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1.
Three paratypes of Arion fagophilus were electrophoretically compared with nine other West European species of the genus Arion. Esterases, glutamate-oxaloacetate-transaminase, a-amylase, superoxide dismutase, phosphoglucomutase, fumarase, α-glycerophosphate dehydrogenase and phosphogluconate dehydrogenase were screened in the hepatopancreas and general proteins in the albumen gland. A. fagophilus appears to be a very well defined species, which may be assigned to the subgenus Kobeltia. The subgeneric division of the genus Arion is preliminary discussed with respect to electrophoretic and chromosomal data. It is concluded to retain four subgenera, which may be grouped two by two: Mesarion and Arion s. s. on one hand, and Kobeltia and Carinarion on the other. It is remarked that the electrophoretic differences between Norwegian and Belgian A. ater suggest a separation into two taxa.  相似文献   

2.
The Iberian Peninsula contains the majority of the Paleartic land slug species of the genus Arion, which exhibits diverse taxonomic problems. The present study investigated Arion taxonomy on the basis of analyses of the mitochondrial ND1 gene and nuclear internal transcribed spacer 1 (ITS1) sequences. The Iberian endemic species were monophyletically clustered in two divergent sister clades. The topotype specimens of Arion lusitanicus and the closely related species Arion nobrei and Arion fuligineus, as well as Arion hispanicus and Arion flagellus, were grouped into an ‘Atlantic’ clade, whereas Arion baeticus, Arion gilvus, Arion anguloi, Arion wiktori and Arion paularensis were included in a ‘Continental–Mediterranean’ clade. Calibration of mutation rate in the ND1 gene suggested that the divergence of these two clades occurred around the Pliocene–Pleistocene boundary, with subsequent speciation events during the Pleistocene. A group of ancestral and divergent endemic species with distribution centred in the Pyrenean mountain range (Arion molinae, Arion lizarrusti, Arion antrhacius and Arion iratii) arose in the Pliocene and survived through the Pleistocene in geographically confined small populations. Arion lusitanicus showed up to be polyphyletic: specimens, sampled outside the geographic range of the topotype in the north‐western Iberian Peninsula, were included in a non‐monophyletic clade together with the widely distributed species Arion ater and Arion rufus. The divergent species with a wide European distribution (Arion subfuscus, Arion hortensis, Arion fagophilus and Arion intermedius) were located in basal positions in all topologies. The evolutionary history of these slug species (highly sensitive to climatic factors, with capacity for both outcrossing and selfing, and with low dispersal ability) appears to have been moulded by Pliocene–Pleistocene climate events and by the rugged topography of southern Europe, giving rise to repeated cycles of population isolation during periods of glaciation alternating with interglacial expansions limited by geographic barriers.  相似文献   

3.
4.
This review relates the ecology and physiology of apple snails (Ampullariidae) to their impact on rice‐production systems. Two species in particular, Pomacea canaliculata and Pomacea maculata, have been introduced to several rice‐growing regions. Flooded rice systems represent a high‐quality habitat for these apple snails because of similarities in the environmental conditions (water temperature, salinity, pH, water flow velocity) necessary for both rice production and for snail survival and development. Furthermore, amphibious respiration, a capacity to aestivate during dry periods, as well as cold acclimation and tolerance (particularly in P. canaliculata), increases the resilience of apple snails to rice farming practices, including agrochemical applications, intermittent drainage and crop rotations – under a wide range of climatic conditions. Risks to regional rice production depend on four principal factors: these are (a) regional climate, (b) regional rice‐production systems, (c) prevailing production practices, and (4) the presence/absence of invasive, non‐native apple snails. Based on these criteria, lowland irrigated rice in tropical and subtropical regions that is wet‐direct seeded is most vulnerable to damage from both native and non‐native apple snails (albeit with greater losses from non‐native snails because of normally higher densities). Adequate quarantine regulations, particularly in vulnerable tropical regions that are adjacent to centres of recent outbreaks (e.g. India and Bangladesh adjacent to Myanmar, Peru and Colombia adjacent to Ecuador) and attention to the preparedness of farming systems could reduce potential impacts as these highly invasive snails continue to spread. The urgent development of labour‐saving crop‐establishment methods that reduce dependencies on chemical molluscicides is necessary to achieve sustainable rice production in regions at risk from non‐native apple snails.  相似文献   

