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1.
In Kinabalu National Park, Borneo we observed four colonies of the Malaysian giant ant Camponotus gigas in a primary forest. These predominantly nocturnal ants have underground nests, but forage in huge three-dimensional territories
in the rain forest canopies. The colony on which our study was mainly focused had 17 nests with about 7000 foragers and occupied
a territory of 0.8 ha. To improve observation and manipulation possibilities, these nests were linked at ground level by 430 m
of artificial bamboo trail. A group of specialist transport worker ants carried food from `source' nests at the periphery
to the central `sink' nest of the queen. Transport of food between nests started immediately after the evening exodus of the
foragers. Transporter ants formed a physical subcaste among the minors and behaved according to predictions of the central-place
foraging theory. Their load size was about five times that of the average forager and grew proportionally with head width.
Longer distances were run by ants with greater head width and larger gross weight. Transporter ants that ran more often took
heavier loads. Experiments with extra-large baits revealed that C. gigas used long-range recruitment to bring foragers from different nests to “bonanzas” at far distant places. The foraging strategy
of C. gigas is based on a polydomous colony structure in combination with efficient communication, ergonomic optimization, polyethism
and an effective recruitment system.
Received: 16 March 1998 / Accepted: 24 August 1998 相似文献
2.
A previously undocumented association between earthworms and red wood ants (Formicaaquilonia Yarr.) was found during an investigation of the influence of wood ants on the distribution and abundance of soil animals
in boreal forest soil. Ant nest mounds and the surrounding soil of the ant territories were sampled. The ant nest mound surface
(the uppermost 5-cm layer) harboured a much more abundant earthworm community than the surrounding soil; the biomass of the
earthworms was about 7 times higher in the nests than in the soil. Dendrodrilusrubidus dominated the earthworm community in the nests, while in soils Dendrobaenaoctaedra was more abundant. Favorable temperature, moisture and pH (Ca content), together with abundant food supply (microbes and
decomposing litter) are likely to make a nest mound a preferred habitat for earthworms, provided that they are not preyed
upon by the ants. We also conducted laboratory experiments to study antipredation mechanisms of earthworms against ants. The
experiments showed that earthworms do not escape predation by avoiding contact with ants in their nests. The earthworm mucus
repelled the ants, suggesting a chemical defence against predation. Earthworms probably prevent the nest mounds from becoming
overgrown by moulds and fungi, indicating possible mutualistic relationships between the earthworms and the ants.
Received: 21 November 1996 / Accepted: 3 April 1997 相似文献
3.
Effects of harvester ants on plant species distribution and abundance in a serpentine grassland 总被引:3,自引:0,他引:3
Seed harvesting ants can have important effects on the composition and structure of plant communities. We investigated two
effects of Messor andrei, the black seed-harvesting ant, on a serpentine grassland plant community in northern California. First, to determine if
selective seed predation by ants affects plant community composition, we excluded harvester ants from 1-mediameter circular
plots of grassland. Abundances of all species on these plots and on control plots were measured before and after exclosure.
Second, to determine if M. andrei nest mounds affect plant community composition, we compared plant species abundances on and off nest mounds. M. andrei deposit large amounts of organic matter on their nest mounds over a foraging season, so mounds may alter the edaphic environment.
The exclusion of seed-harvesting activity did not cause changes in the plant community. Nest mounds had a strong effect on
plant communities: there were many more grasses and fewer forbs on ant mounds, although at least one forb, Lepidium nitidum, produced twice as many seeds when it grew on nest mounds. We found that nest mounds formed islands of higher-temperature
soil in the serpentine grassland.
Received: 31 March 1997 / Accepted: 6 May 1997 相似文献
4.
