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1.
In the present study, the effect of chemical cues from two fish species (mosquitofish and pumpkinseed), at different concentrations,
was tested in life history experiments with Daphnia longispina. The two fish species used represent the most abundant planktivores of many Mediterranean shallow lakes (SW Europe), where
the indigenous fish communities have been replaced by such exotic assemblages. Results have shown a similar response of D. longispina to both fish species: kairomones stimulated daphnids to produce more offspring, which resulted in higher fitness (r), relatively to a fishless control. Fish presence also induced an earlier first reproduction, a smaller size at maturity
of daphnids, and the production of smaller-sized neonates. Significant correlations with fish concentration (indirect measure
of fish kairomone concentration) were found for size at maturity and neonate size, for both fish species. These results are
in accordance to the “positive response” observed by other authors, which represents a defence mechanism to face losses caused
by fish predators. The chemically mediated size reduction of mature females and neonates is an adaptive response to the size-selective
predation exerted by fish. Pumpkinseed introduction is very recent in the lake of origin of the daphnids used in the experiments
and its kairomone produced similar effects to mosquitofish in the life history of D. longispina. These results are contrary to the existence of a species-specific kairomone and support the hypothesis of a general fish
kairomone.
Guest editor: Piet Spaak
Cladocera: Proceedings of the 7th International Symposium on Cladocera 相似文献
2.
Štepánka Dlouhá Anne Thielsch Robert H. S. Kraus Jaromír Seda Klaus Schwenk Adam Petrusek 《Hydrobiologia》2010,643(1):107-122
Daphnia galeata Sars, D. longispina O. F. Müller and D. cucullata Sars (Crustacea: Cladocera) are closely related species which often produce interspecific hybrids in natural populations.
Several marker systems are available for taxon determination in this hybridizing complex, but their performance and reliability
has not been systematically assessed. We compared results from identifications by three molecular methods. More than 1,200
individuals from 10 localities in the Czech Republic were identified as parental species or hybrids by allozyme electrophoresis
and the analysis of the restriction fragment length polymorphism of the internal transcribed spacer (ITS-RFLP); over 440 of
them were additionally analyzed and identified by 12 microsatellite loci. Identification by microsatellite markers corresponded
well with allozyme analyses. However, consistent discrepancies between ITS-RFLP and other markers were observed in two out
of 10 studied localities. Although some marker discrepancies may have been caused by occasional recent introgression, consistent
deviations between ITS-RFLP and other markers suggest a long-term maintenance of introgressed alleles. These results warn
against its use as a sole identification method in field studies. Additionally, we quantitatively evaluated the discriminatory
power of geometric morphometric (elliptic Fourier) analysis of body shapes based on photos of over 1,300 individuals pre-classified
by allozyme markers. Furthermore, a randomly selected subset of 240 individuals was independently determined from photos by
several experts. Despite a tendency for morphological divergence among parental Daphnia species, some taxa (especially D. galeata, D. longispina, and their hybrids) substantially overlapped in their body shapes. This was reflected in different determination success
for particular species and hybrids in discriminant analysis based on shape data as well as from photographs. 相似文献
3.
4.
We here exploit two large datasets on zooplankton in Norwegian lakes, spanning a wide range of geographical, physical, chemical
and biological properties, to assess the ecological niches and habitats of Bythotrephes longimanus and Leptodora kindtii. The species overlapped geographically, yet co-occurred only in a limited number of lakes. Bythotrephes inhabited virtually all types of lakes, except alpine localities and productive lakes dominated by cyprinid communities where
the hyaline Leptodora was most abundant. The zooplankton communities also differed in Bythotrephes and Leptodora lakes, probably both reflecting different predatory regimes, but also water quality and other lake-specific properties. We
found no evidence for species being excluded by the presence of Bythotrephes, rather the diversity in general was higher in lakes with these predators present compared with those without. We found,
however, a very close association between Bythotrephes and Daphnia galeata and to some extent also between Bythotrephes and D. longispina, suggesting that these species also may benefit from Bythotrephes invasion. Both Bythotrephes and Leptodora species occur naturally in this region, and knowledge about the ecological preferences and the zooplankton community composition
in Bythotrephes—and Leptodora lakes will provide valuable information about the long-term effects of Bythotrephes invasion and potential interaction with of Leptodora as top invertebrate predator. 相似文献
5.
