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1.
Abstract Portia is a behaviourally complex and aberrant salticid genus. The genus is of unusual importance because it is morphologically primitive. Five species were studied in nature (Australia, Kenya, Malaysia, Sri Lanka) and in the laboratory in an effort to clarify the origins of the salticids and of their unique, complex eyes. All the species of Portia studied were both web builders and cursorial. Portia was also an araneophagic web invader, and it was a highly effective predator on diverse types of alien webs. Portia was an aggressive mimic, using a complex repertoire of vibratory behaviour to deceive the host spiders on which it fed. The venom of Portia was unusually potent to other spiders; its easily autotomised legs may have helped Portia escape if attacked by its frequently dangerous prey. Portia was also kleptoparasitic and oophagic when occupying alien webs. P. fimbriata from Queensland, where cursorial salticids were superabundant, used a unique manner of stalking and capturing other salticids. The display repertoires used during intraspecific interactions were complex and varied between species. Both visual (typical of other salticids) and vibratory (typical of other web spiders) displays were used. Portia copulated both on and away from webs and frequently with the female hanging from a dragline. Males cohabited with subadult females on webs, mating after the female matured. Adult and subadult females sometimes used specialised predatory attacks against courting or mating males. Sperm induction in Portia was similar to that in other cursorial spiders. Portia mimicked detritus in shape and colour, and its slow, mechanical locomotion preserved concealment. Portia occasionally used a special defensive behaviour (wild leaping) if disturbed by a potential predator. Two types of webs were spun by all species (Type 1, small resting platforms; Type 2, large prey-capture webs). Two types of egg sacs were made, both of which were highly aberrant for a salticid. Responses of different species and both sexes of Portia were quantitatively compared for different types of prey. Many of the trends in behaviour within the genus, including quantitative differences in predatory behaviour, seemed to be related to differences in the effectiveness of the cryptic morphology of Portia in concealing the spider in its natural habitat (‘effective crypsis’). The results of the study supported, in general, Jackson & Blest’s (1982a) hypothesis of salticid evolution which, in part, proposes that salticid ancestors were web builders with poorly developed vision and that acute vision evolved in conjunction with the ancestral spiders becoming proficient as araneophagic invaders of diverse types of webs. 相似文献
2.
W. J. Knight 《New Zealand journal of zoology.》2013,40(4):475-493
The cosmopolitan subfamilies Aphrodinae, Jassinae, Xestocephalinae, Idiocerinae, and Macropsinae are diagnosed and the New Zealand species described and illustrated. Each subfamily is represented in New Zealand by only one or two species, those in Idiocerinae having been introduced from Europe or North America. The species Euacanthella brunnea Evans (Aphrodinae) is synonymised with the Australian species E. insularis Evans (new synonymy). 相似文献
3.
4.
Depreissia is a little known genus comprising two hymenopteran-mimicking species, one found in Central Africa and one in the north of Borneo. The male of Depreissia
decipiens is redescribed, the female is described for the first time. The carapace is elongated, dorsally flattened and rhombus-shaped, the rear of the thorax laterally depressed and transformed, with a pair of deep pits; the pedicel is almost as long as the abdomen. The male palp is unusual, characterized by the transverse deeply split membranous tegulum separating a ventral part which bears a sclerotized tegular apophysis and a large dagger-like retrodirected median apophysis. The female epigyne consists of one pair of large adjacent spermathecae and very long copulatory ducts arising posteriorly and rising laterally alongside the spermathecae continuing in several vertical and horizontal coils over the anterior surface. Relationships within the Salticidae are discussed and an affinity with the Cocalodinae is suggested. Arguments are provided for a hypothesis that Depreissia
decipiens is not ant-mimicking as was previously believed, but is a mimic of polistinine wasps. The species was found in the canopy in the Kinabalu area only, in primary and old secondary rainforest at 200–700 m.a.s.l. Overlap of canopy-dwelling spider species with those in the understorey are discussed and examples of species richness and endemism in the canopy are highlighted. Canopy fogging is a very efficient method of collecting for most arthropods. The canopy fauna adds an extra dimension to the known biodiversity of the tropical rainforest. In southeast Asia, canopy research has been neglected, inhibiting evaluation of comparative results of this canopy project with that from other regions. More use of fogging as a collecting method would greatly improve insight into the actual species richness and species distribution in general. 相似文献
5.
