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1.
A new species, Huernia humpatana Bruyns (Apocynaceae–Ceropegieae), closely related to H. similis N.E.Br., is described from the Chela Mountains of Huila Province in southern Angola. The two species are distinguished by the 5-angled and erect stems with more prominent tubercles up to 6 mm long joined into clear angles and separated by V-shaped grooves in H. humpatana as opposed to very obtusely 4-angled stems with tubercles only 2 mm long and only indistinct grooves between the angles in H. similis. Furthermore, in H. similis the nodding corolla is ± 9 mm in diameter with sepals ± 2 mm long, while in H. humpatana the horizontally facing corolla is 18–20 mm in diameter with sepals 4–6 mm long.  相似文献   

2.
A highly localised new species from the Cederberg Mountains near Wuppertal in the Western Cape Province is described. Annesorhiza asparagoides B.-E. Van Wyk, collected for the first time in 2009, differs from all other species of Annesorhiza (and the closely related Chamarea) in the unusual leaf structure, with crowded, subsessile, acicular leaf segments, resulting in dense, bottlebrush-like pinnae. The new species has a cluster of 10 or more slender roots, small (< 150 mm long), sparsely hairy leaves and small (± 8 mm long), oblong, conspicuously ribbed, homomericarpic fruits.  相似文献   

3.
The new species, Annesorhiza calcicola Magee and J.C. Manning, is described. It is known only from a few limestone outcrops around Jacobsbaai on the Saldanha Peninsula on the West Coast of South Africa. The species differs from all others in the genus in its small stature (inflorescence less than 0.3 m and leaves less than 150 mm long), the hysteranthous, pilose leaves which are completely absent at flowering (in the other species dead or dying at flowering and usually glabrous), the greyish-black, pilose inflorescence (yellowish-brown and glabrous in the other species) and the smaller homomericarpic fruit less than 5 mm long.  相似文献   

4.
Juvenile or adult Artemia sp. are often used as live prey for the rearing of early life stages of some crustacean, fish and cephalopod species. The improvements of both Artemia growth and its biochemical composition are key issues for the suitable use of Artemia biomass in these rearing processes. In this study we evaluated the growth and survival rates of Artemia fed with the cryptophyte Rhodomonas lens in comparison with different microalgal species commonly used in aquaculture: the prasinophyte Tetraselmis suecica, the prymnesiophyte Isochrysis galbana Parke, and the eustigmatophyte Nannochloropsis gaditana. Microalgae were cultured semi-continuously in nutrient saturated conditions and with a daily renewal rate of 30% of the volume of cultures, to obtain biomass of controlled and optimized composition. Considerable differences in Artemia growth were observed, as well as in the survival rate. At day 8 of rearing, Artemia fed R. lens had the highest length (4.9 ±0.6 mm, P < 0.001), followed by individuals fed T. suecica (4.2 ± 0.7 mm), I. galbana (3.6 ± 0.7 mm) and finally those fed N. gaditana (1.5 ± 0.2 mm). The survival rate of Artemia fed N. gaditana (18 ± 3%) was much lower (P < 0.001) than values found for the remaining groups (69 to 88%). The growth rate of Artemia obtained with R. lens was in general much higher than with other microalgal diets previously reported in the literature. The higher protein content of R. lens could explain the higher growth obtained with this species, but differences of Artemia growth with the different diets could not be explained solely on the basis of the gross composition of microalgae. Factors such as cell size and digestibility all seem to contribute to the results observed. Another trial was carried out to investigate differences in Artemia growth and on its biochemical composition when fed the best two diets: R. lens or T. suecica. The fatty acid (FA) and total amino acid (AA) composition of both microalgal species and the composition of Artemia were assessed as well. As found in the first experiment individuals fed R. lens (group ARHO) grew faster than those fed T. suecica (group ATET), attaining 3.6 ± 0.3 mm and 3.2 ± 0.4 mm (P < 0.001), respectively, after 5 days of rearing. The much higher AA content obtained in R. lens may be on the basis of the higher growth obtained with this species. Protein and carbohydrate levels in Artemia juveniles were very similar in both groups (64-68% of dry weight, and 8-10%, respectively). Lipid was slightly lower in ARHO (12%) than in ATET (15%, P < 0.01). Regarding the FA composition, juveniles from group ARHO contained higher levels of eicosapentaenoic acid (EPA, 6.2%) than juveniles from ATET (4.1%, P < 0.01), whereas docosahexaenoic acid (DHA) was only found in juveniles from ARHO (1.1%). Taking into account that the daily productivity of R. lens culture was higher than, or at least equal, the remaining microalgal species this cryptophyte is confirmed as an excellent diet to optimize the growth of Artemia, as well as to improve its biochemical composition.  相似文献   

