关键词： Bones   Scavenging   Hyenas   Lions   Carnivores   Savannas   Fossils   Habitat preferences   Lakes  

摘要： Modern East African savannas serve as the primary model for the paleoenvironments of early hominids. However, throughout the Neogene there have been cooling and drying trends through time and fluctuations in seasonality. As a result, many modern East African savannas are drier, with more severe dry seasons, than during some periods in the Plio/Pleistocene in which early hominids lived. Our understanding of these moister and less seasonal periods is crucial for reconstructing early hominid lifeways. This paper presents a study of the ecology and bone taphonomy of a savanna less dry and less seasonal than the East African ones, the Central African savanna in Parc National des Virunga, Zaire. The natural bone distributions across the landscape of Parc National des Virunga contain information about the spatial distribution of scavenging opportunities and the effects on bone deposition of ecological variables such as large-herbivore biomass, proximity to water, and tree density. This information is a significant for taphonomic interpretation of fossil distributions in paleosols and the paleoecology of hominid scavenging. My results indicate that the Central African savanna differs in bone distributions and scavenging opportunities from the savannas of East Africa. Bone deposition is higher in open grasslands than in wooded areas near rivers, and there is no dry-season glut of carcasses. There is also no evidence for increased bone deposition near permanent water or ephemeral water holes. These differences are ultimately the result of the less seasonal rainfall pattern. For early periods in human evolution, Central African savannas may be a useful analog, and the implications for site formation and the ecology of scavenging are profound.

关键词： HOMINOID EVOLUTION   MITOCHONDRIAL DNA DIVERSITY   CYTOCHROME OXIDASE SUBUNIT II GENE  

摘要： Here we present a DNA sequence study that incorporates intraspecific variation from all five genera of hominoids (apes and humans). Recently it has been claimed that using single individuals to analyze species' relationships might be misleading if within-species variation is great. Our results indicate that despite high intraspecific variation in mitochondrial cytochrome oxidase subunit II gene sequences of some hominoids, humans and chimpanzees are nonetheless significantly most closely related. We also report the observation that variation within the gorilla species exceeds that between common and pygmy chimpanzee species, a finding with implications for conservation. In contrast, humans are less mitochondrially diverse than lowland gorillas inhabiting western Africa.

关键词： ECHINOIDEA   CASSIDULOIDA   NEOLAMPADOIDA   OLIGOPYGOIDA   CLYPEASTEROIDA   PHYLOGENETIC ANALYSIS   HOMLOPLASY   STRATIGRAPHIC DEPT  

摘要： The Neognathostomata (comprising the orders Clypeasteroida, Oligopygoida, Neolampadoida, and the paraphyletic Cassiduloida) form one of the three major clades of irregular echinoids. Despite the group's apparent success since the Jurassic and impressive peak diversity in the mid-Cretaceous, most included clades are now severely reduced. A phylogeny is essential for reconstructing the taxonomic, environmental and biogeographic patterns of this decline, and understanding the causal processes responsible for them. I examined the distribution of qualitative morphological characters (including those defining genera) for 97 species from 77 non-clypeasteroid genera and the three clypeasteroid suborders. Following preliminary analyses, I reduced the data to 40 characters (having 60 apomorphic states) and 71 representative genera. Goloboff's data decisiveness, the skewness of tree length distributions, and permutation tests all reveal significant phylogenetic structure in the data. Heuristic searches conducted with PAUP found more than 72 500 trees of 217 steps (CI = 0.276), but only the first 30 000 were evaluated. These exhibit considerable instability in the relationships among taxa. Successive approximations weightings did not reduce the numbers of favoured trees. Analyses using only less homoplasious characters failed to improve the resolution. Fisher's stratigraphic debt provides an objective means of selecting a very few of the morphologically most-parsimonious trees. Most nodes are supported by only one to three character changes, and these are generally reversed or paralleled elsewhere. The results suggest some cassiduloid families can not be separated, and support the reassignment of several genera. Despite the high levels of homoplasy, the most-parsimonious trees require fewer changes than had been previously suggested for evolutionary trends in several characters. Whether the rampant homoplasy present in the data reflects incorrect character analysis, limited str

关键词： Integrated pest management   Mite fauna, phytoseiid   Orchard tree, apple   Pest control, biological   Vegetation effect, surrounding  

摘要： Predaceous phytoseiid mites were collected from 14 apple orchards and from nearby deciduous trees and bushes in southern Finland. Phytoseiids were rare in insecticide-treated orchards bordered by just a few suitable host plants, whereas they were more abundant in other sprayed orchards that were surrounded by many suitable host plants. Phytoseius macropilis was the dominant phytoseiid species on unsprayed apple trees, but Euseius finlandicus was more common in sprayed orchards. In a 2 ha orchard surrounded by deciduous trees and bushes, the mean phytoseiid mite density was high only 15 days after a dimethoate treatment. Phytoseiid mites, primarily E. finlandicus, were encountered in the vicinity on the following trees: bird cherry (0.3 mites per leaf), hazel (9.8 per leaf), honeysuckle (2.7 per leaf), lime (2.4 per leaf), oak (1.2 per leaf) and great sallow (0.8 per leaf). Phytoseiid densities on adjacent vegetation had a noticeable effect on phytoseiid densities and species composition on apple orchard trees. Tall trees, such as oak and lime, are probably more important than low bushes as natural sources of phytoseiids for aerial dispersal into orchards. The migration of E. finlandicus into orchards from surrounding vegetation is concluded to be faster than that of Phytoseius macropilis.

