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1.
Within‐Species Mate Preferences Do Not Contribute to the Maintenance of Sexually Monomorphic Mating Signals in Green Lacewings 下载免费PDF全文
Suegene Noh Charles S. Henry 《Ethology : formerly Zeitschrift fur Tierpsychologie》2015,121(7):714-724
We know much less about the evolutionary forces and constraints that maintain similar mating displays in females and males than we do about sexually dimorphic mating displays. Both female and male green lacewings have sexually monomorphic vibrational mating signals and are equally choosy against heterospecific mating signals. This similarity in between‐species sex roles may explain a large part of the presence of species‐specific female signals in these species, but does not necessarily predict why female and male signals are similar. We tested for within‐species sex‐specific similarities in mate preferences in Chrysoperla lucasina that may contribute to the maintenance of sexually monomorphic mating signals in this species. We found weak preferences and low levels of discrimination for signals with varying fine‐scale temporal features (volley duration, period, and volley‐duty cycle). The longer signals that both sexes produced in response to playback were sexually monomorphic, but some females and most males also produced shorter signals with significantly reduced volley durations and periods. Notably, all of these signals had indistinguishable volley‐duty cycles, the ratio of volley duration to volley period. We propose that mating signals in C. lucasina are maintained in both sexes because of similar between‐species mate preferences, but the sexually monomorphic mating signals cannot be attributed to significant within‐species mate preferences. What differences are present in within‐species sex roles may be resolved by a male‐biased signal polymorphism, in long and short signals that are hypothesized to have distinct functions during mate calling and courtship. 相似文献
2.
Natalie L. Hyslop Dirk J. Stevenson John N. Macey Lawrence D. Carlile Chris L. Jenkins Jeffrey A. Hostetler Madan K. Oli 《Population Ecology》2012,54(1):145-156
Demographic data provide a basis for understanding the life history and ecology of species, factors which are vital for informing
conservation efforts; however, little is known regarding the population ecology of most snake species, including the threatened
Eastern Indigo Snake (Drymarchon couperi). We used 11 years (1999–2009) of capture-mark-recapture (CMR) and 2.5 years (2003–2005) of radiotelemetry data from southeastern
Georgia, USA, in a CMR modeling framework to estimate apparent survival, capture and transition probabilities, and evaluate
factors influencing these parameters. The model-averaged estimate of overall apparent annual survival probability was 0.700
(±0.030 SE) and is comparable to that obtained from known fate analysis (radiotelemetry) at the same site. Body size positively
influenced survival, regardless of sex. Capture probability differed seasonally by sex, suggesting lower capture probability
for females in fall and males in winter. There was no evidence for effect of precipitation or site-specific differences in
survival. Model averaged estimate of annual adult survival estimated using multistate CMR models was 0.738 ± 0.030 and 0.515 ± 0.189
for subadults. We estimated population growth rate (λ) and elasticity (proportional sensitivity) of λ to vital rates using a stage-structured matrix population model. Population growth rate ranged from 0.96 to 1.03 depending
on the value of the probability of transitioning from subadult to adult stage. The λ was proportionally most sensitive to changes in adult survival rate, followed by subadult survival. Our results suggest that
protecting adult snakes and their habitats would result in the highest likelihood of long-term population stability and growth. 相似文献
3.
Anja Gladbach Christina Braun Anja Nordt Hans-Ulrich Peter Petra Quillfeldt 《Polar Biology》2009,32(9):1315-1321
Seabirds show a range of patterns of sexual size dimorphism and sex-specific parental investment, but the underlying causes
remain poorly understood. The aim of the present study was to test two longstanding hypotheses of parental investment in a
sexually monomorphic species, Wilson’s storm petrel Oceanites oceanicus, namely that males attend chicks more frequently and females deliver larger meals (Beck and Brown in Br Antarct Surv Sci
Rep 69:1–54, 1972). We recorded in eight seasons, both during incubation and chick rearing, which adult was caught first in a nest and found
no difference in the probability of catching a male or a female first in any year. Additionally, in five seasons we employed
a miniature video camera to record nest attendance during chick rearing and found no significant difference except for 2006,
a year with very low krill availability, where females visited the nest less often than males. We then combined video observations
with periodic weighing of chicks to estimate mean daily feeding mass (g/day) of males and females and found no difference
in the amount of food delivered per day between the sexes. However, in years with low krill availability, males and females
tended to use different strategies to achieve the same feeding rates, with females undertaking longer foraging trips and delivering
heavier meals. Thus, our results do not support the hypothesis of a general sex-specific parental investment in Wilson’s storm
petrels, but a tendency for a context-dependent sex-specific investment in the years of food shortage. 相似文献
4.
