Distribution Peculiarities of the Sand (<Emphasis Type="Italic">Riparia riparia</Emphasis> Linnaeus 1758) Martin and the Pale Sand (<Emphasis Type="Italic">Riparia diluta</Emphasis> Sharpe et Wyatt 1893) Martin (Passeriformes,Hirundinidae) in the Sympatry Zone in Southern Central Siberia

The relationships between the sand martin (Riparia riparia Linnaeus 1758) and the pale sand martin (Riparia diluta Sharpe et Wyatt 1893) in sympatric conditions in southern Central Siberia are discussed. New data on the distribution patterns of these two closely related martin species in the study area, the location of the breeding colonies, and nesting in mixed-species colonies are presented. Information on the morphology and habitat preferences of R. riparia and R. diluta, including conesting species, is provided. In the sympatry zone in southern Central Siberia, the pale sand martin is shown to be more abundant, with mixed colonies of R. riparia and R. diluta also being found. Both species studied differ significantly in the morphometric characters. When looking for the location of a breeding colony, R. riparia and R. diluta display different habitat requirements.     

Avoidance of host resistance in the oviposition-site preferences of rose bitterling

A contemporary outcome of dynamic host–parasite coevolution can be driven by the adaptation of a parasite to exploit its hosts at the population and species levels (parasite specialisation) or by local host adaptations leading to greater host resistance to sympatric parasite populations (host resistance). We tested the predominance of these two scenarios using cross-infection experiments with two geographically distant populations of the rose bitterling, Rhodeus ocellatus, a fish brood parasite of freshwater mussels, and four populations of their mussel hosts (two Anodonta woodiana and two Unio douglasiae populations) with varying degrees of geographic sympatry and local coexistence. Our data support predictions for host resistance at the species level but no effect of local coexistence between specific populations. Rhodeus ocellatus showed a preference for allopatric host populations, irrespective of host species. Host mussel response, in terms of ejection of R. ocellatus eggs, was stronger in the more widespread and abundant host species (A. woodiana) and this response tended to be higher in sympatric populations. These outcomes provide support for the importance of host resistance in bitterling oviposition-site decisions, demonstrating that host choice by R. ocellatus is adaptive by minimizing egg ejections. These findings imply that R. ocellatus, and potentially other bitterling species, may benefit from exploiting novel hosts, which may not possess appropriate adaptive responses to parasitism.     

Sympatric reinforcement of reproductive barriers between <Emphasis Type="Italic">Neotinea tridentata</Emphasis> and <Emphasis Type="Italic">N. ustulata</Emphasis> (Orchidaceae)

Reinforcement is the process by which selection favors traits that decrease mating between two incipient species in response to costly mating or the production of maladapted hybrids, causing the evolution of greater reproductive isolation between emerging species. I have studied a pair of orchids, Neotinea tridentata and N. ustulata, to examine the level of postmating pre- and post-zygotic isolating mechanisms that maintain these species, and the degree to which the boundary may still be permeable to gene flow. In this study, I performed pollen tube growth rate experiments and I investigated pre- and post-zygotic barriers by performing hand pollination experiments in order to evaluate fruit set, embryonate seed set and seed germination rates by intra- and interspecific crosses. Fruit set, the percentage of embryonate seeds and germinability of interspecific crosses were reduced compared to intraspecific pollinations, showing significant differences between sympatric and allopatric populations. While in allopatric populations the post-pollination isolation index ranged between 0.40 and 0.11, in sympatric populations orchid pairs showed total isolation due to post-pollination prezygotic barriers, guaranteed at the level of pollen–stigma interactions. Indeed, in sympatric populations, pollen tubes reached the ovary after 24 h in only 8 out of 45 plants; in the remaining cases, the pollen tubes did not enter the ovary, and thus no fruit set occurred. This pair of orchids is characterized by postmating pre-zygotic reproductive isolation in sympatric populations that prevents the formation of hybrids. This mechanism of speciation, starting in allopatry and triggering the reinforcement mechanisms of reproductive isolation in secondary sympatry, is the most likely explanation for the pattern of evolutionary transitions found in this pair of orchids.     