P. E. Ziegler R. Wehner 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,181(1):13-20
In foraging and homing, desert ants of the genus Cataglyphis employ two different systems of navigation: a vector-based or dead-reckoning mechanism, depending on angles steered and distances
travelled, and a landmark-based piloting mechanism. In these systems the ants use either celestial or terrestrial visual information,
respectively. In behavioural experiments we investigated how long these types of information are preserved in the ant's memory,
i.e. how long the ants are able to orient properly in either way. To answer this question, ants were tested in specific dead-reckoning
and piloting situations, whereby the two vector components, direction and distance, were examined separately. The ability
to follow a particular vector course vanishes rapidly. Information about a given homing direction is lost from the 6th day
on (the time constant of the exponential memory decay function is τ = 4.5 days). The homing distances show a significantly
higher dispersion from the 4th day on (τ = 2.5 days). Having learned a constellation of landmarks positioned at the corners
of an equidistant triangle all ants were oriented properly after 10 days in captivity, and 64% of the ants exhibited extremely
precise orientation performances even when tested after 20 days. Thus, the memory decay functions have about the same short
time-course for information on distance and direction, i.e. information used for dead-reckoning. In contrast, landmark-based
information used in pinpointing the nest entrance is stored over the entire lifetime of a Cataglyphis forager.
Accepted: 18 January 1997 相似文献
5.
Changes in the metabolic rate of the foraging honeybee: effect of the carried weight or of the reward rate? 总被引:1,自引:0,他引:1
L. Moffatt 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2000,186(3):299-306
The metabolic rate of free flying honeybees (Apis mellifera ligustica) foraging on a multiple automatic feeder was measured in complete absence of perturbation. Each time the sucrose flow rate
was doubled, the metabolic rate increased by 18.2 ± 2.0% (14.7 μl CO2 min−1) and final crop load by 25.1 ± 2.4% (7.04 μl). The possibility that the heavier load carried by the bees caused the increase
in the metabolic rate was analyzed in detail. It was found that, for the same weight in the crop, the metabolic rate increased
with the increasing reward rate. Therefore, a factor other than the carried weight might account for this increase: a motivational
drive, whose intensity may depend on the reward rate at the food source. Although at higher reward rates metabolic rate increased
during the visit, at lower reward rates it remained constant, suggesting that the effect of the carried weight on the metabolic
rate might be controlled by this motivational drive. The hypothesis that honeybees maximize individual efficiency by reducing
their crop load loses support, as foraging costs are not determined by the carried weight. The functional meaning of the reduction
in crop load would be to increase the informational exchange at the hive.
Accepted: 8 January 2000 相似文献
6.
The species composition and structure of plant communities related to the activity of Formica rufa ants were studied in green moss pine forests located in Nerusso-Desnyanskoe Polesye (Bryansk Province). Four types of microsites
were established and examined: (1) the mound of an active ant nest, (2) the soil bank around an active ant nest, (3) the mound
of an abandoned nest, and (4) the soil bank around an abandoned nest. The background plant community was considered as the
fifth type. According to MRPP method, all pairs of microsites except (3–4) were different both in plant species composition
and species abundance. The microsites created by Formica rufa increase the habitat capacity and β diversity of the plant communities due to the appearance of meadow species requiring
richer soils. 相似文献
7.
David A. Holway 《Oecologia》1998,115(1-2):206-212
Predicting the success of biological invasions is a major goal of invasion biology. Determining the causes of invasions,
however, can be difficult, owing to the complexity and spatio-temporal heterogeneity of the invasion process. The purpose
of this study was to assess factors influencing rate of invasion for the Argentine ant (Linepithema humile), a widespread invasive species. The rate of invasion for 20 independent Argentine ant populations was measured over 4 years
in riparian woodlands in the lower Sacramento River Valley of northern California. A priori predictors of rate of invasion included stream flow (a measure of abiotic suitability), disturbance, and native ant richness.
In addition, baits were used to estimate the abundance of Argentine ants and native ants at the 20 sites. A multiple regression
model accounted for nearly half of the variation in mean rate of invasion (R
2 = 0.46), but stream flow was the only significant factor in this analysis. Argentine ants spread, on average, 16 m year−1 at sites with permanent stream flow and retreated, on average, −6 m year−1 at sites with intermittent stream flow. Rate of invasion was independent of both disturbance and native ant richness. Argentine
ants recruited to more baits in higher numbers in invaded areas than did native ants in uninvaded areas. In addition, rate
of invasion was positively correlated with the proportion of baits recruited to by native ants in uninvaded areas. Together, these findings suggest
that abiotic suitability is of paramount importance in determining rate of invasion for the Argentine ant.
