首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
We tested the hypothesis that fruit quantity and quality vary vertically within trees. We quantified intratree fruit production before exploitation by frugivores at different heights in 89 trees from 17 species fed on by primates in Kibale National Park, Uganda. We also conducted a pilot study to determine if the nutritional value of fruit varied within tree crowns. Depending on the species and crown size, we divided tree canopies into 2 or 3 vertical layers. In 2-layered trees, upper crowns produced fruits that were 9.6–30.1% bigger and 0.52–140 times the densities of those from lower crowns, with one exception. Among 2-layered trees, upper crowns produced a mean of 46.9 fruits/m3 (median 12.1), while lower crowns produced a mean of 14.1 fruits/m3 (median 2.5). Among 3-layered trees, upper crowns produced a mean density of 49.9 fruits/m3 (median 12.5), middle crowns a mean of 16.8 fruits/m3 (median 6.6), and lower crowns a mean of 12.8 fruits/m3 (median 1.8). Dry pulp and moisture were systematically greater per fruit in the highest compared to the lowest canopy layers (22.4% and 16.4% respectively in 2-layered trees, 49.7% and 21.8% respectively in 3-layered trees). In 1 tree of Diospyros abyssinica, a pilot nutritional study showed that upper crown ripe fruit contained 41.9% more sugar, 8.4% more crude proteins, and 1.8 times less of the potentially toxic saponin than lower crown ripe fruit, but the result needs to be verified with more individuals and species of trees. We discuss the consequences of intratree variations in fruit production with respect to competition among frugivorous primates.  相似文献   

2.
The distribution of most recently discovered or described lemur species remains poorly known, but many appear to have small geographical ranges, making them vulnerable to extinction. Research can contribute to future conservation actions on behalf of these species by providing accurate information on local distribution and abundance. The distribution of the world’s smallest primate, the endangered Madame Berthe’s mouse lemur (Microcebus berthae), is limited to the Menabe Central region of western Madagascar. This species was discovered in the 1990s, but many fundamental aspects of its ecology remain unknown. The aims of our study were therefore to determine the actual distribution of Microcebus berthae across the forests of this region, to estimate population density, and to examine the species’ response to anthropogenic activities. We established 35 1-km line transects across Menabe Central, on which we surveyed mouse lemurs by distance sampling and live trapping. Microcebus berthae does not occur in all remaining forests of this small region and its population density is highly heterogeneous, both across its geographic range and locally. Within its area of occupancy, the population of Microcebus berthae not only was distributed according to spatial heterogeneities of the habitat, but also responded to anthropogenic disturbances and varied seasonally. Our results indicate that Microcebus berthae is susceptible to habitat degradation and avoids human environments spatially. As none of the forest remnants in which the species still occurs were officially protected until recently, immediate conservation actions should focus on effectively protecting Kirindy and Ambadira forests.  相似文献   

3.
乙烯诱导下草莓果实采后RNA代谢与蛋白质合成活性的变化   总被引:3,自引:0,他引:3  
草莓草果实在乳白时期采收(开花后约40d),分别用10μl/L,50μl/L和100μl/L的外源乙烯进行处理。处理后的果实大分子RNA和poly(A)+RNA水平以及poly(A)+RNA与总RNA的比例均有增高。果实体内RNA酶活性和体外蛋白质的合成水平也升高。乙烯很可能是促进草莓果实成熟衰老的因素之一。  相似文献   

4.
5.
Plants producing toxic plant secondary metabolites (PSMs) deter folivores from feeding on them. Animals that can cope with noxious PSMs have a niche with a competitive advantage over other species. However, the ability to cope with toxic PSMs incurs the costs of detoxification. To assess possible compensations for the ingestion of toxic PSMs, we compare the chemical quality of plants consumed by bamboo lemurs (genera Hapalemur and Prolemur; strepsirrhine primates of Madagascar) in areas with and without bamboo. Some bamboo lemurs consume bamboo containing concentrations of cyanogenic substances 10–50 times above the average lethal dosage for mammals, and we postulate that animals consuming cyanogenic substances need supplementary protein or readily available energy for detoxification. We compared the chemical composition of food consumed by three species of bamboo lemurs that feed mainly (>80% of their time) on bamboo in the evergreen rainforest of Ranomafana (Madagascar) with published data of the diets of bamboo lemurs at two sites without highly cyanogenic plants (reed beds of Lac Alaotra and the evergreen littoral forest of Mandena) and with food of sympatric folivorous lemur species that do not feed on bamboo. Lemurs feeding on bamboo consumed up to twice as much protein as bamboo lemurs in areas without bamboo and sympatric lemur species that feed on leaves of trees. Concentrations of nonstructural carbohydrates (a source of energy) showed the opposite trend. This result supports the hypothesis that feeding on cyanogenic plants is linked to high protein intake, either as a source of protein or for sulfur-containing amino acids that can be used for detoxification. Owing to the high protein concentrations in bamboo, however, we cannot distinguish between the hypothesis that lemurs that eat bamboo target additional food items with higher protein from the hypothesis that lemurs feeding on bamboo unavoidably obtain higher concentrations of protein than animals feeding on leaves of trees, without an added nutritional benefit.  相似文献   

