共查询到20条相似文献,搜索用时 296 毫秒
1.
Gauri R. Pradhan Antje Engelhardt Carel P. van Schaik Dario Maestripieri 《Behavioral ecology and sociobiology》2006,59(3):333-343
Female copulation calls are mating-associated vocalizations that occur in some species of Old World monkeys and apes. We argue
that copulation calls have two immediate functions: to encourage mating attempts by other males and to increase mate guarding
by the consort male. We hypothesize that female copulation calls have evolved under the selective pressures of risk of infanticide
and sperm competition. When male mate guarding is effective, copulation calls allow females to concentrate paternity in dominant
males and benefit from their protection against the risk of infanticide. When mate guarding is ineffective, copulation calls
may bring genetic benefits to females through facilitation of sperm competition. We present a quantitative model in which
interspecific variation in females' promiscuity predicts their tendency to use copulation calls in conjunction with mating.
The model predicts that in species with little female promiscuity, copulation calls should be rare and exhibited only in association
with mating with dominant males. In species in which females are highly promiscuous, copulation calls should be frequent and
unrelated to male dominance rank. The limited data available to test the model support its main predictions as well as the
predicted relation between copulation calls and male dominance rank.
相似文献
Dario MaestripieriEmail: |
2.
We analyzed how offspring sex ratio varies with maternal condition in order to obtain evidence on the population structure in two aphid species with different life cycles. When fitness returns per unit investment differ for the production of daughters and sons, selection will favor an increasing investment into the sex with the higher returns. Therefore, the offspring sex ratios of individual mothers should become more biased towards the sex with the higher fitness returns as their condition or fecundity improves. The pattern of sex ratio adjustment we found in Uroleucon cirsii indicates local mate competition among males, while the pattern we found in Rhopalosiphum padi suggests local resource competition among sexual females. This might be the first evidence for local resource competition among females in an invertebrate species. Local mate competition means that fitness returns are limited by the availability of females as mates within local breeding groups, whereas local resource competition means that fitness returns are limited by the availability of resources for females competing within local groups. We discuss how the life cycles of both species fit to these hypotheses.
相似文献
Joachim L. DaggEmail: Phone: +49-551-393730Fax: +49-551-3912105 |
3.
The influence of multiple anchored fish aggregating devices (FADs) on the spatial behavior of yellowfin (Thunnus albacares) and bigeye tuna (T. obesus) was investigated by equipping all thirteen FADs surrounding the island of Oahu (HI, USA) with automated sonic receivers
(“listening stations”) and intra-peritoneally implanting individually coded acoustic transmitters in 45 yellowfin and 12 bigeye
tuna. Thus, the FAD network became a multi-element passive observatory of the residence and movement characteristics of tuna
within the array. Yellowfin tuna were detected within the FAD array for up to 150 days, while bigeye tuna were only observed
up to a maximum of 10 days after tagging. Only eight yellowfin tuna (out of 45) and one bigeye tuna (out of 12) visited FADs
other than their FAD of release. Those nine fish tended to visit nearest neighboring FADs and, in general, spent more time
at their FAD of release than at the others. Fish visiting the same FAD several times or visiting other FADs tended to stay
longer in the FAD network. A majority of tagged fish exhibited some synchronicity when departing the FADs but not all tagged
fish departed a FAD at the same time: small groups of tagged fish left together while others remained. We hypothesize that
tuna (at an individual or collective level) consider local conditions around any given FAD to be representative of the environment
on a larger scale (e.g., the entire island) and when those conditions become unfavorable the tuna move to a completely different
area. Thus, while the anchored FADs surrounding the island of Oahu might concentrate fish and make them more vulnerable to
fishing, at a meso-scale they might not entrain fish longer than if there were no (or very few) FADs in the area. At the existing
FAD density, the ‘island effect’ is more likely to be responsible for the general presence of fish around the island than
the FADs. We recommend further investigation of this hypothesis.
相似文献
Laurent Dagorn (Corresponding author)Email: |
Kim N. HollandEmail: |
David G. ItanoEmail: |
4.
Chang Xuan Mao 《Environmental and Ecological Statistics》2007,14(4):473-481
Consider the removal experiment used to estimate population sizes. Statistical methods towards testing the homogeneity of
capture probabilities of animals, including a graphical diagnostic and a formal test, are presented and illustrated by real
biological examples. Simulation is used to assess the test and compare it with the χ2 test.