Age and growth of ocellated icefish, Chionodraco rastrospinosus DeWitt and Hureau, 1979, from the South Shetland Islands 总被引:1,自引:0,他引:1
Age and growth of ocellated icefish, Chionodraco rastrospinosus, were investigated using counts of annual growth increments from sagittal otoliths. Samples were collected during research
surveys by benthic trawl carried out around Elephant and South Shetland Islands in January–February 2002 and December 2006–January
2007. A total of 290 specimens were selected for the study, consisting of 120 females and 170 males. The age of fish was estimated
by counting annuli on transverse sections obtained by grinding and polishing whole otoliths embedded in epoxy resin. The precision-of-age
estimates within and between readers were tested applying both the average percent error (APE) and the coefficient of variation
(CV). The estimated age-range was 1–12 for both sexes of C. rastrospinosus. Applying the von Bertalanffy growth function to the age–length data, a growth curve was obtained for each sex. The estimated
values of VB growth parameters L
∞
and k were, respectively, 47.9 cm and 0.28 for females and 42.9 cm and 0.36 for males. Compared to other congeneric species, the
growth performance of C. rastrospinosus was relatively high, being 2.82 and 2.81 in males and females, respectively. Age at sexual maturity was estimated to be about
4 years in both sexes. C. rastrospinosus captured in the studied area consisted mainly of adult specimens between 3 and 8 years, with few older fish. 相似文献
5.
Gregory D. Williams Kelly S. Andrews Deborah A. Farrer Gregory G. Bargmann Phillip S. Levin 《Environmental Biology of Fishes》2011,91(4):379-388
The broadnose sevengill shark (Notorynchus cepedianus) is a high-order marine predator distributed worldwide in shallow coastal waters of temperate seas. Recent reports have suggested
it may be a prevalent component of Pacific Northwest coastal estuarine communities, although biological characteristics of
the shark population remain undocumented despite growing interest in recreational harvest of the species. Longline sampling
was conducted in Willapa Bay and Grays Harbor, Washington, USA seasonally during 2003–2006 to collect sevengill shark size,
maturity, and sex ratio data, and establish some baseline catch rate information. Sevengill sharks were collected on 65% of
longline sets and catches were composed of subadult and mature individuals (122–283 cm TL) of both sexes. Most male sevengill
sharks were large sexually mature adults, based on external clasper calcification levels, whereas most comparably sized females
were considered subadults, based on literature-based size-at–maturity estimates. Neonates and young sharks <120 cm were not
collected, nor have they been reported in other historic estuary sampling efforts. Sex ratios were skewed toward males in
Willapa Bay and suggest some degree of sexual segregation for the species, as has been shown for populations elsewhere. We
suggest sevengill sharks are a largely ignored but potentially important predator in Pacific Northwest estuaries. This study
therefore provides some of the first, basic information for guiding management decisions associated with a late-maturing,
slow-growing shark species in these coastal habitats. 相似文献
6.
Long-term behavioral studies require the permanent identification of individuals. The need for individual identification is even more crucial for sexually monomorphic species since not even the sexes can be differentiated by the field observer. Owl monkeys (Aotus spp.) are sexually monomorphic primates inhabiting the forests of Central and South America. We report here on the methods and drug dosages used to capture, mark, and identify individual owl monkeys (Aotus azarai azarai) in Eastern Formosa, Argentina. We successfully captured 70 owl monkeys using blowpipes or a CO2 rifle, but attempts to capture them with baited traps proved unsuccessful. During the marking and collaring procedures, we gave individuals on average a total of 50 mg of ketamine hydrochloride, including the dose in the dart. To mark them, we freeze-branded portions of their tails and fitted them with radio or bead collars. There was no death or physical life-threatening injury while capturing or marking individuals. The procedures we describe should allow one to safely capture and to mark small arboreal primates when trapping is not possible. 相似文献
7.