Intraflock variation in the speed of escape-flight response on attack by an avian predator 总被引:5,自引:2,他引:5
The benefits of flocking to prey species, whether through collective
vigilance,dilution of risk, or predator confusion, depend on flock members
respondingin a coordinated way to attack. We videotaped sparrowhawks
attackingredshank flocks to determine if there were differences in thetiming
of escape flights between flock members and the factorsthat might affect any
differences. Sparrowhawks are surpriseshort-chase predators, so variation in
the time taken to takeflight on attack is likely to be a good index of
predation risk.Most birds in a flock flew within 0.25 s of the first bird
flying,and all birds were flying within 0.7 s. Redshanks that werevigilant,
that were closest to the approaching raptor, and thatwere close to their
neighbors took flight earliest within aflock. Birds in larger flocks took
longer, on average, to takeflight, measured from the time that the first bird
in the flockflew. Most birds took flight immediately after near neighbors
tookoff, but later flying birds were more likely to fly immediatelyafter
more distant neighbors took flight. This result, alongwith the result that
increased nearest neighbor distance increasedflight delay, suggests that most
redshanks flew in responseto conspecifics flying. The results strongly
suggest that thereis significant individual variation in predation risk
withinflocks so that individuals within a flock will vary in benefitsthat
they gain from flocking. 相似文献
6.
The Chinese representatives of Raveniola Zonstein, 1987 are currently recognized to comprise seven species. Four new species - Raveniola montanasp. n. (♂♀), Raveniola shangrilasp. n. (♂), Raveniola songisp. n. (♂) and Raveniola yunnanensissp. n. (♂) - are described from the highlands of Yunnan Province, China. According to some characters (shape of the palpus, palpal tibia and tibia I in males) they can be placed together with Raveniola hebeinica Zhu, Zhang & Zhang, 1999 and with Raveniola guangxi (Raven & Schwendinger, 1995), comb. n., transferred here from Sinopesa Raven & Schwendinger, 1995. The current generic position of Raveniola xizangensis (Hu & Li, 1987) is confirmed. Other Chinese nemesiids referred previously to Raveniola are transferred to Sinopesa: Sinopesa chinensis (Kulczyński, 1901), comb. n., Sinopesa sinensis (Zhu & Mao, 1983), comb. n. and Sinopesa chengbuensis (Xu & Yun, 2002), comb. n. The relationships between these Asian genera and their relations to Afrotropical nemesiids are discussed. 相似文献
7.
The apple snail Pomacea canaliculata is an invasive species and a serious pest of rice in many Asian countries. We studied predatory activities of various animals
living in Japanese freshwater habitats, by keeping each individual of a potential predator species with 36 snails of various
sizes for three days in the aquarium. Forty-six species were tested, and 26 in eight classes fed on small snails. A species
of leech, crabs, the common carp, turtles, the mallard duck and the Norway rat attacked even adult snails of 20–30 mm in shell
height. These findings will be helpful in identifying effective predators for biological control of the pest snail. In addition,
most of the animals attacking snails are reported to be common in rivers or ponds, but few live in modernized paddy fields
having little connections with natural water systems. This may be a reason why this snail maintains large populations in paddy
fields but not in other freshwater habitats. 相似文献
8.
This study tested the hypothesis that small birds at their nest sites avoid areas around dens of the red fox (Vulpes vulpes, Linneaus 1758) in an intensively used farmland. Birds were counted at 18 points (radius 100m) located near dens, as well as at 18 control points that were located at least 600m away from the nearest den. These two types of points did not differ with respect to the number of recorded bird species. However, a negative effect of the proximity of fox dens on the total density of the bird community was observed. This effect was also recorded for the most abundant bird species, the skylark (Alauda arvensis, Linneaus 1758). In agreement with our expectations, these results indicate a negative impact of fox presence on a breeding bird community in an open farmland. 相似文献
9.
