Insect Gut Bacterial Diversity Determined by Environmental Habitat,Diet, Developmental Stage,and Phylogeny of Host

Insects are the most abundant animals on Earth, and the microbiota within their guts play important roles by engaging in beneficial and pathological interactions with these hosts. In this study, we comprehensively characterized insect-associated gut bacteria of 305 individuals belonging to 218 species in 21 taxonomic orders, using 454 pyrosequencing of 16S rRNA genes. In total, 174,374 sequence reads were obtained, identifying 9,301 bacterial operational taxonomic units (OTUs) at the 3% distance level from all samples, with an average of 84.3 (±97.7) OTUs per sample. The insect gut microbiota were dominated by Proteobacteria (62.1% of the total reads, including 14.1% Wolbachia sequences) and Firmicutes (20.7%). Significant differences were found in the relative abundances of anaerobes in insects and were classified according to the criteria of host environmental habitat, diet, developmental stage, and phylogeny. Gut bacterial diversity was significantly higher in omnivorous insects than in stenophagous (carnivorous and herbivorous) insects. This insect-order-spanning investigation of the gut microbiota provides insights into the relationships between insects and their gut bacterial communities.     

Trophic Niche in a Raptor Species: The Relationship between Diet Diversity,Habitat Diversity and Territory Quality

Recent research reports that many populations of species showing a wide trophic niche (generalists) are made up of both generalist individuals and individuals with a narrow trophic niche (specialists), suggesting trophic specializations at an individual level. If true, foraging strategies should be associated with individual quality and fitness. Optimal foraging theory predicts that individuals will select the most favourable habitats for feeding. In addition, the “landscape heterogeneity hypothesis” predicts a higher number of species in more diverse landscapes. Thus, it can be predicted that individuals with a wider realized trophic niche should have foraging territories with greater habitat diversity, suggesting that foraging strategies, territory quality and habitat diversity are inter-correlated. This was tested for a population of common kestrels Falco tinnunculus. Diet diversity, territory occupancy (as a measure of territory quality) and habitat diversity of territories were measured over an 8-year period. Our results show that: 1) territory quality was quadratically correlated with habitat diversity, with the best territories being the least and most diverse; 2) diet diversity was not correlated with territory quality; and 3) diet diversity was negatively correlated with landscape heterogeneity. Our study suggests that niche generalist foraging strategies are based on an active search for different prey species within or between habitats rather than on the selection of territories with high habitat diversity.     

Individuality in Problem Solving: String Pulling in Two Carduelis Species (Aves: Passeriformes)

The research reported here was designed to study the individual peculiarities of birds in solving a problem. Goldfinches Carduelis carduelis and siskins C. spinus were tested with the string‐pulling task: sitting on a perch from which a small food container is suspended by a string the test bird had to lift the container, using the bill to pull the string stepwise up and a foot to hold it, and repeat that until they could reach the food. Fifty‐two goldfinches and 29 siskins raised under controlled conditions were tested individually. Three groups became apparent: ‘inventors’ (23% of goldfinches; 62% of siskins) solved the problem by themselves; ‘imitators’ (25% of goldfinches; 10% of siskins) succeeded after seeing a performing conspecific; ‘duffers’ (52% of goldfinches, 28% of siskins) did not succeed either way. The species – but not the sexes – differed significantly in string‐pulling ability. The results of our experiments indicate that string pulling is an acquired combination of innate behaviour elements. An individual's string‐pulling competence may depend on prior experience of handling branchlets, on trial‐and‐error learning and on social learning (emulation). However, some individuals succeeded without these facilitating factors, while others did not succeed at all despite all of them present. Although functionally and motivationally related to feeding, the learned string pulling is often shown as a playful activity without an obvious reward.     

Habitat Preference, Reproduction and Diet of the Earthworm Eel, Chendol keelini (Teleostei: Chaudhuriidae)

The ecology of the earthworm eel, Chendol keelini, was studied in the field over a period of nine months. In addition this information was supplemented by aquarium observations. The species was most abundant in pools where it was associated with leaf litter and mats of fine tree roots along the banks. It fed on benthic invertebrates, especially chironomid and ephemeropteran larvae. C. keelini is sexually dimorphic; adult males develop a headhump and grow to a larger size than females. Reproduction was seasonal; the reproductive phase coincided with the wet season and lasted for several months. Fecundity was around 40 eggs per clutch. The eggs were spherical, between 1.2 and 1.5mm in diameter, and possessed a pair of long filaments for adhesion to the substrate. Females probably spawned more than once during the breeding season. The length frequency distributions and juvenile growth suggest that C. keelini is a short-lived species that matures during the first year with few individuals surviving to the second breeding season.     

