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471.
产品环境试验顺序的优化选择 总被引:2,自引:2,他引:0
首先介绍了产品进行环境试验的目的及其重要性,对环境试验项目之间的相互影响及合理顺序进行了分析,并阐述了选择环境试验项目顺序所遵循的一般原则,说明在进行环境试验时,必须针对具体试验项目,注意合理的试验顺序,才能确保试验结果的真实性、代表性和可比性。 相似文献
472.
Solid waste management (SWM) is at the forefront of environmental concerns in the Lower Rio Grande Valley (LRGV), South Texas.
The complexity in SWM drives area decision makers to look for innovative and forward-looking solutions to address various
waste management options. In decision analysis, it is not uncommon for decision makers to go by an option that may minimize
the maximum regret when some determinant factors are vague, ambiguous, or unclear. This article presents an innovative optimization
model using the grey mini-max regret (GMMR) integer programming algorithm to outline an optimal regional coordination of solid
waste routing and possible landfill/incinerator construction under an uncertain environment. The LRGV is an ideal location
to apply the GMMR model for SWM planning because of its constant urban expansion, dwindling landfill space, and insufficient
data availability signifying the planning uncertainty combined with vagueness in decision-making. The results give local decision
makers hedged sets of options that consider various forms of systematic and event-based uncertainty. By extending the dimension
of decision-making, this may lead to identifying a variety of beneficial solutions with efficient waste routing and facility
siting for the time frame of 2005 through 2010 in LRGV. The results show the ability of the GMMR model to open insightful
scenario planning that can handle situational and data-driven uncertainty in a way that was previously unavailable. Research
findings also indicate that the large capital investment of incineration facilities makes such an option less competitive
among municipal options for landfills. It is evident that the investment from a municipal standpoint is out of the question,
but possible public–private partnerships may alleviate this obstacle. 相似文献
473.
474.
The capture of genetic variation by sexual traits due to their condition dependence is hypothesized to underlie the genetic
benefits of mate choice. Here, we investigate condition dependence of sexual attractiveness of bank vole Myodes glareolus males by manipulating their diet during the period of maturation. We find that reducing diet quality negatively affected
both male mating success and development of preputial glands used in sexual signaling. Preputial glands showed stronger condition
dependence than other organs measured (testes, heart, intestines). In contrast to mating success, male dominance was not significantly
affected by diet manipulation and was not correlated with male mating success. Thus, our results support condition dependence
of sexual attractiveness but not of intrasexual competitiveness. 相似文献
475.
Recent theoretical and empirical studies have shown that male dominance is often at odds with female mate preference and that
indirect (genetic) benefits of mate choice may not be related to male dominance. We tested whether female preference corresponded
to male dominance and whether mating with dominant males conveyed benefits to offspring fitness in a small freshwater fish,
the African annual killifish Nothobranchius korthausae (Cyprinodontiformes), a species without parental care. The experimental design used controlled for the effect of male age,
possibility of sperm and egg depletion, and accounted for a potential that females express their preference through maternal
effects by manipulation of egg mass during ovulation. By sequentially mating females with males of known dominance, we found
that female N. korthausae showed no mate preference in terms of egg numbers deposited with respect to male dominance or body size and no congruent
mate preference to specific males was detected. However, males sired offspring with consistently higher hatching success and
the effect was repeatable across individual females. Thus, some males provided females with indirect benefits related to additive
genetic quality (“good genes”) and expressed via increased hatching rate, but this benefit was not related to male dominance
status or body size. 相似文献
476.
Informational constraints can be an important limitation on the accuracy of recognition. One potential constraint is the use
of recognition information from the same sources in multiple discriminatory contexts. Worker wood ants, Formica fusca, discriminate eggs based on their maternal sources of origin in two main contexts: recognition of eggs laid by nestmate versus
non-nestmate queens and recognition of worker-laid versus queen-laid eggs. We manipulated the experience of F. fusca workers in laboratory colonies to both worker-laid and queen-laid eggs by transferring eggs between colonies in order to
investigate whether these two contexts of egg discrimination are independent. Experience of non-nestmate queen-laid eggs significantly
increased worker acceptance of both familiar (18% accepted) and unfamiliar (10%) queen-laid eggs compared to control workers
without experience of eggs other than those laid by their own colony’s queen (2%). In contrast, worker acceptance of worker-laid
eggs was not affected by variation in the egg experience of workers (14% in workers from control colonies exposed only to
eggs from their own colony’s queen versus 19% and 17% in workers from colonies which had received eggs laid by either a non-nestmate
queen or nestmate workers, respectively). Our results suggest that these two recognition contexts do not strongly constrain
each other and are different in their ontogeny. In particular, worker-laid eggs are universally discriminated against by workers
from colonies with a queen whatever the egg experience of the workers, while non-nestmate queen-laid eggs are strongly discriminated
against only by workers without experience of eggs laid by more than one queen. 相似文献
477.
