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1.
The growth rate, reproductive aspects, and natural mortality of chimaeras and ratfish are poorly known. In this study, life-history
parameters for cockfish Callorhinchus callorhynchus (Holocephali—Callorhinchidae) are estimated, which is an important fish resource exploited in Chile. Specimens were sampled
from the artisanal fishery captures, from November 2006 to November 2007. The standard length (SL) of males fluctuated between
20 and 62 cm, and between 21 and 70 cm for females. Von Bertalanffy growth parameters were estimated through length-frequency
data analysis using MULTIFAN. The length-weight relationship and von Bertalanffy growth parameters were significantly different
for males and females, as well as the length at 50% maturity. For males a model with 5 age-classes was the best, with asymptotic
length L
∞ = 52 cm SL, growth coefficient K = 0.473 yr−1, and age at length zero t
0 = −0.690 yrs. For females the best model was represented by 10 age-classes (L
∞ = 70.3 cm SL, K = 0.193 yr−1, t
0 = −1.158 yrs) in the length-frequency data sets. Length at 50% maturity of males was estimated in 43.7 cm SL, and in 50.2 cm
SL for females. The natural mortality rate fluctuated between 0.42 and 0.82 yr−1 for males and between 0.12 and 0.37 yr−1 for females, depending upon the method used. It is concluded that C. callorhynchus is a species with life-history parameters significantly different between males and females, and such differences should
be taken into account in future population dynamics analysis. 相似文献
2.
Atsushi Nanami Takeo Kurihara Yutaka Kurita Yoshimasa Aonuma Nobuaki Suzuki Hideaki Yamada 《Ichthyological Research》2010,57(3):240-244
The humpback red snapper Lutjanus gibbus (Lutjanidae) is an important species for fisheries in the Kagoshima and Okinawan region of Japan. The present study estimated
the age, growth and reproduction of this lutjanid species in the waters around Ishigaki Island, southern part of Okinawa.
An opaque zone was formed on the otolith every year, and this formation correlated with their spawning season; these zones
were identified as annual rings. Maximum ages of 21 and 24 years were observed for males and females, respectively. The von
Bertalanffy growth parameters clarifying the age–fork length relationship were as follows: L
∞ = 390.5 mm, K = 0.210 year−1 and t
0 = −1.88 year for males, and L
∞ = 303.4, K = 0.256 year−1 and t
0 = −3.05 year for females. The main spawning season was estimated as between May and October, since greater values of gonadosomatic
index for females as well as maturation oocytes and/or postovulatory follicles were observed during those six months. 相似文献
3.
Delphinium staphisagria is an endemic annual or biennial herb from the Mediterranean Basin, widely distributed in isolated populations of variable
size. We evaluated the allozyme diversity of 31 populations along its distribution range via starch gel electrophoresis, assaying
12 enzyme systems and scoring 17 loci. The low levels of genetic variability detected (A = 11.8, A
p = 1.6, H
o = 0.026, H
e = 0.057), are discussed in relation to the life-history traits of the species, such as short life-span, selfing or gravity
seed dispersion. Other factors influencing genetic diversity, such as evolutionary history and spreading are also considered.
Due to its historical medicinal uses, this plant has probably become widespread in the Mediterranean area. Human-mediated
distribution could have promoted few migrant genotypes, recent founder events and long distance dispersal. These events would
explain the genetic homogeneity found within and among populations, as well as the absence of a clear biogeographic structure.
The limited genetic variability, the high genetic similarity among populations and the dysploidy of this species make it worthy
of conservation. Management strategies are proposed mainly to preserve its genetic pool. 相似文献
4.