The effect of temperature on the development of immature stages of the predator Cheyletus malaccensis Oudemans, produced by either fertilized or virgin females, was studied at 17.5, 20, 25, 30, 32.5, and 35°C, 80 ± 5% relative
humidity, in complete darkness, and fed Tyrophagus putrescentiae (Schrank). The population maintained at 15°C failed to reproduce. The thermal data obtained were used for the estimation
of the thermal requirements (developmental thresholds, thermal constant, optimum temperature) of this predator by a linear
and nonlinear model (Logan type I model). Upper and lower developmental thresholds ranged between 37.4–37.8 and 11.6–12.0°C,
respectively. Optimum temperature for development was estimated at between 33.1 and 33.5°C. The thermal constant ranged between
238.1 and 312.5 degree-days. Based on the data of the total pre-imaginal period, immatures’ survival peaked at 25°C. Arrhenotokous
parthenogenesis (haplodiploidy) is confirmed in the species: virgin females always produce males, whereas fertilized females
give rise to offspring of both sexes. Survival of the immature stages and offspring sex ratio were not significantly influenced
by temperature. 相似文献
8.
Thea Ø. Bechshøft Christian Sonne Frank F. Rigét Øystein Wiig Rune Dietz 《Polar Biology》2008,31(8):945-958
Size, growth and sexual dimorphism of nine skull traits was studied in 300 East Greenland and 391 Svalbard polar bears (Ursus maritimus). Two traits were significantly larger in bears from East Greenland compared to Svalbard bears, and trait size was smaller
after 1960 in five traits. For both localities and both age groups (subadult, adult), mean trait size values were higher in
males than females (all: P < 0.05). Gompertz growth models showed trait size increasing with age in seven traits. Depending on the trait, males reached
95% asymptotic trait size at age 3–10, females at age 2–6. The females of both localities matured at approximately the same
age, whereas the Svalbard males generally matured years later than their East Greenland peers. The differences found in the
present study between the two polar bear subpopulations support the notion that East Greenland and Svalbard polar bears probably
should be managed as separate units. 相似文献
9.
Sexual selection theory implies a tight coupling between the evolution of male sexual display and the sensory capabilities
of the female. In sexually dimorphic species it is proposed that this might lead to sex differences in a species’ perceptive
abilities. However, supporting evidence for this is rare, and to date there is only one example; three-spined sticklebacks,
Gasterosteus aculeatus. Here, the female’s visual system is reported to become more red-sensitive during the summer breeding season; a time when
sexually mature males display a red throat and belly to potential mates. In contrast, a shift in sensitivity is not apparent
in males. These results, although commonly quoted, are surprising because previous observations suggest that both sexes may
benefit from the detection of the male’s red colour patch; in females the intensity of red coloration can influence the choice
of mate, and in males the conspicuous red colouration can aid the detection of rival males. To investigate this paradox we
repeated the original optomotor experiment using a fully controlled design. In contrast to the earlier result, we found that
both males and females exhibit a shift in their sensitivity to red during the reproductive period. These new data therefore
do not support the hypothesis that sex differences in perceptual abilities occur in sexually dimorphic species. 相似文献
10.