Host Life History Strategy,Species Diversity,and Habitat Influence Trypanosoma cruzi Vector Infection in Changing Landscapes

Background

Anthropogenic land use may influence transmission of multi-host vector-borne pathogens by changing diversity, relative abundance, and community composition of reservoir hosts. These reservoir hosts may have varying competence for vector-borne pathogens depending on species-specific characteristics, such as life history strategy. The objective of this study is to evaluate how anthropogenic land use change influences blood meal species composition and the effects of changing blood meal species composition on the parasite infection rate of the Chagas disease vector Rhodnius pallescens in Panama.

Methodology/Principal Findings

R. pallescens vectors (N = 643) were collected in different habitat types across a gradient of anthropogenic disturbance. Blood meal species in DNA extracted from these vectors was identified in 243 (40.3%) vectors by amplification and sequencing of a vertebrate-specific fragment of the 12SrRNA gene, and T. cruzi vector infection was determined by pcr. Vector infection rate was significantly greater in deforested habitats as compared to contiguous forests. Forty-two different species of blood meal were identified in R. pallescens, and species composition of blood meals varied across habitat types. Mammals (88.3%) dominated R. pallescens blood meals. Xenarthrans (sloths and tamanduas) were the most frequently identified species in blood meals across all habitat types. A regression tree analysis indicated that blood meal species diversity, host life history strategy (measured as r_max, the maximum intrinsic rate of population increase), and habitat type (forest fragments and peridomiciliary sites) were important determinants of vector infection with T. cruzi. The mean intrinsic rate of increase and the skewness and variability of r_max were positively associated with higher vector infection rate at a site.

Conclusions/Significance

In this study, anthropogenic landscape disturbance increased vector infection with T. cruzi, potentially by changing host community structure to favor hosts that are short-lived with high reproductive rates. Study results apply to potential environmental management strategies for Chagas disease.     

Genetic Variability and Taxonomical Considerations about Six Species of European Cardueline Finches (Aves, Passeriformes)

Electrophoretic patterns of seven enzyme systems and two nonenzymatic proteins, albumin and haemoglobin, representing 13 loci, have been investigated in six species of cardueline finches with Palearctic distribution. A new locus, SOD-3, has been characterized in this subfamily. The two nonenzymatic proteins turned out to be the best genetic markers. From the analysis of the genetic distances it emerges that the mean values between species are higher than those reported for other groups of birds. However, the same results were obtained for other species of the same subfamily native to North America. In both cases this result is probably due to a classification that disagrees with the real cardueline phylogeny. In the present study, the attribution of the Greenfinch to the genus Carduelis raises the mean value of distance between species.     

Diet,Food Intake of Phrynocephalus frontalis （Agamidae） and Its Potential Role in Desert Habitat

We examined the dietary diversity and food intake of Phrynocephalus frontalis, compared the difference of insect diversity in the natural habitats with different lizard densities, and discussed the potential role of this lizard in the desert ecosystem. The results show that： （1） arthropodans of the orders Coleoptera, Hymenoptera and Hemiptera were major dietary components of P. frontalis; （2） coleoptera larvae always formed the predominant component of lizard diets; （3） dietary diversities of P. frontalis were not significantly different between summer and autumn or between the two sexes; （4） the similarity in trophic niches between seasons was 0.756, whereas the similarity in trophic niches between sexes was 0.994; （5） stomach content weight of lizards varied significantly among different seasons, but there was no significant difference in stomach content weight between sexes; （6） insect diversity differed significantly among the groups of the habitat with different degrees of lizard density, and the habitat with moderate lizards density had the highest insect diversity. We infer that P. frontalis prey mainly on insects and change their diet and food intake with season; males and females consumed similar preys in types and weights. As an important predator, P. frontalis could affect the insect community in the arid ecosystem of Hunshandak Desert on the Mongolian Plateau.     