C. Pérez-Martínez J. Barea-Arco J. M. Conde-Porcuna R. Morales-Baquero 《Hydrobiologia》2007,594(1):75-82
For three consecutive years, a population study of Daphnia pulicaria was undertaken in Río Seco Lake, a small high-mountain lake, in order to elucidate the reproductive strategies adopted by
Daphnia in this system. Daphnia appears to colonize this lake every spring by hatching from ephippia and reproduce by means of subitaneous (non-diapausing)
and ephippial (diapausing) eggs. D. pulicaria in this lake is an obligate parthenogenetic population. There is a short time period for subitaneous egg production and a
much longer period for ephippial egg production. The contribution of subitaneous eggs to Daphnia population density and structure appears to be low. Diapause onset showed a high temporal synchronization in the three studied
years in Río Seco Lake, and day-length emerged as the main cue triggering diapause onset and the main explanatory factor for
the proportion of ephippial females observed. The development and reproduction of D. pulicaria in Río Seco Lake involves taking a gamble on resting forms to guarantee inter-annual Daphnia persistence in the lake, giving priority to investment in future generations.
Guest editor: Piet Spaak
Cladocera: Proceedings of the 7th International Symposium on Cladocera 相似文献
6.
Uromyces appendiculatus, inclusive of three varieties, is distinguished from U. vignae primarily by the position of urediniospore germ pores and putative host specificity. However, opinions concerning these morphological and physiological features as taxonomic characters have varied greatly, and distinction of these species has often been confused. To clarify the taxonomy of these two species, morphological features of urediniospores and teliospores of 225 rust fungus specimens on species of Phaseolus, Vigna, Apios, Lablab, and Dunbaria were examined by light microscopy and scanning electron microscopy. Forty-five specimens were subjected to molecular phylogenetic analyses. As a result, the position of germ pores in urediniospores and the teliospore-wall thickness were considered as good characters to separate three morphological groups. In molecular analyses, the specimens fell into two and three clades based on the nucleotide sequence at D1/D2 domain of LSU rDNA and ITS regions, respectively. One of the D1/D2 clades corresponded to one morphological group whereas another D1/D2 clade included two other morphological groups. In contrast, each of the three ITS clades corresponded to a separate morphological group. Neither morphological groups nor molecular clades were host limited. It is suggested that the three morphological groups that corresponded to three distinct ITS clades constitute distinct species.Contribution no. 186 from the Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan 相似文献
7.
Christian Pietri Paulo Célio Alves José Melo-Ferreira 《European Journal of Wildlife Research》2011,57(2):313-321
The Italian hare, Lepus corsicanus, was first described in Corsica more than 100 years ago, but the knowledge on the status of the species in this island remains
scarce. Moreover, frequent introductions of thousands of individuals from other hare species, namely Lepus europaeus and Lepus granatensis, into Corsica are known to have occurred and an updated assessment of the prevalence of L. corsicanus in Corsica is therefore of utmost importance. Here, to estimate the relative prevalence of the hare species present in Corsica,
we conducted a molecular analysis on 67 samples collected by hunters between 2002 and 2007 in 36 Corsican communes. Sequencing
of portions of the nuclear gene transferrin and of the control region of the mitochondrial DNA allowed classifying most of
the collected samples as belonging to L. corsicanus (70.1%). Of the sampled Corsican communes, 86.1% contained this species, while only in 11.1%, L. europaeus was present. Three of the analyzed specimens showed an inconsistent molecular assignment between markers suggesting a hybrid
origin: L. corsicanus × L. europaeus, L. corsicanus × L. granatensis, and L. europaeus × L. granatensis. The first two cases of hybridization had never been described in nature, even in studies focusing on hares from Italy where
L. corsicanus and L. europaeus are often sympatric. These results stress the real risk of corrosion of the native gene pool of L. corsicanus via hybridization with introduced species. We highlight the need of urgently rethinking the management plan of hare populations
in Corsica. 相似文献
8.
