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1.
Ecology and Evolution of Social Organization in Arctic Sandpipers   总被引:1,自引:0,他引:1  
A comparative analysis of sandpiper social systems on arcticand subarctic breeding grounds (24 species in the family Scolopacidae,subfamily Calidridinae) shows four major patterns. In a majorityof the species (15), populations are dispersed through a stronglydeveloped territorial system, with strong monogamous pair bondsand only minor yearly fluctuations in numbers. The second patternis seen in three species in which the female of a pair may laytwo sets of eggs in quick succession, one for each member ofthe pair to incubate. This opens opportunities for facultativepolygyny or polyandry (‘serial polygamy’) and forthe evolutionary weakening of the strong pair bond seen in thefirst pattern. The third and fourth patterns are those of polygyny(three species) and promiscuity (three species). These six speciesshow clumped dispersions; their year-to-year fluctuations tendto be strong; the males defend compressible, often small, territories;and high densities can occur locally. It is suggested that thepattern of overdispersion and monogamy represents a conservativemode of adapting to high-latitude environments, while the patternof clumped dispersion with polygyny or promiscuity representsan opportunistic mode in that the birds are concentrated intobreeding areas where and when weather, food, and/or some otherenvironmental factors are particularly favorable. Apparentlyfalling evolutionarily between these two basic patterns areseveral species conservative in their life-styles, but polygamousat least occasionally and showing some features of opportunism.There is thus a striking diversity of social systems in calidridinesandpipers, that is, in the styles of habitat exploitation theyhave evolved in the arctic and subarctic habitats to which theirbreeding is confined. A graphic model suggesting paths of evolutionarydevelopment and of interplay among factors considered criticalin the evolution of these systems is proposed.  相似文献   

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Approximately 45 species of kangaroos and their smaller relativesoccupy virtually every terrestrial habitat in Australia. Themost social macropod is the whiptail wallaby, which lives inpermanent, discrete mobs of up to 50 individuals of mixed ageand sex. Group formation is facilitated by their grazing habits,open forest and pasture habitat, partly diurnal activity, andlow level of intraspecific aggressiveness. Pressure from cursorialpredators, plus the whiptail's non-seasonal breeding and briefestrus, make group living adaptive. Ancestral macropods arebelieved to have been rabbit-sized inhabitants of dense forest,omnivorous, nocturnal, and essentially solitary. The major evolutionarytrends in the family have been toward larger size and grazinghabits; the trends toward diurnality and group living have hadmore modest results. Progressive stages in macropod social evolutionmay be represented by the present-day musk rat-kangaroo, thequokka, and the whiptail wallaby.  相似文献   

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Thermotolerance was studied in a wide spectrum of Drosophilaspecies and strains originating from different climatic zones and considerably differing from one another in the ambient temperature of their habitats. The species that lived in hot climate have a higher thermotolerance. Most species of the virilisgroup exhibited positive correlation between the HSP70 accumulation after heat exposure and thermotolerance; however, this correlation was absent in some species and strains. For example, the D. melanogasterOregon R strain, which had the highest sensitivity to heat shock (HS) among all strains and species studied, displayed the maximum level of HSP70 proteins after HS. The patterns of induction of various heat shock protein (HSP) families after heat exposure in a wide spectrum of Drosophila species were compared. The results obtained suggest that the HSP40 and low-molecular-weight HSPs (lmwHSPs) play a significant role in thermotolerance and adaptation to hot climate. Polymorphism in hsp70 gene clusters ofDrosophila and variation in the numbers of gene copies andhsp70 isoforms in group viriliswere found. The evolutionary role of the variation in the number of hsp70 gene copies observed in the strains and species of genusDrosophilais discussed.  相似文献   

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Currently no mandatory standards or guidelines exist for Point-of-Care Testing (PoCT) in Australia. In 2001, a report on the role and value of ‘near patient testing’ in general practice outlined work that was required to assist the Australian Government to decide how to manage PoCT. Phillips Fox reported that adoption of mandatory accreditation requirements was not justified by the level of risk associated with PoCT.If implemented appropriately, PoCT could be useful with frontline management of chronic disease, relieving stress on general practice and expanding the reach of pathology.Interim PoCT standards in general practice were developed by a Quality Use of Pathology committee, and formed an accreditation framework for the PoCT in General Practice Trial. This trial concluded that PoCT has a role in supporting the primary healthcare team to manage chronic disease patients.While results of the trial are still being considered, the potential impact of funding PoCT in general practice is being treated as part of the wider review of pathology funding currently taking place in Australia.Although Australia has local models from which to draw experience, it has yet to decide the quality framework it would adopt if it was to roll out PoCT in general practice. The quality framework that Australia adopts for PoCT must achieve high quality pathology results that enhance clinical care.  相似文献   