5.
A new orchid, Disa albomagentea, is described from the Hottentots Holland Mountains in the Western Cape Province of South Africa. It is an obligately fire-dependent species closely related to Disa obtusa (sect. Disella), from which it can be easily distinguished by the larger flowers, i.e. galea 7-9 mm long versus 4-7 mm long, which are patent and bicoloured, i.e. magenta, white and not spotted versus purple brown, white to cream to greenish, and variously purple spotted. It appears to be endemic to seeps and marshes on the high peaks.  相似文献   

6.
A small isometric virus has been isolated from larvae of the Guatemala potato tuber moth, Tecia solanivora (Povolny), collected in Ecuador. It was designated the Anchilibi virus (AnchV). The non-enveloped viral particles have an estimated diameter of 32 ± 2 nm. Three major proteins were found in virions, with estimated sizes of 102.0 ± 2.1, 95.8 ± 2.0 and 92.4 ± 1.5 kDa for AnchV as determined by polyacrylamide gel electrophoresis. After denaturing agarose gel electrophoresis, the genome of AnchV appeared to be a tri-segmented single-stranded RNA with fragment sizes of 4.1 ± 0.2, 2.8 ± 0.2 and 1.65 ± 0.2 kb. In addition to a high virulence towards its original host, AnchV also caused high mortality in larvae of two other potato tuber moth species, Phthorimaea operculella (Zeller) and Symmetrischema (tangolias) plaesiosema (Turner). Electron microscopy confirmed that AnchV replication occurs in the cell cytoplasm, mainly in vesicles. Several important characteristics exhibited by this virus differ from those reported for known families of insect viruses. Thus, AnchV might be member of a new taxonomic group.  相似文献   

7.
Two species of bark lice, Xanthocaecilius sommermanae Mockford and Polypsocus corruptus Hagen, collected in a canopy Malaise trap placed in Great Smoky Mountains National Park as part of a survey of the park’s fauna, were found to be infected with microsporidia. Diagnosis was originally based on light microscopy, and was confirmed by PCR amplification and electron microscopy. This is the first record of microsporidia infection in the insect order Psocoptera. Four morphological spore types corresponded to four original SSUrDNA sequences (Genbank accession no. FJ865221-24), suggesting infection with four microsporidia species. Two of those species were examined by electron microscopy. We describe here one new genus and two new species based on morphological and sequence data: Antonospora psocopterae sp. n. with elongated diplokaryotic spores, 4.4 ± 0.05 × 1.9 ± 0.03 μm and Mockfordia xanthocaeciliae gen. n. sp. n. with ovocylindrical monokaryotic spores, 2.5 ± 0.10 × 1.4 ± 0.02 μm. A. psocopterae displayed high sequence (95%) and structural similarity with Antonospora scoticae, fell within a well supported dichotomy with A. scoticae inside the Antonospora-Paranosema clade in phylogenetic analyses by NJ, PS and ML. M. xanthocaeciliae did not exhibit much sequence or structural similarity with any of known microsporidia species, except Encephalitozoon spp. M. xanthocaeciliae fell within one clade with Encephalitozoon spp. in phylogenies and shared with encephalitozoons structural resemblance and about 80% of SSUrDNA sequence identity. The other two species were not described and provisionally were placed to the collective genus Microsporidium as Microsporidium sp. 1 and Microsporidium sp. 4 from bark lice because of insufficient morphological data. The finding that samples fixed and stored for months in propylene glycol (“antifreeze”) are good enough for DNA sequence analysis and can be used for morphological analyses (if no better fixation alternatives are available), is promising for future surveys for microsporidia.  相似文献   

8.
A new species of microsporidia is described from adults of the thief ant, Solenopsis carolinensis, collected in Florida, USA. Morphological and genetic characterization of this new species showed that it is most closely related to the genus Kneallhazia and is therefore formally designated, Kneallhazia carolinensae sp. nov. Masses of ovoid, binucleate spores were localized to fat body of adult workers and measured 6.2 ± 0.1 × 3.1 ± 0.1 μm (fresh) and 6.0 ± 0.1 × 3.4 ± 0.1 μm (fixed). These spores were in direct contact with the cell cytoplasm and contained an isofilar polar filament with 12-15 coils. Blastn analysis revealed that the K. carolinensae 16S rDNA sequence exhibited 91% identity with the 16S rDNA gene of K. solenopsae. The morphological and sequence data support the conclusion that K. carolinensae is a novel microsporidian species distinct from K. solenopsae.  相似文献   