Tatyana Humle Christelle Colin Matthieu Laurans Estelle Raballand 《International journal of primatology》2011,32(2):456-473
The release of wild or captive-bred mammals within their historical ranges typically aims to reestablish populations in areas
where they have become extinct or extirpated, to reinforce natural populations, or to resolve human–wildlife conflicts. Such
programs, which also typically in parallel help foster the protection of the release site, concern a wide range of endangered
mammalian species, including our closest living relatives: chimpanzees. In June 2008, the Chimpanzee Conservation Center (CCC),
which is located in the High Niger National Park (HNNP) in Guinea, released a group of 12 chimpanzees (Pan troglodytes verus) comprised of 6 females and 6 males (8–20 yr old). The selected release site lies 32 km from the sanctuary in the Mafou,
a core area of HNNP where wild chimpanzees are also known to occur. The purpose of this release was therefore to reinforce
the natural chimpanzee population within the Mafou core area and to promote the protection of the HNNP. Nearly 2 yr postrelease,
9 chimpanzees still remain free-living. Two thirds of the release chimpanzees were equipped with VHF-GPS store-on-board tracking
collars. We used data from retrieved collars to explore the release chimpanzees’ habitat use, individual day range, and core
area use (50% and 80%) during the first year of the release. Males traveled significantly further than females. Although minimum
day range did not differ between the sexes or vary seasonally, some release males were active for longer during the day than
the females. Males also ranged over larger areas and used a wider network of core areas than the females. Habitat use was
similar to that recorded in wild chimpanzees in the HNNP. As of September 2010, 2 males and 3 females form a group at the
release site. Two of these females gave birth to healthy offspring respectively 16 and 20 mo postrelease. Another female successfully
immigrated into a wild chimpanzee community. We suggest that the success of this chimpanzee release can be attributed to the
CCC’s lengthy rehabilitation process and the savanna-mosaic habitat of the HNNP. This release demonstrates that under special
socioecological circumstances, the release of wild-born adult chimpanzees of both sexes is a viable strategy, which can also
function as an effective conservation tool. 相似文献
11.
Sex‐related variation in survival is common in birds and, as it influences effective population size and population growth, is important for conservation and species management. Here we assessed incubation behaviour and sex‐related survival in a threatened sexually monomorphic shorebird, the St Helena Plover Charadrius sanctaehelenae. Males incubated at night, the period of highest activity of cats, which are likely to be predators of breeding birds. In spite of behavioural differences between the sexes, adult survival was not significantly different between males and females, suggesting that sex‐biased behaviour need not lead to sex‐related survival, and thus behavioural differences may not impact upon the adult sex ratio. 相似文献
12.
Le Gouar PJ Schekkerman H van der Jeugd HP Boele A van Harxen R Fuchs P Stroeken P van Noordwijk AJ 《Oecologia》2011,166(2):369-379
The little owl (Athene noctua) has declined significantly in many parts of Europe, including the Netherlands. To understand the demographic mechanisms
underlying their decline, we analysed all available Dutch little owl ringing data. The data set spanned 35 years, and included
more than 24,000 ringed owls, allowing detailed estimation of survival rates through multi-state capture–recapture modelling
taking dispersal into account. We investigated geographical and temporal variation in age-specific survival rates and linked
annual survival estimates to population growth rate in corresponding years, as well as to environmental covariates. The best
model for estimating survival assumed time effects on both juvenile and adult survival rates, with average annual survival
estimated at 0.258 (SE = 0.047) and 0.753 (SE = 0.019), respectively. Juvenile survival rates decreased with time whereas
adult survival rates fluctuated regularly among years, low survival occurring about every 4 years. Years when the population
declined were associated with low juvenile survival. More than 60% of the variation in juvenile survival was explained by
the increase in road traffic intensity or in average temperature in spring, but these correlations rather reflect a gradual
decrease in juvenile survival coinciding with long-term global change than direct causal effects. Surprisingly, vole dynamics
did not explain the cyclic dynamics of adult survival rate. Instead, dry and cold years led to low adult survival rates. Low
juvenile survival rates, that limit recruitment of first-year breeders, and the regular occurrence of years with poor adult
survival, were the most important determinants of the population decline of the little owl. 相似文献
13.
Chronological ages of Alouattaon Barro Colorado Island (BCI) were estimated from longitudinal dental wear. Combining these data with visual censuses, we
approximated the study population’s age profile. A stable model was then constructed; from it we derived agespecific mortality
rates. Mortality of immature animals is high, with 88% of the males and 65% of the females dying before 5 years. Adult mortality
is low until 11 years, when it accelerates. The average adult life span is 16.6 years for males and 15.5 for females. The
maximum life span is over 20 years. A pubertal male growth spurt occurs from 3 to 5 years, at which time females are primiparous.
