Author Keywords: behaviour; Colubridae; ecology; Masticophis flagellum; radiotelemetry; Reptilia; Serpentes; temperature; thermoregulation 相似文献
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991.
Patterns of feeding ecology among the living macaques conform poorly with recognized phyletic distinctions within the genus
because there is an important ecological division which cross-cuts phyletic groupings. This division, between weed species
and non-weed species, is based on the differing abilities of macaques to tolerate and even prosper in close association with
human settlements. Based on available information about their ecology in the wild, we tentatively assign macaque species to
these two categories. Finally, we consider the implications of our argument for scenarios of the initial spread of the macaques. 相似文献
992.
Carey P. Yeager 《International journal of primatology》1989,10(6):497-530
Proboscis monkey (Nasalis larvatus) feeding behavior and ecology were studied at the Natai Lengkuas Station, Tanjung Puting National Park, Kalimantan Tengah,
Indonesia. Data on feeding behavior were collected using scan sampling during group follows. Three vegetational plots containing
1,732 trees were established and monitored monthly for changes in fruit, flower, and young leaf production. Basal area and
canopy cover were calculated and used in estimating food abundance. Proboscis monkeys were found to be folivore/frugivores,
specializing in seed consumption. At least 55 different plant species were used as food sources, with a marked preference
for Eugenia sp. 3/4,Ganua motleyana and Lophopetalum javanicum. These tree species were among the most frequent and most dominant. However, proboscis monkeys were selective feeders; use
of tree species as food sources was not based simply on relative density. During times of low food abundance and/or availability
proboscis monkeys switched dietary strategies and increased dietary diversity. The average total home range was estimated
to be 130.3 ha, with an average group density of 5.2 groups per km2. The average biomass per km2 was estimated to be 499.5 kg. Given their high biomass and predilection for consuming seeds of dominant species, proboscis
monkeys may help to maintain and increase vegetational diversity. 相似文献
993.
E. N. Kondratieva E. V. Zacharova V. I. Duda V. V. Krivenko 《Archives of microbiology》1989,151(2):117-122
A new anaerobic thermophilic Gram-positive, nonsporeforming bacterium strain ZE-1 was isolated from a hot spring of Kamchatka (USSR). The cells are rod-shaped, (0.5–0.8 · 2.0–20 m), non-motile. The bacterium can grow between 42 and 75°C; the optimal temperature is 65°C. The growth is possible between pH values 5.0 and 8.5; optimal pH is 7.0. The cultures grow on the media containing peptone, yeast extract, or casein hydrolysate as nitrogen sources in the presence of glucose or some other sugars, mannitol or starch. The main fermentation products of glucose are ethanol, acetate, lactate, H2, CO2; byproducts are propionic, butyric and isovaleric acids. Glucose is metabolized via Embden-Meyerhoff-Parnas pathway. Molecular hydrogen does not inhibit growth. The bacterium does not reduce aceton to isopropanol, but is able to form H2S from elemental sulfur. The bacterium contains a soluble hydrogenase. This enzyme catalyzes both evolution and uptake of H2 and is active in the presence of methyl viologen. The DNA-base composition is 34.6 mol%; the genome size 2.08x109 D. The name proposed for the isolated bacterium strain ZE-1 is Thermoanaerobium lactoethylicum spec. nov. 相似文献
994.
On the solution of mathematical models of herd immunity in human helminth infections 总被引:1,自引:0,他引:1
Marco V. José 《Journal of mathematical biology》1989,27(6):707-715
The general solution of the mathematical model of herd immunity to human helminth infections recently proposed by Anderson and May [3] is obtained. The numerical solution of a more accurate biological model is indistinguishable from the corresponding exact solution of a more tractable mathematical model. Computer simulations of some particular cases of this model support the notion that both ecological and immunological factors determine the observed convex patterns of age-prevalence and age-intensity curves of human helminth infections.This work was made thanks to the advise and support of Dr. Robert M. May while the author was Postdoctoral Fellow at Princeton University 相似文献
995.
Geoffrey A. Hammerson 《Journal of thermal biology》1989,14(4):219-224
1. 1.|Body temperature (Tb) and activity of the snake Masticophis flagellum were studied by radiotelemetry in an outdoor enclosure.
2. 2.|Mean diurnal Tb varied little over a wide range of weather conditions, but weather variation was accompanied by major changes in sun exposure and in the timing and duration of activity.