Summary Seven new names at species rank are proposed in Memecylon sect. Afzeliana Jacq.-Fél., a group of forest shrubs and small trees confined to Guineo-Congolian Africa. The group is centred in Cameroon,
where 17 of the 20 species occur. A new flower type, the “star-flower” in Memecylon is revealed, and its taxonomic and ecological importance discussed. Three new, locally endemic species from the South West
Province of Cameroon are described, mapped and illustrated: M. kupeanum R. D. Stone, Ghogue & Cheek, M. bakossiense R. D. Stone, Ghogue & Cheek, and M. rheophyticum R. D. Stone, Ghogue & Cheek. Two new names, M. accedens R. D. Stone, Ghogue & Cheek and M. hyleastrum R. D. Stone & Ghogue and one new combination, M. mamfeanum (Jacq.-Fél.) R. D. Stone, Ghogue & Cheek are provided at species level for three taxa originally proposed as varieties of
M. afzelii G. Don. The taxon M. arcuatomarginatum var. simulans Jacq.-Fél. is also elevated to species status, as M. simulans (Jacq.-Fél.) R. D. Stone & Ghogue. Conservation assessments are provided for all the newly named taxa. A key is provided
to the species of Memecylon sect. Afzeliana. 相似文献
9.
Previous studies confirmed the presence of melatonin in Daphnia magna and demonstrated diurnal fluctuations in its concentration. It is also known that in several invertebrate species, melatonin
affects locomotor activity. We tested the hypothesis that this hormone is involved in the regulation of Daphnia diel vertical migration (DVM) behaviour that is well recognized as the adaptive response to predation threat. Using ‘plankton
organs’, we studied the effect of three concentrations of exogenous melatonin (10−5, 10−7, 10−9 M) on DVM of both female and male D. magna in the presence or absence of chemical cue (kairomone) of planktivorous fish. Depth distribution was measured six times a
day, using infrared-sensitive closed circuit television cameras. Our results showed a significant effect of melatonin on the
mean depth of experimental populations, both males and females, but only when melatonin was combined with fish kairomone.
Females stayed, on average, closer to the surface than males, both responding to the presence of kairomone by descending to
deeper strata. In the presence of exogenous melatonin and with the threat of predation, Daphnia stayed closer to the surface and their distribution was more variable than that of individuals, which were exposed to the
kairomone alone. Approaching the surface in the presence of predation threat seems to be maladaptive. We postulate the role
of melatonin as a stress signal inhibitor in molecular pathways of response to predation threat in Cladocera. 相似文献
10.
S. Fondevilla Z. Satovic D. Rubiales M. T. Moreno A. M. Torres 《Molecular breeding : new strategies in plant improvement》2008,21(4):439-454
Aschochyta blight, caused by Mycosphaerella pinodes, is one of the most economically serious pea pathogens, particularly in winter sowings. The wild Pisum sativum subsp. syriacum accession P665 shows good levels of resistance to this pathogen. Knowledge of the genetic factors controlling resistance
to M. pinodes in this wild accession would facilitate gene transfer to pea cultivars; however, previous studies mapping resistance to M. pinodes in pea have never included this wild species. The objective of this study was to identify quantitative trait loci (QTL) controlling
resistance to M. pinodes in P. sativum subsp. syriacum and to compare these with QTLs previously described for the same trait in P. sativum. A population formed by 111 F6:7 recombinant inbred lines derived from a cross between accession P665 and a susceptible pea cultivar (Messire) was analysed
using morphological, isozyme, RAPD, STS and EST markers. The map developed covered 1214 cM and contained 246 markers distributed
in nine linkage groups, of which seven could be assigned to pea chromosomes. Six QTLs associated with resistance to M. pinodes were detected in linkage groups II, III, IV and V, which collectively explained between 31 and 75% of the phenotypic variation
depending of the trait. While QTLs MpIII.1 and MpIII.2 were detected both for seedlings and field resistance, MpV.1 and MpII.1 were specific for growth chamber conditions and MpIII.3 and MpIV.1 for field resistance. Quantitative trait loci MpIII.1, MpII.1, MpIII.2 and MpIII.3 may coincide with other QTLs associated with resistance to M. pinodes previously described in P.
sativum. Four QTLs associated with earliness of flowering were also identified. While dfIII.2 and dfVI.1, may correspond with other genes and QTLs controlling earliness in P. sativum, dfIII.1 and dfII.1 may be specific to P. sativum subsp. syriacum. Flowering date and growth habit were strongly associated with resistance to M. pinodes in the field evaluations. The relation observed between earliness, growth habit and resistance to M. pinodes is discussed. 相似文献
11.
