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181.
Wolfgang Forstmeier Dennis Hasselquist Staffan Bensch Bernd Leisler 《Behavioral ecology and sociobiology》2006,59(5):634-643
Song complexity is often regarded as a sexually selected trait that reflects the overall quality of a male. In many passerine
species, old males possess larger song repertoires than younger males. This may be either because individual males improve
their performance as they get older (longitudinal increase) or because poor singers have reduced viability and, hence, are
underrepresented in old age classes (cross-sectional increase). We studied the age dependence of repertoire size and other
song traits in a German and a Swedish great reed warbler (Acrocephalus arundinaceus) population. We found marked differences between longitudinal and cross-sectional approaches, as well as between the two
study populations. In the German population, we found that syllable switching, a measure of immediate versatility and strophe
length, increased with age in a cross-sectional analysis. This was not because birds improved with age (longitudinally) but
because syllable switching was positively correlated with male longevity. However, in Sweden, syllable switching seemed to
be unrelated to age and longevity. In the Swedish population, individual males increased their repertoire size as they got
older (longitudinal increase), but this did not happen in the German population. Hence, two populations, even when belonging
to the same subspecies, may differ in whether or not they show delayed song maturation. 相似文献
182.
183.
184.
Bryan F. J. Manly 《Environmental and Ecological Statistics》2004,11(4):367-383
Recently the two-phase adaptive stratified sampling design proposed by Francis (1984) has been extended by Manly et al. (2002) for situations where several biological populations are sampled simultaneously, and where this is done at several different geographical locations in order to estimate population totals or means. The method uses the results from a first phase sample to decide how best to allocate a second phase sample to locations and strata, in order to maximise a criterion (based on estimated coefficients of variation) that measures the accuracy of estimation for population totals, for all variables at all locations. One potential problem with this method is bias in the estimators of the population totals and means. In this paper bootstrapping is considered as a means of overcoming these biases. It is shown using model populations of Pacific walrus and shellfish, based on real data, that bootstrapping is a useful tool for removing about half of the bias. This is also confirmed from some simulations using artificial data. 相似文献
185.
4个岷江柏种群的球果和种子形态特征及其地理空间差异 总被引:12,自引:0,他引:12
研究了我国四川和甘肃地区特有珍稀濒危植物岷江柏(Cupressus chenggiana S.Y.Hu)的4个地理种群球果和种子的形态特征,分析了不同生境条件下岷江柏的地理差异.结果表明:岷江柏球果呈椭球形,长(l)为1.5~2.5cm,宽(6)为1.5~2.0cm,重(m)为1.5~4.5g,球果鳞片数为8~11片,球果内种子粒数为40~70粒.在调查的4个岷江柏种群中,小金县种群的球果最大、球果内种子数最多,马尔康县种群和金川县种群的球果重量、球果内种子数居中,理县种群的球果最小、球果内种子数最少.讨论认为,4个种群球果和种子大小特征存在极显著差异,不同种群球果和种子的形态差异与岷江柏的种群遗传特征、气候特征和生境特征有着密切的关系.图3表7参25 相似文献
186.
Mathias Kölliker 《Behavioral ecology and sociobiology》2007,61(9):1489-1497
The evolution of parental care and family group formation critically depends on offspring survival benefits and parental fecundity
costs of care under given ecological conditions. Investigations of the functional significance of care in insect species that
exhibit facultative parental care have been relatively rare but may be of particular interest for better understanding of
benefit and cost schedules at an early evolutionary stage. In this study, aspects of benefits and costs of care were addressed
in the sub-social European earwig (Forficula auricularia; Dermaptera: Forficulidae) by manipulating the presence of tending mothers and brood size in a fully crossed experimental
design. Larvae growing in broods tended by their mother or of reduced size showed a higher survival probability than larvae
growing in untended or large broods, as predicted if maternal care is beneficial and shaped by a trade-off between number
and quality of offspring. Analysis of patterns of food consumption and developmental time further suggested that the benefit
of maternal attendance is mediated by the maternal provisioning of food, while the quality–quantity trade-off seemed to be
driven by sibling rivalry. Further, tending mothers delayed the production of a second clutch, indicating a potential cost
of care in terms of lifetime fecundity. This study experimentally shows benefits and potential costs of maternal care and
family group formation in the European earwig. More detailed behavioural experiments will be required to fully understand
how behavioural interactions among family members mediate these reproductive outcomes. 相似文献
187.