Effect of nitrate and nitrite on sulfide production by two thermophilic,sulfate-reducing enrichments from an oil field in the North Sea 总被引:1,自引:0,他引:1
Kaster KM Grigoriyan A Jenneman G Jennneman G Voordouw G 《Applied microbiology and biotechnology》2007,75(1):195-203
Thermophilic sulfate-reducing bacteria (tSRB) can be major contributors to the production of H2S (souring) in oil reservoirs. Two tSRB enrichments from a North Sea oil field, NS-tSRB1 and NS-tSRB2, were obtained at 58°C
with acetate-propionate-butyrate and with lactate as the electron donor, respectively. Analysis by rDNA sequencing indicated
the presence of Thermodesulforhabdus norvegicus in NS-tSRB1 and of Archaeoglobus fulgidus in NS-tSRB2. Nitrate (10 mM) had no effect on H2S production by mid-log phase cultures of NS-tSRB1 and NS-tSRB2, whereas nitrite (0.25 mM or higher) inhibited sulfate reduction.
NS-tSRB1 did not recover from inhibition, whereas sulfate reduction activity of NS-tSRB2 recovered after 500 h. Nitrite was
also effective in souring inhibition and H2S removal in upflow bioreactors, whereas nitrate was similarly ineffective. Hence, nitrite may be preferable for souring prevention
in some high-temperature oil fields because it reacts directly with sulfide and provides long-lasting inhibition of sulfate
reduction. 相似文献
10.
Spatial variability in material fluxes within large river basins may arise from point source inputs, variable contributions from sub-basins and longitudinal variation in material transformation and retention. By measuring instantaneous fluxes throughout the Ohio River basin, we were able to draw inferences about the importance of these factors in determining the overall export of C, N and P from the basin. Our study spanned the lower 645 km of the Ohio River and included all tributaries that contributed at least 1% of the volume of the Ohio River at its confluence with the Mississippi. The intensively cultivated northern sub-basin (Wabash River) contributed a large fraction of N and P entering the Ohio River. In the southern sub-basins (Tennessee and Cumberland Rivers), impoundments and less intense cultivation appear to diminish and delay material delivery particularly with respect to N. The southern rivers account for a proportionately larger fraction of the water entering the Mississippi River during low discharge conditions and this fraction has increased during the past 50 years. The upper portion of the study reach was found to be a net source of CHLa and DOC and a net sink for inorganic N suggesting that this portion of the river provided a generally favorable environment for autotrophic production. Point source loadings of NH4 were significant inputs to the upper sub-reach but a relatively small component of the overall budget for dissolved inorganic N. 相似文献
11.
A wasp venom, mastoparan, rapidly increased the cytosolic free Ca2+ concentration ([Ca2+]i) and activated phosphorylase in rat hepatocytes in a concentration-dependent manner. Mastoparan could increase [Ca2+]i even in the absence of extracellular Ca2+, but a larger increase was observed in the presence of extracellular Ca2+. Thus, mastoparan mobilized Ca2+ from intracellular and extracellular Ca2+ stores. It also activated inositol triphosphate (IP3) accumulation, but did not stimulate cAMP production. From these results, we conclude that mastoparan activates rat hepatic glycogenolysis mediated by the accumulation of IP3, which causes an increase of [Ca2+]i but not that mediated by cAMP. 相似文献
12.
The improvement of plant N acquisition from an ammonium-treated,drought-stressed soil by the fungal symbiont in arbuscular mycorrhizae 总被引:8,自引:0,他引:8
The ability of the external mycelium in arbuscular mycorrhiza for N uptake and transport was studied. The contribution of the fungal symbiont to N acquisition by plants was studied mainly under waterstressed conditions using 15N. Lettuce (Lactuca sativa L) was the host for two isolates of the arbuscular mycorrhizal fungi Glomus mosseae and G. fasciculatum. The experimental pots had two soil compartments separated by a fine mesh screen (60 m). The root system was restricted to one of these compartments, while the fungal mycelium was able to cross the screen and colonize the soil in the hyphal compartment. A trace amount of 15NH
4
+
was applied to the hyphal compartment 1 week before harvest. Under water-stressed conditions both endophytes increased the 15N enrichment of plant tissues; this was negligible in nonmycorrhizal control plants. This indicates a direct effect of arbuscular mycorrhizal fungi on N acquisition in relatively dry soils. G. mosseae had more effect on N uptake and G. fasciculatum on P uptake under the water-limited conditions tested, but both fungi improved plant biomass production relative to nonmycorrhizal plants to a similar extent. 相似文献
13.