Received: 16 September 1997 / Accepted: 8 February 1998 相似文献
8.
Virginie Rolland Jeffrey A. Hostetler Tommy C. Hines H. Franklin Percival Madan K. Oli 《European Journal of Wildlife Research》2011,57(4):717-727
Reproductive success is a critical component of individual fitness, and also an important determinant of growth rates of populations
characterized by early maturity and high fecundity. We used radiotelemetry data collected during 2003–2008 to estimate reproductive
parameters in a declining northern bobwhite (Colinus virginianus) population in South Florida, and to test hypotheses regarding factors influencing these parameters. The overall clutch size
was 12.10 ± 0.22, but females laid more eggs in their first clutch (12.43 ± 0.24) than in subsequent clutches (10.19 ± 0.53)
within a nesting season. Daily nest survival was higher for first (0.966 ± 0.003) than subsequent nests (0.936 ± 0.011). Hatchability
(proportion of laid eggs that hatched conditional upon nest survival to hatching) was 0.853 ± 0.008, but was higher for nests
incubated by females (0.873 ± 0.009) than those incubated by males (0.798 ± 0.018). The proportion of individuals attempting
a second nest was 0.112 ± 0.024 and 0.281 ± 0.040 when the first nest was successful and failed, respectively. Hatchability
was lower when the nesting habitat was burned the previous winter. We found no evidence that food strip density (a management
practice to provide supplemental food) influenced any of the reproductive parameters. Mean summer temperature affected hatchability,
nest survival, and proportion of nests incubated by males. Overall, the reproductive output in our study population was lower
than that reported for most other bobwhite populations, indicating that low reproductive performance may have contributed
to bobwhite population declines in our study site. These results suggest that current management practices, particularly those
related to habitat and harvest management, need careful evaluation. 相似文献
9.
Hideshi Ogawa Gen’ich Idani Jim Moore Lilian Pintea Adriana Hernandez-Aguilar 《International journal of primatology》2007,28(6):1397-1412
We conducted ecological studies of chimpanzees (Pan troglodytes) in the Ugalla area, western Tanzania. Ugalla is one of the driest habitats of chimpanzees and the Ugalla River is the eastern
boundary of chimpanzee distribution. Most of Ugalla is occupied by savanna woodlands dominated by deciduous trees of Brachystegia and Julbernardia. Chimpanzees tended not to make nests in riverine forests in plains, but in small patchy forests dominated by Monopetalanthus richardsiae and valley forests dominated by Julbernardia unijugata on slopes in mountainous areas. We estimated population density of chimpanzees to be 7–9 × 10−2 individuals/km2 based on nest censuses, suggesting that 2–3 × 102 individuals inhabited the 3352 km2 area of Ugalla. The size of the largest nest cluster (n=23) suggests that 1 unit group (community) comprised 30–35 individuals.
In the daytime, chimpanzees formed small feeding parties (mean 2.0 individuals), but larger ones in the evening (mean 4.8
individuals and 5.2 individuals based on fresh nest clusters). The pattern might reduce the predation risk from large nocturnal
carnivores such as lions and leopards. The sleeping sites may function as both a safe sleeping site and a meeting point for
chimpanzees with a huge home range that may have difficulty in finding other members of their unit group. 相似文献
10.