5.
A phylogeny of the 37 known species and subspecies of the micropterous snow fly genus Chionea Dalman is presented using adult morphological characters. The genus contains two major clades: a strictly Palaearctic clade, and a combined Nearctic‐Palaearctic clade with representatives in the Nearctic and Western Palaearctic regions. As there is little congruence between the recovered phylogeny of Chionea and the currently used subgeneric division in Chionea s.s. and Sphaeconophilus Becker, we propose to abandon the use of subgeneric taxa in Chionea. A strictly morphological analysis appears to be insufficient to fully resolve the phylogeny of the genus at the species level, and future molecular work should provide additional evidence for the establishment of relationships among the members of Chionea. The large‐scale historical biogeography of Chionea was analysed using dispersal‐vicariance analysis. The initial distribution area of the genus probably extended in the Eastern Palaearctic, and the Nearctic and the origin of Chionea could be dated in the Late Cretaceous. The various dispersal and vicariance events that led to the major speciation events in the genus are set against major paleogeographic developments. The ancestor of the Western Palaearctic group in the second major clade originated from the Nearctic. The presence of the cold‐adapted Chionea in currently temperate to warm climatic zones in the southern parts of its distribution was analysed using ecological niche modelling. It appears that prolonged periods of climate cooling, as occurred during the Last Glacial Maximum, enabled Chionea to cover large parts of central and southern Europe and reach the southern distribution areas where the genus is present today. A similar biogeographic pattern was less evident in the Nearctic region.  相似文献   

6.
《Acta Oecologica》1999,20(2):109-118
As part of a study on the significance of seed provenances in schemes to enhance biodiversity in agricultural habitats, juvenile plants of Cichorium intybus, Daucus carota, Leucanthemum vulgare and Silene alba of different European origins were exposed to grazing by two slug species, Deroceras reticulatum and Arion lusitanicus. Living plants were offered in trays, either in a glasshouse (Deroceras) or outdoors (Arion). The amount of herbivory was origin-dependent, with higher losses for all four species from German and Hungarian provenances compared with English and Swiss plants. The main trend was similar for both slug species except in the case of Daucus, and there was a significant ‘origin × plant species’ interaction. We found strong correlations between provenance-specific herbivory and certain climatic characteristics of the corresponding regions, i.e. winter minimum temperatures, and dryness in spring and late summer, which are crucial for the development of slugs. The results can be interpreted in terms of a SW-NE European climatic gradient and may be a consequence of differences in the need for plant defences against herbivory by slugs. Additionally, the data on palatability were compared with susceptibility towards two parasites which occurred in a field experiment, a leaf miner on Leucanthemum vulgare and a rust fungus on Silene alba. While specific leaf mining frequencies on Leucanthemum contrasted with the palatability of the different provenances to slugs, the rust infection on Silene was low on local and German plants, and higher on the more distant provenances from England and Hungary.  相似文献   

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A phylogeny of the lacewing family Nymphidae based on morphology and DNA sequences is presented including representatives of all living genera and selected fossil genera. Widely distributed Jurassic and Cretaceous genera gave rise to recent taxa now restricted to Australasia. Two previously defined clades (i.e. Nymphinae and Myiodactylinae) were recovered and reflect the diverging adult and larval morphology of members of these two subfamilies. From Chinese Cretaceous deposits, a new genus (Spilonymphes gen. nov.) is described with one new species, as well as new species described in the genera Baissoleon Makarkin and Sialium Westwood.  相似文献   

9.
对近来记述的古北区东部地区的毛地蜂属Panurginus Nylander全部14个种作了补充研究。中国对该属的研究较少,仅知2种:黑足毛地蜂Panurginus nigripes Morawitz 和黄跗毛地蜂Panurginus flavotarsus ? Wu。黑毛地蜂Panurginus niger Nylander为该属的模式种,分布于俄罗斯和蒙古,本文报道该种为中国新记录种。目前,中国已知该属3种,分属于2个组即niger-group和herzi-group。文中提供了中国已知种类检索表。  相似文献   