Sexual size differences develop primarily during this time. The 1976 age profile had anomalously few animals aged 7 years
and males aged 8–9 and 15–16 years. With corroborating evidence, we hypothesize that these deficits resulted from excessive
rainfall in 1963 and 1971, which reduced the fall fruit crop and led to a high juvenile mortality. Within half of our study
troops, some adult males have nearly identical ages, suggesting an active process of agemate coalition. We hypothesize a form
of kin selection, wherein peripheral male cohorts from the same natal troop have greater survival and social success than
solitary animals. The stable model suggests an annual growth rate of 1.5% during the 1970s. Estimates of 16.7 and 4% for the
previous two decades, following a yellow-fever epidemic, imply that the BCI population is becoming stationary. A very different
age structure existed on neighboring Orchid Island in 1976, suggesting general food limitation. By contrast, the lowered,
but continuing growth on BCI suggests a less drastic limiting mechanism. We hypothesize that intratroop social competition
limits population growth by regulating subadult survival rates during food scarcity cycles. 相似文献
14.
Satoko Seki Masanori Kohda Gousuke Takamoto Kenji Karino Yasuhiro Nakashima Tetsuo Kuwamura 《Journal of Ethology》2009,27(2):215-220
The occurrence of polygyny requires specific environmental conditions such as female aggregation or patchy resource distribution.
However, it is difficult to determine the factors responsible for polygyny in species in which the territories of both sexes
overlap. To overcome this, we performed female removal experiments in the polygynous triggerfish Sufflamen chrysopterum (Balistidae) in the Okinawa coral reef. Both sexes defended their territories exclusively against consexuals of the same
species, and female aggregation was absent. Each male territory included 1–3 female territories, and nonterritorial males
were significantly smaller than territorial males. Further, the body size of territorial males was positively correlated with
that of the largest female in their territories, and larger males tended to mate with more females. The results of the female
removal experiments (n = 10 females) indicated that females competed for better territories rather than larger mates. In contrast, males abandoned
the territories once the females emigrated. These results strongly suggest that males defend females rather than sites and
compete for larger and a greater numbers of females. Thus, in S. chrysopterum, female defense polygyny occurs in the absence of female aggregation. 相似文献
15.
E. Lodewijckx 《Behavioural processes》1984,9(4):431-444
From April 1978 to April 1980 the exploratory behaviour of more than 1000 wild wood mice was studied in a modified open field test situation. The influence of sex, sexual condition and age on the exploratory activity was investigated. Sufficient data being available, the exploratory activity of both sexually active and sexually inactive adult males and adult females, of both sexually active and sexually inactive subadult males and subadult females and of both sexually inactive juvenile males and females was compared by means of a one way analysis of variance for each two-month period. In other analyses the influence of age of adult males and adult females on the exploratory behaviour was further examined. No differences could be found in the exploratory activity displayed by males or females and by sexually active or sexually inactive animals. Also a clear influence of age was absent. The interindividual variation was very large. 相似文献
16.
Age and growth of the ajime-loach,niwaella delicata, in the yura river, kyoto, japan 总被引:1,自引:1,他引:0
Yuichi Kano 《Ichthyological Research》2000,47(2):183-186
The age of the Ajime-loach,Niwaella delicata (a species endemic to Japan), was determined from the number of concentric rings appearing on the cross-sectional surface
of the erectile spine (peculiar to Cobitidae). The ages of loaches caught in the Yura River, Kyoto, were determined and growth
rates for each sex estimated. It was found that size dimorphism in this species was due to different growth patterns between
the sexes, 2.5 years old males being larger than females and usually sexually mature, unlike the latter. Females older than
3.5 years were sexually mature and larger than males of equivalent age. 相似文献
17.
