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21.
Determining the age of cyclomorphic rodents: Functional-ontogenetic determination,ecological aspects
G. V. Olenev 《Russian Journal of Ecology》2009,40(2):93-104
Functional-ontogenetic determination of age-dependent dental changes (ADCs) in voles has been demonstrated. The relationship between ADCs and the functional state of animals has been analyzed. A scheme and a table for determining individual chronological and biological ages in the bank vole (Clethrionomys glareolus Sch.) are proposed, which markedly improve the accuracy of results. Cases of rodent maturation and breeding in winter are considered. 相似文献
22.
In small rodents, differences in the average home range size, depending on the type of ontogeny and animal sex, have been revealed. The dynamics of changes in the spatial structure of populations during the breeding season are described. 相似文献
23.
Nguyen Cong Hao Nguyen Cuu Thi Huong Giang Nguyen Cuu Khoa Nguyen Thanh Son 《Resources, Conservation and Recycling》1996,18(1-4)
Detrimental effects of synthetic pesticides on health, environment and organisms have necessitated the exploration of alternative strategies for insect control. The insect attractants represent an important link within these systems. In Vietnam, since 1970, methyleugenol and its analogues have been synthesized for mass trapping of the fruitfly Daccus dorsalis Hendel. This chemical reduced the damage on the oranges of many plantations in our country. In the period 1978–1980, for the first time some selected types of pheromones were tested. The trials verified and provided evidence of the occurrence of six species of moth in southeast Vietnam: Archips micaceanus, Archips seminubilus, Cadra caustella, Spodoptera exigua, Chysodeixis eriosoma and Parapoynx sp. The last decade has seen intense activity in the elaboration and application of some complex systems of fighting plant pests. Pheromones of moth and weevils have been prepared in the Institute of Agrochemistry and the Institute of Tropical Biology NCST: Ostrinia nubilalis Hbn, Heliothis armigera Hbn, Plutella xylostella Curt, Adoxophyes sp, Lyonetia clerckella, Trogoderma granarium, Diabrotica virgifera virgifera, Diabrotica undecimpunctata, Blattela germanica, Diprion, Neodiprion, Scolytus multistriatus, Scolytus scolytus, Lasioderma sericorne, Tribolium cofusum. Some synthetic aspects of these pheromones are described. The use of pheromone traps for monitoring and mass trapping the Scolytus multistriatus, Tribolium confusum, Plutella xylostella Curt, Heliothis armigera Hbn, Cylas formicarius elegantulus will be discussed. 相似文献
24.
Fabrice Vinatier Françoise LescourretPierre-François Duyck Philippe Tixier 《Agriculture, ecosystems & environment》2012,146(1):52-59
The development of alternative pest-control strategies based on the spatial design of cropping systems requires a thorough understanding of the spatial links between the pest and its environment. Mechanistic models, especially individual-based models (IBMs), are powerful tools for integrating key behaviours, such as habitat selection and dispersal, with spatial heterogeneity. In this paper, we used an IBM calibrated and evaluated from real data to represent the spatial dynamics of the banana weevil in relation to the cropping system. We considered crop fragmentation and mass trapping as tools for suppressing pest numbers. Our simulation results showed that manipulating crop residues in the area surrounding each pheromone trap greatly improved trap efficiency. For an intensive banana plantation in fallow, traps were most effective when situated at the transition zone between banana area and fallow so as to maximize the trapping of weevils escaping the fallow. The model also showed that weevil numbers decreased when fragmentation of banana plantations was reduced. 相似文献
25.
Two populations of creeping thistle (Cirsium arvense) growing in a field uncultivated for many years and on the sloping bank of an artificial pond were studied with respect to the demographic and chemical composition. The results showed that the contents of some elements in plants depend on specific features of the soil and plant population parameters (abundance, biomass, and ontogenetic composition). Some indices of the content of mineral substances in the population and soil proved to be difficult to interpret unambiguously. 相似文献
26.
