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1.
Naive European minnows (Phoxinus phoxinus) do not show a fright reaction when they first encounter the odour of a natural predator (the pike: Esox lucius) or the odour of a non-piscivorous exotic (tilapia: Tilapia mariae). A conditioned fright response to both these odours will however develop if minnows experience them in a potentially dangerous situation, for example, in conjunction with Schreckstoff, the ostariophysian alarm pheromone. Although minnows respond to both odours the reaction to the tilapia odour is reduced. This suggests that a constraint on learning is involved. Olfactory recognition is particularly valuable for detecting predators that hunt in conditions where visibility is poor.  相似文献   

2.
Earth mounds at seven sites in upland areas of Kenya were examined. Termite activity was recorded from 91% of mounds and the major termite genus present was Odontotermes. Generally, signs of the mole rat, Tachyoryctes splendens were few and were present on only 18% mounds. All termite activity was mound-centred but only at Kiserian were mounds obvious centres for mole rat activity. At Molo, where Tachyoryctes were abundant, neither mounds nor much sign of termite activity were observed. The data are discussed in relation to the work of Cox and Gakahu. No convincing evidence was found to support the conclusion made by these workers for a mole rat origin of large earth mounds. The weight of the data suggests that a termite origin for these mounds is more likely.  相似文献   

3.
The authors define experience as an intersubjective medium of microcultural and infrapolitical processes in which something is at stake for participants in local worlds. Experience so defined mediates (and transforms) the relationship between context and person, meaning and psychobiology in health and illness and in healing. Building on this theoretical background, an approach to ethnography is illustrated through an analysis of suffering in Chinese society. The embodied memory of a survivor of serious trauma during the Cultural Revolution provides an example. From there, the authors go on to describe a framework of indigenous Chinese categories for the analysis of experience — mianzi (face), quanxi (connections), renqing (situated emotion), bao (reciprocity). The paper concludes with a discussion of the existential limits of this and other anthropological approaches to the study of experience as moral process.  相似文献   

4.
At the turn of the seventeenth and nineteenth centuries, Earth sciences were in a period of heated debates, with an arduous acquisition of basic principles for geology. Among the unresolved debates, was the well-known between Neptunists and Plutonists, and there was still disagreement between the supporters of a catastrophic flood and a long permanence of the sea in areas currently occupied by emerged lands. In such a climate of uncertainty appears the ‘Theory of the Earth’ of Ermenegildo Pini, an Italian Barnabite cleric. Pini was a many-faceted figure, including naturalist-scientist and technician, with interests ranging from architecture and engineering to natural sciences sensu lato. As a Diluvialist and a Neptunist, Pini strongly rejected the igneous theory – with Earth completely molten in origin – preferring instead one involving a fluidity in water and formation of ‘primary mountains’ due of centrifugal acceleration induced by Earth’s rotation. Alternatively, the so-called ‘transitional’ and ‘secondary’ mountains were entirely attributed to the rapid, catastrophic and universal flood literally interpreted from the Holy Scriptures. Despite his strongly theistic approach to the evolution of our planet, some of the intuitions and methodological approaches of Pini are extremely interesting and worthy of review and renewed discussion.  相似文献   

5.
This study investigated whether rainbow darters Etheostoma caeruleum can learn to recognize unfamiliar predators through the process of classical conditioning. Etheostoma caeruleum were conditioned by exposing them simultaneously to their chemical alarm cues (a known fright stimulus) and either chemical cues from larval ringed salamanders Ambystoma annulatum (unfamiliar predator) or to a blank water cue (control). Conditioning could result in either specific learning of the A. annulatum cue or increased wariness in response to any novel cue (neophobia). To distinguish between these possibilities, E. caeruleum in both groups were exposed to either A. annulatum cues alone or to chemical cues from western rat snakes Pantherophis obsoletus (novel cue) 2 days after conditioning. Treatment (A. annulatum‐conditioned) E. caeruleum, but not control E. caeruleum, showed a fright response when they were exposed to both the conditioned (A. annulatum) and novel (P. obsoletus) cues, indicating increased sensitivity to new stimuli. When E. caeruleum were retested after an additional 32 days, however, the fright response occurred only following exposure to the conditioned (A. annulatum) stimulus, indicating that specific learning of the A. annulatum cue had been retained whereas the neophobia to novel stimuli was temporary.  相似文献   