Park JJ Kim M Lee JH Shin KI Lee SE Kim JG Cho K 《Experimental & applied acarology》2011,54(3):243-259
Laboratory bioassays were conducted to evaluate the sublethal effects of fenpyroximate and pyridaben on life-table parameters
of two predatory mites species, Neoseiulus (= Amblyseius) womersleyi and Phytoseiulus persimilis. In these assays, young adult females were treated with three sublethal concentrations of each acaricide. The life-table
parameters were calculated at each acaricide concentration, and compared using bootstrap procedures. For each acaricide, the
LC50 estimates for both species were similar, yet the two species exhibited completely different susceptibility when the population
growth rate was used as the endpoint. Exposure to both acaricides reduced the net reproduction rate (R
o
) in a concentration-dependent manner and their EC50s were equivalent to less than LC7. Two different scales of population-level endpoints were estimated to compare the total effect between the species and treatments:
the first endpoint values were based on the net reproductive rate (fecundity λ) and the second endpoint values incorporated
the mean egg hatchability into the net reproductive rate (vitality λ). The fecundity λ decreased in a concentration-dependent
manner for both acaricide treatments, but the vitality λ decreased abruptly after treatment of N. womersleyi with pyridaben. The change in the patterns of λ revealed that the acaricide effects at the population level strongly depended
on the life-history characteristics of the predatory mite species and the chemical mode of action. When the total effects
of the two acaricides on N. womersleyi and P. persimilis were considered, fenpyroximate was found to be the most compatible acaricide for the augmentative release of N. womersleyi after treatment. 相似文献
5.
Romolo Caniglia Elena Fabbri Sarah Cubaynes Olivier Gimenez Jean-Dominique Lebreton Ettore Randi 《Conservation Genetics》2012,13(1):53-64
Non-invasive genetic sampling (NGS) is increasingly used to estimate the abundance of rare or elusive species such as the
wolf (Canis lupus), which cannot be directly counted in forested mountain habitats. Wolf individual and familial home ranges are wide, potentially
connected by long-range dispersers, and their populations are intrinsically open. Appropriate demographic estimators are needed,
because the assumptions of homogeneous detection probability and demographic closeness are violated. We compiled the capture–recapture
record of 418 individual wolf genotypes identified from ca. 4,900 non-invasive samples, collected in the northern Italian
Apennines from January 2002 to June 2009. We analysed this dataset using novel capture–recapture multievent models for open
populations that explicitly account for individual detection heterogeneity (IDH). Overall, the detection probability of the
weakly detectable individuals, probably pups, juveniles and migrants (P = 0.08), was ca. six times lower than that of the highly detectable wolves (P = 0.44), probably adults and dominants. The apparent annual survival rate of weakly detectable individuals was lower (Φ = 0.66)
than those of highly detectable wolves (Φ = 0.75). The population mean annual finite rate of increase was λ = 1.05 ± 0.11,
and the mean annual size ranged from N = 117 wolves in 2003 to N = 233 wolves in 2007. This procedure, combining large-scale NGS and multievent IDH demographic models, provides the first
estimates of abundance, multi-annual trend and survival rates for an open large wolf population in the Apennines. These results
contribute to deepen our understanding of wolf population ecology and dynamics, and provide new information to implement sound
long-term conservation plans. 相似文献
6.
Schizopygopsis younghusbandi younghusbandi is an endemic species whose distribution is restricted to the middle reaches of the Yarlung Zangbo River, being one of the
most important commercial fishes in this area. Age and growth of 606 specimens captured between October 2002 and April 2005
were studied. The range in standard length (L) was 65.7–387.3 mm and total weight (W) was 3.3–772.0 g. The relationship between
L and W was W = 0.000909L2.2493 for males and W = 0.000259L2.4781 for females. Age, determined from anal scales and lapillus otoliths, ranged from 3 to 18 years. The parameters of von Bertalanffy
growth functions, estimated by back-calculated length, were L¥ = 442.7mm LL_\infty = 442.7mm\;L, k = 0.0738 year−1 and t
0
= −1.4 year for males, and L¥ = 471.4mm LL_\infty = 471.4mm\;L, k = 0.0789 year−1 and t
0 = 0.2 year for females. Males and females exhibited statistically significant differences in growth. χ
2-test indicated that von Bertalanffy growth functions could well describe the growth of S. y. younghusbandi. The longevities were 39.2 and 38.2 years for males and females, respectively. Growth inflexion points were 10.2 and 12.0 years
for males and females, respectively, but 84.8% of the captures were at the smaller ages. So conservation and management schemes
for this population should be considered urgently. In addition, we found that populations from the upstream of the Lhasa River,
the downstream of the Lhasa River and the middle reaches of the Yarlung Zangbo River showed statistically significant differences
in growth patterns. 相似文献
7.