9.
A new Steinernema species was isolated from three different sandy soil samples along the Platamona Beach, in the north-west coast of Sardinia Island (Italy). This new species is characterized by the following morphological characters: infective third-stage juvenile with a body length of 866 ± 61 (767-969) μm, distance from head to excretory pore of 63 ± 2.7 (59-68) μm, tail length of 81 ± 3.2 (76-89) μm, ratio E (%) 77 ± 3.4 (68-83); male tail with a mucron only in the second generation, spicule length of 66 ± 1.4 (64-67) μm and gubernaculum length of 44 ± 1.4 (43-46) μm in the first generation male; female of first generation with a slight vulval protrusion and ratio D (%) of 53 ± 4.0 (47-63). The new species differs distinctly from the related species (S. feltiae, S. kraussei, S. litorale, S. oregonense and S. cholashanense) in some morphometric values such as percentage of hyaline portion, ratios of gubernaculum/spicule length, spicule head length/width. The DNA analyses of the internal transcribed spacers and D2D3 regions show that the studied nematode isolates are a new species. Cross hybridisation tests with S. feltiae, S. kraussei, S. litorale, S. weiseri and S. oregonense showed that these species were reproductively isolated.  相似文献   

10.
Virulence (speed of kill) of a fungal entomopathogen against a particular host insect depends on biological properties of the specific isolate-host combination, together with factors such as fungal dose. How these intrinsic and extrinsic factors affect the actual pattern and extent of fungal growth invivo is poorly understood. In this study we exposed adult house flies (Muscadomestica L.) to surfaces treated with high and low doses of Beauveriabassiana (isolates BbGHA and Bb5344), Metarhiziumanisopliae (strain MaF52) and M.anisopliae var. acridum (isolate Ma189) and used quantitative real-time PCR with species-specific primers to examine the relationship between fungal growth kinetics and virulence. At the highest dose, all fungal isolates killed flies significantly faster than controls, with BbGHA, Bb5344 and MaF52 roughly equivalent in virulence (median survival time (±SE) = 5.0 ± 0.10, 5.0 ± 0.08 and 5.0 ± 0.12 days, respectively) and Ma189 killing more slowly (MST = 8.0 ± 0.20 days). At the lower dose, effective virulence was reduced and only flies exposed to isolates BbGHA and Bb5344 died significantly faster than controls (MST = 12 ± 1.36, 15 ± 0.64, 18 ± 0.86 and 21.0 ± 0.0 days for BbGHA, Bb5344, MaF52 and Ma189, respectively). Real-time PCR assays revealed that flies exposed to surfaces treated with the high dose of spores had greater spore pickup than flies exposed to the low dose for each isolate. After pickup, a general pattern emerged for all isolates in which there was a significant reduction of recovered fungal DNA 48 h after exposure followed by a brief recovery phase, a stable period of little net change in fungal sequence counts, and then a dramatic increase in sequence counts of up to three orders of magnitude around the time of host death. However, while the patterns of growth were similar, there were quantitative differences such that higher final sequence counts were recovered in insects infected with the most lethal isolates and with the higher dose. These results suggest that variation in virulence between isolates, species and doses is determined more by quantitative rather than qualitative differences in fungal growth kinetics.  相似文献   

11.
The most extensively studied ficins have been isolated from the latex of Ficus glabrata and Ficus carica. However the proteases (ficins) from other species are less known. The purification and characterization of a protease from the latex of Ficus racemosa is reported. The enzyme purified to homogeneity is a single polypeptide chain of molecular weight of 44,500 ± 500 Da as determined by MALDI-TOF. The enzyme exhibited a broad spectrum of pH optima between pH 4.5-6.5 and showed maximum activity at 60 ± 0.5 °C. The enzyme activity was completely inhibited by pepstatin-A indicating that the purified enzyme is an aspartic protease. Far-UV circular dichroic spectra revealed that the purified enzyme contains predominantly β-structures. The purified protease is thermostable. The apparent Tm, (mid point of thermal inactivation) was found to be 70 ± 0.5 °C. Thermal inactivation was found to follow first order kinetics at pH 5.5. Activation energy (Ea) was found to be 44.0 ± 0.3 kcal mol−1. The activation enthalpy (ΔH), free energy change (ΔG) and entropy (ΔS) were estimated to be 43 ± 4 kcal mol−1, −26 ± 3 kcal mol−1 and 204 ± 10 cal mol−1 K−1, respectively. Its enzymatic specificity studied using oxidized B chain of insulin indicates that the protease preferably hydrolyzed peptide bonds C-terminal to glutamate, leucine and phenylalanine (at P1 position). The broad specificity, pH optima and elevated thermal stability indicate the protease is distinct from other known ficins and would find applications in many sectors for its unique properties.  相似文献   