Albert K. Sparks 《Journal of invertebrate pathology》1982,40(2):242-254
Fifty-three Tanner crabs with varying degrees of surface encrustations and internal invasion by Trichomaris invadens were necropsied, processed, and examined to determine the extent of internal tissue invasion and histopathological effects of the infection. Sufficient data were accumulated to provide some insight on the progression, but not the rate, of tissue invasion. The epidermis and subepidermal layers are invaded and virtually replaced by proliferating hyphae. The invasion then proceeds internally, predominantly via the connective tissue. Major muscles and blood vessels are invaded, then invasion of deeper organs, including the hemopoietic tissue, gastrointestinal tract wall, and wall of the heart follows. The eyestalk is infected, usually early in the disease, and the invasion follows a similar pattern to that in the cephalothorax. Massive invasion and destruction of the retina is the major pathological effect. The gill may also be involved, with destruction of the lamellar tissues and invasion and destruction of podocytes in the stem of the gill. 相似文献
14.
Alan Olness 《Plant and Soil》1984,76(1-3):67-73
Summary Nitrogen (N) accumulation data from a replicated field study were fitted to a tanh (time) function and the derivate obtained to determine relative maximum rates of accumulation by maize. Both positive and negative effects of tillage on N accumulation rates were observed. Most of the N accumulation occurred over a 30-day period and time of N accumulation was not affected by tillage. Tilled profiles tend to contain greater NO3–N, greater aeration, and lower moisture contents than untilled profiles, and these characteristics interact to affect plant N accumulation. 相似文献
15.
Anders Svenson 《Plant and Soil》1986,94(2):227-234
Summary The hydrolysis of phosphate from phytic acid by the acid soil phytase system was reduced in the presence of metal ions. Copper
was most effective in this respect — zinc and cadmium were less inhibitory. Binding to metals did not completely inhibit the
hydrolysis of phytic acid. At higher metal concentrations, where binding to other soil constituents, like humic acids, interfered
less, the inhibition of the phytase activity was stronger than that of acid phosphatase. 相似文献
16.
Kazunori Maruyama Hiromichi Nagasawa Akira Isogai Hironori Ishizaki Akinori Suzuki 《Journal of Protein Chemistry》1992,11(1):13-20
The mode of disulfide linkages in bombyxin-IV, an insulin superfamily peptide consisting of A- and B-chains, was determined as A6–A11, A7–B10, and A20–B22. An intermolecular bond of A20–B22 was identified by sequencing and mass spectrometric analysis of the fragments generated by thermolysin digestion of natural bombyxin-IV. The mode of the remaining two bridges was determined by chemical and selective synthesis of three possible disulfide bond isomers of bombyxin-IV. A- and B-chains were synthesized by solid-phase method, and three disulfide bonds were bridged stepwise and in a fully controlled manner. Retention time on reversed-phase high-performance liquid chromatography (HPLC), thermolysin digests, and biological activity of the synthetic [A6–A11, A7–B10, A20–B22-cystine]-bombyxin-IV revealed that it was identical with the natural bombyxin-IV. Two other isomers with respect to disulfide bond arrangement, [A6–A7, A11–B10, A20–B22-cystine]- and [A6–B10, A7–A11, A20–B22-cystine]-bombyxin-IVs, were distinguishable from the natural one by use of HPLC, thermolysin digestion, and bioassay. 相似文献
17.