Consequences of the arms race between <Emphasis Type="Italic">Maculinea teleius</Emphasis> social parasite and <Emphasis Type="Italic">Myrmica</Emphasis> host ants for myrmecophilous butterfly conservation

The arms race between Maculinea butterflies and Myrmica host ants leads to local host-parasite adaptations. In our study, we assessed whether sympatric and allopatric Myrmica scabrinodis populations exhibit behavioural differences towards Maculinea teleius larvae during the adoption-period when butterfly larvae need to be taken inside the Myrmica nest. The second aim was to assess the butterfly survival rate inside ant colonies from different populations. We used one sympatric host population and three allopatric populations: one infested by M. teleius and two uninfested populations. We found that ants from the sympatric population showed a higher number of positive behaviours toward M. teleius larvae during adoption than ants from the allopatric populations. There were no differences in the number of inspection or negative behaviour events. The survival of butterfly larvae was highest inside sympatric host colonies and differed from the survival of M. teleius reared by ants from the allopatric, uninfested populations. No difference was found for the survival rate of M. teleius raised by infested, allopatric host colonies compared to sympatric host populations. Our results suggest the lack of behavioural counter-adaptations of local hosts of M. teleius that more easily adopt and rear butterfly caterpillars compared to naive M. scabrinodis colonies. Our results may also have implications for Maculinea butterfly conservation, especially for reintroduction programmes. We suggest that the existence of behavioural host defences should be checked for the source host population, as well as for the Myrmica population from the reintroduction site. It may also be reasonable to introduce several Myrmica host colonies from the source butterfly host population.     

Changes in use of lake habitat by experimentally segregated populations of cutthroat trout and Dolly Varden char

The role of competition in a lacustrine community of two salmonid species, cutthroat trout Oncorhynchus clarki and Dolly Varden char Salvelinus malma , was studied in three coastal British Columbia lakes Habitat use by the species alone (allopatric) and in coexistence with each other (sympatric) was investigated by gill netting at 0-40 m depth contours (surface to bottom) so that several habitats (littoral, epipelagic. pelagic, epibenthic) were sampled From June to October, trout used mainly littoral and epipelagic habitats in sympatry and allopatry Char used all habitats in allopatry. and deep habitats (pelagic, epibenthic) not frequented by trout in sympatry The two species were thus spatially segregated with depth in sympatry Diel (day, night) and seasonal changes (spring, summer, autumn) in habitat use were not pronounced The shift in habitat use by experimentally allopatric char but not trout suggests that the effects of competition between sympatric trout and char for habitat resources are greater on the char     

Loaches of the genus <Emphasis Type="Italic">Barbatula</Emphasis> (Nemacheilinae) of the Zavkhan River basin (Western Mongolia)

Two sympatric species of Siberian loaches are recorded in the Zavkhan River basin (Great Lakes Depression, Western Mongolia) and described as new for science: Barbatula conilobus and B. dsapchynensis spp. n. The former species, most likely, is widely distributed over the entire river basin, and the latter species, apparently, occurs locally, but in sympatry with B. conilobus. Morphological differences of the new species from other representatives of the genus Barbatula and their relationships are analyzed. Ecological distinctions between the species of the genera Barbatula and Triplophysa in the Zavkhan River basin are described. Possible mechanisms of development of the present fauna of loaches in Mongolia and adjacent territories with an appearance of sympatric species pairs in a single water basin are discussed.     

Ecological niche differentiation between native and non-native shrimps in the northern Baltic Sea

Invasions of non-native species are modifying global biodiversity but the ecological mechanisms underlying invasion processes are still not well understood. A degree of niche separation of non-native and sympatric native species can possibly explain the success of novel species in their new environment. In this study, we quantified experimentally and in situ the environmental niche space of caridean shrimps (native Crangon crangon and Palaemon adspersus, non-native Palaemon elegans) inhabiting the northern Baltic Sea. Field studies showed that the non-native P. elegans had wider geographical range compared to native species although the level of habitat specialization was similar in both Palaemon species. There were clear differences in shrimp habitat occupancy with P. elegans inhabiting lower salinity areas and more eutrophicated habitats compared to the native species. Consequently, the non-native shrimp has occupied large areas of the northern Baltic Sea that were previously devoid of the native shrimps. Experiments demonstrated that the non-native shrimp had higher affinity to vegetated substrates compared to native species. The study suggests that the abilities of the non-native shrimp to thrive in more stressful habitats (lower salinity, higher eutrophication), that are sub-optimal for native shrimps, plausibly explain the invasion success of P. elegans.     