This study tests population genetic patterns across the Eurasian dreissenid mussel invasions of North America—encompassing
the zebra mussel Dreissena polymorpha (1986 detection) and the quagga mussel D. rostriformis
bugensis (detected in 1990, which now has largely displaced the former in the Great Lakes). We evaluate their source-spread relationships
and invasion genetics using 9–11 nuclear microsatellite loci for 583 zebra mussels (21 sites) and 269 quagga mussels (12 sites)
from Eurasian and North American range locations, with the latter including the Great Lakes, Mississippi River basin, Atlantic
coastal waterways, Colorado River system, and California reservoirs. Additionally, mtDNA cytochrome b gene sequences are used to verify species identity. Our results indicate that North American zebra mussels originate from
multiple non-native northern European populations, whereas North American quagga mussels trace to native estuaries in the
Southern Bug and Dnieper Rivers. Invasive populations of both species show considerable genetic diversity and structure (zebra
F
ST = 0.006–0.263, quagga F
ST = 0.008–0.267), without founder effects. Most newer zebra mussel populations have appreciable genetic diversity, whereas
quagga mussel populations from the Colorado River and California show some founder effects. The population genetic composition
of both species changed over time at given sites; with some adding alleles from adjacent populations, some losing them, and
all retaining closest similarity to their original composition. Zebra mussels from Kansas and California appear genetically
similar and assign to a possible origin from the St. Lawrence River, whereas quagga mussels from Nevada and California assign
to a possible origin from Lake Ontario. These assignments suggest that overland colonization pathways via recreational boats
do not necessarily reflect the most proximate connections. In conclusion, our microsatellite results comprise a valuable baseline
for resolving present and future dreissenid mussel invasion pathways. 相似文献
8.
Dustin G. Loftis Anthony A. Echelle Haruko Koike Ronald A. Van Den Bussche C. O. Minckley 《Conservation Genetics》2009,10(2):453-463
Data from 10 microsatellite DNA loci were used to describe the genetic structure of the two extant species (Cyprinodon macularius and C. eremus) of the endangered Desert Pupfish complex of southwestern United States and northwestern Mexico. Variation at microsatellite
loci was significantly correlated (Mantel test) with that of previous mtDNA results, both for the complex and for the relatively
wide-ranging C. macularius alone. Both species showed unusually high levels of microsatellite diversity for non-marine fish (H
e = 0.84–0.93; AR = 11.9–17.0). There was evidence (R
ST > F
ST) that the two extant populations of C. eremus have been isolated sufficiently long for mutation to contribute significantly to genetic divergence, whereas divergence among
the nine assayed populations of C. macularius could be attributed to genetic drift alone. Correspondingly, 10% of the diversity in C. eremus was attributable to differences between the two populations, whereas, for C. macularius, only 2.7% was attributable to among-population variation. Within C. macularius, a small (0.8%), but statistically significant, portion was attributable to differences between populations in the Salton
Sea area and those on the lower Colorado River delta. The two populations of C. eremus and five groups of populations of C. macularius are recommended as management units for conservation genetics management of the two species. 相似文献
9.
Previous studies have reached different discussions about the genetic variation and genetic structure of Quercus crispula populations in northeastern Japan. This is a common oak species in Eastern Asia. Some studies have suggested that the populations
in northeastern Japan were derived from those remaining in the southwest after the last glacial maximum (LGM), whilst other
studies have found evidence that populations persisted in northeastern Japan during the LGM. Using seven highly polymorphic
nuclear simple sequence repeat loci, we investigated the genetic structure of 16 Q. crispula populations along a latitudinal gradient in northeastern Japan (northern Honshu and Hokkaido), spanning about half of the
species’ biogeographic range in the country. Although the level of population differentiation was low (F
ST = 0.021;
G¢\textST G^{\prime}_{\text{ST}} = 0.090), two geographically differentiated clusters were detected by STRUCTURE analysis. The first cluster included most
of the populations in Hokkaido, and may indicate continued survival throughout past glacial periods. We found a significant
decrease in allelic richness with latitude, so the second cluster may represent an expansion of the lineage from Honshu during
the post-glacial period. These results should enhance our understanding of historical north–south migrations of this species
in northeastern Japan. 相似文献
10.