12.
Vermicomposting potential of Allolobophora parva is well proven in recent experiments but little is known about its growth and reproduction performance. Efforts were made in this study to assess the biological productivity of A. parva in cattle waste solids under laboratory conditions. The growth and reproduction performance of A. parva was monitored up to its termination state in experimental beddings. A. parva was weighed weekly and cocoons produced during the interval were also counted. The maximum individual biomass and maximum growth rate (wt. mg worm−1 week−1) was 190.9 ± 0.07 mg (after 13 weeks) and 2.66 (after 12th week), respectively. A. parva showed the maximum values of cocoon number (within a week) and reproduction rate: 26 ± 1.12 and 0.74 ± 0.05 cocoon worm−1 week−1, respectively, during the 8th week of vermiculture. Cocoon production in earthworms was terminated after the 17th week of culture. Data suggested that A. parva may acts as a potential candidate to convert negligible organic waste resources into worm biomass for sustainable environmental management.  相似文献   

13.
Nineteen bacteria isolates recovered from shellfish samples (mussels and oysters) showed a new and specific 16S rDNA-RFLP pattern with an Arcobacter identification method designed to recognize all species described up to 2008. These results suggested that they could belong to a new species. ERIC-PCR revealed that the 19 isolates belonged to 3 different strains. The sequence of the 16S rRNA gene of a representative strain (F98-3T) showed 97.6% similarity with the closest species Arcobacter marinus followed by Arcobacter halophilus (95.6%) and Arcobacter mytili (94.7%). The phylogenetic analysis with the16S rRNA, rpoB, gyrB and hsp60 genes placed the shellfish strains within the same cluster as the three species mentioned (also isolated from saline habitats) but they formed an independent phylogenetic line. The DDH results between strain F98-3T and A. marinus (54.8% ± 1.05), confirmed that it represents a new species. Several biochemical tests differentiated the shellfish isolates from all other Arcobacter species. Although the new species was different from A. mytili, they shared not only the same habitat (mussels) but also the characteristic of being so far the only Arcobacter species that are simultaneously negative for urea and indoxyl acetate hydrolysis. All results supported the classification of the shellfish strains as a new species, for which the name Arcobacter molluscorum sp. nov. with the type strain F98-3T is proposed (=CECT 7696T = LMG 25693T).  相似文献   

14.
Wetlands have proven effective at improving water quality of treated wastewater effluent, which in turn promotes increased primary productivity and vertical accretion. Baldcypress (Taxodium distichum) seedlings grown under different conditions (bare root and potted) were planted in four subunits of an effluent assimilation marsh and a control marsh in southeast Louisiana, USA, and basal diameter growth was monitored over one growing season. Mean basal diameter growth for seedlings in the assimilation subunits ranged from 16.1 (±1.4) mm to 9.5 (±0.9) mm, whereas growth for seedlings planted in the control marsh was 6.4 (±0.9) mm. Seedlings planted nearest the outfall experienced greater basal diameter growth (18.1 ± 2.6) compared to those planted 700 m away (8.0 ± 0.9), with growth generally decreasing with distance. Potted seedlings experienced greater growth (19.1 ± 1.0 and 20.6 ± 1.0 for five-month-olds and ten-month olds, respectively) than bare root seedlings (4.6 ± 0.6 and 4.0 ± 0.4 for one-year-olds and two-year olds, respectively). Planting assimilation marshes with baldcypress seedlings can be an effective restoration tool for coastal Louisiana, which will provide hurricane protection and improved surface water quality. Wastewater treatment wetlands may offer an effective tool for restoring coastal baldcypress (T. distichum)-water tupelo (Nyssa aquatic) swamps in Louisiana.  相似文献   