Vikram K. Iyengar 《Behavioral ecology and sociobiology》2009,63(6):847-855
Determining the factors that affect male mating success is essential to understanding how sexual selection operates, including
explanations of the adaptive value of female preferences and how variation in male traits is maintained in a population. Although
females may appear to choose males based on a single parameter, female mate choice is often a complex series of assessments
of male quality that can only be revealed through manipulation of multiple male traits. In the moth Utetheisa ornatrix (Lepidoptera: Arctiidae), females have been shown to judge males primarily on their production of a courtship pheromone,
hydroxydanaidal, derived from defensive chemicals acquired as larvae. Recent work, however, suggested that other factors,
including prior mating experience by males, may also influence the outcome of precopulatory interactions with females. I ran
mating trials with one female and two males to determine whether there were any differences in male mating success based on
their prior exposure to females, mating experience, and time between matings. Previously mated males were favored over virgins
when both males lacked the pheromone, but courting experience and mating interval did not explain these differences in male
mating success. Furthermore, multiply mated males lacking the pheromone were favored over virgin males that produced the pheromone,
thus reversing the commonly observed trend of female precopulatory bias towards males with higher levels of the pheromone.
These results demonstrate that males with mating experience can secure copulations despite deficiencies in the pheromone,
and I provide possible mechanisms and discuss their implications regarding sexual selection. 相似文献
478.
The persistence of species in reserves depends in large part on the persistence of functional ecological interactions. Despite their importance, however, ecological interactions have not yet been explicitly incorporated into conservation prioritization methods. We develop here a general method for incorporating consumer–resource interactions into spatial reserve design. This method protects spatial consumer–resource interactions by protecting areas that maintain the connectivity between the distribution of consumers and resources. We illustrate our method with a conservation planning case study of a mammalian predator, American marten (Martes americana), and its two primary prey species, Red-backed vole (Clethrionomys rutilus) and Deer mouse (Peromyscus maniculatus). The conservation goal was to identify a reserve for marten that comprised 12% of a forest management unit in the boreal forest in Québec, Canada. We compared reserves developed using analysis variants that utilized different levels of information about predator and prey habitat distributions, species-specific connectivity requirements, and interaction connectivity requirements. The inclusion of consumer–resource interactions in reserve-selection resulted in spatially aggregated reserves that maintained local habitat quality for the species. This spatial aggregation was not induced by applying a qualitative penalty for the boundary length of the reserve, but rather was a direct consequence of modelling the spatial needs of the interacting consumer and resources. Our method for maintaining connectivity between consumers and their resources within reserves can be applied even under the most extreme cases of either complete spatial overlap or complete spatial segregation of consumer–resource distributions. The method has been made available via public software. 相似文献
479.
冶勒自然保护区林麝对生境选择研究 总被引:20,自引:0,他引:20
1995年在相岭山系的冕宁冶勒自然保护区,采用作者新近提出的临时空间样方法,以Vanderloeg和Scavia选择指数对林麝对生境的选择进行了研究,结果表明7~8月份,林麝喜欢活动于竹子密度不大(n=0~15m 相似文献
480.
In insects, the last male to mate with a female often gains access to a disproportionate number of subsequent fertilizations.
This study examined last-male sperm precedence patterns in doubly and triply mated Tribolium castaneum females. Sperm storage processes were investigated by measuring the quantity of sperm stored within the female spermatheca
following single, double, and triple matings. Both doubly mated and triply mated females exhibited high last-male sperm precedence
for progeny produced during the first 48 h following the last mating, with females in both groups exhibiting parallel declines
in sperm precedence 1 and 2 weeks later. The number of sperm stored by females increased by 33% between singly mated and doubly
mated females, indicating that the spermatheca is filled to only two-thirds capacity following insemination by the first male.
Based on the proportion of stored sperm from first and second matings, we tested predictions about sperm precedence values
based on models of random sperm mixing. High initial last-male sperm precedence strongly supports stratification of last-male
sperm. By 1–2 weeks after double matings, sperm precedence declined to levels indistinguishable from values expected under
random mixing. These results provide insight into mechanisms of sperm storage and utilization in this species.
Received: 20 August 1997 / Accepted after revision: 24 May 1998 相似文献