关键词： SYSTEMATICS   PHYLOGENY   INTRASPECIFIC VARIATION   HUMANS   APES   DNA SEQUENCES  

摘要： Molecular evolutionary processes modify DNA over time, creating both newly derived substitutions shared by related descendant lineages (phylogenetic signal) and ''false'' similarities which confound phylogenetic reconstruction (homoplasy). However, some types of DNA regions, for example those containing tandem duplicate repeats, are preferentially subject to homoplasy-inducing processes such as sporadically occurring concerted evolution and DNA insertion/deletion. This added level of homoplasic ''noise'' can make DNA regions with repeats less reliable in phylogenetic reconstruction than those without repeats. Most molecular datasets which distinguish among African hominoids support a human-chimpanzee clade;the most notable exception is from the involucrin gene. However, phylogenetic resolution supporting a chimpanzee-gorilla clade is based entirely on involucrin DNA repeat regions. This is problematic because (1) involucrin repeats are difficult to align, and published alignments are contradictory;(2) involucrin repeats are subject to DNA insertion/deletion;(3) gorillas are polymorphic in that some do not have repeats reported to be synapomorphies linking chimpanzees and gorillas. Gene tree/species tree conflicts can occur due to the sorting of ancestrally polymorphic alleles during speciation. Because hominoid females transfer between groups, mitochondrial and nuclear gene flow occur to the same extent, and the probability of conflict between mitochondrial and nuclear gene trees is theoretically low. When hominoid intraspecific mitochondrial variability is taken into account [based on cytochrome oxidase subunit II (COII) gene sequences], humans and chimpanzees are most closely related, showing the same relative degree of separation from gorillas as when single individuals representing species are analyzed. Conflicting molecular phylogenies can be explained in terms of molecular evolutionary processes and sorting of ancient polymorphisms. This perspective can enhanc

关键词： LAS   SEDIMENT   TOXICITY   MUSSELS  

摘要： The toxicity of LAS on aquatic animals has been evaluated in particular relation to its concentration in water, although it is well known that sediments play an important role as repositories and sources of many contaminants, including surfactants. The aim of this study was to evaluate the effects of sediment-sorbed LAS on the marine mussel Mytilus galloprovincialis exposed to sediments drugged with 132 mg/kg dry weight of LAS mixtures. Four experiments were performed and some physiological parameters (filtration, oxygen uptake, nitrogen excretion) were measured on control and treated animals. In order to study uptake and release of sediment-sorbed LAS by mussels, quantification of weight, percentage of organic matter, LAS concentration and LAS homologue distribution on faeces were determined. Results showed no significant differences in physiological responses of treated mussels compared to controls, and the absence of a toxic action of LAS contaminated sediments. Moreover one notable aspect was that higher LAS concentrations were found in faeces than in uningested sediments recovered from water. This fact is tentatively explained either as the result of decreased desorption in the mussel intestinal tract with respect to circulating water, or as enrichment in fine particles by mussel filter feeding activity.

关键词： BARK FAUNA   COLPODEA   COLPODIDAE   HAWAIIAN ARCHIPELAGO   INFRACILIATURE   METROSIDEROS POLYMORPHA  

摘要： Corticocolpoda kaneshiroae n. g., n. sp. was discovered in the bark of Ohia trees (Metrosideros polymorpha) from the Hawaiian Archipelago. Its morphology and infraciliature were studied in live cells, with the scanning electron microscope, as well as in specimens impregnated with protargol, silver nitrate, and silver carbonate. The new genus, Corticocolpoda, belongs to the family Colpodidae and is unique in having a left oral ciliary field (polykinetid) composed of 13-20 equidistantly spaced, paired rows of monokinetids. The new species, C. kaneshiroae, measures 100-300 x 60-250 mu m and has a huge vestibulum used to capture large food items, mainly other ciliates. The oral ciliary fields are within the vestibulum and of equal length;the right field is a paroral membrane composed of a single row of dikinetids. Several micronuclei are attached to the ellipsoid macronucleus. The mucocysts are inconspicuous and arranged around the somatic dikinetids. The resting cyst is globular and has a 1-2 mu m thin, firm, yellowish inner wall and a 20-mu m-thick, fragile, hyaline outer wall. Convergent evolutionary paths and a possible polyphyly of the Colpodidae are discussed. An improved key to the genera of the family Colpodidae is provided. Twenty-three species of ciliates and one flagellate (Hemimastix amphikineta), which occurred together with C. kaneshiroae, are new for the fauna of Hawaii and listed in the ecology section.