Volkan Cevik Carol D. Ryder Alexandra Popovich Kenneth Manning Graham J. King Graham B. Seymour 《Tree Genetics & Genomes》2010,6(2):271-279
The FRUITFULL (FUL) and SHATTERPROOF (SHP) genes are involved in regulating fruit development and dehiscence in Arabidopsis. We tested the hypothesis that this class of genes are also involved in regulating the development of fleshy fruits, by exploring
genetic and phenotypic variation within the apple (Malus domestica) gene pool. We isolated and characterised the genomic sequences of two candidate orthologous FUL-like genes, MdMADS2.1 and MdMADS2.2. These were mapped using the reference population ‘Prima x Fiesta’ to loci on Malus linkage groups LG14 and LG06, respectively. An additional MADS-box gene, MdMADS14, shares high amino acid identity with the Arabidopsis SHATTERPROOF1/2 genes and was mapped to Malus linkage group LG09. Association analysis between quantitative fruit flesh firmness estimates of ‘Prima x Fiesta’ progeny
and the MdMADS2.1, MdMADS2.2 and MdMADS14 loci was carried out using a mixed model analysis of variance. This revealed a significant association (P < 0.01) between MdMADS2.1 and fruit flesh firmness. Further evidence for the association between MdMADS2.1 and fruit flesh firmness was obtained using a case–control population-based genetic association approach. For this, a polymorphic
repeat, (AT)n, in the 3′ UTR of MdMADS2.1 was used as a locus-specific marker to screen 168 apple accessions for which historical assessments of fruit texture attributes
were available. This analysis revealed a significant association between the MdMADS2.1 and fruit flesh firmness at both allelic (χ
2 = 34, df = 9, P < 0.001) and genotypic (χ
2 = 57, df = 32, P < 0.01) levels. 相似文献
11.
Xu XJ Chen CQ Wang ZY Zhang Y Hou AX Li CH Liu Y 《Biological trace element research》2009,127(3):269-277
The antibacterial effect of Zn(II), tetraphenyl porphyrin (TPP), propdioxyl bridged tetraphenyl bisporphyrin 1, and its metallobisporphyrin complexes (ZnMnbisporphyrin 2 and ZnZnbisporphyrin 3) towards Staphylococcus aureus growth was investigated by microcalorimetry at 37°C. Differences in their capacities to inhibit the growth metabolism of
S. aureus were observed. By analyzing the power–time curves, crucial parameters such as the rate constant of bacterial growth (k), inhibitory ratio (I), and generation time (t
G) were determined. The growth rate constant (k) of S. aureus (in the log phase) in the presence of the drugs decreased linearly with increasing concentrations of the complexes. The sequence
of the antibacterial activities of these compounds tested was 3 > 2 > 1 > Zn(II) > TPP. ZnZnbisporphyrin 3 is proposed to benefit from the synergetic effects of Zn(II) and 1. 相似文献
12.
We recorded nesting data at 569 fresh night nest sites, comprising 7032 individual nests, of Cross River gorillas inhabiting
the Kagwene Mountain in western Cameroon. The mean night nest group size was 12.4. Overall, 55% of night nests were constructed
on the ground and 45% in trees. Significantly more arboreal nests were constructed in the wet season (69%), vs. the dry season
(19%). Day nest construction was common at Kagwene (n = 260 nest sites, mean nest group size = 5.98) and we encountered significantly more day nest sites in the wet season. Nest
site reuse was also common (35%), though not related to season. Our results of nesting habits concur with those from other
western gorilla studies, in which rainfall influences arboreal nesting. However, we encountered wet season arboreal nesting,
day nest construction, and overall nest site reuse more frequently than reported for other sites. Our observations have considerable
implications when estimating group size and density using traditional nest count data. The gorillas at Kagwene inhabit the
highest altitudinal range of all Cross River gorilla subpopulations and rainfall is also high; therefore other subpopulations
may demonstrate different nesting characteristics. However, one should consider our findings when attempting to estimate Cross
River gorilla density at other localities through nest site data. 相似文献
13.