6.
Earth Ovens ( Píib ) in the Maya Lowlands: Ethnobotanical Data Supporting Early Use. Earth oven cooking is very important among the Yucatec Maya. It is used for daily, festive, and ceremonial occasions, contrasting with other Mesoamerican cultures that use this technique sporadically. In this paper we present an ethnobotanical analysis of the use of earth ovens in a Maya community in Yucatan, Mexico, and discuss its possible antiquity, probable reasons for its continuity, and its current and past importance. We found four oven types in daily use as well as in ritual and celebratory contexts. These involve both men and women in a way that favors transmission of traditional knowledge to the next generation and promotes social bonding and ethnic identity. Of the 46 plant species used in their construction or for the dishes cooked in them, 82% are native and produced in traditional agricultural systems: milpa (kool in Maya) maize-bean-squash association and conuco (pach pakal in Maya) based on tubers such as manioc (Manihot esculenta Crantz). Research suggests that this food preparation technology has the same antiquity as its associated agricultural systems (approximately 3400 to 3000 B.C.E.). Earth ovens were probably used to cook roots and meat in the Archaic and then to cook tamales (vegetal-wrapped maize dough) beginning in the Preclassic. Continuity of traditional agricultural and cultural practices has favored preservation of earth ovens.  相似文献   

7.
We used a laboratory behaviour assay to investigate how innate predator recognition, handling stress, retention time, and number of conditioning events might affect chemically mediated anti-predator conditioning for hatchery-reared chinook salmon, Oncorhynchus tshawytscha. Juvenile chinook salmon with no prior exposure to predatory stimuli exhibited innate fright responses to northern pikeminnow, Ptychocheilis oregonensis, odour, regardless of whether the salmon came from a population that exists in sympatry or allopatry with northern pikeminnows. Juvenile chinook salmon exhibited enhanced predator recognition following a single conditioning event with conspecific extract and northern pikeminnow odour. Handling similar to what hatchery salmon might experience prior to release did not substantially reduce the conditioned response. When we conditioned juvenile chinook salmon in hatchery rearing vessels, fish from tanks treated once exhibited a conditioned response to northern pikeminnow odour in aquaria, but only for one behaviour (feeding response), and fish treated twice did not respond. The results suggest that enhanced recognition of predator stimuli occurs quickly, but may be to some extent context-specific, which may limit conditioned fright responses after release into the natural environment.  相似文献   

8.

Invasive species, because of their lack of co-evolutionary history with recipient communities, can act as “evolutionary traps” causing disconnects between natural enemy behavioural responses and the suitability of the invasive species as a prey/host resource. Invasion of exotic species in non-native environments may have several ecological effects, including consequences for the experience-mediated behavioural responses of indigenous foragers. Experience is usually thought to help resident species to buffer against negative impacts of new invasive species, including escaping from evolutionary traps. Here we hypothesized that the impact of foraging experience depends on whether an indigenous egg parasitoid can correctly assess the resource suitability of a new invasive species for offspring development. We showed that the invasive stink bug Halyomorpha halys acts as an evolutionary trap for the indigenous egg parasitoid Trissolcus basalis leading to unsuccessful development of?~?95% of the eggs laid in this host species. In a mixed scenario in which the associated resident stink bug Nezara viridula co-occurs with the invasive H. halys, we showed that oviposition experience in the low quality invasive host induces in T. basalis similar responses to those of the associated host. These results suggest that foraging experience does not lead to avoidance of an evolutionary trap. We discuss parasitoid foraging experience and reproductive success in the light of the evolutionary trap framework with implication for biological control.

