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1.
Effective parasitoid production or mass-rearing is one of the key components in practicing biological control with parasitoids. Selection of host species for rearing parasitoids is a major approach to improve the production efficiency. The stone leek leafminer Liriomyza chinensis (Kato) is a destructive pest of onion crops in many Asian countries, which is difficult to control with chemicals. The present study examined whether the production of Neochrysocharis okazakii Kamijo, a promising native biological agent of L. chinensis, could be effective if kidney bean-Liriomyza trifolii (Burgess) system was used as an alternative rearing procedure. The suitability of L. chinensis and L. trifolii as hosts of N. okazakii was investigated in the laboratory. Neochrysocharis okazakii completed its development on both two host species, and the total development time was similar on these hosts. Longevity of N. okazakii females provided with L. chinensis was longer than those on L. trifolii. There were no significant differences in fecundity and offspring sex ratio when females had been provided with these two host species. The adult parasitoids emerged from L. chinensis were significantly larger than those from L. trifolii. However, the intrinsic rate of increase was higher, and mean generation time was lower, for L. trifolii than L. chinensis. Thus, mean net reproductive rate (Ro) was higher when L. trifolii was used as host. Although the two host species were equally suitable as host for N. okazakii, our findings suggested that L. trifolii and kidney bean is an ideal system for N. okazakii production.  相似文献   

2.
In the Falklands, heavy mortality of rock-hopper penguins Eudyptes chrysocome occurred during the 1985-86 breeding season. Starvation was diagnosed as the primary cause of death, possibly caused by a shortage of euphausiid crustaceans (krill) due to unusual meterological conditions. 'Puffinosis' may possibly have been a contributory factor; otherwise no conclusive evidence of infectious disease or toxicosis was found and also no evidence of radioactive contamination. In the 1986-87 breeding season no unusual mortality occurred, but 99 apparently healthy penguins were examined, i.e., rockhoppers Eudyptes chrysocome syn E. crestatus, gentoos Pygoscelis papua and Magellanics Spheniscus magellanicus. Full necropsies were carried out on 54. Tissue examinations were made for cadmium, copper, iron, manganese, mercury, lead and zinc. High tissue cadmium concentrations found in healthy birds in 1987 were similar to those in penguins which died in 1986, and therefore not considered to be of pathological significance. Although there has been no repetition of the unusually hot 1985-86 breeding season in the Falklands, penguins and other seabirds have had fluctuating breeding successes since then. The precise cause, including the roles of meteorological conditions and overexploitation of some forms of prey species, is unclear.  相似文献   

3.
A three-year survey of entomophthoralean pathogenic fungi of aphids from horticultural crops in La Plata, Argentina, was conducted. Nine species of aphids, including Aphis fabae Scopoli, Aphis gossypii Glover, Brevicoryne brassicae (L.), Lipaphis erysimi (Kaltenbach), Macrosiphum euphorbiae (Thomas), Myzus sp., Myzus persicae (Sulzer), Nasonovia ribisnigri (Mosley) and Capitophorus elaeagni (del Guercio) were recorded as hosts of entomopathogenic fungi. Six species of Entomophthorales that infected and killed aphids were found in vegetable crops. The fungal species identified were Conidiobolus obscurus (Hall & Dunn) Remaudière & Keller, Entomophthora planchoniana Cornu, Neozygites fresenii (Nowakowski) Remaudière & Keller, Pandora neoaphidis (Remaudière & Hennebert) Humber, Zoophthora radicans (Brefeld) Batko and Zoophthora sp. Pandora neoaphidis was the most predominant pathogen of aphids and was found throughout the summer (December–March) 2004. The recovery of C. obscurus, N. fresenii and P. neoaphidis represent first records of these fungi for South America.  相似文献   