Do novel weapons that degrade mycorrhizal mutualisms promote species invasion?

Non-native plants often dominate novel habitats where they did not co-evolve with the local species. The novel weapons hypothesis suggests that non-native plants bring competitive traits against which native species have not adapted defenses. Novel weapons may directly affect plant competitors by inhibiting germination or growth, or indirectly by attacking competitor plant mutualists (degraded mutualisms hypothesis). Japanese knotweed (Fallopia japonica) and European buckthorn (Rhamnus cathartica) are widespread plant invaders that produce potent secondary compounds that negatively impact plant competitors. We tested whether their impacts were consistent with a direct effect on the tree seedlings (novel weapons) or an indirect attack via degradation of seedling mutualists (degraded mutualism). We compared recruitment and performance using three Ulmus congeners and three Betula congeners treated with allelopathic root macerations from allopatric and sympatric ranges. Moreover, given that the allelopathic species would be less likely to degrade their own fungal symbiont types, we used arbuscular mycorrhizal (AMF) and ectomycorrhizal (ECM) tree species to investigate the effects of F. japonica (no mycorrhizal association) and Rhamnus cathartica (ECM association) on the different fungal types. We also investigated the effects of F. japonica and R. cathartica exudates on AMF root colonization. Our results suggest that the allelopathic plant exudates impact seedlings directly by inhibiting germination and indirectly by degrading fungal mutualists. Novel weapons inhibited allopatric seedling germination but sympatric species were unaffected. However, seedling survivorship and growth appeared more dependent on mycorrhizal fungi, and mycorrhizal fungi were inhibited by allopatric species. These results suggest that novel weapons promote plant invasion by directly inhibiting allopatric competitor germination and indirectly by inhibiting mutualist fungi necessary for growth and survival.     

All natural habitat edges matter equally for endangered <Emphasis Type="Italic">Maculinea</Emphasis> butterflies

An obvious consequence of habitat fragmentation is an increasing role of habitat edges for species survival. Recently it has been suggested that the endangered butterfly Maculinea nausithous prefers forested edges of its meadow habitats. However, the prevalence of forests in the study area used for this analysis makes it impossible to distinguish whether the effect detected is a genuine preference for forest edges or a preference for any natural patch edges as opposed to patch interiors. We investigated habitat selection by Maculinea nausithous and Maculinea teleius occurring sympatrically at five habitat patches surrounded by mosaic landscape. Butterfly capture positions were marked with GPS and subsequently analysed with GIS software. Both species avoided the interiors of their patches and concentrated in the edge zone, but these preferences were visible only at three larger patches exceeding 1 ha in area. Among different types of edges those bordering densely built-up areas were avoided, whereas all natural edges (adjacent to forests, reeds or grasslands) were similarly used. We hypothesise that preferences towards natural patch edges, regardless of their type, can be explained by the spatial interactions between Maculinea butterflies and Myrmica ants they parasitise. Patch surroundings constitute refuge space for the ants, and hence their densities may be expected to be higher near patch edges. Our findings indicate the importance of patch surroundings for the persistence of Maculinea populations. Regretfully, current legal framework makes it difficult to protect patch surroundings, where neither priority species nor their habitats occur.     

Geographic distribution,habitat characterization,and conservation status of <Emphasis Type="Italic">Bolboschoenus</Emphasis> bulrushes (Cyperaceae) in the Hudson River Estuary,USA