Since fishery management regulations have shifted much of the groundfish trawl effort in the northeastern Pacific from the
continental shelf to the slope, fishery impacts on unassessed demersal slope rockfish species like the aurora rockfish (Sebastes aurora) may have increased. Understanding the life history of these species is a critical first step in developing management strategies
to protect them from overharvest. In this study we employ cross-dating methods to validate the annual periodicity of growth
increments and investigate the age, growth and maturity of aurora rockfish, a species for which life history information is
quite limited. Specimens were collected on an opportunistic basis from Oregon commercial landings and from research cruises,
over the years 2003–2006. Age was estimated for 438 individuals using otoliths processed via the break-and-burn method. The
maximum estimated age was 118 years for females (n = 324) and 81 years for males (n = 114). The von Bertalanffy growth function showed that males grow faster and reach a smaller maximum size than females (males:
L
inf = 34, K = 0.09, t
0 = −1.9; females: L
inf = 37, K = 0.06, t
0 = −5.5), though both sexes demonstrate relatively slow growth. Visual assessment of ovaries showed that the aurora rockfish
is a synchronous spawner with parturition occurring in May and June off Oregon. Female age and length at 50% maturity were
calculated at 12.6 years and 26 cm, respectively (n = 307). Maturity and age data provided evidence for a protracted adolescence in this species. 相似文献
11.
Ines Fürtbauer Oliver Schülke Michael Heistermann Julia Ostner 《International journal of primatology》2010,31(4):501-517
Information on basic reproductive parameters and life-history traits is crucial for the understanding of primate evolution,
ecology, social behavior, and reproductive strategies. Here, we report 4 yr of data on reproductive and life-history traits
for wild female Assamese macaques (Macaca assamensis) at Phu Khieo Wildlife Sanctuary, northeastern Thailand. During 2 consecutive reproductive seasons, we investigated reproductive
behavior and sexual swelling size in 16 females and collected 1832 fecal samples. Using enzyme immunoassays, we measured fecal
estrogen and progesterone metabolites to assess ovarian activity and timing of ovulation and to ascertain conceptions and
pregnancies. Timing of reproduction was strictly seasonal (births: April–July, 86% in April–June, 4 yr, n = 29; conceptions: October–February, 65% in December–January, 2 yr, n = 17). Females showed no cyclic ovarian activity outside the mating season and conceived in their first or second cycle (mean:
1.2 cycles to conception, n = 13). Gestation length was on average 164.2 d (range: 158–170, n = 10), and females had their first infant at an age of 5 yr (n = 4). Interbirth intervals were bimodally distributed, with females giving birth on average every 13.9 or 23.2 mo. Shorter
interbirth intervals were linked to early parturition within the birth season. Most females displayed subcaudal sexual swellings
which, however, did not reliably indicate female reproductive status or fertility. Overall, our results fall within the range
of findings reported for other macaque species. These results thus add to the growing body of information available for wild
macaques, facilitating comparative studies for a better understanding of interspecific differences in social and reproductive
patterns. 相似文献
12.
Lu N Yang Y Wang Y Liu Y Fu G Chen D Dai H Fan X Hui R Zheng Y 《Molecular biology reports》2012,39(6):6581-6589
The polymorphisms of angiotensin-converting enzyme 2 (ACE2) gene have been suggested to be linked to increase risk of essential hypertension in multiple populations. However, the
results are still debatable. To assess the association between ACE2 G8970A genetic polymorphism and essential hypertension, we conducted a meta-analysis of case–control studies across different
ethnicity. PubMed, Embase, CBM, Wanfang and VIP databases were searched, and a total of 11 separate studies in females and
nine separate studies in males met the inclusion criteria. Because ACE2 is on the X chromosome, data for each sex were analyzed separately. The selected studies contained 7,251 (4,472 females/2,779
males) hypertensive patients and 3,800 (2,161 females/1,639 males) normotensive controls. A statistically significant association
was observed between the G8970A gene polymorphism and essential hypertension risk in female hypertensive group in the recessive
genetic model (AA vs. GG+GA: P = 0.03, OR = 1.15, 95% CI = 1.02–1.30, P
heterogeneity = 0.40, I
2 = 5%, fixed-effects model). Although no association was shown between the frequency of the A allele and the genetic susceptibility
to essential hypertension in all male patients (A Allele: P = 0.38, OR = 1.10, 95% CI = 0.89–1.38, P
heterogeneity = 0.02, I
2 = 56%, random-effects model), we found that the relationship between carrier of A allele and the essential hypertension risk
in Han-Chinese male patients subgroup (A Allele: P = 0.006, OR = 1.21, 95% CI = 1.06–1.38, P
heterogeneity = 0.10, I
2 = 44%, fixed-effects model). The current meta-analysis provided solid evidence suggesting that ACE2 gene polymorphism G8790A was probably a genetic risk factor for essential hypertension across different ethnic populations
in female subjects and in Han-Chinese male subjects. 相似文献
13.