15.
The Iberian Peninsula encompasses more than 80% of the species richness of European aquatic ranunculi. The floristic diversity of the phytocoenosis characterised by aquatic Ranunculus and the main physical–chemical factors of the water were studied in 43 localities of the central Iberian Peninsula. Four aquatic Ranunculus communities are found in most of the aquatic environments. These are species-poor and have an uneven distribution: three species of Batrachium are heterophyllous and their communities are distributed in different aquatic ecosystems on silicated substrates; one species is homophyllous and its community occurs in various aquatic ecosystems with carbonated waters. In the Mediterranean climate, Ranunculus species are present in different habitats, as shown by the results of all the statistical analyses. Ranunculus trichophyllus communities occur in base-rich waters with a high buffering capacity (2273.44 ± 794.57 mg CaCO3 L−1) and a high concentration of cations (Ca2+, 121 ± 33.12 mg L−1; Mg2+, 71.64 ± 82.77 mg L−1), nitrates (2.89 ± 4.80 mg L−1), ammonium (2.19 ± 1.36 mg L−1) and sulphates (216.25 ± 218.54 mg L−1). Ranunculus penicillatus communities are found in flowing waters with a high concentration of phosphates (0.48 ± 0.6 mg L−1) and intermediate buffering capacity (683.66 ± 446.76 mg CaCO3 L−1). Both Ranunculus pseudofluitans and Ranunculus peltatus communities grow in waters with low buffering capacity (R. pseudofluitans, 385.91 ± 209.2 mg CaCO3 L−1; R. peltatus, 263.3 ± 180.36 mg CaCO3 L−1), and a low concentration of cations (R. pseudofluitans: Ca2+, 12.57 ± 9.42 mg L−1; Mg2+, 3.42 ± 1.67 mg L−1; R. peltatus: Ca2+, 15 ± 18.26 mg L−1; Mg2+, 6.26 ± 8.89 mg L−1) and nutrients (R. pseudofluitans: nitrates, 0.23 ± 0.2 mg L−1; phosphates, 0.09 ± 0.1 mg L−1; R. peltatus: nitrates, 0.19 ± 0.21 mg L−1; phosphates, 0.09 ± 0.12 mg L−1); the first in flowing waters, the latter in still waters.  相似文献   

16.
A case study on Centaurea gymnocarpa Moris & De Not., a narrow endemic species, was carried out by analyzing its morphological, anatomical, and physiological traits in response to natural habitat stress factors under Mediterranean climate conditions. The results underline that the species is particularly adapted to the environment where it naturally grows. At the plant level, the above-ground/below-ground dry mass (1.73 ± 0.60) shows its investment predominately in the above-ground structure with a resulting total leaf area per plant of 1399 ± 94 cm2. The senescent attached leaves at the base of the plant contribute to limit leaf transpiration by shading soil around the plant. Moreover, the dense C. gymnocarpa leaf pubescence, leaf rolling, the relatively high leaf mass area (LMA = 12.3 ± 1.3 mg cm−2) and leaf tissue density (LTD = 427 ± 44 mg cm−3) contribute to limit leaf transpiration, also postponing leaf death under dry conditions. At the physiological level, a relatively low respiration/photosynthesis ratio (R/PN) in spring results from high R [2.26 ± 0.59 μmol (CO2) m−2 s−1] and PN [12.3 ± 1.5 μmol (CO2) m−2 s−1]. The high photosynthetic nitrogen use efficiency [PNUE = 15.5 ± 0.4 μmol (CO2) g−1 (N) s−1] shows the large amount of nitrogen (N) invested in the photosynthetic machinery of new leaves, associated to a high chlorophyll content (Chl = 35 ± 5 SPAD units). On the contrary, the highest R/PN ratio (1.75 ± 0.19) in summer is due to a significant PN decrease and increase of R in response to drought. The low PNUE [1.5 ± 0.2 μmol (CO2) g−1 (N) s−1] in this season is indicative of a greater N investment in leaf cell walls which may contribute to limit transpiration. On the contrary, the low R/PN ratio (0.05 ± 0.02) in winter is resulting from the limited enzyme activity of the respiratory apparatus [R = 0.23 ± 0.08 μmol (CO2) m−2 s−1] while the low PNUE [3.5 ± 0.2 μmol (CO2) g−1 (N) s−1] suggests that low temperatures additionally limit plant production. The experiment of the imposed water stress confirms that the C. gymnocarpa growth capability is in conformity with the severe conditions of its natural habitat, likewise as it may be the case with others narrow endemic species that have occupied niches with similar extreme conditions.  相似文献   