Wang Xi-Ling Zhou Jin-Xing Yu Mao-De Li Zhen-Gang Jin Xiao-Yun Li Qi-You 《In vitro cellular & developmental biology. Plant》2011,47(3):434-440
Efficient plant regeneration is essential for successful transformation and in vitro polyploidy induction in mulberry. A high frequency (80%) of plant regeneration from hypocotyls occurred under in vitro conditions in mulberry (Morus multicaulis Poir.). We identified three key factors for enhancing successful regeneration based on earlier work: (1) hypocotyl position,
(2) the combination and concentration of growth regulators, and (3) the addition of AgNO3. The highest frequency of shoot regeneration was achieved using hypocotyl segments, which are proximal to apical meristems,
and the optimal culture conditions were Murashige and Skoog’s (MS) (Murashige and Skoog, 1962) basal medium supplemented with 3.0 mg l−1 6-benzylamino purine, 0.3 mg l−1 indole-3-acetic acid, 0.1% polyvinypyrrolidone, and 1.0 mg/l silver nitrate (AgNO3) under subdued light at 25 ± 2°C. Treating the shoots with 0.2% colchicine (dipping for 72 h) resulted in a 14% tetraploid
frequency, whereas a 20% tetraploid frequency resulted from using a 0.25% colchicine (dripping for 5 d) treatment, as determined
by chromosome number counts. The diploid plant chromosome number was 28 (2n = 2x = 28) and that of tetraploid plants was 56 (2n = 4x = 56). Regenerated shoots rooted easily in 8–10 d using half-strength basal MS medium with 0.5 mg l−1 indole-3-butyric acid and were successfully established in the soil. 相似文献
14.
Frederico Ozanan Barros Monteiro Leandro Nassar Coutinho Eliane do Socorro de Souza Pompeu Paulo Henrique Gomes de Castro Celsemy Eleutério Maia Washington Luis Assunção Pereira Wilter Ricardo Russiano Vicente 《International journal of primatology》2009,30(2):327-336
We evaluated the uterus and ovaries of owl monkeys (Aotus azarai infulatus) via gynecological ultrasound examination. We evaluated the subjects in 2 different time periods. The first period (P1) was
characterized by the absence of mating, with daily examinations, during 4 mo (n = 10). At the end of P1, we paired the subjects for 30 d, but without ultrasonographic evaluation. The second period (P2)
was characterized by the presence of mating, with examinations once a week, during 7 consecutive months (n = 9). We evaluated the uterus and ovaries in sagittal and transverse scans, using a 5–12 MHz linear array probe. The uterine
volume (UV) was directly proportional to the number of previous parturitions. The right ovary volume (RtOV) is greater than
the left (LtOV) in P1 and P2. There is a positive correlation (p < 0.05) between the females’ mass, RtOV (r = 0.28) and LtOV (r = 0.16). 相似文献
15.
Mohamed A. Haidara Mohamed D. Morsy Hesham A. Abdel-Razek Dimitri P. Mikhailidis Esma R. Isenovic 《Journal of physiology and biochemistry》2010,66(3):255-264
Septicemia leads to oxidative stress with overproduction of reactive-oxygen species (ROS) and consumption of endogenous antioxidant
enzymes. We tested a twofold hypothesis: (1) does oxidative stress (OxS) induced by sepsis acting alone or in concert with
augmented inflammatory processes contributes to sepsis-related vascular dysfunction, and, (2) whether ozone (O3) and l-canavanine (CAV) mitigate the negative impact of the aforementioned phenomena. We investigated the relative impact of treatment
with CAV and/or O3 on vascular OxS associated vascular functional changes in septicemic rats. For this study, 60 male Sprague–Dawley rats were
used and divided into six experimental groups (n = 10): control group (C), sham-operated (Sham), septicemic rats (S), S rats treated with CAV (100 mg/kg. i.p; S + CAV), S
rats treated with O3 (1.2 mg/kg, i.p.; S + O3) and S rats treated with both O3 and CAV (S + O3 + CAV). After 22 h, the mean arterial blood pressure (MAP), the aortic ring vascular reactivity to phenylephrine, abdominal
aortic blood flow (AABF), serum tumor necrosis factor-α (TNF-α) and plasma nitrite/nitrate (NOx) concentration were measured.
In addition, hepatic antioxidant enzyme activities sodium dismutase (SOD) and glutathione peroxidase (GSH-Px) were estimated.
