论品牌文化建设中的环保之路

随着社会的发展，企业品牌已成为市场竞争的重要因素，本文主要对当前中国企业品牌文化建设及其环保理念进行了探讨。     

Immigration pattern and success in red squirrels

Summary We studied the characteristics of immigrants and the effects of immigration on reproductive activity and spacing behaviour in red squirrels living in high-quality woodlands. Male immigration peaked in spring, female immigration in autumn. There was no sex bias in dispersal distance of local recruits or in the proportion of male/female immigrants, but more subadults than adults immigrated on the study plots. Hence, hypotheses explaining sex-biased dispersal were irrelevant in explaining immigration patterns in our study populations. Immigrant females were not in breeding condition, nor had they produced a litter prior to immigration. Hence breeding dispersal did not occur. Red squirrels are promiscuous, and females defend intrasexual territories while males have overlapping home ranges with a dominance hierarchy (Wauters et al. 1990; Wauters and Dhondt 1992). Site fidelity is very important to reproductive success and most parents still have a high residual reproductive value after having produced a litter. Under such circumstances, the resident fitness hypothesis (RFH; Anderson 1989) predicts that parents can benefit by forcing emigration of offspring if the latter are likely to find nearby vacancies. The settlement pattern of successful immigrants, which had a higher probability of becoming established when they had high body mass and when they were settling in plots with reduced intrasexual competition, agreed with the RFH and with the proximate dispersal mechanism suggested by Gliwicz (1992), that dispersal tendency in both sexes depends on the degree of intrasexual competition under local conditions. The fact that close inbreeding was never observed could indicate that random immigration of both sexes, within the social environment of a partly territorial, relatively long-lived species, has evolved not only to reduce competition for resources between parents and offspring but also as an inbreeding avoidance mechanism. Correspondence to: L. Wauters     

黑麦草与入侵杂草紫茎泽兰苗期的相对竞争力

为研究利用黑麦草(Lolium perenne)替代种植治理外来入侵杂草紫茎泽兰(Eupatorium adenophorum)再入侵或新入侵丢荒地,采取复合deWit取代试验设计方法用盆栽植物研究了黑麦草和紫茎泽兰在苗期的相对竞争力,观察在若干密度梯度每密度下不同比例条件下两种植物的相对产量、相对产量总和以及竞争攻击力等参数,并比较其表型特征在不同竞争格局下的异同.黑麦草与紫茎泽兰在所有密度及其比例下的相对产量总和(RYT)均近似于1.0,说明这两种植物面临着对相同资源的直接竞争.竞争的结果是,在所有密度及其比例下,紫茎泽兰混种时的生物量均显著小于单种时的生物量(即相对产量RY小于1.0);而黑麦草的相对产量(RY)变化则恰恰相反.黑麦草的株高和地上生物量并不受混种竞争的显著影响(与单种无显著差异),分蘖数反而高于单种,表现出很强的竞争性;而紫茎泽兰在混种竞争下的株高、分株数和地上生物量均显著低于单种(无竞争),表现出较弱的竞争性.对利用黑麦草替代种植治理紫茎泽兰在机械防治后再入侵以及对丢荒地新入侵问题的可行性进行了讨论.图1表3参18     

Differential use of stored sperm during oviposition in the damselfly Calopteryx splendens xanthostoma (Charpentier)

Female Calopteryx splendens xanthostoma (Charpentier) (Odonata), have two discrete sperm storage organs, the bursa copulatrix and the paired spermathecae. We used the Random Amplified Polymorphic DNA(RAPD) profiling technique to determine from which sperm storage organ spermatozoa were used to fertilise eggs during behaviourally distinct oviposition bouts. During oviposition bouts following remating sperm from the bursa copulatrix are largely used to fertilise eggs, but when females avoid remating before an oviposition bout the sperm used to fertilise eggs are derived mainly from the paired spermathecae. Our observations suggest that female C. s. xanthostoma can avoid male paternity assurance mechanisms by a combination of behavioural and anatomical adaptation: the reason(s) they do so is unclear. Received: 28 November 1995/Accepted after revision: 5 August 1996     

Small testes size despite high extra-pair paternity in the pair-living nocturnal primate Phaner furcifer

Sperm competition will be the inevitable consequence of polyandrous mating behavior if two or more males inseminate a single female. It has been demonstrated for a wide variety of animals that males adapt to this situation behaviorally, physiologically and morphologically, e.g. by evolving relatively large testes size to produce more sperm. All pair-living primates investigated so far were found to have relatively small testes, suggesting a monandrous mating system. We investigated the relationship between extra-pair paternity (EPP) rate as a measure of sperm competition intensity and relative testes size in a pair-living primate, the fork-marked lemur (Phaner furcifer). Paternity exclusion analyses for seven offspring using six polymorphic DNA-microsatellite markers suggested a high EPP rate. Female nocturnal travel distances were longer during the mating season, suggesting that females take an active role in achieving extra-pair copulations (EPCs). Surprisingly, fork-marked lemur testes size was relatively small compared to 23 other lemuroid primates, a result that is in contrast to predictions of sperm competition theory. Neither possible behavioral and morphological adaptations to an alternative paternity guard (i.e. mate guarding), nor sampling biases, phylogenetic constraints, and population density effects explain the absence of large testes in a species with high EPP, a phenomenon also known from birds with moderate to low EPP rates. We conclude that more data are needed on the frequency of EPCs, the timing of in-pair and extra-pair copulations, as well as the role of female choice, to explain why males of some species apparently do not adapt to sperm competition.Communicated by S. Alberts     