Monica J. Chau Anita I. Stone Sally P. Mendoza Karen L. Bales 《Ethology : formerly Zeitschrift fur Tierpsychologie》2008,114(10):989-998
Monogamy is a relatively rare social system in mammals, occurring only in about 3% of mammalian species. Monogamous species are characterized by the formation of pair‐bonds, biparental care, and a very low level of sexual dimorphism. Whereas in most polygynous species males engage in more rough‐and‐tumble play than females, we predicted that males and females of monogamous species would have similar, or monomorphic, play behavior. In this study, we focused on two monogamous species: coppery titi monkeys (Callicebus cupreus) and prairie voles (Microtus ochrogaster). We documented the development of play behavior in both species, and quantified different types of play behavior. We did not find any sex differences in either species in the frequencies and types of play. However, we did find sex differences in the choice of play partner in titi monkeys: female offspring spent a higher proportion of time playing with their father, while male offspring played equally with their mother and father. It is possible that rough‐and‐tumble play behavior is monomorphic in many monogamous mammals, perhaps reflecting differences from polygynous species in the effects of exposure to early androgens or in the estrogen receptor distribution. However, more subtle differences in monomorphic play behavior, such as choice of partner, may still exist. 相似文献
18.
Population of the freshwater amphipod Gammarus fossarum was investigated in a calcareous stream with almost constant temperature (7–8°C) in the Chočské Vrchy Mts (West Carpathians,
Slovakia). Quantitative samples of G. fossarum taken during 2005 showed population densities varying from 100 m−2 in August to 585 m−2 in late November. The population was split into juveniles, mature males, mature females without eggs and females with eggs.
The percentage of juveniles (40–64%) was always the highest of any of the categories. Ovigerous females occurred throughout
the year. The mean sex ratio was 1: 2.4 (male: female), although its values varied considerably with the time of year. Breeding
was continuous, although juvenile recruitment peaked in early spring, summer and early winter. Three discrete cohorts were
distinguished from the size frequency distributions. The life span was 6–7 months and the individuals matured approximately
in the half of life cycle. The mean fecundity was 9.6 embryos per brood. Variation in fecundity was mostly explained by size
of the incubating females. The absolute growth of this species was best described by the Gompertz growth function. Relative
growth rates (% body DM day−1) fluctuated in a nonlinear manner with size and age. The highest values of daily growth (2–4% of dry mass per day) were noted
approximately in the half of life cycle. Annual production, estimated by the size-frequency method, was 1618.9 g dry mass
m−2 and P/B ratio was 5.15. 相似文献
19.
Normative odontometric data are presented on a sample of 66 adult thick-tailed bushbabies Otolemur crassicaudatus(34 male, 32 female). This species is characterized by low levels of sexual dimorphism, with univariate differences centered
on the canines and the maxillary third molar. Multivariate canonical analysis isolates a third discriminator, the maxillary
second molar. Stepwise discriminant analyses, performed after jackknifing, indicate high percentages of correct classification
(males, 79.8–81.8%;females, 81–85.2%). When variability profiles consisting of arrays of CVs are compared, males and females are found to share
similar patterns. Data for maxillary teeth offer support for Gingerich’s occlusal complexity model, while morphogenetic clusterings
within regressions of variability on tooth size conform to those previously reported in other species. These relationships
are lost in the mandibular dentition, suggesting an independence of upper from lower toothsize determination. 相似文献
20.
Conservation of threatened tree species requires basic information on growth rates and ages. This information is lacking for
many species, but can be obtained relatively easily from tree ring analysis. We studied four threatened Vietnamese species:
three conifers from high-elevation forests (Calocedrus macrolepis, Dacrydium elatum and Pinus
kwangtungensis) and one broad-leaved species from lowland forest (Annamocarya sinensis). We collected increment cores from remnant populations in protected areas and measured ring width. We built chronologies
and found significant correlations with rainfall (all species) and temperature (two species), indicating that rings were formed
annually. Diameter-age trajectories showed that species reached reproductive size at 60–80 years. Maximum observed ages were
128–229 years. Some species showed large variation in long-term growth rates among individuals, which was partially explained
by strong persistence of growth differences. We also assessed whether growth rates changed over time. For certain size categories
in some species, we found higher recent growth rates of juvenile trees compared to those in the distant past. This shift requires
a cautious interpretation, but is consistent with a CO2 fertilization effect. For other size categories, we found contrasting results: extant large trees had higher growth rates
as small juveniles compared to extant small trees. Such correlations, which we found for all species, suggest a ‘juvenile
selection effect’: the preferential survival of fast-growing juveniles to the canopy. Information on ages, historical growth
rates and juvenile selection effect is relevant for the planning of conservation actions. 相似文献