相似文献
Chang Xuan MaoEmail: |
5.
Frederic Paik Schoenberg Jamie Pompa Chien-Hsun Chang 《Environmental and Ecological Statistics》2009,16(2):251-269
This paper explores the use of, and problems that arise in, kernel smoothing and parametric estimation of the relationships
between wildfire incidence and various meteorological variables. Such relationships may be treated as components in separable
point process models for wildfire activity. The resulting models can be used for comparative purposes in order to assess the
predictive performance of the Burning Index.
相似文献
Frederic Paik SchoenbergEmail: |
6.
B. Gail Ivanoff 《Environmental and Ecological Statistics》2009,16(2):153-171
The concept of the renewal property is extended to processes indexed by a multidimensional time parameter. The definition
given includes not only partial sum processes, but also Poisson processes and many other point processes whose jump points
are not totally ordered. Various properties of renewal processes are discussed. Renewal processes are proposed as a basis
for modelling the spread of a forest fire under a prevailing wind.
相似文献
B. Gail IvanoffEmail: |
7.
Dimitris Karlis Vassilis G. S. Vasdekis Maria Banti 《Environmental and Ecological Statistics》2009,16(3):355-367
Heteroscedastic additive and multiplicative models are proposed to disaggregate household data on water consumption from Athens
and provide individual consumption estimates. The models adjust for heteroscedasticity assuming that variances relate to covariates.
Household characteristics that can influence consumption are also included into models in order to allow for a clearer measurement
of individual characteristics effects. Estimation is accomplished through a penalized least squares approach. The method is
applied to a sample of real data related to domestic water consumption in Athens. The results show a greater consumption of
water for males while the single-female households are these that use the lowest quantities of water. The consumption curves
by age and gender are constructed presenting differences between the two sexes.
相似文献
Vassilis G. S. VasdekisEmail: |
8.
Den Boychuk W. John Braun Reg J. Kulperger Zinovi L. Krougly David A. Stanford 《Environmental and Ecological Statistics》2009,16(2):133-151
We consider a stochastic fire growth model, with the aim of predicting the behaviour of large forest fires. Such a model can
describe not only average growth, but also the variability of the growth. Implementing such a model in a computing environment
allows one to obtain probability contour plots, burn size distributions, and distributions of time to specified events. Such
a model also allows the incorporation of a stochastic spotting mechanism.
相似文献
Reg J. KulpergerEmail: |
9.
Fiat boundaries: some implications for interpretation,decision-support,and multi-temporal analysis 总被引:1,自引:0,他引:1
Kim Lowell 《Environmental and Ecological Statistics》2008,15(4):369-383
Polygon-based thematic maps can be composed of boundaries that exist by definition—i.e., bona fide boundaries—or those that
exist relative to a specific interpretation of a spatial phenomenon—i.e., fiat boundaries. The construction of maps composed
of fiat boundaries is usually based on a subjective interpretive methodology that is affected by the data used to construct
the map and the minimum mapping unit employed. That fiat boundaries are not the same as bona fide boundaries affects their
use in computer-based spatial decision support tools. This is discussed both in terms of an analysis conducted at one specific
moment, and in respect to increasingly common multi-temporal analysis.
相似文献
Kim LowellEmail: |
10.
Perhaps the most common form of cooperation among primates is the formation of coalitions. Competition among males within a group concerns a constant quantity of the limiting resource (fertilizations). Contest competition over fertilizations is known to produce payoffs that are distributed according to the priority-of-access model, and hence show an exponential decline in payoff with rank. We develop a model for rank-changing, within-group coalitions among primate males. For these coalitions to occur, they must be both profitable (i.e. improve fitness) for all coalition members and feasible (i.e. be able to beat the targets). We assume that the value of the coalition is the sum of the payoffs of the partners in their original ranks. We distinguish three basic coalition configurations, depending on the dominance ranks of the coalition partners relative to their target. We predict five basic coalition types. First, all-up, rank-changing coalitions targeting individuals ranking above all coalition partners; these are expected to involve coalition partners ranking just below their target, concern top rank, and be small, just two or three animals. Second, bridging, rank-changing coalitions, where higher-rankers support lower-rankers to rise to a rank below themselves; these are expected to be most common where a high-ranking male in a despotic system can support a low-ranking relative. Third, bridging non-rank-changing coalitions; these are expected to be common whenever high-ranking males have low-ranking close relatives. Fourth, non-rank-changing coalitions by high-rankers against lower-ranking targets; these are expected to serve to counteract or prevent the first type. Fifth, non-rank-changing, leveling coalitions, in which all partners rank below their target and which flatten the payoff distribution; these are expected to be large and mainly involve lower-ranking males. Bridging, rank-changing coalitions are expected in situations where contest is strong, all-up rank-changing coalitions where contest is intermediate, and leveling coalitions where contest is weak. We review the empirical patterns found among primates. The strong predictions of the model are confirmed by observational data on male-male coalitions in primates.