Williams CT Sheriff MJ Schmutz JA Kohl F Tøien Ø Buck CL Barnes BM 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(8):1101-1109
Precise measures of phenology are critical to understanding how animals organize their annual cycles and how individuals and
populations respond to climate-induced changes in physical and ecological stressors. We show that patterns of core body temperature
(T
b) can be used to precisely determine the timing of key seasonal events including hibernation, mating and parturition, and
immergence and emergence from the hibernacula in free-living arctic ground squirrels (Urocitellus parryii). Using temperature loggers that recorded T
b every 20 min for up to 18 months, we monitored core T
b from three females that subsequently gave birth in captivity and from 66 female and 57 male ground squirrels free-living
in the northern foothills of the Brooks Range Alaska. In addition, dates of emergence from hibernation were visually confirmed
for four free-living male squirrels. Average T
b in captive females decreased by 0.5–1.0°C during gestation and abruptly increased by 1–1.5°C on the day of parturition. In
free-living females, similar shifts in T
b were observed in 78% (n = 9) of yearlings and 94% (n = 31) of adults; females without the shift are assumed not to have given birth. Three of four ground squirrels for which
dates of emergence from hibernation were visually confirmed did not exhibit obvious diurnal rhythms in T
b until they first emerged onto the surface when T
b patterns became diurnal. In free-living males undergoing reproductive maturation, this pre-emergence euthermic interval averaged
20.4 days (n = 56). T
b-loggers represent a cost-effective and logistically feasible method to precisely investigate the phenology of reproduction
and hibernation in ground squirrels. 相似文献
14.
J. Terraube B. E. Arroyo F. Mougeot T. E. Katzner E. A. Bragin 《Journal of Ornithology》2010,151(3):713-722
The ecology and conservation status of Central Asian populations of Montagu’s Harriers Circus pygargus are poorly known. We studied the breeding biology of this species during 3 years in the Naurzum region, north-central Kazakhstan.
Most Montagu’s Harriers in the study area nested in the forest-steppe transition area, in bushy areas dominated by dogrose
Rosa canina, which was apparently the nesting vegetation type providing highest and densest nest cover in the study area. Laying occurred
from 26 April to 7 June (average 13 May, n = 49) and, although it varied significantly between years, was earlier than in western European populations of similar latitude.
Mean (±SD) clutch size was 4.44 ± 0.86 (range 2–6; n = 50), in the higher range observed for the species. There was no significant interannual variation in clutch size, despite
large variations in the abundance of small mammals in the area. Diet was mainly composed of lizards (54.2%, n = 533 identified prey in all 3 years), with small mammals (17.1%), passerine birds (14.3%) and insects (13.6%) also being
consumed. Mean brood size at the last visit was 2.55 ± 2.10 (range 0–6; n = 51). Failure rate was relatively high; the main identified cause of nest failure was predation. We compare the data obtained
in this population breeding in natural steppes with breeding parameters from the well-studied western European populations,
and discuss the implications for the conservation of this species. 相似文献
15.
Tomomi Dan Hajime Ikeda Yuki Mitsui Yuji Isagi Hiroaki Setoguchi 《Conservation Genetics》2009,10(4):859-867
Continental island systems harbour relict biota and populations that might have migrated during glacial periods due to the
formation of landbridges. Here we analysed the genetic structure of relict populations of the temperate plant Shortia rotundifolia on the subtropical island of Iriomotejima, Japan. This plant, which inhabits riparian environments, is designated “near threatened”.