Habitat selection and metapopulation structure: a multi-year study of distribution of the Hodgson's pipit, Anthus Hodgsoni Richm. (Aves, Passeriformes)

Numbers and distribution of the Hodgson's pipit (Anthus hodgson Richm.: Aves, Passeriformes) were studied in the Yenissei middle taiga region over an area of about 450 sq km. Distribution of breeding pairs was mapped on fixed study plots (up to 450 ha in total) annually during 15 years. Habitat properties were described and measured in detail on 53 4-ha homogeneous plots within the area. It is shown by means of multiple regression, an average bird abundance over these plots depends on five habitat features (R2 = 0.74) including development and accessibility of moss cover and absence of a potential competitor, the tree pipit (A. trivialis L.). Correlation with these factors ruterated every year, therefore the average bird abundance was used as an index of habitat favourability. Density deviations from the mean in years of high and low numbers appeared to be closely related to habitat favourability; in particular, the relationship can alter the sign depending on the spatial scale of population structures. Changes in abundance reversely related to favourability in adjacent habitats, according to the prediction of despotic distribution hypothesis (Fretwell, Lucas, 1970), strictly indicating dominance behaviour during selection of a breeding territory. The numbers in larger population groups occupying a patchy habitat complex changed synchronously and proportionally to their average habitat quality. This assumes another mechanism governing the distribution of individuals, requiring no local knowledge and no dominance relationships. Dynamics and distribution of individuals among population groups of different hierarchic ranks agree with investigations on establishing of individual site fixation in birds and allow splitting the process into four consecutive steps. 1. During the juvenile dispersal, birds spread around quite evenly, disregarding of habitat quality. This maintains entirety of the metapopulation and occupation of isolated habitat spots. 2. The juvenile dispersal ends with switching to a search for a nearest site containing potential breeding territories. Such a site gets imprinted as the site for next breeding. According to our data, it covers an area of a few square kilometers. 3. During the pre-breeding period, an individual chooses a territory regarding to the favourability, but dominance of old residents forces it to search around for an empty patch within the imprinted area. As a result, dominance relationships affect both breeding density in best habitats and availability of empty patches. 4. The next years, an individual keeps connection with the breeding site fixed due to site tenacity. Rising of the social status allows the individual to occupy a better territory in future. Thus, a population group proportionate to individually imprinted area, with a concentration of favourable patches in the central part, comprises an elementary structural and functional unit of a metapopulation. Its individual members share the same well-known imprinted area and the social structure in common. Its numbers are regulated by density-dependent dominance relationships. Individuals spread over such groups in proportion to their carrying capacity in density-independent manner. Groups with best habitats can be more profitable at population lows, and less densely populated ones can offer more profit at population tops. Despite this, lack of information restricts profitable movements between them. Hence each group offers the same average fitness to its members.     

Propagule Limitation,Disparate Habitat Quality,and Variation in Phenotypic Selection at a Local Species Range Boundary

Adaptation to novel conditions beyond current range boundaries requires the presence of suitable sites within dispersal range, but may be impeded when emigrants encounter poor habitat and sharply different selection pressures. We investigated fine-scale spatial heterogeneity in ecological dynamics and selection at a local population boundary of the annual plant Gilia tricolor. In two years, we planted G. tricolor seeds in core habitat, margin habitat at the edge of the local range, and exterior habitat in order to measure spatial and temporal variation in habitat quality, opportunity for selection, and selection on phenotypic traits. We found a striking decline in average habitat quality with distance from the population core, yet some migrant seeds were successful in suitable, unoccupied microsites at and beyond the range boundary. Total and direct selection on four out of five measured phenotypic traits varied across habitat zones, as well as between years. Moreover, the margin habitat often exerted unique selection pressures that were not intermediate between core and exterior habitats. This study reveals that a combination of ecological and evolutionary forces, including propagule limitation, variation in habitat quality and spatial heterogeneity in phenotypic selection may reduce opportunities for adaptive range expansion, even across a very local population boundary.     

Adaptation to Ephemeral Habitat May Overcome Natural Barriers and Severe Habitat Fragmentation in a Fire-Dependent Species,the Bachman's Sparrow (Peucaea aestivalis)

Bachman''s Sparrow (Peucaea aestivalis) is a fire-dependent species that has undergone range-wide population declines in recent decades. We examined genetic diversity in Bachman''s Sparrows to determine whether natural barriers have led to distinct population units and to assess the effect of anthropogenic habitat loss and fragmentation. Genetic diversity was examined across the geographic range by genotyping 226 individuals at 18 microsatellite loci and sequencing 48 individuals at mitochondrial and nuclear genes. Multiple analyses consistently demonstrated little genetic structure and high levels of genetic variation, suggesting that populations are panmictic. Based on these genetic data, separate management units/subspecies designations or translocations to promote gene flow among fragmented populations do not appear to be necessary. Panmixia in Bachman''s Sparrow may be a consequence of an historical range expansion and retraction. Alternatively, high vagility in Bachman''s Sparrow may be an adaptation to the ephemeral, fire-mediated habitat that this species prefers. In recent times, high vagility also appears to have offset inbreeding and loss of genetic diversity in highly fragmented habitat.     