Copulatory plugs do not assure high first male fertilisation success: sperm displacement in a lizard

Sperm competition selects for opposing male defensive and offensive reproductive traits, and its outcome may be determined by the effectiveness to which one trait has evolved to out-compete the other. We tested the effectiveness of a first male plug physical interference with a second male insemination (defence) vs the effectiveness of plug and associated sperm displacement by a second male (offence) on the outcome of sperm competition in Iberian rock lizards. We conducted a double mating experiment where we compared the proportion of eggs per clutch fertilised by the same second males (against the same first males) when they copulated with females 30 min (first male plug adhered firmly inside the female cloaca) and 4 h (first male plug loosely adhered or shed from the female cloaca) after first males. We found that second males fertilised the majority of the eggs per clutch in the 30-min treatment, whereas fertilisations were equally shared between the two males in the 4-h treatment. These results show that plugs have little defensive effectiveness, and thus, do not assure high first male fertilisation success. Instead, sperm displacement appears to be associated with plug displacement. That is, because sperm embedded in first male plugs, and displaced from competition for fertilisations by second males, is expected to increase in number with decreasing time allowed for female sperm transport, second males thus enjoy higher fertilisation success. This study shows that offensive plug displacement out-competes plug defensive role in Iberian rock lizards. Moreover, it reveals sperm displacement as a novel sperm competition mechanism in reptiles.     

Sex ratio adjustment and maternal condition in two aphid species

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.

Determinants of male territorial behavior in a Hungarian collared flycatcher population: plumage traits of residents and challengers

In intrasexual conflicts, contestants can rely on relative or absolute size of status badges to mediate aggressive behavior. Most studies focus on the response of focal animals to variation in status badges of their competitors; few have simultaneously considered the traits of both participants under experimental conditions. By simulating territorial intrusions, we tested the importance of two sexual traits [forehead patch size (FPS) and wing patch size (WPS)] in territorial behavior of males in a Hungarian population of the collared flycatcher, Ficedula albicollis. We presented a stimulus male to an unpaired resident male to examine whether the characteristics of the territory owner or those of the challenger were associated with the latency of the first attack of the owner, which is a good predictor of the territorial behavior in general. WPS of the stimulus male was a significant determinant of the latency of the first attack, as males with a larger WPS elicited quicker attacks from the residents than males with a small WPS. From the residents’ perspective, age appeared to influence their territorial behavior, as yearlings had shorter attack latencies than older males. Additionally, latency could be considered an individual-specific attribute because it varied consistently among males, even when the WPS of the stimulus male was controlled, and it was associated with pairing success. Contrary to findings in a Swedish population, FPS seemed to be unimportant in male–male competition in our population, which suggests population differences in the role of the two plumage traits. Our results indicate that in a territorial conflict, the characteristics of both participants are important.     

To flee or not to flee: predator avoidance by cheetahs at kills

Mammalian carnivores are unusual because their primary competitors for food are often their primary predators. This relationship is most evident at persistent kills where dominant competitors are attracted to both the carcass (as a free meal) and to the killers (as potential prey). Cheetahs (Acinonyx jubatus) are frequent victims of kleptoparasitism, and cubs, and sometimes adults, are killed by lions (Panthera leo) or spotted hyenas (Crocuta crocuta). Between 1980 and 2002, we observed 639 kills made by cheetahs in Serengeti National Park, Tanzania. These kills were often visited by scavengers, including relatively innocuous species such as vultures and jackals and potentially dangerous species, like spotted hyenas and lions. We used cheetah behavior at kills to test a number of predictions about how cheetahs should minimize risk at kill sites given they face an increased risk of predation of themselves or their cubs. In particular, we examined the propensity of cheetahs of different age/sex classes to hide carcasses after making a kill, vigilance at kills, and the delay in leaving after finishing feeding with respect to ecological factors and scavenger presence. The behavior of single females at kills did not suggest that they were trying to avoid being killed, but the behavior of males, often found in groups, was in line with this hypothesis. In contrast, the behavior of mother cheetahs at kills appeared to be influenced greatly by the risk of cubs being killed. Our results suggest that cheetahs use several behavioral counterstrategies to avoid interspecific predation of self or cubs.     

Male size and mating tactic influence proximity to females during sperm competition in bluegill sunfish

Many fishes are characterized by intense sperm competition between males that use alternative mating tactics. In externally fertilizing fishes, males’ proximity to females during spawning can be an important determinant of fertilization success. Here, we assess how mating tactic, body length, speed during streak spawns, and periphery cover affect males’ proximity to females during sperm competition in the externally fertilizing bluegill (Lepomis macrochirus). Bluegill are characterized by three mating tactics referred to as parental, sneaker, and satellite. Parentals are territorial and construct nests, while sneakers use a streaking behavior, and satellites use female mimicry to steal fertilizations from parentals. We show that a small body length is important for sneakers but not for satellites to obtain a close position to the female during spawning. Specifically, smaller sneakers obtain a closer position to females than larger sneakers in part by positioning themselves closer on the periphery of a parental’s nest before streaking but show no difference in the speed at which they streak. The amount of peripheral vegetation around a parental’s nest did not appear to affect proximity of sneakers to females, and there was no relationship between the amount of peripheral vegetation and the frequency of intrusions by either sneakers or satellites. Finally, parentals were farther from the female when a sneaker or satellite intruded than when they spawned alone with the female.