6.
7.
8.
9.
We examined the effects of fruit patch size, density, and distribution on feeding subgroup size and feeding bout duration in four Neotropical primates—Lagothrix lagotricha, Ateles belzebuth, Cebus apella, and Alouatta seniculus—based on 2494 hr of focal animal sampling in Tinigua National Park, Colombia. All four species show positive correlations between patch size (tree diameter at breast height; DBH) and subgroup size (maximum number of individuals from the focal group feeding at the same time), but the determination coefficients are very low and this relationship does not seem to influence strongly the actual size of the groups. Ateles showed the weakest correlation between patch size and feeding party size, and their fission–fusion sociality is best explained as a mechanism to reduce intragroup competition rather than to adjust the subgroup size to the availability of patches. Feeding associations as well as proximal spacing patterns, in general, are more alike in species with similar ecological requirements.  相似文献   

10.
Researchers have proposed several hypotheses to explain pair-living in primates. In particular, when males are not involved in direct parental care, pair-living may be related to female dispersal, infanticide prevention, or male mate/resource defense. We aimed to evaluate, through a better understanding of the ranging patterns of avahis, which hypotheses may best account for pair-living in these nocturnal lemurs. We collected focal observations over 26 nights, June–September 2004, in a littoral forest (Sainte Luce, southeastern Madagascar) on 4 adult radiocollared avahis [Avahi laniger (Tattersall, I. (1982). The Primates of Madagascar. Columbia University Press, New York.) or Avahi meridionalis (Zaramody in Primate Reports 74:9–22, 2006)]. We followed 2 males and 2 females from 2 groups: B, a male-female couple, and A, comprising the parental pair and 1-yr-old female offspring. The adult females birthed in August. We recorded resting and feeding tree points (via global positioning system) for home range calculation through minimum convex polygon and kernel methods. We provide the first quantitative information on the ranging behavior of 2 male and 2 female avahis. Home range/daily path length values (means) are higher than the ones previously reported for the same and other folivorous pair-living lemur species. On average, the 2 females spent more time feeding and traveled shorter distances than the 2 males did. Male–female cohesion (mean values), possibly enhanced by offspring presence, was higher in A and after births than in B and before births, respectively. Although male avahis may be forced into pair-living owing to energy constraints related to size, locomotion, and diet, females might accept pair-living in exchange for indirect territory defense and mate guarding.  相似文献   

11.
We captured, ectoparasite-combed, and blood-sampled cave-roosting Madagascan fruit bats (Eidolon dupreanum) and tree-roosting Madagascan flying foxes (Pteropus rufus) in four single-species roosts within a sympatric geographic foraging range for these species in central Madagascar. We describe infection with novel Bartonella spp. in sampled Eidolon dupreanum and associated bat flies (Cyclopodia dubia), which nest close to or within major known Bartonella lineages; simultaneously, we report the absence of Bartonella spp. in Thaumapsylla sp. fleas collected from these same bats. This represents the first documented finding of Bartonella infection in these species of bat and bat fly, as well as a new geographic record for Thaumapsylla sp. We further relate the absence of both Bartonella spp. and ectoparasites in sympatrically sampled Pteropus rufus, thus suggestive of a potential role for bat flies in Bartonella spp. transmission. These findings shed light on transmission ecology of bat-borne Bartonella spp., recently demonstrated as a potentially zoonotic pathogen.  相似文献   

12.
We examine demographic patterns from a long-term study (1987–1996) of the population of ring-tailed lemurs in the Beza-Mahafaly Special Reserve, in southwestern Madagascar. In particular, we focus on the effects that a severe drought in 1991 and 1992 had on the population. The population of adult animals peaked in 1991 but decreased rapidly during the subsequent drought and immediate postdrought years. In the 1992 birth season (and second year of the drought) infant mortality reached 80%, and 20.8% of all adult females in the reserve died. The following year, adult female mortality reached a high of 29.9%. Juvenile mortality in 3 intensively studied groups was 57% during the second year of the drought. We compare these data with infant, juvenile, and adult female mortality in non-drought years. We are not able to calculate adult male mortality, as they often emigrate from the reserve to the adjacent forest; however, in the same 3 intensively studied groups, 89% of the males disappeared during the 2 immediate postdrought years. By 1996, the population had begun to recover after the decline that correlated with the drought conditions. Annual reproduction, high birth rates (.80–.86 annually), early sexual maturity, and dietary adaptability may be contributing factors to the recovery. Effects of and recovery from this type of natural disaster in the Beza Mahafaly ring-tailed lemur population parallel responses of some species of macaques and baboons with respect to the adaptability of edge species.  相似文献   