Four New Species of the Feather Mite Genus Vanginyssus Mironov, 2001 (Astigmata: Pteronyssidae) from the Vangas (Passeriformes: Vangidae) in Madagascar

Four new feather mite species of Vanginyssus Mironov, 2001 are described from vangas (Passeriformes: Vangidae), an endemic passerine family from Madagascar: Vanginyssus euryceros n. sp. from the helmet vanga Euryceros prevostii Lesson, V. madagascarinus n. sp. from the blue vanga Cyanolanius madagascarinus (Linnaeus), V. mystacornis n. sp. from the Crossley’s babbler Mystacornis crossleyi (Grandidier) and V.␣orioliae n. sp. from the Bernier’s vanga Oriolia bernieri Geoffroy Saint-Hilaire. A key to the five known species of Vanginyssus is provided.     

Effects of the Host Species and the Number of Parasitoids per Host on the Size of Some Trichogramma Species (Hymenoptera: Trichogrammatidae)

The size of some Trichogramma spp. adults and especially the ovipositor length depends on the species, but is also related to the host species and to the number of parasitoids per host. The length is greater in T. evanescens than in T. pretiosum itself greater than in T. exiguum, but the width is similar in the three species. For T. evanescens, the size obtained in Mamestra brassicae host when three or four insects emerged is similar to that obtained in Ephestia kuehniella host when singly parasitized. The size of the ovipositor is important because it may influence the possibility of in vitro egg laying in artificial host eggs. A shorter or a narrower ovipositor could cause difficulties in egg-laying into artificial host eggs composed of a membrane of unsuitable thickness.     

Phylogeny and biogeography of Oriolidae (Aves: Passeriformes)

Understanding oscine passerine dispersal patterns out of their Australian area of origin is hampered by a paucity of robust phylogenies. We constructed a molecular phylogeny of the oscine family, Oriolidae, which is distributed from Australia through to the Old World. We used the phylogeny to assess direction and timing of dispersal and whether dispersal can be linked with the well‐documented movements of geological terranes in the Indonesian Archipelago. We sampled 29 of 33 species of Oriolidae from fresh tissue and from toe pads from museum specimens, and examined two nuclear introns and two mitochondrial genes. Model‐based phylogenetic analyses yielded strong support for clades that generally mirrored classical systematics. Biogeographical analyses and divergence time estimates demonstrated that the family originated in the Australo‐Papuan region from where it dispersed first to Asia and then onwards to Africa and the Philippines before back‐colonising Asia and the Indonesian archipelago. Thus, contrary to several other avian families in the region, Oriolidae represents a sequential dispersal pattern from Australia to Africa via Asia. However, it is noteworthy that the Pacific islands and archipelagos remain uncolonised and that members inhabiting Wallacea are recent colonisers suggesting that Oriolidae are poorly adapted to island life.     

Local Adaptation of Frankia to Different Discaria (Rhamnaceae) Host Species Growing in Patagonia

Frankia BCU110601 (Da) and Frankia BCU110345 (Dc) were isolated from root nodules of Discaria articulata and Discaria chacaye, respectively; Frankia BCU110501 (Dt) was previously isolated from Discaria trinervis. The strains were identical at the 16S sequence and after analysis of RFLP of 16S and 23S rDNA intergenic region. Diversity was revealed at the molecular level after fingerprint analysis by BOX–polymerase chain reaction. The strains were infective and effective on the original host plants. A cross-inoculation assay intra Discaria genus, including D. trinervis, D. articulata, and D. chacaye, with each of these isolated Frankia strains caused effective symbioses with a similar dry weight in each plant species regardless of the inoculated strain. Nevertheless, a differential degree of recognition was revealed: Homologous symbiotic pairs in the case of D. chacaye–Frankia BCU110345 (Dc), D. articulata–Frankia BCU110601 (Da), and D. trinervis–Frankia BCU110501 (Dt) had faster nodulation rates than heterologous pairs. The differences in nodulation rate would suggest the existence of a subspecific level of recognition within a certain cross-inoculation group, pointing to subspecific adaptation occurring in this actinorhizal symbiosis.     

