialized diet in L. gibbosus presence. Both of these native fishes also demonstrated a concomitant and significant reduction in their trophic position in L. gibbosus presence, with a significant decrease also evident in the somatic growth rate and body condition of G. gobio. Thus, there were marked changes detected in the isotopic ecology and growth rates of the native fish in the presence of non-native L. gibbosus. The implications of these results for present and future invaded pond communities are discussed.     

Genetic structure and environmental niche modeling confirm two evolutionary and conservation units within the western spadefoot (<Emphasis Type="Italic">Spea hammondii</Emphasis>)

The western spadefoot (Spea hammondii) is a Species of Special Concern in California and is now under review by the U.S. Fish and Wildlife Service for listing under the Endangered Species Act. We delineated potential conservation units within S. hammondii by analyzing spatial genetic structure across the species’ range using five nuclear and one mitochondrial loci. For both nuclear and mitochondrial markers we found that S. hammondii consists of two genetically distinct, allopatric clusters divided by the Transverse Ranges. To corroborate the northern and southern genetic clusters as conservation units from an ecological perspective, we applied a niche identity test to environmental niche models of the two groups. We found that the niche models of the northern and southern clusters were significantly different, suggesting they may be ecologically non-exchangeable. Given our demonstration of significant genetic and ecological differentiation between allopatric clusters of S. hammondii, we recommend that ongoing conservation efforts consider each as a separate unit with potentially unique management needs.     

Climatic niche evolution in the Andean genus <Emphasis Type="Italic">Menonvillea</Emphasis> (Cremolobeae: Brassicaceae)

The study of how climatic niches change over evolutionary time has recently attracted the interest of many researchers. Different methodologies have been employed principally to analyze the temporal dynamics of the niche and specially to test for the presence of phylogenetic niche conservatism. Menonvillea, a genus of Brassicaceae including 24 species, is distributed primarily along the Andes of Argentina and Chile, with some taxa growing in southern Patagonia and others in the Atacama Desert and the Chilean Matorral. The genus is highly diversified morphologically but also presents a remarkably wide ecological range, growing from the high Andean elevations, to the dry coastal deserts in Chile, or the Patagonia Steppe in Argentina. In this study, we used molecular phylogenies together with climatic data to study climatic niche evolution in the genus. The results show that the main climatic niche shifts in Menonvillea occurred between the sections Cuneata-Scapigera and sect. Menonvillea throughout the Mid-Late Miocene, and associated with the two main geographical distribution centers of the genus: the highlands of the central-southern Andes and the Atacama Desert-Chilean Matorral, respectively. Climatic niches in these lineages were mainly differentiated by the aridity and potential evapotranspiration, the minimum temperatures of the coldest month, and the temperature annual range and seasonality. Niche evolution in Menonvillea deviated from a Brownian motion process, with most of the climatic dimension best-fitting to an Ornstein-Uhlenbeck model of multiple adaptive peaks. Our results also indicated that higher aridity levels and lower annual temperature ranges were associated with the evolution of the annual habit, as exemplified by the distribution of sect. Menonvillea. Finally, the results suggested that climatic niche evolution in Menonvillea exhibited some degree of phylogenetic niche conservatism, fundamentally within the two main lineages (sect. Menonvillea and sects. Cuneata-Scapigera).     

Biodiversity and ecology of flower-associated actinomycetes in different flowering stages of <Emphasis Type="Italic">Protea repens</Emphasis>

Actinomycete bacteria have previously been reported from reproductive structures (infructescences) of Protea (sugarbush/suikerbos) species, a niche dominated by fungi in the genera Knoxdaviesia and Sporothrix. It is probable that these taxa have symbiotic interactions, but a lack of knowledge regarding their diversity and general ecology precludes their study. We determined the diversity of actinomycetes within Protea repens inflorescence buds, open inflorescences, young and mature infructescences, and leaf litter surrounding these trees. Since the P. repens habitat is fire-prone, we also considered the potential of these bacteria to recolonise infructescences after fire. Actinomycetes were largely absent from flower buds and inflorescences but were consistently present in young and mature infructescences. Two Streptomyces spp. were the most consistent taxa recovered, one of which was also routinely isolated from leaf litter. Lower colonisation rates were evident in samples from a recently burnt site. One of the most consistent taxa isolated from older trees in the unburnt site was absent from this site. Our findings show that P. repens has a distinct community of actinomycetes dominated by a few species. These communities change over time and infructescence developmental stage, season and the age of the host population. Mature infructescences appear to be important sources of inoculum for some of the actinomycetes, seemingly disrupted by fire. Increased fire frequency limiting maturation of P. repens infructescences could thus impact future actinomycete colonisation in the landscape. Streptomyces spp. are likely to share this niche with the ophiostomatoid fungi, which merits further study regarding their interactions and mode of transfer.     

Deep sequencing analysis of bacterial community structure of Soldhar hot spring,India

We investigated the bacterial community structure of Soldhar hot spring with extreme high temperature 95°C located in Uttarakhand, India using high throughput sequencing. Bacterial phyla Proteobacteria (88.8%), Deinococcus-Thermus (7.5%), Actinobacteria (2.3%), and Firmicutes (1.07%) were predominated in the sequencing survey, whereas Bacteroidetes, Verrucomicrobia, Aquificae and Acidobacteria were detected in relatively lower abundance in Soldhar hot spring. At the family level, Comamonadaceae (52.5%), Alteromonadaceae (15.9%), and Thermaceae (7.5%) were mostly dominated in the ecosystem followed by Chromatiaceae, Microbacteriaceae, and Cyclobacteriaceae. Besides, members of Rhodobacteraceae, Moraxellaceae, Xanthomonadaceae, Aquificaceae, Enterobacteriaceae, Bacillaceae, Methylophilaceae, etc. were detected as a relatively lower abundance. In the present study we discuss the overall microbial community structure and their relevance to the ecology of the Soldhar hot spring environment.