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1.
Parasitic castration, the specific blocking of host reproductive output by an individual parasite, is a host-parasite interaction common to many invertebrates, particularly crustaceans, echinoderms and molluscs. It can reduce host density, alter host population dynamics and the evolution of host life history traits. Here we show that parasitisation by a single female cymothoid isopod, Anilocra apogonae, castrates its vertebrate host, the five-lined cardinalfish, Cheilodipterus quinquelineatus. Parasitised male fish fail to mouthbrood their young. The gonads of parasitised fish are smaller and parasitised female fish have substantially fewer and smaller ova than do the gonads of unparasitised fish. As for parasitic castrators of invertebrate hosts, A. apogonae on C. quinquelineatus are uniformly dispersed amongst infested hosts (one adult female isopod per host), are site specific, and their body size is highly correlated with that of their host. These isopods are large relative to the body size of their hosts, averaging 3.8% of the weight of the host. Parasitised fish also weigh less and are shorter than unparasitised fish of the same age. Despite the presence of other potential hosts, A. apogonae only infests C. quinquelineatus. The consistency of the ecological correlates amongst known parasitic castrators suggests that the parasitic castrator host-parasite relationship will be recognised for other parasites of vertebrates. 相似文献
2.
J. A. Galarza S. Roques J. Carreras-Carbonell E. Macpherson G. F. Turner C. Rico 《Conservation Genetics》2007,8(5):1251-1253
Eight polymorphic microsatellite loci were isolated and characterized for the Cardinal fish (Apogon imberbis), a coastal-reef fish endemic to the Mediterranean Sea. Characterization of 30 Cardinal fish individuals form the western
Mediterranean showed moderate to high allelic diversity ranging from 6 to 19 alleles per locus. Two loci showed significant
departures from Hardy-Weinberg equilibrium presumably due to null alleles. No evidence of linkage disequilibrium was found
for any locus pairwise comparasions. This microsatellite set could be useful for any basic population genetic studies of this
species. 相似文献
3.
We examined the diurnal refuges occupied by the nocturnal squirrelfish, Holocentrus rufus, to describe refuges and the behavior associated with their use and to determine which, if any, refuge characteristics were
selected. We tagged 21 H. rufus on two sites on a fringing reef in Barbados, West Indies, identified the refuges they used (n = 57), measured ten characteristics of each refuge and the surrounding microhabitat, and monitored their refuge use for 4 weeks.
To evaluate refuge selection, we measured the same characteristics on a comparable number of unused potential refuges (n = 67) on the same reefs and used classification tree models to determine which characteristics separated used from unused
refuges. Each fish used 1–9 refuges, which did not overlap among individuals and were defended against intrusion by conspecifics
and some heterospecifics. Fish with more than one refuge frequently moved among them. There was strong site fidelity with
no immigration of untagged fish or emigration of tagged fish on either reef during the study period and no additional refuges
being occupied over the 4-week period. Refuges were primarily holes, open at one or two ends, which varied in size, distance
from the reef edge, entrance orientation, and vertical relief at the entrance. Holes used as refuges differed significantly
from unused holes mainly in characteristics related to the vertical position of their entrance, but the classification tree
models differed for the two sites. This study provides the first detailed information on characteristics of daytime refuges
used by a nocturnally active reef fish and the first evidence of selectivity of refuges. It suggests that the abundance and
characteristics of holes on reefs could influence the density of H. rufus on natural reefs. 相似文献
4.
Will F. Figueira Sean J. Lyman Larry B. Crowder Gil Rilov 《Environmental Biology of Fishes》2008,81(3):297-311
The demographic responses of reef fish to their environment can be complex and in many cases, quite strong. Growth, mortality,
longevity, and even reproductive effort have been demonstrated to vary for the same species of reef fish over scales of 100s
to 1,000s of kilometers due to physiological and ecological interactions. Though few studies have explicitly documented it,
this sort of habitat-mediated demography can also exist at very local scales. Here we present the results of a 2-year study
of the bicolor damselfish, Stegastes partitus, in the Florida Keys, USA. We measured density and distribution, calculated key demographic rates (growth, survival, and
fecundity), and characterized the environment (resident fish assemblage, substrate type and complexity, and food availability)
of populations living in two adjacent but different habitats, the continuous fore reef and patchy back reef. Fish on the fore
reef had an elevated growth rate and asymptotic size, increased mortality, and higher fecundity than fish on the back reef.
We identified four potential causative mechanisms for these differences: food availability; competition; intraspecific density-dependent
effects; and predation risk. Our data did not support an effect of either food availability or intraspecific density-dependence,
but rather suggested that demographic responses are affected by both competition and predation risk. 相似文献
5.