The Use of Habitat Models in Conservation of Rare and Endangered Leafhopper Species (Hemiptera,Auchenorrhyncha)

For conservation of Auchenorrhyncha species, knowledge of their habitat requirements is essential. However, for most species there is no ‘quantitative’ knowledge that would allow e.g. spatially explicit predictions. Such predictions can be made by habitat models, which quantify the relationship between the environment and the occurrence of species. In two plot-based case studies – the endangered leafhopper Verdanus bensoni in mountainous grasslands and four endangered Auchenorrhyncha in urban brownfields – we used habitat models to quantify the habitat requirements of these five species and to exemplify their use for creating habitat suitability maps. In the first case study, the multivariate model showed that occurrence probabilities of the leafhopper V. bensoni increase with both decreasing nitrogen indicator values and decreasing tree cover. On urban brownfields, successional age was a driving factor for species’ occurrence. Site age largely determines a range of vegetation characteristics, which, in multivariate models, often replaced the variable age. Internal validation showed the robustness of all models. The models allow predictions of habitat quality under different management regimes (e.g. response to fertilization or abandonment for V. bensoni or to different turnover rates on brownfield sites). We discuss the application of habitat models in the conservation of Auchenorrhyncha, especially the use of habitat suitability maps.     

Host Range Assessment of Helicotylenchus pseudorobustus (Tylenchida: Hoplolaimidae) on Pasture Species

The host status of 15 commonly occurring pasture species for Helicotylenchus pseudorobustus was tested in a greenhouse trial. Only tall fescue, with and without Neotyphodium endophyte infection, was a good host (Pf/Pi = final/initial population > 1). Inoculation survival was tested in a second trial, which showed that only 10% of the H. pseudorobustus nematodes survived the first 7 days after inoculation. When the Pf/Pi was adjusted to account for a 10% survival, all of the grass and clover hosts tested had a Pf/Pi > 1. Both trials showed a positive correlation between increased numbers of H. pseudorobustus and free-living nematodes.     

Physiological Plasticity to Water Flow Habitat in the Damselfish,Acanthochromis polyacanthus: Linking Phenotype to Performance

The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1) whether aspects of swimming physiology and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology.     

Phylogeny of babblers (Aves, Passeriformes): major lineages, family limits and classification

Babblers, family Timaliidae, have long been subject to debate on systematic position, family limits and internal taxonomy. In this study, we use five molecular regions to estimate the relationships among a large proportion of genera traditionally placed in Timaliidae. We find good support for five main clades within this radiation, and propose a new classification, dividing the babblers into the families Sylviidae and Timaliidae. Within the latter family, four subfamilies are recognized: Zosteropinae, Timaliinae, Pellorneinae and Leiothrichinae. Several taxa, previously not studied with molecular data, are phylogenetically placed within Sylviidae or Timaliidae. This is, however, not the case for the genus Pnoepyga , for which we propose the family name Pnoepygidae fam. n.     

Phylogeny, biogeography and taxonomy of the African wattle-eyes (Aves: Passeriformes: Platysteiridae)

The African wattle-eyes (genera Platysteira and Dyaphorophyia) comprise 10 species endemic to Africa. We analyzed both mitochondrial and nuclear DNA sequence data to test the monophyly of this group and its two genera, provide a preliminary assessment of species limits, and gain insight into the phylogeographic history of the wattle-eye radiation. Analyses based on mitochondrial ND2 sequences failed to recover wattle-eye monophyly, but the alternatives were not well-supported. In contrast, analyses of two nuclear introns (myoglobin intron-2 and beta-fibrinogen intron-5) recovered wattle-eye monophyly, as did combined analyses of mitochondrial and nuclear data. These analyses, however, did not support reciprocal monophyly of the two wattle-eye genera typically recognized, suggesting instead that Platysteira is nested within a paraphyletic Dyaphorophyia. The diversification of most wattle-eye species and many subspecies occurred through the divergence of allopatric populations well before the Pleistocene. Species and subspecies with disjunct distributions are typically characterized by deep genetic divergences, suggesting that many of these populations are evolutionary independent and could be recognized as additional phylogenetic species. In D. castanea and D. chalybea, for example, divergent haplotypes from geographically disjunct populations were paraphyletic with respect to those of D. tonsa and D. jamesoni, respectively. Similarly, Platysteira laticincta is highly divergent from its sister taxon P. peltata ( approximately 9.5% ND2 sequence divergence), consistent with species level recognition of this endangered species. In contrast, more broadly distributed taxa inhabiting a greater diversity of habitats (e.g., P. peltata and P. cyannea) show evidence of gene flow and connectivity among regions, suggesting that previously isolated populations expanded and fused into one another. Our study provides a framework for additional analyses of intraspecific phylogeography and species limits in these colorful birds.