4.
The Rhizophydiales is the most recently circumscribed order in the Chytridiomycota. Past studies focused on soil chytrids from North America and Australia to determine the range of diversity within this clade of chytrids and established three families (Rhizophydiaceae, Terramycetaceae, and Kappamycetaceae) in the new order. Although Rhizophydiales contains seemingly simple chytrids morphologically, analyses of ribosomal gene sequences and zoospore characters have demonstrated unexpected genetic and ultrastructural diversity, highlighting the need for broader habitat and geographic sampling to reveal the actual diversity within this new order. To enlarge our sampling, in this study we investigated 38 newly cultured chytrids collected from aquatic habitats in Argentina, a territory under-explored for chytrid diversity. From analyses of thallus morphology, zoospore ultrastructure, and 28S and ITS1–5.8S–ITS2 ribosomal gene sequences, we expand the concept of Rhizophydiales, describing seven new families (Alphamycetaceae, Angulomycetaceae, Aquamycetaceae, Globomycetaceae, Gorgonomycetaceae, Pateramycetaceae, and Protrudomycetaceae) and eight new genera (Alphamyces, Angulomyces, Aquamyces, Globomyces, Urceomyces, Gorgonomyces, Pateramyces, and Protrudomyces). Results of this study underscore that even more extensive sampling from varied habitats and geographies is needed to adequately ascertain the diversity of chytrids in the Rhizophydiales.  相似文献   

5.
Li Y  Zhou W  Hu B  Min M  Chen P  Ruan RR 《Bioresource technology》2011,102(23):10861-10867
The objectives of this study are to find the robust strains for the centrate cultivation system and to evaluate the effect of environmental factors including light intensity, light–dark cycle, and exogenous CO2 concentration on biomass accumulation, wastewater nutrient removal and biodiesel production. The results showed that all 14 algae strains from the genus of Chlorella, Haematococcus, Scenedesmus, Chlamydomonas, and Chloroccum were able to grow on centrate. The highest net biomass accumulation (2.01 g/L) was observed with Chlorella kessleri followed by Chlorella protothecoides (1.31 g/L), and both of them were proved to be capable of mixotrophic growth when cultivated on centrate. Environmental factors had significant effect on algal biomass accumulation, wastewater nutrients removal and biodiesel production. Higher light intensity and exogenous CO2 concentration with longer lighting period promote biomass accumulation, biodiesel production, as well as the removal of chemical oxygen demand and nitrogen, while, lower exogenous CO2 concentration promotes phosphorus removal.  相似文献   

6.
Palaeontological and palaeoichnological studies were made along the southeastern coast of Buenos Aires province, Argentina. Continental Late Pleistocene and continental, transitional and marine Holocene stratigraphic units were identified. The former are represented by fossil mammal bones and ichnites dated from 16,000 to 12,000 y. B.P. Continental Early Holocene beds dated circa 8,100 years B.P. contain fish, rodent and bird remains. Middle Holocene sediments 6,930 to 6,570 years B.P. are recorded by deposits bioturbated by estuarine crabs. During the Late Holocene, between 5,000 and 4,800 B.P., a marine transgression is recorded by a very rich mollusc fauna. The palaeoenvironmental variety recorded along a few tens of kilometers of the coast is a distinctive feature of this part of the Argentine coastal region. At Monte Hermoso beach, in the eastern part of the studied zone, archaeological materials were dated 7,300 years B.P., and human footprints dated 7,125 years B.P. were also recorded. In January 2005 some isolated human footprints were found at Pehuen-Co palaeoichnological site, which are older than those found at Monte Hermoso beach and of the same age as the oldest human archaeological findings in Patagonia, that is about 12,000 yeas B.P.  相似文献   

7.
A sudden and nearly synchronous emergence of the red tide forming dinoflagellate Cochlodinium along more than 800 km of California coastline was initially observed in late summer 2004. Thereafter high cell concentrations have been detected on an annual basis. Here, we present quantitative and semi-quantitative data indicating that Cochlodinium was uncommon in the phytoplankton community in California prior to 2004 and is now persisting as a more regular component and one that seasonally can cause red tides. The quantitative portion of this study was primarily conducted in Monterey Bay, where cell densities reached at least 6 × 104 cells L−1 during the initial outbreak. A semi-quantitative comparison of California coastal counties by the California Department of Health Services (CDHS) was also made: of the 15 counties surveyed (most with multiple sites per county), cells were detected only from Los Angeles County in the south to San Mateo County in the central region (seven counties), but not in the northern part of the state (six counties). Two counties in the central region of the state, San Luis Obispo and Santa Cruz, displayed intense and frequent periods of elevated Cochlodinium cell abundances. Although not observed in the state-wide CDHS survey, we occasionally found cells in San Diego County with densities up to 2.7 × 104 cells L−1. Though these colonial dinoflagellates have been recognized in California for over 80 years, with several “blooms” recorded prior to 2004, the species’ geographic range and abundance in recent years suggest significant shifts in the nearshore phytoplankton community of this region of the eastern Pacific.  相似文献   