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9.
Fathead minnows (Cyprinidae: Pimephales promelas) from a population that is sympatric with predatory northern pike (Esocidae: Esox lucius) exhibited a fright reaction to the visual stimulus of a live northern pike significantly more often than minnows from a population that is allopatric with pike. The fright response included increased use of shelter, dashing and freezing. Minnows from the pike-sympatric population also exhibited a significantly greater fright response, measured as a reduction in activity, following exposure to chemical stimuli from pike (i.e. water from a tank that had contained a pike) than did minnows from the pike-allopatric population. There was no significant change in activity by minnows from either population following exposure to chemical stimuli from nonpiscivorous peacock gudgeons (Eleotridae: Tateurndina ocellicauda), suggesting that the difference between the two populations is specific to stimuli from pike rather than a general difference in response to chemical stimuli from heterospecific fishes. Fathead minnows apparently utilize at least a two-tiered predator recognition system that incorporates both visual and chemical cues.  相似文献   

10.
In highland Ecuador, pena refers to a state of mind characterized by a mixture of sadness and anxiety as well as to an illness state resembling depression. This paper attempts to illustrate, through an analysis of the discourse on pena, how the ideology in which it is embedded serves to interpret a bodily problem at the same time as it reflects a more global attitude toward life. In essence, the folk theory states that the physical complaints caused by suffering are the result of a disturbance of the heart, the central organ of man, and of the emotional life which it controls. Because this suffering is often attributed to the immediate family group of the victim, the community at large often formulates accusations against one of its members. Though the therapy is limited to a cure of the symptoms through herbal remedies, a formal request can be made to a perceived wrongdoer to amend his behavior. The pena is also a state which can lead to colerin, a dangerous and sometimes lethal illness which is characterized by a sudden explosion of anger or madness and which will follow an unattended state of pena.  相似文献   

11.
The exotic vine, Clematis vitalba L. (F. Ranunculaceae), has been in forest reserves around Taihape in the Rangitikei Ecological Region of the central North Island, New Zealand, for about 70 years. Before this weed was abundant, Taihape forests were rich in species of indigenous vascular plants, especially woody species. Clematis vitalba and its control are contributing to a loss of forest structure and of indigenous biodiversity at the ecosystem and species levels, to a lack of recruitment of indigenous species, to an influx of other weeds and to changes in growth forms of indigenous shrubs. Species that have disappeared or become uncommon in forest with C. vitalba tend to be those that are nationally threatened or uncommon, have restricted distributions or are biogeographically significant. Current control of C. vitalba in the Taihape forest is piecemeal and long-term. It is based on mechanical and chemical methods, followed by grazing with sheep to prevent regeneration. Recommendations are made for rapid removal of C. vitalba from all untreated parts of the reserve, followed by manual control or spot- spraying, permanent removal of sheep, control of other serious weeds and implementation of a restoration programme.  相似文献   

12.
Abstract. Communities formed by the potentially invasive European Ammophila arenaria (marram grass) are compared with those dominated by indigenous dune plant species in coastal dune systems. Sampling of communities was carried out along the Cape coast for species richness, species diversity, importance values and species associations. The influence of soil and other environmental factors on vegetation were also compared. While species richness values in A. arenaria communities appear similar to those of indigenous dune plant communities, diversity indices are significantly lower. However, on the basis of importance values of individual species, A. arenaria does not show extreme dominance to the exclusion of other species, as it does on the North American Pacific coast, where it has also been introduced. Because of its growth in dense tufts, A. arenaria is accompanied mostly by small chamaephytes and therophytes, while indigenous stands support more phanerophytes. Moreover, A. arenaria forms weaker species associations than dominant indigenous dune plant species. The alien status of A. arenaria in South Africa is confirmed by applying classification and ordination analyses which failed to differentiate A. arenaria communities according to their geographical origin as achieved with indigenous communities. This may be attributed to the lack of vigorous indigenous plants in A. arenaria communities, which accounts for the low variety in species composition of A. arenaria communities along the coastline. With regard to environmental factors, A. arenaria communities were observed to be less sensitive to extrinsic factors, such as climate, than indigenous dune plant communities. Results confirm that A. arenaria is an alien plant species in South Africa, but do not imply its invasiveness in the present or near future.  相似文献   