10.
The species composition of cyanobacteria from 12 lakes of Southern Transbaikal Region was studied. In the studied lakes, a total of 28 species of cyanobacteria were detected, including 10 species previously not retrieved from the lakes of Southern Transbaikal Region. The morphological and ecophysiological characteristics, as well as the phylogenetic position, of pure cyanobacterial cultures were determined. According to the results of 16S rRNA sequencing, the Cya 1, Cya 2, and Cya 10 cultures were identified as representatives of the genus Phormidium; the Cya 5 and Cya 6 cultures were assigned to the genus Nodularia. On the basis of its morphological properties, the Cya 4 culture was identified as Pseudanabaena frigida. The studied microorganisms were moderate alkaliphiles and could grow within a broad salinity range (0–100 g/l NaCl).  相似文献   

11.
Collado, G. A., Vila, I. & Méndez, M. A. (2011). Monophyly, candidate species and vicariance in Biomphalaria snails (Mollusca: Planorbidae) from the Southern Andean Altiplano. —Zoologica Scripta, 40, 613–622. The landscape of the Neotropical southern Andean Altiplano is characterized by a succession of closed basins originated from the Miocene to the Holocene. In this region, the number of species and phylogenetic relationships among freshwater snails of the genus Biomphalaria are uncertain. Here we obtained sequences of the mitochondrial gene cytochrome oxidase subunit I from 17 Altiplano populations, including topotypes of three nominal species, which were analyzed together with published sequences of the genus using different methods of phylogenetic reconstruction and a species of Helisoma as outgroup. The Altiplano populations conform a monophyletic group whose sister group is the Neotropical species Biomphalaria peregrina. Within this clade we recovered four main lineages well supported and congruent with geographical distributions. One clade includes topotypes restricted exclusively to the Ascotán basin, the type locality of the nominal species Biomphalaria crequii. A second clade includes sequences that correspond to topotypes restricted to the Isluga and Carcote basins, the type localities of the nominal species Biomphalaria aymara and Biomphalaria costata, respectively. Two monophyletic groups clustered snails restricted to several aquatic systems within the Caquena and Lauca basins, which may represent candidate species. The branching pattern of the sequences suggests that in the diversification of these snails, events of vicariance inferred in the Pleistocene have predominated over dispersal phenomena.  相似文献   

12.
Three recent genera are included in the supertribe Stomatosematidi: Stomatosema (16 species), Vanchidiplosis (4 species), and Didactylomyia (3 species). Seven species of the genus Stomatosema and two species of the genus Vanchidiplosis occur in the Palaearctic Region. No reliable findings of representatives of the supertribe were known in fossilized condition. One new genus and 3 new species are described from amber of the Late Eocene age (Rovno Region): Stomatosema iljieteugeniae sp. n., Clarumreddera korneyevi gen. n. et sp. n., and C. conceptiva sp. n.  相似文献   

13.
Several European species of the terrestrial slug genus Arion have been introduced into North America. A case in point is the species complex A. subfuscus s.l. which has become one of the most abundant slug taxa in North America. In Europe this complex consists of at least two cryptic species, viz. A. fuscus and A. subfuscus s.s., the latter of which is further subdivided in five strongly divergent mtDNA lineages (A. subfuscus S1–S5). In order to determine which of these A. subfsucus s.l. taxa are present in the NE USA and in order to assess their population genetic structure, we compared mtDNA, nDNA and allozyme variation between populations from the NE USA and Europe. Our results show that (1) at least A. subfuscus S1 has become successfully established in the NE USA, (2) founder effects are the most likely explanation for the loss of a large amount of molecular genetic variation in populations from the NE USA (i.e. a loss of 96% of the 16S rDNA haplotypes, 67% of the ITS1 alleles and 46% of the alleles at polymorphic allozyme loci), and (3) part of the remaining genetic variation in NE USA populations was probably due to multiple introductions from the British Isles and the European mainland, and the hybrid structure of most of these source populations. Apparently, the extreme loss of molecular genetic variation in this introduced species has not prevented it from successfully establishing and spreading in novel environments.  相似文献   