Septicemia caused significant elevation of serum TNF-α (p < 0.001) and plasma NOx (p < 0.001) and significant (p < 0.001) reduction of AABF (p < 0.001), aortic vascular response to phenylephrine (p < 0.001), MAP (p < 0.001) and hepatic SOD and GSH-Px activity (p < 0.001) compared with the C group, while treatment with O3 and/or CAV induced significant amelioration of all those increases. Abnormalities were attenuated to a similar extent with
treatment with both O3 and CAV. These results suggested that concomitant administration of O3 and CAV alleviated the compromised vascular reactivity in septicemic conditions and prevent its progression into septic shock
compared with each alone. 相似文献
16.
Two different high-cell-density cultivation processes based on the mutant Saccharomyces cerevisiae GE-2 for simultaneous production of glutathione and ergosterol were investigated. Compared with keeping the ethanol volumetric
concentration at a constant low level, feedback control of glucose feeding rate (F) by keeping the descending rate of ethanol volumetric concentration (ΔE/Δt) between −0.1% and 0.15% per hour was much more efficient to achieve a high glutathione and ergosterol productivity. This
bioprocess overcomes some disadvantages of traditional S. cerevisiae-based cultivation process, especially shortening cultivation period and making the cultivation process steady-going. A classical
on or off controller was used to manipulate F to maintain ΔE/Δt at its set point. The dry cell weight, glutathione yield and ergosterol yield reached 110.0 ± 2.6 g/l, 2,280 ± 76 mg/l, and
1,510 ± 28 mg/l in 32 h, respectively. 相似文献
17.
The caterpillars of Eutachytptera psidii (Lepidoptera: Lasiocampidae) mark trails between their nest and distant feeding sites with a trail pheromone secreted from
the ventral surfaces of their last abdominal segments. The threshold sensitivity to artificial trails prepared from an hexane
extract of the pheromone was 0.75 × 10−3 caterpillar-equivalents per cm of trail. In tests of trail-specificity involving four other social species, the caterpillars
responded only to trails prepared from a pheromone extract of the closely related genus Gloveria. Tests were conducted to determine the efficiency with which colonies abandon exhausted feeding sites in favor of new food
finds. On their first forays after their food sources were experimentally moved from established feeding sites to new sites,
67.5 ± 3.6% of all the evening’s activity occurred on pathways leading to the previously established sites. During their next
two forays, 86.3 ± 3.7% and 92.1 ± 2.0% of all activity occurred on pathways leading to the new sites. Efficient abandonment
of exhausted feeding sites is attributed to the persistence of the trail pheromone, differential marking of new and old pathways
and to the caterpillar’s ability to discern trail strength and to choose stronger over weaker trails at choice points. 相似文献
18.
Arash Rasekh J. P. Michaud Hossein Allahyari Qodratollah Sabahi 《Journal of Insect Behavior》2010,23(3):165-179
A series of laboratory experiments examined the foraging behavior of a thelytokous strain of Lysiphlebus fabarum (Marshall), a strongly proovigenic parasitoid of Aphis fabae Scopoli, in Iran. Females use chemical camoflage to forage undisturbed in ant-tended aphid colonies and solicit honeydew
from aphids in the manner of ants. Rates of oviposition are very low (∼ 1.2 eggs / h) despite many aphid encounters and persistent
ovipositor probing which appears to prime aphids for subsequent honeydew solicitation. Starved females spent 3.6 times longer
in host patches (leaf disks with 15 2nd–3rd instar A. fabae) than did females sated on honey, and 40% of this time was spent soliciting honeydew. Five d-old females spent longer in
patches than did one d-old females, and parasitized three times as many aphids. A 24 h pre-trial foraging experience did not
reduce mean egg load significantly compared to a one h experience, but was sufficient to reduce patch residence time and number
of aphids parasitized. Wasps reared under short day conditions (L:D = 10:14) were more pessimistic foragers (remained longer
in patches and parasitized more aphids) than females raised under long days (L:D = 16:8). Wasps that encountered aphids previously
parasitized by conspecifics began to superparasitize and remained longer in patches than females that encountered only unparasitized
aphids. Encounters with other females had no effect on foraging behavior, possibly because cuticular camoflage interferes
with conspecific recognition. The exceptionally low oviposition rate of this wasp may reflect a life history in which individual
fitness has evolved to be strongly dependent on continued ant attendance throughout the period of progeny development. 相似文献
19.