In protogynous sex-changing fishes, females are expected to compete for the opportunity to change sex following the loss of
a dominant male and may exhibit growth and behavioural traits that help them maintain their dominant status after sex change.
A male removal experiment was used to examine changes in female growth and behaviour associated with sex change in the haremic
wrasse Halichoeres miniatus and to test whether any changes in growth associated with sex change were recorded in otolith microstructure. Dominant females
began displaying male-characteristic behaviour almost immediately after the harem male was removed. The frequency of interactions
between females increased following male removal. In contrast, feeding frequency of females decreased. The largest one to
three females in each social group changed sex following male removal and exhibited an increase in growth associated with
sex change. Sex changers grew more than twice as fast as non-sex changers during the experimental period. This growth acceleration
may enable new sex-changed males to rapidly reach a size where they can defend the remaining harem from other males. An optical
discontinuity (check mark) was present in the otoliths of sex-changed fish, and otolith accretion rate increased significantly
after the check mark, corresponding with the increased growth rate of sex-changing females. Wild caught males, but not females,
exhibited an analogous check mark in their otoliths and similar increases in otolith increment widths after the check. This
indicates that an increase in growth rate is a regular feature of sex-change dynamics of H. miniatus.
Communicated by Environment Editor Prof. Rob van Woesik 相似文献
6.
Synopsis We identify fishery management implications from a long-term monitoring program focusing on spawning aggregations of high
valued reef fish in Komodo National Park (KNP), Eastern Indonesia. Management objectives of KNP are not only to protect biodiversity,
but also to conserve spawning stocks of high-valued commercial species for the replenishment of surrounding fishing grounds.
We monitored two sites twice monthly over five years for two species of grouper, Epinephelus fuscoguttatus and Plectropomus areolatus. One site had an aggregation of both E. fuscoguttatus and P. areolatus, whereas the other site contained an aggregation of P. areolatus only. Over the five years monitoring period, aggregations typically formed during each full moon between September and February.
Additionally, P. areolatus occasionally aggregated during new moons between April and July. We observed spawning only once, but because formation of
aggregations were correlated to a higher incidence of behavior and signs indicative of reproduction and because most fish
present were adults, it is likely that the formation of aggregations was associated with spawning. Over the five years monitoring
period there was a reduction in mean fish size of up to 8 cm for P. areolatus, and a reduction in numbers of aggregating E. fuscoguttatus. Despite limited protection initiated in 2001, both sites are still heavily fished by local artisanal fishers. Because the
observed reductions in size and in numbers could be caused by fishing pressure, managers should follow the precautionary principle
by putting additional protective management in place. Since both species are relatively long-lived, at least five years of
continued monitoring may be necessary to determine the outcome of management intervention. The variability in timing of aggregation
in respect to season and moon phase in P. areolatus indicates that long-term monitoring must cover the entire year and both moon phases. 相似文献
7.
When large, predatory fishes and invertebrates were excluded from areas of a coral reef in the Florida Keys, USA, densities
of the normally rare gastropod Cyphoma gibbosum, a principal predator of gorgonian corals, increased 19-fold. Gorgonians in predator exclosures were grazed more frequently
and extensively by C. gibbosum than were gorgonians in uncaged areas. In exclosures, 14% of all gorgonians showed recent predation by C. gibbosum, with 62% of the entire colony surface being removed from these attacked individuals. In areas where predators of C. gibbosum were not excluded, only 5% of gorgonians exhibited recent damage, with only 26% of the colony surface being removed from
these few damaged individuals. Thus, the increases in both frequency and extent of attack combined to produce an 8× increase
in gorgonian damage following removal of large predators. These patterns suggest that predators typically suppress C. gibbosum populations, that overfishing of these predators could release C. gibbosum from top-down control, and that this release will allow increased damage to gorgonian corals. 相似文献
8.