13.
The shrub, Lantana camara L. (Verbenaceae), of tropical American origin, is a serious weed in South Africa and is the target of a biological control programme. The stem-sucking membracid, Aconophora compressa Walker (Homoptera: Membracidae), from Mexico was reported to be very damaging and was therefore imported into South Africa for biology and host range studies. The female partially inserts the eggs into the woody portion of actively growing stems, and guards them against potential predators. Nymphs develop through five instars to the adult stage in about 45 days. The adults and nymphs feed on the sap of stems causing the leaves to wilt, the flowers to abort and the gradual dieback of stems. No-choice experiments showed that adult survival, egg production, and nymphal emergence was high on L. camara, and also on related ornamental and indigenous species. The adult reproductive performance was higher on some indigenous Lippia species than on L. camara. Furthermore, the nymphs developed faster on these indigenous species and high rates of reproductive performance on these non-target species were sustained over several generations. In multiple-choice trials, equal or larger numbers of egg batches were recorded from indigenous Lippia species and the ornamental plant, Aloysia citrodora Palau, than on L. camara. The treehopper, A. compressa, poses an unacceptable threat to indigenous Lippia species and has therefore been rejected as a biocontrol agent for L. camara in Africa.  相似文献   

14.
This survey investigated the prevalence of ethnomedical syndromes and examined treatments and treatment-seeking in Mayan Guatemalans living in United Nations High Commissioner for Refugee (UNHCR) camps in Chiapas, Mexico. Methods included a rapid ethnographic assessment to refine survey methods and inform the cross-sectional survey, which also examined mental health outcomes; 183 households were approached for interview, representing an estimated 1,546 residents in five refugee camps and 93% of all households. One adult per household (N = 170) was interviewed regarding his or her health; an additional 9 adults in three surveyed households participated and were included in this analysis; of the 179 participants, 95 primary child-care providers also answered a children’s health questionnaire for their children. Results indicated that ethnomedical syndromes were common in this sample, with 59% of adults and 48.4% of children having experienced susto (fright condition) and 34.1% of adults reporting ataques de nervios (nervous attacks); both conditions were significantly associated with symptoms consistent with posttraumatic stress disorder, anxiety and depression and are mental health conditions recognized by the American Psychiatric Association. Combining healthcare provider and indigenous treatments such as physician prescribed medication (65%), medicinal plants (65.7%), and limpias (spiritual cleansings) (40.6%) was reported. Most participants (86%) sought routine medical treatment from UNHCR trained health promoters in their camp. Assessing ethnomedical health is important for informing mental health programs among this population.  相似文献   

15.
Emson  R. H.  Whitfield  P. J. 《Hydrobiologia》1991,(1):27-33
Feeding habit and diet composition of two colonizing mullids, Upeneus asymmetricus and U. moluccensis, and two indigenous goatfish Mullus barbatus and M. surmuletus (Mullidae), in the eastern Mediterranean were investigated. The most important taxonomic group in the diet of all four species was the Decapoda which were identified to the specific level, enabling precise assessment of trophic partitioning. Leptochela pugnax, a pasiphaeid of Red Sea origin, was by far the most important prey of all mullids studied, which resulted in considerable trophic overlap between all of the species. Trophic separation does not play an important role in resource partitioning of the eastern Mediterranean mullids. Consequently, coexistence between colonizing and indigenous mullids is presumably achieved by spatial segregation.  相似文献   

16.
Understanding the relationships between indigenous people and their threatened economic plants can aid the conservation effort on many levels. Understanding ethnic perceptions of the taxon is critical toin situ andex situ conservation projects and enhances the accompanying educational effort. Examples are discussed from the experience of a grassroots conservation group in southwestern United States, Native Seed/SEARCH. Four levels of economic plant vulnerability are examined among 1) wild-harvested plants, 2) husbanded wild plants, 3) domesticates, and 4) wild relatives of domesticates. Legal interpretations of endangered husbanded and domestic plants are discussed, and further documentation encouraged. Genetic dynamism of threatened indigenous crops is examined and the concept of Systems Conservation (i.e. the plant/human interactive systems) is introduced. Guidelines are offered for incorporating better cultural responsibility intoex situ conservation strategies. The concept of Biocultural Restoration is introduced with an example from an O'odham community. Examples are given of ways indigenous peoples and their knowledge can assist in the conservation effort.  相似文献   