Only five extant populations have been found on the island. Our analyses of 10 nuclear microsatellite loci detected genetic
diversity of H
E = 0.488 and H
O = 0.358 for all populations of S. rotundifolia on the island. A high inbreeding coefficient for all populations together (F
IS = 0.316) and each population separately (F
IS = 0.258–0.497) might be attributable to crossing among closely related descendants within a population, an idea that is supported
by the relatedness coefficient. These results and an examination of the populations’ demographic histories suggest that the
extant populations on Iriomotejima have not experienced a recent population bottleneck. The five extant populations were genetically
differentiated (F
ST = 0.283; P < 0.001), suggesting low seed dispersal by gravity and/or low pollen flow via pollinators in the riparian environment. In
addition, population differentiation was not related to genetic distance, implying that at one time, ancestral populations
might have been distributed over a wider area of the island. However, population fragmentation and range contraction might
have occurred at random during the postglacial period. 相似文献
16.
Rebecca L. Bentzen Abby N. Powell Laura M. Phillips Robert S. Suydam 《Polar Biology》2010,33(8):1075-1082
Incubating birds balance their energetic demands during incubation with the needs of the developing embryos. Incubation behavior
is correlated with body size; larger birds can accumulate more endogenous reserves and maintain higher incubation constancy.
King eiders (Somateria spectabilis) contend with variable and cold spring weather, little nesting cover, and low food availability, and thus are likely to rely
heavily on endogenous reserves to maintain high incubation constancy. We examined the patterns of nest attendance of king
eiders at Teshekpuk and Kuparuk, Alaska (2002–2005) in relation to clutch size, daily temperature, and endogenous reserves
to explore factors controlling incubation behavior. Females at Kuparuk had higher constancy (98.5 ± 0.2%, n = 30) than at Teshekpuk (96.9 ± 0.8%, n = 26), largely due to length of recesses. Mean recess length ranged from 21.5 to 23.7 min at Kuparuk, and from 28.5 to 51.2 min
at Teshekpuk. Mean body mass on arrival at breeding grounds (range; Teshekpuk 1,541–1,805, Kuparuk 1,616–1,760), and at the
end of incubation (Teshekpuk 1,113–1,174, Kuparuk 1,173–1,183), did not vary between sites or among years (F < 1.1, P > 0.3). Daily constancy increased 1% with every 5°C increase in minimum daily temperature (β
min = 0.005, 95% CI 0.002, 0.009). Higher constancy combined with similar mass loss at Kuparuk implies that females there met
foraging requirements with shorter recesses. Additionally, females took more recesses at low temperatures, suggesting increased
maintenance needs which were potentially ameliorated by feeding during these recesses, indicating that metabolic costs and
local foraging conditions drove incubation behavior. 相似文献
17.
Spatiotemporal variation in reproductive rates is a common phenomenon in many wildlife populations, but the population dynamic
consequences of spatial and temporal variability in different components of reproduction remain poorly understood. We used
43 years (1962–2004) of data from 17 locations and a capture–mark–recapture (CMR) modeling framework to investigate the spatiotemporal
variation in reproductive parameters of yellow-bellied marmots (Marmota flaviventris), and its influence on the realized population growth rate. Specifically, we estimated and modeled breeding probabilities
of two-year-old females (earliest age of first reproduction), >2-year-old females that have not reproduced before (subadults),
and >2-year-old females that have reproduced before (adults), as well as the litter sizes of two-year old and >2-year-old
females. Most reproductive parameters exhibited spatial and/or temporal variation. However, reproductive parameters differed
with respect to their relative influence on the realized population growth rate (λ). Litter size had a stronger influence than did breeding probabilities on both spatial and temporal variations in λ. Our analysis indicated that λ was proportionately more sensitive to survival than recruitment. However, the annual fluctuation in litter size, abetted
by the breeding probabilities, accounted for most of the temporal variation in λ.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
Andrew J. Gregory Robb S. A. Kaler Thomas J. Prebyl Brett K. Sandercock Samantha M. Wisely 《Conservation Genetics》2012,13(2):465-474
Island populations and populations established by reintroductions are prone to extinction, in part because they are vulnerable
to deterministic and stochastic phenomena associated with geographic isolation and small population size. As population size
declines, reduced genetic diversity can result in decreased fitness and reduced adaptive potential, which may hinder short-
or long-term population viability. We used 32 microsatellite markers to investigate the conservation genetics of a newly established
population of Evermann’s Rock Ptarmigan (Lagopus muta evermanni) at Agattu Island, in the western Aleutian Archipelago, Alaska. We found low genetic diversity (observed heterozygosity = 0.41,
allelic richness = 2.2) and a small effective population size (N
e
= 28.6), but a relatively large N
e
/N ratio = 0.55, which was attributed to multiple paternity in 80% of the broods and low reproductive skew among males (λ = 0.29).