13.
Primates are now known to possess a keen sense of smell that serves them in various contexts, including feeding. Many primate species are frugivorous and provide essential seed dispersal services to a variety of plants. Studies of pollination ecology, and recently seed dispersal ecology, indicate that animal mutualist behavior exerts selection pressures that drive changes in flower and fruit traits. As a result, the use of olfaction in in primate feeding ecology may have affected the evolution of fruit odor in species that rely on primate seed dispersal. However, this hypothesis is seldom tested. Here, we summarize the available information on how primates may have affected the evolution of fruit odor. We ask what the chemistry of primate fruit odor may look like, what information fruit odor may convey, whether there are geographical differences in fruit odor, and what other factors may affect the odor of fruits consumed by primates. We identify many gaps in the available data and offer research questions, hypotheses, and predictions for future studies. Finally, to facilitate standardization in the field, we discuss methodological issues in the process of odor sampling and analysis.  相似文献   

14.
15.
Rozhkov  S. P.  Goryunov  A. S. 《Biophysics》2022,67(6):876-883
Biophysics - A qualitative approach to the mechanism of occurrence of phase transitions and equilibria of various types in the dispersions of a globular protein in the temperature range, where the...  相似文献   

16.
Catalase activity and induction of delayed chlorophyll fluorescence were shown to be the markers of the plant native state. The dependence of reaction of the plant to exogenous elicitors, stimulators or inhibitors of the defense system, on the age, cultivar and/or species was found. Prolonged effect of the treatment with phytoimmunocorrectors was observed. The necessity of careful choice of elicitors depending on the plant state was shown.  相似文献   

17.
Restoration approaches rely on native plants; yet in some situations, natural vegetation may not grow fast enough to prevent the fragmentation of original vegetation and the consequent negative impacts on fauna. In this context, some introduced plants may grow faster and provide more food than native species, and they may also contribute to human livelihood. We investigate to what extent introduced plant species (1) can serve as habitat and food for endemic vertebrates and (2) provide benefits to local people. We address this question in Madagascar, characterized by high degrees of endemism, long histories of coevolution between endemic species, highly fragmented forests, and a high reliance of the rural population on natural resources. A literature search for interactions between endemic fauna and introduced flora revealed that 100 of 1,379 introduced species recorded for Madagascar are used by endemic vertebrates. They provide food mainly for primates, flying foxes, and birds, and habitat for all terrestrial vertebrate groups. One hundred vertebrate species were reported to use introduced plants, many of which are fast growing and are useful for populations. Although these introduced plants should be approached with caution due to their potentially invasive behavior, many introduced plants can provide services for the native fauna and for humans. For example, trees can provide an interim solution to secure the survival of endemic fauna that otherwise would be lost due to fragmentation effects. These plants could bridge the time lag until native forest regeneration or restoration with native trees will have become effective.  相似文献   

18.
19.

Aim

Functional traits shape the distribution of taxa across environments. However, it remains unclear whether trait and environmental niche evolution are correlated, and what happened first: trait change facilitating environment shifts (pre-adaptation) or environmental change leading to trait change (adaptation). We focus on a species-rich Neotropical legume radiation to shed light on this enigma.

Location

Neotropics.

Time Period

Cenozoic.

Major Taxa Studied

Fabaceae: Papilionoidae: Swartzia.

Methods

We assembled leaflet, fruit and petal size data from monographs and herbarium collections for 86 to 96% of the c. 180 Swartzia species, inferred a dated Swartzia phylogenetic tree from existing DNA sequences covering 38% of the species and integrated these with distribution, soil and climate data. We used phylogenetic linear regression to quantify trait–environment relationships and applied comparative methods to evaluate modes of correlated evolution between traits and environments.

Results

Leaflet and petal size were strongly linked to climate, while fruit size was not associated with climate or soil characteristics. Evolutionary transitions to relatively low rainfall and low temperature environments were conditional on the evolution of small leaflets, whereas transitions to wet and warm environments were preceded by the evolution of larger leaflets. In contrast, transitions to the warmest or coldest environments were followed, rather than preceded, by petal loss.

Main Conclusion

Our results show that the macroevolution of functional traits has influenced the broad-scale distribution of Swartzia across Neotropical rainforest, seasonally dry, montane and inundated habitats. We suggest that trait evolution is conditional on environmental change but both pre-adaptive and adaptive processes may occur. These processes are important to understand the distribution of diversity at both regional (e.g. Amazonia) and global biogeographical scales.  相似文献   

20.
Linum emirnense Bojer subsp.marojejyense Humb. is elevated to a species and the heterostylous condition thought to exist inL. emirnense is determined to be an artifact resulting from a fungal infection of the fruit.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号