Ling Cao Biyu Song Jinmiao Zha Chengtai Yang Xinfu Gong Jianbin Li Weimin Wang 《Environmental Biology of Fishes》2009,86(1):75-88
This study presents fundamental information on the reproductive biology, size and age composition, and growth of yellow catfish,
Peltobagrus fulvidraco. Sampling was carried out monthly from Ce Lake in Hubei province from January 2004 and December 2004. Overall female/male
(F/M) sex ratio was 1.08, not significantly different from expected 1.0 ratio. But sex ratio (F/M) of the spawning group was 1.14:1 with skewness towards females (p < 0.05). The smallest sexually mature male and female massed 20.51 and 16.93 g, and measured 100.1 and 94.3 mm in total length,
respectively. Reproductive period for this species is from April to August when GSI is considerably higher than the rest months
(p < 0.05). The highest GSI values were measured from May to July for both sexes and this period was presumably the peak spawn.
First maturation occurred at age 1+ for both sexes. Fish of age 1+ and 2+ comprised the greatest portion of spawners. The absolute fecundity (AF) of P. fulvidraco ranged from 657 to 11,696 eggs per fish, with mean AF value of 3,570 ± 122 (S.D.) eggs per fish, varying considerably at
given length, weight and age. The fecundity relative to total length (F/L) fluctuated from 58 to 680 eggs/mm, with a mean value of 246 ± 34 (SD) eggs/mm, and fecundity relative to total weight (F/W) varied from 29–133 eggs/g, with a mean value of 67 ± 7 (SD) eggs/g. P. fulvidraco is a single spawner, with low fecundity compared with other Bagrid fish. 相似文献
20.
Fengjuan Zhao Fuli Liu Jidong Liu Put O. AngJr. Delin Duan 《Journal of applied phycology》2008,20(2):191-198
Sargassum muticum is important in maintaining the structure and function of littoral ecosystems, and is used in aquaculture and alginate production,
however, little is known about its population genetic attributes. In this study, random amplified polymorphic DNA (RAPD) and
inter-simple sequence repeat (ISSR) markers were used to investigate the genetic structure of four populations of S. muticum and one outgroup of S. fusiforme (Harv.) Setchell from Shandong peninsula of China. The selected 24 RAPD primers and 19 ISSR primers amplified 164 loci and
122 loci, respectively. Estimates of genetic diversity with different indicators (P%, percentage of polymorphic loci; H, the expected heterozygosity; I, Shannon’s information index) revealed low or moderate level of genetic variations within each S. muticum population, and a high level of genetic differentiations were determined with pairwise unbiased genetic distance (D) and fixation index (F
ST
) among the populations. The Mantel test showed that two types of matrices of D and F
ST
were highly correlated whether from RAPD (r = 0.9706, P = 0.009) or ISSR data (r = 0.9161, P = 0.009). Analysis of molecular
variance (AMOVA) was conducted to apportion the variations among and within the S. muticum populations. It indicated that variations among populations were higher than those within populations, being 55.82% verse
44.18% by RAPD and 55.21% verse 44.79% by ISSR, respectively. Furthermore, the Mantel test suggested that genetic differentiations
among populations were related to the geographical distances (r > 0.6), namely, conformed to the IBD (isolation by distance)
model, as expected from UPGMA (unweighted pair group method with arithmetic averages) cluster analysis. On the whole, the
high genetic structuring among the four S. muticum populations along the distant locations was clearly indicated in RAPD and ISSR analyses (r > 0.9, P < 0.05) in our study. 相似文献