关键词： Seasons   Diet   Arthropods   Rodents   Food consumption   Food   Seeds   Plants   Animal feeding behavior   Vegetation  

摘要： There was relatively little overlap in diet among Dipodomys ordii, Onychomys leucogaster, Neotoma micropus, and Spermophilus spilosoma in the shinnery oak-mesquite (Quercus havardii-Prosopis glandulosa) grassland of southeastern New Mexico. D. ordii primarily consumed Triplasis purpurea, P. glandulosa, Euphorbia, and arthropods;0. leucogaster predominantly consumed arthropods;N. micropus consumed plant fibers, new growth of dicots, Q. havardii, and P. glandulosa;and S. spilosoma primarily consumed arthropods, new growth of dicots, and grasses. Sexual differences in diet were virtually absent for D. ordii and 0. leucogaster, but there was statistically significant variation in diets among seasons, years, and months (P less-than-or-equal-to 0.05). A sample of approximately 60 specimens would be required to obtain a reasonable estimate of the variety of food items consumed by D. ordii and 0. leucogaster.

关键词： DWARF BAMBOO   REGENERATION   SASA   SHADE-TOLERANCE   ZOOCHORE  

摘要： The effects of dwarf bamboos (Sasa spp.) on the regeneration of trees in a natural hardwood forest were studied by analysing the spatial dispersion of seedlings and saplings of anemochores (Acer palmatum var. matsumurae, Fraxinus lanuginosa, and Carpinus laxiflora) and zoochores (Quercus mongolica var. grosseserrata and Q. serrata). Relative photosynthetic photon flux density at 10 cm above ground was significantly correlated with the coverage of dwarf bamboos (r=0.661, P<0.001). Seedlings were abundant and were randomly distributed in the anemochores, other than the shade-intolerant species C. laxiflora which was significantly more sparse in sites with dense Sasa than in sites where Sasa was rare. Distribution of saplings was also random in the shade-tolerant anemochores A. palmatum var. matsumurae and F. lanuginosa but aggregated in sites with sparse Sasa in the shade-intolerant anemochore C. laxiflora. In contrast to the anemochores, seedlings of zoochores were very few and were distributed in sites with sparse Sasa. Saplings were also aggregated and negatively correlated with Sasa cover in the shade-intolerant species Q. serrata and the tolerant species Q. mongolica var. grosseserrata. The acorns put on the forest floor in a site with dense Sasa were quickly removed by small rodents such as Apodemus speciosus and A. argenteus. Trap census of rodents revealed that those mammals prefer the dense Sasa habitat to the sparse Sasa habitat. This suggests that the dwarf bamboos strongly affect the regeneration of zoochorous trees not only by shading the seedlings but also by providing habitats to acorn-feeding small mammals.

关键词： RHIZOPHAGUS-GRANDIS   DENDROCTONUS-MICANS   COLEOPTERA   KAIROMONE   FLIGHT   PREDATOR   SCOLYTIDAE   RHIZOPHAGIDAE   VISUAL ORIENTATION   PICEA-ABIES   OLFACTORY   BARK BEETLE  

摘要： Insects apparently responding to the visual stimulus offered by a tree or other object may also be responding to the variety of physical effects caused by the obstruction, including turbulence, a reduction in wind velocity and eddies. The relative importance of prey odour associated with the bark beetle Dendroctonus micans (Kugelann) (Scolytidae), prey-host-tree odour, silhouette, and physical barrier to the wind, in the orientation and landing behaviour of a predatory beetle, Rhizophagus grandis Gyllenhall (Rhizophagidae), were investigated. *** responded very positively to the frass of its prey when presented on a 'tree' but not to the same quantity of frass presented alone. Frass on black plastic uPVC pipes was significantly more attractive than frass on real host tree logs, suggesting that host-tree volatiles do not enhance the attractiveness of prey frass. The beetles responded to 'transparent' Mylar three-dimensional cylinders in the same way as they did to the black plastic pipes. Beetles were also tested with frass and two-dimensional stimuli offering a visual stimulus or physical barrier alone or in combination. Frass with a two-dimensional visual stimulus was no better than frass alone: few insects landed. Significantly more insects were attracted to the same two-dimensional visual stimulus with a hidden upwind barrier producing turbulence, but a similar number were attracted to the frass in front of a hidden barrier alone. As many plants are similar in size to the logs used in these experiments, comparable effects might influence the behaviour of other phytophagous insects, their predators and parasitoids.