《African Journal of Aquatic Science》2013,38(2):115-120
An intra-basin transfer and the abstraction of water from aquatic systems in the Richards Bay area has led to the construction of six barriers which are restricting faunal movement, a reduction of flow to the Mhlathuze and Nhlabane estuaries and changes in the physico-chemical characteristics of four coastal lakes. These factors have severely impacted on the fauna of the aquatic systems in the area, particularly the fish but also the macrocrustacea and benthos. Preliminary results show that the structure of the interlinked marine-estuarine-river-coastal lakes ecosystem has been disrupted due to a cessation of migratory movements by the fauna which cannot cross the barriers. It is concluded that the construction of fishways will substantially contribute to reducing the current impacts and that the possibility exists that most will be in place within the next two to three years 相似文献
18.
In the present study, anti-metastatic effect of Z-100 on the spontaneous pulmonary metastases of Lewis lung carcinoma (3LL)
was examined in an attempt to regulate suppressor T cells. When Z-100 (10 mg/kg) was daily injected i.p. after 3LL inoculation,
survival rate of these mice was increased significantly (p<0.05). In addition, the number of pulmonary metastatic colonies of 3LL in Z-100-treated mice were significantly decreased
by 38% at 21 days, as compared with that of control mice (p<0.05). Along with the decrease of pulmonary metastases, suppressor cell activity was also gradually reduced in these mice,
as compared with that of control mice. When splenic suppressor cells (5×107 cells) from 3LL-bearing mice were adoptively transferred into normal mice (recipients) just before inoculation of 3LL, the
development of pulmonary metastases in recipients was significantly accelerated. However, splenocytes from 3LL-bearing mice
treated with Z-100 did not affect the development of pulmonary metastasis. The potential to accelerate the metastasis of splenic
mononuclear cells from 3LL-bearing mice was decreased significantly by the treatment with anti-Thy 1.2 monoclonal antibody
(mAb), anti-Lyt 2.2 mAb or anti-CD11b mAb followed by complement. IL-4 activity in the sera of 3LL-bearing mice was detected
15 days after tumor inoculation (13 pg/ml) and gradually increased (18 pg/ml) 20 days after tumor inoculation. However, when
Z-100 (10 mg/kg) was daily injected i.p., IL-4 activity in sera was decreased significantly, and the IL-4 activity was not
detected in these mice on day 20. These results suggest that Z-100 could inhibit the pulmonary metastases in 3LL-bearing mice
through the inhibition of suppressor T cell activity and a possible candidate of its effector molecule, IL-4. 相似文献
19.
J.-C. Li 《Theriogenology》2010,74(4):691-80
Although polymorphonuclear leukocytes (PMNs) are recruited into the uterine lumen to phagocytize sperm, factors controlling the phagocytotic ability of PMNs in cattle are not well documented. The objective was to determine the effects of blood serum, caffeine, and heparin on chemotaxis of PMNs for sperm and phagocytosis of sperm by PMNs in cows. Polymorphonuclear leukocytes were obtained (centrifugation) from a cow's peripheral blood. In Experiment 1, the chemotactic activity of PMNs increased (P < 0.01) when fresh serum was included in the medium (1226 cells/mm2 in serum vs. 1110 cells/mm2 in BSA), regardless of the presence of sperm, whereas heat-inactivated serum (1099 cells/mm2) did not affect their activity (P = 0.65). Phagocytosis of live and dead sperm by PMNs both increased (P < 0.01) in the presence of fresh serum (incidences of 54.5 and 48.0%, respectively), but stimulation was decreased (P < 0.01) by supplementation of the medium with ≥1 mM caffeine (20.6-30.3%). Serum-stimulated chemotactic activity of PMNs (1218 cells/mm2) was also decreased (P < 0.01) in the presence of caffeine (1090 cells/mm2). Furthermore, supplementation of PMNs with heparin in the presence of serum decreased (P < 0.01) both phagocytotic (from 43.8% to 21.5-31.7%) and chemotactic activities of PMNs (from 1124 to 1048-1108 cells/mm2). We inferred that opsonization in the presence of active complement stimulated phagocytotic and chemotactic activities of PMNs, and that both caffeine and heparin decreased serum-stimulated phagocytotic and chemotactic activities of PMNs. 相似文献
20.