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91.
92.
PHYSIOLOGICAL-ENVIRONMENTAL INTERACTIONS IN LICHENS 总被引:1,自引:1,他引:0
93.
MARK GILLESPIE STEVE D. WRATTEN ROB CRUICKSHANK BENJAMIN H. WISEMAN GEORGE W. GIBBS 《Systematic Entomology》2013,38(1):151-163
The butterfly genus Zizina in New Zealand has a complex taxonomic history due to the presence of morphological intermediates between the two species, the endemic Z. oxleyi and the introduced Z. labradus, in a putative hybrid zone on the east coast of the South Island of New Zealand. This makes species identification in the field problematic, particularly as the presence of hybrids has not been confirmed. We address this uncertainty through morphological and molecular analyses. Specimens were collected from a range of locations in New Zealand, as well as from Australia, and measurements were made of male genitalia and ventral wing coloration. Two mitochondrial genes (COI, ND5) and three nuclear gene fragments (28S, ITS2 and wingless) were also sequenced for a selection of individuals, and the presence of Wolbachia species in genomic DNA was tested. The two species were separable in morphological space, although there was some overlap, and the contact zone appeared to be around Kaikoura on the east coast of the South Island. Furthermore, specimens from the putative hybrid zone could be classified as Z. oxleyi using morphological characters individually, but not when these were used in a principal component analysis. Molecular analysis showed that there was a mean sequence divergence of 2.0% between two clades for COI, and 4.1% for ND5, but suggested that the contact zone between them was in the north‐west of the South Island. However, there was only a single clade for each of the three nuclear markers. It is thought that this incongruence between morphological and molecular markers is indicative of hybridization which is more extensive than previously thought. However, the possibility that recent speciation has occurred or is occurring is not ruled out. 相似文献
94.
95.
JOHN D. SCHADE KEELEY MacNEILL STEVE A. THOMAS F. CAMILLE McNEELY JILL R. WELTER JAMES HOOD MARIA GOODRICH MARY E. POWER JACQUES C. FINLAY 《Freshwater Biology》2011,56(3):424-436
1. Nutrient spiralling provides a conceptual framework and a whole‐system approach to investigate ecosystem responses to environmental changes. We use spiralling metrics to examine how the coupling of nitrogen and phosphorus uptake varies between streams dominated by either heterotrophic (i.e. bacteria‐dominated) or autotrophic (algal‐dominated) microbial communities. 2. Algae generally exhibit greater capacity to store nutrients than bacteria because of differences in cellular structures. These differences led us to hypothesise that the uptake of N and P in heterotrophic ecosystems should have reduced stoichiometric variation in response to changes in supply N : P compared to autotrophic ecosystems when assimilation dominates nutrient uptake. 3. To test this hypothesis, we used an array of serial nutrient additions in several streams in the South Fork Eel River watershed in Northern California. In one set of experiments, N and P were added alone and simultaneously in separate experiments to two small, heterotrophic streams to assess uptake rates and interactions between nutrient cycles. In a second set of experiments, N and P were added simultaneously at a range of N : P in one heterotrophic and one autotrophic stream to assess differences in uptake responses to changes in supply N : P. 4. Results of these experiments suggest two important conclusions. First, increased N supply significantly shortened P uptake lengths, while P addition had little impact on N uptake in both streams, indicating that uptake of non‐limiting nutrients is tightly coupled to the availability of the limiting element. Second, changes in P uptake and uptake ratios (UN : UP) with increased supply N : P supported our hypothesis that heterotrophic streams are more homeostatic in their responses to changes in nutrient supply than autotrophic streams, suggesting that physiological controls on nutrient use scale up to influence ecosystem‐scale patterns in nutrient cycling. 相似文献
96.
Revision of the Bicyclus sciathis species group (Lepidoptera: Nymphalidae) with descriptions of four new species and corrected distributional records 下载免费PDF全文
OSKAR BRATTSTRÖM KWAKU ADUSE‐POKU STEVE C. COLLINS TERESA DI MICCO DE SANTO PAUL M. BRAKEFIELD 《Systematic Entomology》2016,41(1):207-228
In this paper we present a thorough revision of the sciathis species group of the butterfly genus Bicyclus (Kirby). Type materials are discussed and in several cases lectotypes are assigned to specimens from original type series. Four new, and morphologically distinct, species are described (B. elishiae Brattström sp.n. , B. heathi Brattström sp.n. , B. sigiussidorum Brattström sp.n. and B. subtilisurae Brattström sp.n. ), along with a comprehensive molecular phylogeny that includes exemplar taxa of all currently recognized species. We also investigate the types of all previously synonymized taxa and in the process invalidate the name B. ewondo Libert. This was done after finding the previously missing holotype of B. makomensis (Strand), which clearly belongs to the same species and thereby gives the older name priority. The phylogeny showed that some distinctly different species were surprisingly closely related, suggesting a high rate of morphological evolution in parts of the sciathis group. The distributional records for the group are updated after investigating over 1700 specimens kept in a range of museum collections. Many species previously thought to be broadly sympatric were found to have much more restricted ranges, with the previous overestimations probably based on misidentified specimens. The higher level of allopatry now established will make identification of many morphologically similar species easier. The fact that species often have smaller ranges than previously known, meaning that the level of endemism for African butterflies is likely to be higher than current estimates, has important implications for conservation management. An identification key for males of all 13 currently recognized species in the species group is included. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:837A9D4C‐779A‐4497‐8176‐7151D409DFA5 . 相似文献
97.