相似文献
Carel P. van SchaikEmail: |
11.
Stefan Krause Lutz Mattner Richard James Tristan Guttridge Mark J. Corcoran Samuel H. Gruber Jens Krause 《Behavioral ecology and sociobiology》2009,63(7):1089-1096
Analyses of animal social networks derived from group-based associations often rely on randomisation methods developed in
ecology (Manly, Ecology 76:1109–1115, 1995) and made available to the animal behaviour community through implementation of a pair-wise swapping algorithm by Bejder
et al. (Anim Behav 56:719–725, 1998). We report a correctable flaw in this method and point the reader to a wider literature on the subject of null models in
the ecology literature. We illustrate the importance of correcting the method using a toy network and use it to make a preliminary
analysis of a network of associations among eagle rays.
相似文献
Stefan KrauseEmail: |
12.
Rudolf Izsák 《Environmental and Ecological Statistics》2008,15(2):143-156
In this paper some properties and analytic expressions regarding the Poisson lognormal distribution such as moments, maximum
likelihood function and related derivatives are discussed. The author provides a sharp approximation of the integrals related
to the Poisson lognormal probabilities and analyzes the choice of the initial values in the fitting procedure. Based on these
he describes a new procedure for carrying out the maximum likelihood fitting of the truncated Poisson lognormal distribution.
The method and results are illustrated on real data. The computer program for calculations is freely available.
相似文献
Rudolf IzsákEmail: |
13.
Léa Fortunato Chantal Guihenneuc-Jouyaux Margot Tirmarche Dominique Laurier Denis Hémon 《Environmental and Ecological Statistics》2009,16(3):341-353
Ecological studies enable investigation of geographic variations in exposure to environmental variables, across groups, in
relation to health outcomes measured on a geographic scale. Such studies are subject to ecological biases, including pure
specification bias which arises when a nonlinear individual exposure-risk model is assumed to apply at the area level. Introduction
of the within-area variance of exposure should induce a marked reduction in this source of ecological bias. Assuming several
measurements per area of exposure and no confounding risk factors, we study the model including the within-area exposure variability
when Gaussian within-area exposure distribution is assumed. The robustness is assessed when the within-area exposure distribution
is misspecified. Two underlying exposure distributions are studied: the Gamma distribution and an unimodal mixture of two
Gaussian distributions. In case of strong ecological association, this model can reduce the bias and improve the precision
of the individual parameter estimates when the within-area exposure means and variances are correlated. These different models
are applied to analyze the ecological association between radon concentration and childhood acute leukemia in France.
相似文献
Léa FortunatoEmail: |
14.
In this paper we examine the use of data augmentation techniques for simplifying iterative simulation in the context of both
Bayesian and classical statistical inference for survival rate estimation. We examine two distinct model families common in
population ecology to illustrate our ideas, ring-recovery models and capture–recapture models, and we present the computational
advantage of this approach. We discuss also the fact that problems associated with identifiability in the classical framework
can be overcome using data augmentation, but highlight the dangers in doing so under both inferential paradigms.
相似文献
I. C. OlsenEmail: |
15.
Coverage, i.e., the area covered by the target attribute in the study region, is a key parameter in many surveys. Coverage
estimation is usually performed by adopting a replicated protocol based on line-intercept sampling coupled with a suitable
linear homogeneous estimator. Since coverage is a parameter which may be interestingly represented as the integral of a suitable
function, improved Monte Carlo strategies for implementing the replicated protocol are introduced in order to achieve estimators
with small variance rates. In addition, new specific theoretical results on Monte Carlo integration methods are given to deal
with the integrand functions arising in the special coverage estimation setting.