14.
Summary Dissection of 1,941 specimens provided data on reproductive cycles in six genera of skinks and three genera of agamids from the Alligator Rivers Region of Australia's Northern Territory. Comparative data on lizards from the temperate zone were gathered by dissecting specimens of three genera, and by reviewing published studies. The Alligator Rivers Region climate exhibits uniformly high temperatures but extremely seasonal rainfall. By analogy with studies on tropical herpetofaunas in other parts of the world, we hypothesised that most species would breed during the wet-season.Instead, a great diversity in the seasonal timing of reproduction in tropical lizards was observed. For example, among the skinks,Cryptoblepharus breeds year-round,Carlia andSphenomorphus breed in the wet-season, whereasLerista, Morethia and most (but not all)Ctenotus breed during the dry-season. Among the agamids,Diporiphora andGemmatophora breed in the wet-season, andChelosania in the dry-season. Temperate-zone lizards in Australia show less interspecific variation: all species breed in late spring and summer.Hypotheses concerning the evolutionary determinants of reproductive seasonality are reviewed in the light of these data. Thermal tolerances of developing embryos are unlikely to be important in determining breeding seasons of the Alligator Rivers Region herpetofauna, as there is little seasonal variation in temperature. Differences in reproductive timing between microsympatric species are inconsistent with hypotheses giving a major role to the seasonality of fire, flooding or intensity of predation. There is no clear association between food habits and reproductive timing. The best predictor of breeding seasonality seems to be the biogeographic history of the taxon. Alligator Rivers Region representatives of arid-zone taxa tend to breed in the dryseason, whereas representatives of mesic-adapted lineages tend to be wet-season breeders. A species from one cosmopolitan genus breeds year-round. We hypothesize that embryonic moisture tolerances may be an important determinant of breeding seasonality in this region, although some cases do not support this conclusion.  相似文献   

15.
Zerynthia cassandra is a butterfly endemic to the Italian peninsula. It was recently recognized as a sister species of Zerynthia polyxena. Z. cassandra is oligophagous as it feeds on a very restricted number of toxic plants belonging to the genus Aristolochia: Aristolochia pallida and A. rotunda. The paper reports the results of a research on the ecology of this species which was studied in the natural reserve "Stagni di Lungavilla" (Northern Italy) where the butterfly was living in a small patch of grassy vegetation bordered by a ditch at the margins of a pond. Z. cassandra develops one generation a year. Oviposition occurred in April. Eggs were mainly laid on the lower side of A. rotunda blades. The height of eggs from the ground depended on climatic trends, which affected the host plant phenology. Eggs mortality was mainly due to consumption of leaves by snails (Cepaea nemoralis) and slugs (Arion sp.). Larvae completed their development from April to May, while chrysalises were the aestivating and overwintering stage. Females did not lay eggs on host plants when they were part of the undergrowth. A decline of the butterfly due to habitat changes was recorded during the research (2001–2005). According to information coming from local butterfly watchers the butterfly used to be quite common in the natural reserve until 70’s. Its decline was caused by agricultural intensification and the natural evolution of vegetation towards woodlands, which gradually reduced the host plant density, so making the habitat unsuitable and causing the local extinction of the butterfly.  相似文献   

16.
Climate adaptation has major consequences in the evolution and ecology of all living organisms. Though phytophagous insects are an important component of Earth's biodiversity, there are few studies investigating the evolution of their climatic preferences. This lack of research is probably because their evolutionary ecology is thought to be primarily driven by their interactions with their host plants. Here, we use a robust phylogenetic framework and species‐level distribution data for the conifer‐feeding aphid genus Cinara to investigate the role of climatic adaptation in the diversity and distribution patterns of these host‐specialized insects. Insect climate niches were reconstructed at a macroevolutionary scale, highlighting that climate niche tolerance is evolutionarily labile, with closely related species exhibiting strong climatic disparities. This result may suggest repeated climate niche differentiation during the evolutionary diversification of Cinara. Alternatively, it may merely reflect the use of host plants that occur in disparate climatic zones, and thus, in reality the aphid species' fundamental climate niches may actually be similar but broad. Comparisons of the aphids' current climate niches with those of their hosts show that most Cinara species occupy the full range of the climatic tolerance exhibited by their set of host plants, corroborating the hypothesis that the observed disparity in Cinara species' climate niches can simply mirror that of their hosts. However, 29% of the studied species only occupy a subset of their hosts' climatic zone, suggesting that some aphid species do indeed have their own climatic limitations. Our results suggest that in host‐specialized phytophagous insects, host associations cannot always adequately describe insect niches and abiotic factors must be taken into account.  相似文献   