In order to investigate the correlation of cell lineage, gene expression, and morphogenesis of uniramous and biramous limbs we studied limb formation in the thorax and pleon of the amphipod Orchestia cavimana and the isopod Porcellio scaber. We took advantage of the fact that in amphipod and isopod crustaceans—both Malacostraca—uniramous limbs evolved independently in the thorax whereas ancestral biramous limbs are formed in the pleon (abdomen). The gene Distal-less is expressed in the early limb buds as in other arthropods. Accordingly, it is likely to be responsible for the development of the proximodistal axis of the appendages. Double staining of Distal-less and Engrailed proteins suggests that Distal-less in the pleon of the amphipod Orchestia might not be under the control of the Wingless protein. Additionally, we studied axis formation of the uniramous and biramous limbs. In both species investigated, biramous limbs originate exclusively by the subdivision of the original limb bud. Both distal elements continuously express Distal-less. There is flexibility in the suppression of the development of additional branches in the crustacean limb. In the amphipod O. cavimana, uniramous thoracopods are formed by downregulation of Distal-less in the area where, in biramous limbs, the exopodites would occur. In contrast, this region never expresses Distal-less in the uniramous thoracopods of the isopod P. scaber. Our results suggest that the gene expression pattern is independent of the cell division pattern. Gene expression domains and morphogenesis of limbs and segments, on the other hand, show a good correlation.Edited by D. Tautz 相似文献
9.
A massive Porites microatoll generally has three types of microhabitat at the top, side, and base of the microatoll. The purpose of the present study was to analyze microhabitat associations of reef fish on microatolls to determine whether habitat characteristics play an important role in the structuring of reef fish assemblages in a patchy habitat. We also investigated temporal stability of reef fish assemblage structures over a period of 17 months to determine whether fish assemblage structures vary in a random manner. The results of correspondence analysis indicated species-specific habitat associations for pomacentrids (five species) and labrids (seven species). The degree of temporal stability of fish assemblage structures, calculated by Piankas index, was relatively high in a large-sized microatoll (0.503–0.831: 3.6m in diameter), in which microhabitat associations of fishes were clearly observed. The present study suggests that a microhabitat association is one of the important factors responsible for organization of reef fish assemblages in a microatoll. 相似文献
10.
Nina Yasuda Satoshi Nagai Chunlian Lian Masami Hamaguchi Takeshi Hayashibara Kazuo Nadaoka 《Conservation Genetics》2008,9(4):1011-1013
We isolated 11 polymorphic microsatellites from blue coral (Heliopora coerulea), whose conservation and management are of great concern. The number of alleles ranged from 3 to 20 with an average of 5.5,
and the observed and expected heterozygosities ranged from 0.115 to 0.833 and from 0.371 to 0.915, respectively. These loci
are useful for conservation genetics in H. coerulea populations. 相似文献
11.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes. 相似文献
12.
Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner.
The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate
larvae Galleria
mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host. 相似文献
13.
Noel H. Holmgren 《Brittonia》2018,70(1):115-139
A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations. 相似文献
14.
Parasitic plants in the Orobanchaceae invade roots of neighboring plants to rob them of water and nutrients. Triphysaria is facultative parasite that parasitizes a broad range of plant species including maize and Arabidopsis. In this paper we describe transient and stable transformation systems for Triphysaria
versicolor Fischer and C. Meyer. Agrobacterium
tumefaciens and Agrobacterium
rhizogenes were both able to transiently express a GUS reporter in Triphysaria seedlings following vacuum infiltration. There was a correlation between the length of time seedlings were conditioned in
the dark prior to infiltration and the tissue type transformed. In optimized experiments, nearly all of the vacuum infiltrated
seedlings transiently expressed GUS activity in some tissue. Calluses that developed from transformed tissues were selected
using non-destructive GUS staining and after several rounds of in vivo GUS selection, we recovered uniformly staining GUS
calluses from which roots were subsequently induced. The presence and expression of the transgene in Triphysaria was verified using genomic PCR, RT PCR and Southern hybridizations. Transgenic roots were also obtained by inoculating A. rhizogenes into wounded Triphysaria seedlings. Stable transformed roots were identified using GUS staining or fluorescent microscopy following transformation
with vectors containing GFP, dsRED or EYFP. Transgenic roots derived from both A.
tumefaciens and A.
rhizogenes transformations were morphologically normal and developed haustoria that attached to and invaded lettuce roots. Transgenic
roots also remained competent to form haustoria in response to purified inducing factors. These transformation systems will
allow an in planta assessment of genes predicted to function in plant parasitism.
Alexey Tomilov and Natalya Tomilova made an equal contribution in the paper. 相似文献
15.
A genetic transformation system has been developed for callus cells of Crataegus
aronia using Agrobacterium
tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with
5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different
types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red
colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli
were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this
is the first time to report an Agrobacterium-mediated transformation system in Crataegus
aronia. 相似文献
16.
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
17.