Bulrushes of the genus Bolboschoenus are robust, ecologically important sedges occurring in wetlands, including intertidal marshes and mudflats. Despite their importance and multiple serious threats to their habitats, estuarine Bolboschoenus species remain poorly known. We conducted herbarium and field research in order to document historic and current geographic distributions, characterize the habitats, and assess the conservation status of Bolboschoenus species in the Hudson River Estuary, New York, U.S.A. Three species of Bolboschoenus grow in intertidal zones in the Hudson Estuary. Bolboschoenus fluviatilis occurs in the northern, upstream, and freshwater portion of the estuary with multi-year mean surface salinities of 0.078–2.0 ppt. Bolboschoenus robustus occupies the southernmost, downstream, and brackish to saline portion of the estuary with salinities of 4.9–16 ppt. Bolboschoenus novae-angliae occurs in the slightly to strongly brackish region between the other two species with salinities of 1.8–8.0 ppt. The geographic ranges of B. fluviatilis and B. robustus do not overlap, but B. novae-angliae has short zones of sympatry with each of the other two species. Syntopy of B. novae-angliae with each of the other two species is rare. In the Hudson Estuary, B. fluviatilis is secure, but B. novae-angliae and B. robustus are critically imperiled. Threats to future survival of Bolboschoenus species in the Hudson Estuary include competition from invasive plant species (especially Phragmites australis), eutrophication resulting from excess nutrient pollution, and habitat destruction. Our data and analyses provide critical new information for management of existing environmental problems and planned habitat restoration efforts in the Hudson River Estuary.     

Host range testing of the nearctic beneficial parasitoid <Emphasis Type="Italic">Neodryinus typhlocybae</Emphasis>

Neodryinus typhlocybae (Ashmead) (Hymenoptera: Dryinidae) is a natural enemy of the planthopper Metcalfa pruinosa (Say) (Hemiptera: Flatidae), introduced from North America into Europe and regionally established as a pest species. Prior to possible utilization of the parasitoid as a biocontrol agent in Austria, its potential negative impacts on eight native plant- and leaf-hopper species were examined in the laboratory. Non-target species were selected according to the following criteria (a) occurrence in Austria, (b) close phylogenetic relationship with M. pruinosa, (c) larvae free-living and surface-dwelling, (d) phenology, (e) larval size, (f) ecological similarity with M. pruinosa and (g) availability of sufficient numbers of individuals. The Auchenorrhyncha species Issus coleoptratus (Fabricius), Chloriona smaragdula (Stål), Conomelus anceps (Germar), Alebra wahlbergi (Boheman), Empoasca sp., Idiocerus stigmaticalis (Lewis), Macrosteles septemnotatus (Fallén) and Japananus hyalinus (Osborn) were chosen for testing. Larvae from both the target and the non-target species were offered separately to N. typhlocybae females in no-choice laboratory tests and all attacks, instances of host feeding and parasitizations were recorded. No non-target species was attacked, fed upon or parasitized by N. typhlocybae, whereas M. pruinosa was attacked frequently. This study supports the assumption that the host range of N. typhlocybae is restricted to Flatidae, of which only the introduced species occurs in Austria. Direct negative effects on other Auchenorryncha species in Austria are therefore unlikely to occur.     

Endemic diversification in the mountains: genetic,morphological, and geographical differentiation of the <Emphasis Type="Italic">Hemidactylus</Emphasis> geckos in southwestern Arabia

In this study, we provide genetic, morphological, and geographical comparisons for 11 species of the southwestern Arabian radiation of Hemidactylus geckos, nine of which are endemic to the region. By using a coalescence-based species-tree reconstruction in combination with divergence time estimations and speciation probability testing, we show that most of the speciation events occurred in the Pliocene, which is more recent than previously thought based on calibrations of concatenated data sets. The current dating indicates that the changing climate at the beginning of the Pliocene, from hot and dry to cold and wet, is likely responsible for increased speciation in Hemidactylus. Analyses of geographic and altitudinal overlap of the species and their morphological differentiation show that most species do not occur in sympatry. Those that overlap geographically are usually differentiated by their altitudinal preference, head shape, body size, or their combination. Our results indicate that the topographically complex mountains of southwestern Arabia support a significant radiation of Hemidactylus geckos by allowing multiple allopatric speciation events to occur in a relatively small area. Consequently, we describe two new species endemic to the Asir Mountains of Saudi Arabia, H. alfarraji sp. n. and H. asirensis sp. n., and elevate two former subspecies of H. yerburii to a species level, H. montanus and H. pauciporosus.     