D. J. Goyder 《Kew Bulletin》2008,63(2):331-333
Summary
Funastrum rupicola Goyder, a new species of Apocynaceae: Asclepiadoideae from Bolivia, is described and illustrated. The conservation status of this species is assessed. 相似文献
12.
Nguyen Van Du 《Kew Bulletin》2008,63(3):491-493
Summary
Typhonium stigmatilobatum V. D. Nguyen, a new species from Vietnam, is described and illustrated. 相似文献
13.
The ability to change the reproduction mode and produce diapausing eggs, which is prevalent in many zooplankton species, significantly
impacts on the evolution and ecology of aquatic communities. The production of diapausing eggs is controlled by multiple effects
of biotic and abiotic factors, including infochemicals. We have investigated the effects of chemicals exuded by conspecifics
and ecologically close competing congers, Moina brachiata and M. macrocopa, which coexist in the same water body, and by larger Cladocera species (Daphnia magna) on the change of reproduction mode, specific growth rate and fecundity of M. brachiata and M. macrocopa females. The production of gametogenetic eggs in both species was detected only in waters from crowded cultures of conspecifics.
The water from crowded cultures of conspecifics reduced the specific growth rate of the juvenile females of both species that
later switched to gametogenesis. While it either did not affect (in M. macrocopa) or even increase (in M. brachiata) the specific growth rate of the juvenile females that later reproduced by parthenogenesis. Females of M. macrocopa released significantly fewer neonates in the water from crowded cultures of conspecifics than in all other treatments, while
the fecundity of M. brachiata females was the same in all treatments. To understand the phenomenon of diapause induction under the effect of chemical cues
in zooplankton, a link between laboratory tests and ecological research should be established, and the chemical composition
of the signals should be determined. 相似文献
14.
Sarawood Sungkaew Atchara Teerawatananon John A. N. Parnell Chris M. A. Stapleton Trevor R. Hodkinson 《Kew Bulletin》2008,63(4):669-673
Summary A new monotypic bamboo genus Phuphanochloa (Poaceae: Bambusoideae) from north-eastern Thailand is described, together with a new species, P. speciosa. 相似文献
15.
Endophytic fungi are rich in orchids and have great impacts on their host plants. 53 endophytes (30 isolates from Dendrobium devonianum and 23 endophytic fungi from D. thyrsiflorum) were isolated, respectively, from roots and stems of Dendrobium species. All the fungi were identified by way of morphological and/or molecular biological methods. 30 endophytic fungi in
D. devonianum were categorized into 11 taxa and 23 fungal endophytes in D. thyrsiflorum were grouped into 11 genera, respectively. Fusarium was the dominant species of the two Dendrobium species in common. Antimicrobial activity of ethanol extract of fermentation broth of these fungi was explored using agar
diffusion test. 10 endophytic fungi in D. devonianum and 11 in D. thyrsiflorum exhibited antimicrobial activity against at least one pathogenic bacterium or fungus among 6 pathogenic microbes (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus). Out of the fungal endophytes isolated from D. devonianum and D. thyrsiflorum, Phoma displayed strong inhibitory activity (inhibition zones in diameter >20 mm) against pathogens. Epicoccum nigrum from D. thyrsiflorum exhibited antibacterial activity even stronger than ampicillin sodium. Fusarium isolated from the two Dendrobium species was effective against the pathogenic bacterial as well as fungal pathogens. The study reinforced the assumption that
endophytic fungi isolated from different Dendrobium species could be of potential antibacterial or antifungal resource. 相似文献
16.
Raghvendra Kumar Mishra Anil Kumar Swati Chaudhary Sushil Kumar 《Journal of genetics》2009,88(2):227-232
The multifoliate pinna (mfp) mutation alters the leaf-blade architecture of pea, such that simple tendril pinnae of distal domain are replaced by compound
pinna blades of tendrilled leaflets in mfp homozygotes. The MFP locus was mapped with reference to DNA markers using F2 and F2:5 RIL as mapping populations. Among 205 RAPD, 27 ISSR and 35 SSR markers that demonstrated polymorphism between the parents
of mapping populations, three RAPD markers were found linked to the MFP locus by bulk segregant analyses on mfp/mfp and MFP/MFP bulks assembled from the F2:5 population. The segregational analysis of mfp and 267 DNA markers on 96 F2 plants allowed placement of 26 DNA markers with reference to MFP on a linkage group. The existence of common markers on reference genetic maps and MFP linkage group developed here showed that MFP is located on linkage group IV of the consensus genetic map of pea. 相似文献
17.