Moreover, successful breeding pairs were less related to each other than random male–female pairs. For conservation efforts
based on reintroductions, a mating system with high rates of multiple paternity may facilitate retention of genetic diversity,
thereby reducing the potential for inbreeding in small or isolated populations. Our results underscore the importance of quantifying
genetic diversity and understanding the breeding behavior of translocated populations. 相似文献
19.
Joël Meunier Janine W. Y. Wong Yamenah Gómez Sabine Kuttler Lilian Röllin Dimitri Stucki Mathias Kölliker 《Evolutionary ecology》2012,26(3):669-682
Whether to reproduce once or multiple times (semelparity vs. iteroparity) is a major life-history decision that organisms
have to take. Mode of parity is usually considered a species characteristic. However, recent models suggested that population
properties or condition-dependent fitness payoffs could help to maintain both life-history tactics within populations. In
arthropods, semelparity was also hypothesised to be a critical pre-adaptation for the evolution of maternal care, semelparous
females being predicted to provide more care due to the absence of costs on future reproduction. The aim of this study was
to characterize potential fitness payoffs and levels of maternal care in semel- and itero-parous females of the European earwig
Forficula auricularia. Based on 15 traits measured in 494 females and their nymphs, our results revealed that iteroparous females laid their first
clutch earlier, had more eggs in their first clutch, gained more weight during the 2 weeks following hatching of the first
clutch, but produced eggs that developed more slowly than semelparous females. Among iteroparous females, the sizes of first
and second clutches were significantly and positively correlated, indicating no investment trade-off between reproductive
events. Iteroparous females also provided more food than semelparous ones, a result contrasting with predictions that iteroparity
is incompatible with the evolution of maternal care. Finally, a controlled breeding experiment reported full mating compatibility
among offspring from females of the two modes of parity, confirming that both types of females belong to one single species.
Overall, these results indicate that alternative modes of parity represent coexisting life-history tactics that are likely
to be condition-dependent and associated with offspring development and specific levels of maternal care in earwigs. 相似文献
20.
The genetic diversity and population structure of the vulnerable Chinese Egret (Egretta eulophotes) were surveyed in the present study from three archipelagoes that cover the most southerly to the very northerly parts of
the Chinese distribution range of this species, using a 433-bp fragment of the mitochondrial control region (CR). Among 90
individual samples, 31 different haplotypes were defined by 30 polymorphic sites. Overall haplotype diversity, nucleotide
diversity and mean sequence divergence (p-distance) of this egret were 0.920, 0.0088 and 1.11%, respectively. NJ tree and
parsimony network for the CR haplotypes of the Chinese Egret showed little genetic structure, and analysis of molecular variance
indicated low but significant genetic differentiation (haplotype-based ΦST = 0.03267, P < 0.05 and distance-based ΦST = 0.04194, P < 0.05) among populations. The significant Fu’s F
S
tests (Fu’s F
S
= −16.946, P < 0.01) and mismatch distribution analysis (τ = 4.463, SSD = 0.0081, P = 0.12) suggested that the low genetic differentiation and little geographical structure of the genetic differentiation might
be explained by the population expansion. The Mantel test (haplotype-based F
ST, r = 0.639, P = 0.34 and distance-based F
ST, r = 0.947, P = 0.15) suggest that the significant genetic differentiation among populations was likely due to isolation by distance. 相似文献