17.
Our study aimed to test the ability of aquatic plants to use bicarbonate when acclimated to three different bicarbonate concentrations. To this end, we performed experiments with the three species Ceratophyllum demersum, Egeria densa, Lagarosiphon major to determine photosynthetic rates under varying bicarbonate concentrations. We measured bicarbonate use efficiency, photosynthetic performance and respiration. For all species, our results revealed that photosynthetic rates were highest in replicates grown at low alkalinity. Thus, E. densa had approx. five times higher rates at low (264 ± 15 μmol O2 g−1 DW h−1) than at high alkalinity (50 ± 27 μmol O2 g−1 DW h−1), C. demersum had three times higher rates (336 ± 95 and 120 ± 31 μmol O2 g−1 DW h−1), and L. major doubled its rates at low alkalinity (634 ± 114 and 322 ± 119 μmol O2 g−1 DW h−1). Similar results were obtained for bicarbonate use efficiency by E. densa (136 ± 44 and 43 ± 10 μmol O2 mequiv. L−1 g−1 DW h−1) and L. major (244 ± 29 and 82 ± 24 μmol O2 mequiv. L−1 g−1 DW h−1). As to C. demersum, efficiency was high but unaffected by alkalinity, indicating high adaptation ability to varied alkalinities. A pH drift experiment supported these results. Overall, our results suggest that the three globally widespread worldwide species of our study adapt to low inorganic carbon availability by increasing their efficiency of bicarbonate use.  相似文献   

18.
Pedro Fiaschi 《Brittonia》2014,66(2):134-150
Three new species of Oxalis sect. Polymorphae are here described and illustrated: Oxalis artemioides, O. calcicola, and O. monochasiata. These species have narrow geographic distributions, each being known from just one location. Oxalis artemioides differs from other species of the section by the glabrous stem, narrow terminal leaflets (8–10.5 × 2 mm), and inflorescences with elongated dichasial branches bearing flowers only in the distal portion. Oxalis calcicola differs from other species by having the young stem with adpressed-retrorse trichomes, inflorescences shorter than adjacent leaves, short dichasial branches (0.5–3 mm long) with flowers densely grouped along the entire length, and glabrous pedicels. Oxalis monochasiata is remarkable because of its monochasial inflorescence and the two-ovulate carpels, both features unique within Oxalis sect. Polymorphae. The new species are compared to similar species of the section, and information on distribution and habitat, phenology, and conservation status according with IUCN criteria are provided. Geographic distribution maps, lists of examined materials and an identification key for species of this section are also presented.  相似文献   

19.
In anuran amphibians, multiple males amplexing a single female to fertilise her eggs has been found for less than 25 species, whereas matings without amplexus are known for less than five species. Here we provide a new example of simultaneous polyandry with multiple males not engaged in amplexus, in Feirana taihangnicus, a stream-dwelling, explosive breeder endemic to central China. Laboratory experiments showed that when one female was kept with one male in a vessel with elevated, flat stones, the female stood on her head with her swollen cloaca against the undersurface of the stone substrate to lay eggs (clutch size ranged from 371 to 533, n = 7 females). Then, 10–102 min after oviposition began, the male stood on his head and released sperm over the eggs distributed as a single layer on the stone surfaces. It took about 3 h for the female to finish oviposition and for the male to finish fertilisation. On average, 96% of eggs were fertilised. In natural oviposition habitats, stream sections with slow flowing, we observed that 1 up to 15 males (8.7 ± 6.6, n = 6 cases), none in amplexus, participated in fertilising the eggs deposited by a single female. Evolutionary implications of this unusual reproductive strategy remain to be explored.  相似文献   

20.
Two techniques are described to calculate energy densities for the bell, gonad and oral arm tissues of three scyphozoan jellyfish (Cyanea capillata, Rhizostoma octopus and Chrysaora hysoscella). First, bomb-calorimetry was used, a technique that is readily available and inexpensive. However, the reliability of this technique for gelatinous material is contentious. Second, further analysis involving the more labour intensive proximate-composition analysis (protein, fat and carbohydrate) was carried out on two species (C. capillata and R. octopus). These proximate data were subsequently converted to energy densities. The two techniques (bomb-calorimetry and proximate-composition) gave very similar estimates of energy density. Differences in energy density were found both amongst different species and between different tissues of the same species. Mean (± S.D.) energy density estimates for whole animals from bomb-calorimetry were 0.18 ± 0.05, 0.11 ± 0.04, and 0.10 ± 0.03 kJ g wet mass− 1 for C. capillata, R. octopus, and C. hysoscella respectively. The implications of these low energy densities for species feeding on jellyfish are discussed.  相似文献   

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