相似文献
Lucio BarabesiEmail: |
16.
Lucio Barabesi 《Environmental and Ecological Statistics》2007,14(4):483-494
Line-intersect sampling based on segmented transects is adopted in many forest inventories to quantify important ecological
indicators such as coarse woody debris attributes. By assuming a design-based approach, Affleck, Gregoire and Valentine (2005,
Environ Ecol Stat 12:139–154) have recently proposed a sampling protocol for this line-intersect setting and have suggested
an estimation method based on linear homogeneous estimators. However, their proposal does not encompass the estimation procedure
currently adopted in some national forest inventories. Hence, the present paper aims to introduce a unifying perspective for
both methods. Moreover, it is shown that the two procedures give rise to coincident estimators for almost all the usual field
applications. Finally, some strategies for efficient segmented-transect replications are considered.
相似文献
Lucio BarabesiEmail: |
17.
Sponges have rich and diverse associated microbial communities, which may have important functions in their metabolism. A
survey of the archaeal communities of 23 poriferan species, focusing on the family Axinellidae, was conducted over the period
2002–2004 using 16S rDNA gene libraries created with archaeal-specific primers. The 28S rDNA sequences of the sponge hosts
were also obtained. Of 23 species, 19 showed evidence of archaeal communities from group C1a (marine group I; Crenarchaeota),
with three of these also showing evidence of Archaea from group E2 (marine group II; Euryarchaeota). Within the Crenarchaeota,
two strongly supported sponge-specific clades were identified corresponding to the sponge family Axinellidae, and a novel
sponge clade denoted clade C. These findings suggest that these archaea have evolved closely with their sponge hosts and are
likely to play an important role in their metabolism.
相似文献
Bradley HolmesEmail: |
18.
Fishery resource management in Chilika lagoon: a study on coastal conservation in the Eastern Coast of India 总被引:1,自引:0,他引:1
A significant proportion of the fishing population comprises small-scale fishermen and many studies illustrate that these
people are exploited by middlemen in the process of fish marketing combined with money lending. The negative dependency gives
rise to poverty and triggers indiscriminate fish catch that threatens fishery resources depletion. This article explores the
root causes of failures in resource-led development from the viewpoint of coastal resource conservation. The study presents
a case study of Chilika lagoon, India and focuses on the interaction between small-scale fishermen and middlemen. The findings
reveal that most of the small-scale fishermen have been exploited by specific middlemen and the underlying causes of the present
fish marketing structure stem from (i) indebtedness and (ii) the unstable situation because of perpetual conflicts over fishery
resources among the fishers across Chilika lagoon. Based on these observations, this article presents some recommendations
on fishery resource conservation from the perspective of a fish marketing structure.
相似文献
Rajib ShawEmail: |
19.
John E. Hathaway G. Bruce Schaalje Richard O. Gilbert Brent A. Pulsipher Brett D. Matzke 《Environmental and Ecological Statistics》2008,15(3):313-327
Composite sampling can be more cost effective than simple random sampling. This paper considers how to determine the optimum
number of increments to use in composite sampling. Composite sampling terminology and theory are outlined and a method is
developed which accounts for different sources of variation in compositing and data analysis. This method is used to define
and understand the process of determining the optimum number of increments that should be used in forming a composite. The
blending variance is shown to have a smaller range of possible values than previously reported when estimating the number
of increments in a composite sample. Accounting for differing levels of the blending variance significantly affects the estimated
number of increments.
相似文献
John E. HathawayEmail: |
20.
Brooke E. Buckley Walter W. Piegorsch R. Webster West 《Environmental and Ecological Statistics》2009,16(1):53-62
In modern environmental risk analysis, inferences are often desired on those low dose levels at which a fixed benchmark risk
is achieved. In this paper, we study the use of confidence limits on parameters from a simple one-stage model of risk historically
popular in benchmark analysis with quantal data. Based on these confidence bounds, we present methods for deriving upper confidence
limits on extra risk and lower bounds on the benchmark dose. The methods are seen to extend automatically to the case where
simultaneous inferences are desired at multiple doses. Monte Carlo evaluations explore characteristics of the parameter estimates
and the confidence limits under this setting.
相似文献
R. Webster WestEmail: |