Transposable elements are important factors driving plant genome evolution. Upon their mobilization, novel insertion polymorphisms
are being created. We investigated differences in copy number and insertion polymorphism of a group of Mariner-like transposable
elements Vulmar and related VulMITE miniature inverted-repeat transposable elements (MITEs) in species representing subfamily Betoideae. Insertion sites of these elements were identified using a modified transposon display protocol, allowing amplification of longer fragments representing
regions flanking insertion sites. Subsequently, a subset of TD fragments was converted into insertion site-based polymorphism
(ISBP) markers. The investigated group of transposable elements was the most abundant in accessions representing the section
Beta, showing intraspecific insertion polymorphisms likely resulting from their recent activity. In contrast, no unique insertions
were observed for species of the genus Beta section Corollinae, while a set of section-specific insertions was observed in the genus Patellifolia, however, only two of them were polymorphic between P. procumbens and P. webbiana. We hypothesize that Vulmar and VulMITE elements were inactivated in the section Corollinae, while they remained active in the section Beta and the genus Patellifolia. The ISBP markers generally confirmed the insertion patterns observed with TD markers, including presence of distinct subsets
of TE insertions specific to Beta and Patellifolia. 相似文献
18.
Kurtzman CP 《Antonie van Leeuwenhoek》2011,100(3):455-462
Ogataea
parapolymorpha sp. n. (NRRL YB-1982, CBS 12304, type strain), the ascosporic state of Candida
parapolymorpha, is described. The species appears homothallic, assimilates methanol as is typical of most Ogataea species and forms hat-shaped ascospores in asci that become deliquescent. O. parapolymorpha is closely related to Ogataea
angusta and Ogataea
polymorpha. The three species can be resolved from gene sequence analyses but are unresolved from fermentation and growth reactions
that are typically used for yeast identification. On the basis of multiple isolates, O. angusta is known only from California, USA, in association with Drosophila and Aulacigaster flies, O. parapolymorpha is predominantly associated with insect frass from trees in the eastern USA but O. polymorpha has been isolated from various substrates in the USA, Brazil, Spain and Costa Rica. 相似文献
19.
As compared to other aquatic invertebrates, relatively little is known about the ecology of predaceous, pelagic water mites.
Studies to date do, however, show that water mites can be important components of aquatic food webs. Here, we used manipulative
field experiments to better understand the trophic ecology of a predaceous water mite (Piona carnea). Three experiments were conducted that examined (i) the effect of P. carnea density on the per-capita interaction strength (PCIS) of P. carnea preying on zooplankton; (ii) how the effects of P. carnea predation change with prey productivity; and (iii) how P. carnea interacts with another pelagic predator (Chaoborus americanus) to affect a shared prey species (Daphnia pulex). Results from the first experiment showed that P. carnea can strongly impact D. pulex populations, and that the PCIS of P. carnea decreases with an increase in P. carnea density. The second experiment showed that the effects of P. carnea on D. pulex populations depend on bottom-up factors that influence D. pulex population biomass and the reproductive potential of a D. pulex population relative to its size. The third experiment uncovered a non-additive interaction between P. carnea and C. americanus that resulted in a risk reducing situation for D. pulex in the presence of both predators. Together these experiments show that P. carnea imposes a strong negative impact on D. pulex, that the magnitude of this negative impact is dependent on the P. carnea density and the productivity of the system, and that the trophic ecology of P. carnea is modified by coexisting predator species. 相似文献
20.
Iain Darbyshire 《Kew Bulletin》2008,63(2):261-268
Summary Three new species are described in Barleria L. sect. Stellatohirta M. Balkwill from tropical Africa: B. aristata from south-central Tanzania, B. aenea from south-western Tanzania and northeast Zambia, and B. purpureotincta from south-western Zambia. Their affinities and conservation status are discussed. 相似文献