Synopsis We studied territorial behaviour of the acanthurid surgeonfish Acanthurus sohal and pomacentrid damselfish Plectroglyphidodon leucozona on fringing reefs in Ras Mohammed National Park, Red Sea, Egypt. We investigated trespass times, the number of agonistic acts, their intensity and the agonism elicited (number agonistic acts/total trespass time) for all intruders. Five families (Pomacentridae, Chaetodontidae, Acanthuridae, Labridae and Scaridae) were dominant among the 14 we recorded in our study sites. Seven species belonging to four families were resident inside A. sohal territories. Of the other 66 species we observed, 45 are intruders. The territory-holder did not react equally agonistically toward all these intruders. A. sohal showed a high number of agonistic acts against conspecifics and the parrotfish Cetoscarus bicolor. The intensity of the agonistic encounters, however, showed a different picture, with a low level for conspecifics and C. bicolor, respectively. A. sohal showed a high degree of agonistic intensity toward only one parrotfish, Chlorurus sordidus. The highest values of Agonism elicited were recorded against Scarus ghobban, followed by Siganus rivulatus and Zebrasoma desjardinii . Despite these high values, the intensity was relatively weak. The territories of A. sohal were large (average 12.5m2); those of P.leucozona were ca. 20 times smaller (average 0.6m2). A. sohal spent most of their time swimming (patrolling) along the territory border, stopping briefly to feed on algae. On the other hand, P. leucozona spent most of their time swimming and sheltering. 相似文献
18.
First year ontogenetic diet patterns and size-dependent diet partitioning of two coexisting piscivorous percids, pikeperch and Volga pikeperch were analysed in Lake Balaton. Diet patterns of the two pikeperches followed a common trend, catching larger preys at larger sizes, but in details they were different. Until 20–30 mm size age-0 pikeperch fed on planktonic microcrustaceans and were found only in the pelagic zone. After this size, from the end of May, a part of the stock shifted habitat and moved to the littoral zone to feed on Limnomysis benedeni. Majority of the stock stayed in the pelagic zone and shifted to Leptodora kindtii. In the pelagic group early piscivory, mainly cannibalism, occurred only sporadically. However, the few individuals that reached 100 mm size during the first year were typically piscivorous. Volga pikeperch stayed in the pelagic zone during the first year and shifted from planktonic microcrustaceans to benthic macroinvertebrates. General patterns of the first year diet ontogeny were similar in the different areas of Lake Balaton in both pikeperches with only some differences in the secondary food resources, especially in the share of chironomids. Chironomids were eaten at highest ratio by the two fish species in the Keszthely basin in accordance with their abundance pattern. Maximum prey sizes increased significantly with predator size in both pikeperch and Volga pikeperch. However, pikeperch ate much larger prey than did Volga pikeperch at the same size although they have a similar mouth gape to length ratio. These two, closely related pikeperches, although occur in the same habitat and have similar patterns of diet ontogeny, effectively partition food resources in Lake Balaton during the first growing season, except in the very beginning of their ontogeny at L = 5–10 mm size. It appears that age-0 Volga pikeperch is not a significant competitor for the economically highly rated pikeperch in Lake Balaton. On the other hand, it is age-0 pikeperch that might affect Volga pikeperch during its early ontogeny, in the planktivorous stage. 相似文献
19.
Exposure of coral reefs to river plumes carrying increasing loads of nutrients and sediments is a pressing issue for coral reefs around the world including the Great Barrier Reef (GBR). Laboratory experiments were conducted to investigate the effects of changes in inorganic nutrients (nitrate, ammonium and phosphate), salinity and various types of suspended sediments in isolation and in combination on rates of fertilisation and early embryonic development of the scleractinian coral Acropora millepora. Dose–response experiments showed that fertilisation declined significantly with increasing sediments and decreasing salinity, while inorganic nutrients at up to 20 μM nitrate or ammonium and 4 μM phosphate had no significant effect on fertilisation. Suspended sediments of ≥100 mg l−1 and salinity of 30 ppt reduced fertilisation by >50%. Developmental abnormality occurred in 100% of embryos at 30 ppt salinity, and no fertilisation occurred at ≤28 ppt. Another experiment tested interactions between sediment, salinity and nutrients and showed that fertilisation was significantly reduced when nutrients and low concentrations of sediments co-occurred, although both on their own had no effect on fertilisation rates. Similarly, while slightly reduced salinity on its own had no effect, fertilisation was reduced when it coincided with elevated levels of sediments or nutrients. Both these interactions were synergistic. A third experiment showed that sediments with different geophysical and nutrient properties had differential effects on fertilisation, possibly related to sediment and nutrient properties. The findings highlight the complex nature of the effects of changing water quality on coral health, particularly stressing the significance of water quality during coral spawning time. Communicated by Environment Editor Professor Rob van Woesik 相似文献
20.
Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species. 相似文献