ABSTRACT Although studies have addressed effects of abrupt transitions in habitat type (e.g., forest-clear-cut or forest-field edges) on amphibian movements, little is known about effects of more subtle habitat transitions on patterns of migration and habitat use in amphibians. We used radiotelemetry to study movement patterns of juvenile gopher frogs (Rana capito) emigrating from ponds that were surrounded by longleaf pine (Pinus palustris) forest that varied in structure as a result of fire suppression. Our primary purpose was to determine if frogs emigrate directionally from their natal ponds and select habitat at random during their first month following metamorphosis. We found that frogs emigrated in nonrandom directions from ponds that were surrounded by heterogeneous habitat and selected fire-maintained habitat that was associated with an open canopy, few hardwood trees, small amounts of leaf litter, and large amounts of wiregrass (Aristida beyrichiana). Fire-maintained habitat contained higher densities of burrows excavated by gopher tortoises (Gopherus polyphemus) and small mammals, which are the priamry refuge sites for both juvenile and adult gopher frogs. Frogs moved up to 691 m from their natal ponds, frequently crossed dirt roads, and even seemed to use these roads as migration corridors. To maintain suitable terrestrial habitat for gopher frogs, including habitat used by migrating individuals, it is important to apply frequent prescribed fire to uplands surrounding breeding ponds that lead all the way to the edges of breeding ponds, as well as through ponds during periodic droughts. 相似文献
98.
CATRIONA J. MACLEOD DAVID M. B. PARISH RICHARD P. DUNCAN STEVE MOREBY & STEPHEN F. HUBBARD 《Ibis》2005,147(2):270-282
The niche hypothesis predicts that some introduced species establish and spread successfully because their new environment provides expanded niche opportunities compared with their native environments. By investigating nestling survival, growth and body condition in relation to diet composition and prey abundance, we tested the prediction that the success of Yellowhammers Emberiza citrinella in New Zealand could be explained by the availability of better quality food resources in its introduced range compared with its native range. We found that Yellowhammer nestlings in New Zealand were larger and heavier than those in Britain, but that nestling survival and body condition did not differ between countries. The preferred prey items, which had some influence on nestling development and survival, were more prevalent in the diet of nestlings in New Zealand, suggesting that nestlings in the introduced range had a superior quality diet. However, there was little evidence to support the prediction that the preferred prey were more abundant in the introduced range, implying that some other factor such as prey accessibility or adult fitness may account for the differences in diet between countries. 相似文献
99.
ABSTRACT. Four littermate, laboratory-reared Palestine vipers, Vipera xanthina palestinae (#149, #150, #151, #152) (Serpentes: Viperidae) were used to determine modes by which Caryospora simplex (Apicomplexa: Eimeriidae) could be transmitted to snakes. Viper #149 was inoculated orally by stomach tube with 5.0 x 104 sporulated oocysts of C. simplex obtained from the feces of an Ottoman viper, V. x. xanthina and began passing unsporulated oocysts of C. simplex 121 days post-inoculation (DPI). Viper #150 was fed five mice that had been inoculated orally £25 days previously with 5.0 x 104 sporulated oocysts of C. simplex and it began passing unsporulated oocysts of C. simplex 33 days after being fed the first two of five mice. Viper #151 was inoculated orally with sporulated oocysts of C. simplex obtained from viper #150 and began passing oocysts 52 DPI. Viper #152 served as an uninoculated control and did not pass oocysts of any species of coccidian. This study demonstrates that snake/snake and mouse/snake transmission of C. simplex readily occurs. 相似文献
100.
A Comparative Study of Lipid Compositions of Cryptosporidium parvum (Apicomplexa) and Madin-Darby Bovine Kidney Cells 总被引:1,自引:0,他引:1
RALENE R. MITSCHLER RUTH WELTI STEVE J. UPTON 《The Journal of eukaryotic microbiology》1994,41(1):8-12
Membrane lipid compositions of Cryptosporidium parvum and Madin-Darby bovine kidney cells, an epithelial-like cell line commonly used to study coccidia in vitro, were analyzed using both thin-layer chromatography and gas-liquid chromatography. Phosphatidylcholine was the predominant lipid in both C. parvum and Madin-Darby bovine kidney cells, comprising 65% and 41% of the total phospholipids, respectively. Phospholipids of C. parvum contained twice the level of 16:0 and twenty-fold more 18:2 than the Madin-Darby bovine kidney cell line. We suggest that the parasite may be capable of sequestering specific complex membrane lipids at concentrations greater than those in the host cells. This study constitutes the first report of the lipid composition of C. parvum . 相似文献