Substrate preferences of coexisting invasive amphipods, <Emphasis Type="Italic">Dikerogammarus villosus</Emphasis> and <Emphasis Type="Italic">Dikerogammarus haemobaphes</Emphasis>, under field and laboratory conditions

Two Ponto-Caspian amphipods, Dikerogammarus villosus and Dikerogammarus haemobaphes, have expanded their geographical ranges from eastern Europe into Great Britain in recent years. This study represents one of the first examining the distribution and habitat preferences of coexisting populations of D. haemobaphes and D. villosus via field and laboratory experiments in the UK. Field surveys of a recently invaded lowland reservoir in the UK are complimented with ex situ laboratory mesocosm experiments examining the substrate preferences of coexisting populations of D. villosus and D. haemobaphes. Results from the field study indicated that D. haemobaphes dominated the macroinvertebrate community within the reservoir and demonstrated a strong affinity for large cobble and artificial substrates. D. villosus occurred at lower abundances but displayed a strong preference for coarse cobble substrates. A third invasive amphipod, Crangonyx pseudogracilis, was largely confined to sand/silt habitats. Laboratory mesocosm experiments clearly supported the field observations of D. villosus and D. haemobaphes with both species demonstrating a preference for cobble substrates. Results from the study highlight the importance of characterising physical habitat when investigating biological invasions and suggest that habitat availability may influence the extent and speed at which range expansion of new amphipod invaders occurs.     

Asymmetric competition drives lake use of coexisting salmonids

To what degree are population differences in resource use caused by competition and the occupation of adjacent positions along environmental gradients evidence of competition? Habitat use may be the result of a competitive lottery, or restricted by competition. We tested to what extent population differences in habitat use of two salmonids, cutthroat trout (Oncorhynchus clarki) and Dolly Varden charr (Salvelinus malma) were influenced by interspecific competition. We hypothesized that the depth distribution of Dolly Varden charr would be affected by competition from the more littoral and surface-oriented cutthroat trout, and that the depth distribution of cutthroat trout would be little affected by competition from Dolly Varden charr. Sympatric populations of cutthroat trout and Dolly Varden charr were created by reciprocal transfers of previously allopatric populations in two experimental lakes. We found evidence of asymmetric competition, as Dolly Varden charr were displaced from littoral habitats when sympatric with cutthroat trout, whereas cutthroat trout remained unaffected by the presence of Dolly Varden charr. Evolved differences between the species, and differences between experimental lakes, also contributed to population differences in habitat use, but asymmetric competition remained as the main driver of different depth distributions in sympatry.     

The ecology of <Emphasis Type="Italic">Altrichthys azurelineatus</Emphasis> and <Emphasis Type="Italic">A. curatus,</Emphasis> two damselfishes that lack a pelagic larval phase

Out of more than 380 species of damselfish, only three lack a pelagic larval phase, Acanthochromis polyacanthus, that ranges from the Philippines to the Great Barrier Reef, and two species in the genus Altrichthys, A. azurelineatus and A. curatus, that are restricted to the Calamian Archipelago (Palawan province) in the Philippines. Therefore in a very restricted geographic area, northern Palawan, Philippines, all three species co-occur. The goal of this study was to fill a knowledge gap about the ecology of Altrichthys, where very little is currently known. Using census and behavioral approaches at 14 sites on six islands, we were able to identify adult densities, nest densities, nesting habitat preference, and brood behavior and abundance. We found that densities were very high (more than 17 individuals/100 m² for one species) and A. azurelineatus may be displacing A. curatus at deeper depths where habitat seems of higher quality. Only one out of 14 surveyed sites contained only one species, Altrichthys curatus. Different habitat use and feeding behavior suggest that niche partitioning may play an important role in the life history of these sympatric species.     

Geographical variation of skull characters in pikas (<Emphasis Type="Italic">Ochotona</Emphasis>, Lagomorpha) of the<Emphasis Type="Italic">alpina-hyperborea</Emphasis> group

A multivariate analysis of 11 skull measurements, along with evaluation of the shape of maxill-premaxill suture at palatine foramina, was carried out in pikas of thealpina-hyperborea group. The study provided rational for recognition of three distinct species in this group:Ochotona alpina (Pallas, 1773),O. hyperborea (Pallas, 1811), andO. turuchanensis Naumov, 1934.O. turuchanensis is a species from central Siberia differing fromO. hyperborea in the chromosome number and type of palatine foramina and fromO. alpina in size of the skull. This species is allopatric withO. alpina and partly sympatric withO. hyperborea. The subspeciessvatoshi is reportedly allocated toO. hyperborea. The taxonomic status ofmantchurica (now allocated tohyperborea) and scorodumovi (treated at present as an isolated subspecies of O. alpina) needs careful investigation.     