8.
General condition, biochemical composition changes and fatty acids in several tissues of I. argentinus at different sexual stages were studied. Ovarian maturation involves a simultaneous increase in ovary mass and in protein and lipid levels. Testes weights were modified less than the ovary with maturation and showed a constant biochemical composition during spermatogenesis. The digestive gland grew through most of the maturation process in both sexes. Water level was high in immature squid and low in mature females and males, and varied inversely to that of lipids. Dorsal mantle maintained a constant biochemical composition, between February (immature) and June (fertilized females and mature males). All tissues contained high concentration of polyunsaturated fatty acids followed by saturated fatty acids and monosaturated fatty acids. This digestive gland of the squid is rich in polyenoic fatty acids, 20:5n-3 and 22:6n-3. This tissue could be a cheap raw material, presently discarded, for production of polyunsaturated fatty acids.  相似文献   

9.
王娟  王玥 《古生物学报》2022,61(3):506-522
本文对华南报道的假希瓦格?Pseudoschwagerina的48个种进行了分类厘定。通过搜集已发表属种的测量数据, 并重新度量部分南京地质古生物研究所标本馆的馆藏标本, 使用Past软件对这些种进行了判别分析。 通过定性及定量研究, 将其分为两个大类、9个小类。第一大类特征为壳长, 纺锤形–长纺锤形, 轴率多大于2.0, 隔壁褶皱较强; 第二大类特征为壳短, 近球形-粗纺锤形, 轴率多在2.0以下, 隔壁褶皱微弱–较强。进一步根据个体大小和幼壳特征的变化可以看出, 壳体较短的种往往具有粗纺锤形至亚球形的幼壳, 且幼壳包卷的圈数少, 仅1.5–2圈;而壳体较长的种通常具有长纺锤形–纺锤形的幼壳, 幼壳包卷圈数相对较多, 常有2–4圈。结合初房大小、幼壳特征和壳长, 第一大类和第二大类又可以细分为9个小类。  相似文献   

10.
A collagenolytic proteinase was purified from the intestines of Atlantic cod by (NH4)2SO4 fractionation, hydrophobic interaction chromatography (phenyl-Sepharose) and ion-exchange chromatography (DEAE-Sepharose). The proteinase has an estimated molecular weight of 24.1 (±0.5) kDa as determined by SDS-PAGE and belongs to the chymotrypsin family of serine proteinases. The enzyme cleaves native collagen types I, III, IV and V, and also readily hydrolyzes succinyl-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide (sAAPFpna), an amide substrate of chymotrypsin, as well as succinyl-l-Ala-l-Ala-l-Pro-l-Leu-p-nitroanilide, a reported elastase substrate, but had no detectable activity towards several other substrates of these proteinases or of trypsin. The pH optimum of the enzyme was between pH 8.0 and 9.5 and it was unstable at pH values below 7. Maximal activity of the enzyme when assayed against sAAPFpna was centered between 45 and 50°C. Calcium binding stabilized the cod collagenase against thermal inactivation, but even in the presence of calcium, the enzyme was unstable at temperatures above 30°C.  相似文献   

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12.
Alkaline phosphatase activity in cultures of the marine diatom Chaetoceros affinis var. willei (Gran) Hustedt was higher than in Skeletonema costatum (Grev.) Cleve. The enzyme activity was localized in coarse cell particles. Acid phosphatase activity was found in the cytoplasmic fraction. Induction of alkaline phosphatase depended on the NP ratio in the culture medium. A NP ratio > 40 in dilution/batch culture and > 30 in large scale batch culture, respectively, induced alkaline phosphatase.Cell phosphorus showed a critical value below which alkaline phosphatase was induced. Alkaline phosphatase in natural phytoplankton from the Trondheimsfjord is unlikely to occur except possibly in special situations.  相似文献   

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14.
Studies of host suitability and preferences of Trichogramma cordubensis Vargas and Cabello (Hymenoptera: Trichogrammatidae) were performed with eggs of six Lepidoptera (Noctuidae) species: Thysanoplusia orichalcea Fabricius, Peridroma saucia (Hübner), Xestia c-nigrum L., Phlogophora meticulosa (L.), Noctua pronuba (L.), and N. atlantica (Warren). Host suitability was studied by analysing separately the effects of the attacked host species and the influence of the rearing host species on different biological parameters of T. cordubensis. Host preference was analysed by offering eggs of two host species simultaneously to a single female wasp without previous oviposition experience (dual-choice tests). Results show that P. saucia, followed by P. meticulosa were the least suitable hosts for T. cordubensis, since on these species the preimaginal development of the parasitoids was significantly longer and, the number of parasitized eggs as well the number of offspring per female were significantly lower. Contrarily, T. cordubensis parasitized at a higher rate the eggs of the endemic non-target species, N. atlantica. Dual choice tests showed that the option of the first host to be accepted by the wasp was random; however, the mean number of parasitized eggs differed significantly when two host species were offered simultaneously to T. cordubensis, always being the host species with heavier eggs the most parasitized.  相似文献   