17.
Theoretical and experimental models for autocatalytic systems leading to the prebiotic origin of chiralityvia the spontaneous symmetry breaking (resolution) of racemic substrates are reviewed. Of the experimental models so far studied, only 2nd order assymetric transformations during crystallization of optically labile enantiometers, leading to their spontaneous resolution under racemizing conditions (SRURC) have been successful. Our objective was to investigate in further detail the most promising of these systems from the point of view of its overall efficiency and its potential viability as a mechanism for the spontaneous generation of molecular chirality on the prebiotic Earth. To this end the 1,4-benzo-diazepinooxazole derivative XI, having a single asymmetric carbon atom, has been synthesized. We here confirm a report in the literature that (±)-XI undergoes SRURC in methanol, both on crystallization and as a slurry. The total spontaneous resolution of (±)-XI has been achieved in a yield of 99%, of which 80% had an optical purity ofca. 93%. Arguments are presented that SRURC of racemic substrates, while thus demonstrably effective in laboratory experiments, was probably not of major importance for the origin or amplification of molecular chirality on the primitive earth.  相似文献   

18.
Thermoelectric materials can convert waste heat into electricity, potentially improving the efficiency of energy usage in both industry and everyday life. Unfortunately, known good thermoelectric materials often are comprised of elements that are in low abundance and require careful doping and complex synthesis procedures. Here, we report dimensionless thermoelectric figure of merit near unity in compounds of the form Cu12xMxSb4S13, where M is a transition metal such as Zn or Fe, for wide ranges of x. The compounds investigated here span the range of compositions of the natural mineral family of tetrahedrites, the most widespread sulfosalts on Earth, and we further show that the natural mineral itself can be used directly as an inexpensive source thermoelectric material. Thermoelectrics comprised of earth‐abundant elements will pave the way to many new, low cost thermoelectric energy generation opportunities.  相似文献   

19.

We hypothesized that near-future elevated CO2 would affect the antipredatory behavior of two freshwater organisms; a pulmonate gastropod (Physella columbiana) and a cladoceran crustacean (Daphnia magna). Studies have found that pCO2 and increased acidification due to CO2 impedes fright responses to predators by activating GABAA receptors. After administration of predator-derived kairomones and conspecific alarm cues, we also briefly exposed some of the animals to gabazine which is a GABAA receptor antagonist to restore a fright response. We found that added carbon dioxide negatively affected the antipredatory behavior of both species but gabazine did not reverse this effect. To further examine the effect of CO2 and gabazine, we also tested the effect of stressful crowding, cold, and acidic conditions on the production of male daphnid offspring. An increase in ratio of male to female offspring is a common and expected response to stress by daphnids. We found that stress increased the production of males and gabazine reversed this at a pH of 5.5 but not at pH 6.2 or 6.5. Our study suggest that while the main negative effects of anthropogenic CO2 enrichment can be robust, the myriad indirect effects of CO2 make predictions about future predator prey systems less clear.

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20.
The negotiation of the illness experience by ayurvedic vaidya and South Kanarese patients suffering from specific sources of psychosocial distress is examined in light of the cultural patterning of illness and communication within the clinical context. The negotiation process is initiated by the posing of rhetorical questions about somatic and affective states and structured by a conceptual framework which relegates such states to humoral interrelationships. By establishing a humoral explanatory model for an illness episode or affective state which takes into account environmental and constitutional factors over which one has little control, responsibility is mollified and dialogue about personal problems eased. A comparison of the interaction between ayurvedic practitioners and patients and astrologers and clients is made in this regard. The socially integrative and adaptive consequences of ayurvedic therapy is considered vis a vis a portrayal of a popular vaidya's therapy for a number of illnesses associated with the somatization of psychosocial stress.  相似文献   

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