Comparison of trophic function between the globally invasive crayfishes <Emphasis Type="Italic">Pacifastacus leniusculus</Emphasis> and <Emphasis Type="Italic">Procambarus clarkii</Emphasis>

Impacts of invasive species may manifest most strongly if these organisms are highly distinct functionally from the native species they often replace. Yet, should we expect functional differences between native and invasive species of generalist organisms like freshwater crayfish? Some existing evidence has pointed to native and invasive crayfish species as ecologically equivalent. We contribute to this literature by comparing the trophic niches of the globally invasive crayfishes Pacifastacus leniusculus and Procambarus clarkii, by applying carbon and nitrogen stable isotope analyses to replicated allopatric (alone) and sympatric (together) lake populations in western Washington State, USA, where P. clarkii has been recently introduced and P. leniusculus is presumed native. Our study corrected for potential inherent differences in lake food webs as a consequence of lake abiotic or biotic characteristics using random effects in linear mixed effects models. We found that although overall trophic niche size or area of these species was not significantly different, P. leniusculus was significantly higher in trophic position than P. clarkii when also accounting for the effects of body size, sex, and lakes as random effects. This pattern of increased trophic position of P. leniusculus over P. clarkii was conserved over time in one sympatric lake for which we had data over multiple years. Cumulatively, our findings point to trophic differences between the globally cosmopolitan crayfishes P. leniusculus and P. clarkii, particularly when accounting for the ways that ecosystem context can affect food web structure of communities and the trophic resources available to these consumers.     

Past hybridization between Quercus macrocarpa and Quercus gambelii

Introgression between two allopatric species,Quercus macrocarpa andQ. gambelii, has been observed in two separate locations: northeastern New Mexico and the Black Hills of western South Dakota and adjacent Wyoming. The probability that this introgression is the result of long-range pollination appears remote. Presumably these two species hybridized during a period of past sympatric association. Further indication of past sympatry in the Black Hills is the presence of a common species of obligate parasite, i.e., wasp(Cynips insulensis) onQ. gambelii in the Rocky Mountains and onQ. macrocarpa of the Black Hills. The hybrid oaks in New Mexico probably reflect a westward migration ofQ. macrocarpa during pluvial periods of the Pleistocene.Quercus gambelii most likely reached the Black Hills during the warmer postglacial hypsithermal era. The hybridization reported here may reflect secondary sympatry, i.e., sympatric occurrence after the species, or their ancestors, became geographically separated.     

The use of Vocalizations of the Sambirano Mouse Lemur (<Emphasis Type="Italic">Microcebus sambiranensis</Emphasis>) in an Acoustic Survey of Habitat Preference

Primate vocalizations convey a variety of information to conspecifics. The acoustic traits of these vocalizations are an effective vocal fingerprint to discriminate between sibling species for taxonomic diagnosis. However, the vocal behavior of nocturnal primates has been poorly studied and there are few studies of their vocal repertoires. We compiled a vocal repertoire for the Endangered Sambirano mouse lemur, Microcebus sambiranensis, an unstudied nocturnal primate of northwestern Madagascar, and compared the acoustic properties of one of their call types to those of M. murinus and M. rufus. We recorded vocalizations from radio-collared individuals using handheld recorders over 3 months. We also conducted an acoustic survey to measure the vocal activity of M. sambiranensis in four forest habitat types at the study site. We identified and classified five vocalization types in M. sambiranensis. The vocal repertoires of the three Microcebus species contain very similar call types but have different acoustic properties, with one loud call type, the whistle, having significantly different acoustic properties between species. Our acoustic survey detected more calls of M. sambiranensis in secondary forest, riparian forest, and forest edge habitats, suggesting that individuals may prefer these habitat types over primary forest. Our results suggest interspecific differences in the vocal repertoire of mouse lemurs, and that these differences can be used to investigate habitat preference via acoustic surveys.