17.
Animal movement varies from undirected dispersal to directed migration. Movement rates may have implications for conservation and resource management, as well as pest control, and they play a key role in invasion success. In slugs, long-distance dispersal is typically passive, whereas active movement is critical for local dispersal and determines access to resources such as food and shelter. Telemetry has recently been used to study individual slug movements in the wild, whereas movement in arena tests has explored mechanisms of interspecific competition and invasiveness in slugs. Studies that relate the performance of individual slugs in arena tests to their post-release behavior in nature are lacking. We measured individual short-term movement speed of commonly occurring native and non-native slugs of the genera Arion and Limax in arena tests and tracked their post-release dispersal movements in a garden by PIT telemetry. We demonstrate clear differences in movement behavior among the species, but non-native slugs did not display higher movement rates than their native congeners. In the arena test, slugs of the genus Limax displayed a higher short-term speed than slugs of the genus Arion, whereas in the field, individuals of Limax maximus showed lower dispersal rates compared to the other slug species. Moreover, there was a positive correlation between short-term speed in the arena test and movement in the field among individuals of L. cinereoniger, indicating the possible existence of behavioral syndromes in slugs, which may link movement ecology, animal personality, and the invasion ecology of pest species.  相似文献   

18.
19.
Electrophoretic surveys of 10 species of hydrobiid snails in two indigenous genera (Fonscochlea and Trochidrobia) living in arid-zone artesian ‘mound’ springs are reported. The study is based on 96 populations of hydrobiid snails living in 32 different springs representing 18 spring groups in the Lake Eyre Supergroup, northern South Australia. The species-level taxonomy of these snails, previously based on morphological differences alone, was tested and modified. The snails were examined within five clear-cut morphological groups: the two largest, fully aquatic species (Fonscochlea accepta and F. aquatica) were treated independently, as was the amphibious F. Zfidleri The morphologically similar three smaller aquatic species were investigated as a group. Within this group one new species is described and, on the basis of the genetic evidence, two others (F. variabilis and F. conica) are considered conspecific. The four species of Trochidrobia are investigated together and T. punicea separately in more detail. Sympatry between Trochidrobia smithi and T. punicea is recorded for the first time. The springs are arranged in an essentially linear pattern and genetic differentiation largely follows an isolation by distance model, although there is a significant genetic discontinuity between two nearby spring groups, Beresford/Warburton Springs and Strangways Spring, which is presumably the result of differential historical continuity of spring habitat. The size of the spring influences the degree of genetic difference between springs within spring groups, with small springs attaining greater levels of differentiation than large springs. The findings suggest diat if genetic diversity is to be conserved, current management strategies protecting only single springs within a group are inadequate. Despite the considerable number of indigenous species found in these springs, currendy all remain on pastoral leases and some are threatened by the continuing expansion of water extraction from the Great Artesian Basin.  相似文献   

20.
The giant edible Placostylus snails of New Caledonia occur across a wide range of environmental conditions, from the dry southwest to the wetter central and northeastern regions. In large, slow‐moving animals such as Placostylus, speciation could be assumed to be largely driven by allopatry and genetic drift as opposed to natural selection. We examined variation in shell morphology using geometric morphometrics and genetic structure within two species of Placostylus (P. fibratus, P. porphyrostomus), to determine the drivers of diversity in this group. Despite the current patchy distribution of snails on New Caledonia, both mtDNA and nuclear SNP data sets (>3000 loci) showed weak admixing between populations and species. Shell morphology was concordant with the genetic clusters we identified and had a strong relationship with local environment. The genetic data, in contrast to the morphological data, did not show concordance with climatic conditions, suggesting the snails are not limited in their ability to adapt to different environments. In sympatry, P. fibratus and P. porphyrostomus maintained genetic and morphological differences, suggesting a genetic basis of phenotypic variation. Convergence of shell shape was observed in two adjacent populations that are genetically isolated but experience similar habitat and climatic conditions. Conversely, some populations in contrasting environments were morphologically distinct although genetically indistinguishable. We infer that morphological divergence in the Placostylus snails of New Caledonia is mediated by adaptation to the local environment.  相似文献   

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