E. M. Oleinikova 《Russian Journal of Ecology》2004,35(6):376-382
The stages of ontogeny and morphogenesis of the common chicory were characterized on the basis of long-term observations. A comparative analysis of seed productivity was performed, and the pool of viable seeds in the soil was determined. The ecological–cenotic relationships and the types of population strategy of the species were estimated. 相似文献
27.
Katrin Strauss Holger Scharpenberg Robin M. Crewe Felix Glahn Heidi Foth Robin F. A. Moritz 《Behavioral ecology and sociobiology》2008,62(9):1523-1531
Queen pheromones interfere with worker reproduction in social insects. However, there is still an unresolved question as to
whether this pheromone acts as an “honest” signal for workers, giving a reliable indication of the queen’s reproductive value,
or as a suppressive agent, inhibiting worker reproduction independent of the queen’s reproductive capacity. In honeybees (Apis mellifera), the queen’s mandibular gland secretion, a mix of fatty acids and some aromatic compounds, is crucial for regulating the
reproductive division of labor in the colony inhibiting ovary development in workers. We quantified the mandibular gland secretions
of virgin, drone-laying, and naturally mated queens using gas chromatography to test whether the queens’ mating, ovary activation,
or the reproductive value for workers correlated with the composition of the secretion. Although the absolute amounts of the
“queen substance” 9-oxo-2(E)-decenoic acid (9-ODA) were similar among the three groups, the proportions of 9-ODA decreased
with increasing reproductive quality. Furthermore, the ratios of queen to worker compounds were similar in all three treatment
groups, irrespective of the reproductive capacity. A multivariate analysis including all six compounds could not separate
drone-laying queens from naturally mated ones, both with active ovaries but only the latter ensuring colony survival. We suggest
that the mandibular gland pheromones are unlikely to function as reliable indicators of queen reproductive value and rather
operate as an agent to suppress worker reproduction. This does not exclude the possibility that other “honest” pheromone signals
exist in the honeybee colony, but these would have to arise from other semiochemicals, which could be produced by both the
queen and the brood. 相似文献
28.
The study of relationships between symbiotic fungi and germinating seeds of the Orchidaceae showed that the effect of a fungus on germination depends on the presence of seed dormancy and its pattern. The specificity of symbiosis varies widely. The development of symbiotic sprouts in situand in vitro differs only in the rate, whereas the morphogenesis of asymbiotic sprouts is characterized by several anomalies. 相似文献
29.
Summary. We describe the use of pieces of silicone tubing
to analyse the mandibular gland components of queen and
worker honeybees and show that these compounds can be
efficiently trapped on bis(trimethylsilyl)trifluoroacetamide
(BSTFA) treated pieces of tubing. The use of this technique
rather than that of solid phase microextraction (SPME) techniques
with commercially available fibres that have been
shown to be efficient at sampling secretions from the cuticle
of insects, is necessitated by a requirement for collection of
large sample numbers in a short space of time or for
sampling in the field. The technique may be generalised for
use with semiochemicals of low volatility in other insect
communciation systems. 相似文献
30.
Summary. The ontogeny of pyrrolizidine alkaloid (PA) synthesis
and constraints on defence level during the seedling stage were examined
in the annual Senecio vulgaris and the monocarpic perennial
Senecio jacobaea. In both species, PAs were actively
synthesized from the onset of seedling growth so that juvenile stages
did not go through an undefended stage. Roots are known to be the
exclusive sites where PAs are produced. Root biomass was the single most
important biomass parameter explaining variation in total PAs per
seedling. All correlation coefficients between—relative growth
rate and PA concentration were negative, but none was significant.
However, a significant negative—correlation was found between
shoot to root ratio and PA concentration in S. jacobaeaseedlings, suggesting a dilution effect of the PAs. Earlier studies have
shown that the shoot to root ratio is positively correlated with
relative growth—rate of established S. jacobaea plants.
It is therefore suggested that young S. jacobaea plants
with a high shoot to root ratio and hence a high growth capacity
necessarily have lower PA defence levels than plants with a low
shoot to root ratio.
Received 10 July 2002; accepted 16 November 2002. 相似文献