Jason Munshi-South 《Behavioral ecology and sociobiology》2007,62(2):201-212
Monogamy is rare in mammals (<5% spp.) but occurs in greater frequency among primates (15%) and their close relatives, the
treeshrews (100%; Order: Scandentia). Two genetic studies of parentage in monogamous primates revealed high rates of extra-pair
paternity (EPP), but to date parentage has not been studied in a treeshrew species. I analyzed the genetic parentage of 22
offspring from two populations of large treeshrews in Sabah, Malaysia (NE Borneo), using seven autosomal microsatellite loci
and one mitochondrial DNA marker. Half of these offspring were sired by males that were not the presumed partner of the mother
(50% EPP), and three litters exhibited evidence of multiple paternity. However, comparative analysis indicated that the high
rate of EPP in Tupaia tana is not associated with intense sperm competition. Relative testis size of treeshrews was similar to testis size in 22 primate
species with uni-male mating systems but smaller than 44 primates with multi-male mating systems. After factoring out the
effects of body size and phylogeny, I also found that the evolution of multi-male mating systems was significantly associated
with the evolution of larger testis size. Male–female pairs of T. tana occupy joint territories but forage and sleep alone (“dispersed pair-living”), and I argue that this form of behavioral monogamy
renders mate guarding ineffective. The adaptive advantages of behavioral monogamy likely differ from the advantages driving
EPP in large treeshrews. However, small testis size suggests that behavioral monogamy is not masking a dispersed multi-male
mating system in this species. 相似文献
188.
黄泥土微团聚体颗粒组对Cu2+的吸附与解吸研究 总被引:1,自引:1,他引:1
采用低能量超声波分散和冷冻机干燥法提取太湖地区黄泥土不同粒径微团聚体颗粒组样品,用平衡液吸附法和CaCl2与HCl溶液的连续解吸法研究原土和不同粒径微团聚体颗粒组对重金属Cu2 的吸附和解吸特征。结果表明,对于Cu2 的吸附,原土用Langmuir方程拟合最佳,而不同粒径微团聚体颗粒组用Freundlich方程拟合最佳。原土和不同粒径微团聚体颗粒组吸附量大小顺序为粘粒级>砂粒级>原土>粉砂级>粗粉砂级,这与其游离氧化铁和有机质含量呈显著正相关。原土和不同粒径微团聚体颗粒组对Cu2 的专性吸附质量分数随吸附量增加而减少,而非专性吸附质量分数则相反。不同粒径微团聚体颗粒组吸附总量小于原土,所以传统风干磨细的研究方法可能高估了土壤对铜固持能力。 相似文献
189.
The benefit of group living is a fundamental question in social evolution. For sociality to evolve, each individual must gain
in terms of some fitness component by living in larger groups. However, in social insects, a decrease in per capita success in brood production has been observed in larger groups. While it has been proposed that this decrease could be outweighed
by an increase in the predictability of success, a functional basis to this hypothesis has so far never been demonstrated.
In this paper, using foraging economics as a functional proxy to colony productivity, we construct a model to explore how
number of foragers in the colony interacts with the ecology of resources to influence per capita foraging success and its
predictability. The results of the model show that there is no increase in per capita foraging success in larger colonies
under most circumstances, though there is an increase in its predictability. We then test the model with empirical data on
the foraging behavior of the primitively eusocial wasp, Ropalidia marginata. The consistency between the data and the model suggests that foraging economics could provide a robust functional basis
in explaining the relationship between colony size and productivity. 相似文献
190.
Janette Wenrick Boughman 《Behavioral ecology and sociobiology》2006,60(6):766-777
Many studies assume that selection molds social traits and have investigated the manner in which this occurs, yet very few studies have measured the strength of selection on social traits in natural populations. In this paper, I report results of phenotypic selection analyses on two social traits – the size of social groups and the frequency of group foraging – in Phyllostomus hastatus, the greater spear-nosed bat. I found significant positive directional selection on individual group foraging frequency, but no directional selection on individuals in different-sized social groups. These results have implications for the structure of social groups, cooperative behavior among group mates, and maternal investment strategies. I argue that combining studies of natural selection on wild populations with experiments to identify the agents and mechanisms of selection can do much to increase our understanding of social evolution. 相似文献