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In an authoritative review on biodiversity conservation in old, climatically buffered infertile landscapes (OCBILs) Hopper (2009) recently argued that Cramer et al. (2008) were ‘overly pessimistic’ to suggest that restoration of historical ecosystems on some old-fields of OCBILs in south-western Australia was unlikely. Here, we argue that this view was realistic rather than pessimistic, and that the conservation of OCBIL biota requires both a radical shift in the willingness of society to make the investment that is currently necessary to restore historical floristically rich OCBILs and further research to find more cost-effective options for broadscale restoration. Advancing the science and practice of ecological restoration in this landscape requires acknowledgement of current constraints. Ultimately, an approach that combines restoration and conservation is required to ensure the persistence of OCBIL biodiversity in the face of ongoing degradation and climate change.  相似文献   

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The results of an investigation on the division of labour in the guest-ant Formicoxenus provancheri, conducted by observing colonies containing individually marked adults, are presented. Five colories of Formicoxenus were installed in the laboratory with their hosts, Myrmica incompleta, in order to document, over 10 d, the location of individuals as well as individual and interactive types of behaviour. The results show that each colony of Formicoxenus consists of three groups: a group of nurses who remain in the Formicoxenus nest (some 21% of the colony's members); a group of scouts who spend most of their time in the external area (18%) and a very large group of individuals specialized in licking (‘shampooing’) the host to obtain regurgitations (61%), who essentially remain in the Myrmica nest. Division of labour in Formicoxenus appears to be a special adaptation to the xenobiotic way of life. The apparent link between social structure and the probability of profiting from trophallactic exchanges with the host species could lead to interesting predictions on the division of labour in other guest-ants.  相似文献   

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The bow more than doubled, likely tripled, the success of individuals bent on killing animal or human targets (Box 1 ). The advent of this revolutionary technology generated different responses in western North America depending on subsistence and sociopolitical organization at the time of its arrival, roughly 2300 ‐ 1300 B.P. 1 Its effect was substantial in California and the Great Basin, particularly on group size, which in many places diminished as a consequence of the bow's reliability. The counter‐intuitive result was to increase within group‐relatedness enough to encourage intensification of plant resources, previously considered too costly. The bow rose to greatest direct economic importance with the arrival of the horse, and was put to most effective use by former Great Basin groups who maintained the family band system that had developed around intensive Great Basin plant procurement, adapting the same organization to a lifestyle centered on the equestrian pursuit of buffalo and warfare.  相似文献   

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Streptococcus iniae causes severe septicemia and meningitis in farmed fish and is also occasionally zoonotic. Vaccination against S. iniae is problematic, with frequent breakdown of protection in vaccinated fish. The major protective antigens in S. iniae are the polysaccharides of the capsule, which are essential for virulence. Capsular biosynthesis is driven and regulated by a 21-kb operon comprising up to 20 genes. In a long-term study, we have sequenced the capsular operon of strains that have been used in autogenous vaccines across Australia and compared it with the capsular operon sequences of strains subsequently isolated from infected vaccinated fish. Intriguingly, strains isolated from vaccinated fish that subsequently become infected have coding mutations that are confined to a limited number of genes in the cps operon, with the remainder of the genes in the operon remaining stable. Mutations in strains in diseased vaccinated fish occur in key genes in the capsular operon that are associated with polysaccharide configuration (cpsG) and with regulation of biosynthesis (cpsD and cpsE). This, along with high ratios of nonsynonymous to synonymous mutations within the cps genes, suggests that immune response directed predominantly against capsular polysaccharide may be driving evolution in a very specific set of genes in the operon. From these data, it may be possible to design a simple polyvalent vaccine with a greater operational life span than the current monovalent killed bacterins.  相似文献   

12.
Aggressive Social Organization in Nectarivorous Birds   总被引:1,自引:0,他引:1  
I argue that a net benefit model of aggressive social organizationis consonant with observed variation between territorial anddominance systems. For nectarivores net benefits are associatedwith obtaining nectar. Costs are time and energy associatedwith aggression and possible risks of injury. The fitness criterionprobably varies across situations and may be long or short-term.An important problem for behaviorists is to understand the positionin a time hierarchy at which particular social interactionsare important.  相似文献   