3. 3.|Recently fed snakes reduced activity and exhibited neither a thermophilic response nor increased precision of thermoregulation compared to fasting snakes.
996.
Joel B. Hagen 《Biology & philosophy》1989,4(4):433-455
Ecology has often been characterized as an immature scientific discipline. This paper explores some of the sources of this alleged immaturity. I argue that the perception of immaturity results primarily from the fact that historically ecologists have based their work upon two very different approaches to research. 相似文献
997.
T. Payson Wilber Jr. 《Oecologia》1989,81(1):6-15
Summary Two populations (salt marsh and seagrass bed) of the hermit crab Pagurus longicarpus were sampled to examine associations between shell characteristics and egg production. Multivariate statistical analyses controlled for crab size and time of year, variables that otherwise could be confounded with shell effects. Although correlations between shell characteristics and reproduction existed in both populations, generalizations could not be made because associations varied within and between populations. Shell species was not associated with a female's reproductive state (i.e., whether or not she was barren when sampled) in either population. In the seagrass population, medium-large and large females occupying severely damaged or fouled shells were half as likely to be reproductive as females occupying other shell conditions. However, there was no association between shell condition and reproductive state for small and small-medium females in the seagrass population or among all females in the salt marsh population. In the seagrass population, small through medium-large reproductive females occupied shells more similar to their predicted shell size, regardless of whether the occupied shell was relatively small or large, than nonreproductive females. In contrast, relative shell sizes of reproductive and nonreproductive females were similar for large females in the seagrass population and all females in the salt marsh population. Clutch sizes were enhanced for females occupying Polinices duplicatus shells or shells larger than their predicted shell size in the seagrass population. Relative shell size also was associated with clutch size in the salt marsh population, but crabs occupying shells similar to their predicted shell size had the largest clutches. 相似文献
998.
Response of grasshoppers (Orthoptera: Acrididae) to livestock grazing in southeastern Arizona: differences between seasons and subfamilies 总被引:3,自引:0,他引:3
Summary Grasshopper densities were compared between grazed and ungrazed semidesert grassland sites in southeastern Arizona. Bouteloua-dominated perennial grass cover was about 1.5 times greater on the livestock exclosure. Grasshoppers were 3.7 times more abundant on the protected area in the summers of 1983 and 1984, when dominant species were grass-feeding members of the subfamily Gomphocerinae. In fall 1984, grasshoppers were 3.8 times more common on the grazed site, when dominants were mainly herb-feeders in the subfamily Melanoplinae. These results indicate important seasonal and taxonomic differences in the responses of grasshoppers to the activities of vertebrate grazers. 相似文献
999.
Influence ofGlycine max nodulation on the persistence in soil of a genetically markedBradyrhizobium japonicum strain 总被引:1,自引:0,他引:1
L. D. Kuykendall 《Plant and Soil》1989,116(2):275-277
Since competition with indigenous strains limits nodule occupancy by bacteria applied to seeds, the ecology of Bradyrhizobium inoculum strains used for soybean is of concern. A genetically marked strain,B. japonicum I-110 ARS, was directly enumerated from soil on selective medium. A clear long-term positive influence of even limitedGlycine max nodulation was shown by comparisons of population densities obtained with or without plant removal prior to nodule senescence in the first year and with an incompatible as well as a compatible soybean variety after 5 years. 相似文献
1000.
On choice of substrate and habitat in brachionid rotifers 总被引:9,自引:9,他引:0
Information on the distribution of 28 rotifers of the family Brachionidae from diverse waters in south and central Sweden was analyzed to reveal their relationships to substrate and habitat. Some brachionids are preferably planktic, others periphytic and/or benthic. Some non-planktic habitats are utilized more than others, but there is no evidence of a chemical attraction from any substrate. Instead, some substrates seem to be avoided, possibly depending on a poorer flora of periphytic algae. Besides substrate type, the following factors are found to be important for creating separate ecological niches in the brachionid family: temperature, oxygen content, trophic degree, chemical environment, food choice and sensitivity to predation. It is possible to delineate separate ecological niches for all brachionid rotifers, implying that Hutchinson's ideas about the plankton paradox are contradicted. Some species are specialists, other are generalists, the latter being characterized by a great morphological variation. The species are adapted in different ways to their preferential habitats, as regards foot, egg-carrying, protrusions and other lorical structures etc. Longer spines, for instance, are generally found in more transparent water, being a supposed protection against visual predators. 相似文献