15.
It has been argued that the successive appearance of a distinct set of test morphologies by planktic foraminifera represents evidence for the multiple evolution of mechanical optima (Steineck and Fleisher, 1978). However, morphometric, isotopic and biostratigraphic analyses of the globigerine speciesSubbotina linaperta from Middle-Late Eocene Atlantic Ocean deep sea cores suggests that changes in developmental pathways may also play an important role in planktic foraminiferal evolution. During a period of prolonged and global change in the Middle-Late Eocene marine environment, at least one western Atlantic population ofS. linaperta was characterized by a marked decrease in mean test size that persisted throughout the remainder of this species' teilzone. In addition, this Late Eocene population exhibited anomalous relative abundances and a pronounced change in depth habitat when compared to conspecific populations in the Gulf of Mexico and South Atlantic. Quantitative morphometric analyses indicate the observed size reduction to be a secondary result of selection for the ontogenetically accelerated attainment of sexual maturity; a mode of developmentally mediated evolution termed progenesis. The temporal persistence of this progenetically dwarfed population throughout the remainder of the Late Eocene at this locality serves to illustrate the potential of this evolutionary mechanism to produce sustained morphological and ecological changes within populations of marine plankton as well as implying that this population was at least partially isolated from the general circulation of the Gulf Stream during this time interval. In addition, similarities between the nature of phenotypic change in this population and the common anecdotal observation of test size reduction in a number of planktic foraminiferal lineages at the Cretaceous-Tertiary boundary and during the Paleogene-Neogene faunal transition suggest that selection for different developmental patterns may provide an alternative explanation for the reappearance of simple globigerine morphotypes after major planktic foraminiferal extinction events.  相似文献   

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18.
在安徽省萧县凤凰山剖面炒米店组中上部(江山阶上部到第十阶)岩层中采得丰富的索克虫科三叶虫标本。共计4属6种(含2新种), 包括Eosaukia bella (Walcott, 1906)、E. anhuiensis sp. nov.、Lophosaukia orientalis (Kobayashi, 1933)、Prosaukia campe (Walcott, 1905)和P. xiaoxianensis sp. nov.、Lichengia onigawara Kobayashi, 1942。在对属征进行修订与讨论的基础上, 通过对比这些属的模式种及其他种, 对4个旧种进行了再研究和种征厘定, 最后对这6个种的谱系关系展开了简要讨论。  相似文献   

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20.
This survey examined the association between the hyperiid amphipod Hyperoche martinezii and ctenophores off the Argentinian coast (38°08′17″S, 57°31′18″W) through the evaluation of seasonality, prevalence and intensity of infection during an annual cycle. Medusae were also examined but only the ctenophores Mnemiopsis leidyi, Pleurobrachia pileus and Beroe ovata showed this association during the austral mid-spring to mid-summer. A total of 502 hyperiids were obtained; most (422 individuals) were larval stages, 53 juveniles and 27 adults. Mnemiopsis leidyi had the highest number of hyperiids with 98.6%, followed by P. pileus (0.80%), and B. ovata (0.60%). Total prevalence was 2.0 and intensity of infection ranged between 1 and 17 hyperiids per ctenophore. The host with highest prevalence was B. ovata (4.54), followed by M. leidyi (3.76) and P. pileus (0.1). Prevalence values had some correlations with the increase in the total length of B. ovata (r?=?0.480, P?=?0.006) and M. leidyi (r?=?0.501, P?B. ovata (r?=?0.425, P?=?0.017). The hyperiid was found in different parts of the host body: larval stages were found in the canal close to the subtentacular comb row and the stomodeum, whereas juvenile/adult stages were observed with a resting posture on the external surface of the ctenophores. The known geographic distribution of H. martinezii was extended; this finding represents the addition of three new hosts for this hyperiid.  相似文献   

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