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We characterize the spatial organization of red-tailed sportive lemurs (Lepilemur ruficaudatus) as a key aspect of their social organization and social system. Sportive lemurs are small (<1000 g), nocturnal and folivorous primates endemic to Madagascar. We studied a population of 57 individually-marked individuals in Kirindy Forest, western Madagascar, between 1995 and 2001. We radio-tracked 20 males and 26 females of the marked population to obtain detailed information on the size and location of their home ranges. Census data and morphometric measurements provided complementary data sets. Males and females occupied small (<1 ha) home-ranges. Long-term records from 9 individuals revealed home-range stability over several years. In 4 cases home ranges overlapped extensively with that of one member of the opposite sex; in 2 cases, a spatial association of 1 male and 2 females occurred. However, home ranges overlapped very little with neighboring individuals of both sexes. During the study period, spatially associated individuals used on average 5.6 sleeping trees within 117 days, but they spent on average only about every fourth night together. The data suggest that home ranges in red-tailed sportive lemurs are exclusively used by pairs or trios and that the modal social organization of red-tailed sportive lemurs is pair-living.  相似文献   

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Based on the theory of organization and evolution of colonies in an extinct group of hemichordate graptolites (Urbanek, 1960, 1990) the relationship between the events in the late astogeny of bryozoan colonies and their somatic and reproductive cycle is proposed. The bryozoan colonies with simple organization are compared with graptoloid colonies and their structure is interpreted within the framework of the morphogen gradient theory. A morphogen produced by the founder-zooid (oozooid) diffuses along the long axis of the colony and controls the phenotypic expression of the size and structure of zooids. Evolutionary changes in the graptoloid colonies involve introduction of new characters and their spreading is also accompanied by gradient changes of their manifestation. Evolutionary mechanisms in bryozoan colonies are considered in terms of penetrance and expressivity of genes. In contrast to graptolites, many bryozoan colonies display multiple zones of astogenetic changes and repetitions.  相似文献   

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Asian and African elephant species have diverged by ca. 6 million years, but as large, generalist herbivores they occupy similar niches in their respective environments. Although the multilevel, hierarchical nature of African savannah elephant societies is well established, it has been unclear whether Asian elephants behave similarly. Here we quantitatively compare the structure of both species’ societies using association data collected using the same protocol over similar time periods. Sociality in both species demonstrates well-defined structure, but in contrast to the African elephants of Samburu the Uda Walawe Asian elephants are found in smaller groups, do not maintain coherent core groups, demonstrate markedly less social connectivity at the population level, and are socially less influenced by seasonal differences in ecological conditions. The Uda Walawe Asian elephants, however, do maintain a complex, well-networked society consisting of ≥2 differentiated types of associates we term ephemeral and long-term affiliates. These findings imply we must broaden our recognition of multilevel social organization to encompass societies that fall along a gradient of nestedness, and not merely those that exhibit hierarchical nesting. This in turn suggests that multilevel structures may be more diverse and widespread than generally thought, and that phylogenetic comparisons within species-rich clades, such as that of primates, using the methods presented can provide fresh insights into their socioecological basis.  相似文献   

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Attachment relationships between animals are often studied by separating a pair of individuals and recording their subsequent behavior. Studies of non‐human primates have shown that separation results in changes that are indicative of both psychological and physiological stress. Similar results have been found in several non‐primate species with differing social structures. This study examined the behavior of two female giraffe at Zoo Atlanta after the removal of the resident male. Data were collected on the giraffe before and after separation, using an instantaneous scan sampling technique to record levels of activity, social behaviors, solitary behaviors, proximity, and habitat utilization. After the removal of the resident male, both giraffe exhibited increased levels of activity, stereotypical behavior, contact behavior (particularly neck‐rubbing), and decreased habitat utilization. These results are similar to those found in earlier primate separation studies, supporting the hypothesis that complex social structure is not necessary for the formation of social attachments. Because social separation is often accompanied by behavioral and physiological indications of stress, an understanding of the variables involved in a species' response to separation is vital to the promotion of the psychological and physical well‐being of captive animals. Zoo Biol 19:41–51, 2000. © 2000 Wiley‐Liss, Inc.  相似文献   

20.
Abstract: In the 2007 Journal of Wildlife Management article “Dinosaur Ramblings,” Scalet described a shift in university and agency programs away from applied management research toward basic ecological research. We interpret Scalet's commentary as primarily synonymizing applied management research to game management and basic ecological research to nongame management and theoretical research. Although we agree with Scalet that a change in management practices has occurred, we believe that change is more an integration of applied and basic research as opposed to a shift away from management. We provide a hierarchical framework to alternatively explain Scalet's perceived shift in which we place applied management and basic theoretical research under the science of ecology. We believe integration of basic and applied research has been driven by the evolving structure of society and the public's changing view of natural resources. The integration of basic and applied research is necessary for informed and, thence, better management practices.  相似文献   

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