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1.
Yoichi Shirai 《Researches on Population Ecology》1995,37(2):269-277
Plutella xylostella in the temperate zone shows a clear seasonal change in adult body size. In the laboratory, large and small moths were produced
during immature stages at 15°C and 25°C, respectively. These moths were then used to evaluate longevity, age-specific flight
ability, flight ability of mated and unmated females, and the influence of flight experience on the subsequent reproductive
success. The large moths lived longer and displayed a greater flight ability over 3 weeks. Irrespective of body size, unmated
females flew for a longer time than mated females, and flight experience affected their subsequent reproductive success. Females
of both sizes mated and laid eggs soon after emergence, without any obvious pre-reproductive period. More flight experience
did not delay oviposition, but did reduce egg production. It is likely that large moths with a longer adult life span and
greater flight ability are better fitted for long-distance flight and more fecund than small ones. These experimental results
may explain why long-distance migration ofP. xylostella is mostly seen during cool seasons, when relatively large moths with long forewing appear in the field. 相似文献
2.
N. A. C. Kidd 《Researches on Population Ecology》1990,32(2):189-208
Summary The large pine aphid,Cinara pinea lives exclusively onPinus species, where it feeds on the foliated shoots of the current and previous year. The paper describes the development of a
computer model designed to simulate the aphid’s population dynamics on saplings in the controlled environment of the laboratory,
i.e. in the absence of natural enemies. The model was able to account for about 80% of the variation in aphid numbers within
and between trees over a three month period. Sensitivity analysis revealed that the number of pine aphids is limited primarily
by nymphal emigration, the operation of which is sensitive both to density and to plant quality as reflected in aphid growth
rates. Of secondary importance are changes in reproduction acting through increased reproductive delay, again a result of
altered growth rates and adult size. Development, too, has an important secondary influence. Contrary to expectation and conventional
belief, however, alate production proved to be of negligible importance, either in limiting or regulating population numbers.
Alatae are produced in too few numbers and for too short a period to significantly alter the pattern of population change. 相似文献
3.
We studied seasonal changes in the larval population structure, adult size, and autogeny (egg production without a bloodmeal)
of the mosquitoAedes togoi on the seacoast of northern Kyushu, Japan. The effects of temperature, photoperiod and food conditions on larval development,
adult size and autogeny were studied in the laboratory.Aedes togoi overwintered in both the egg and larval stages and was multivoltine. Adult size was greater in spring and autumn and smaller
in summer. Autogeny occurred in spring and autumn but not in summer. Autogenous females were larger than anautogenous females,
and larger autogenous females produced more eggs. Laboratory experiments showed that autogeny was promoted under low temperature
and short-day conditions which corresponded with spring/autumn conditions in the field. Experimental food limitation in the
larval stage greatly reduced adult size and autogenous egg production. In the field, large inter-pool variations in adult
size and autogeny rate probably resulted from variations in nutrient and crowding conditions. Seasonal autogeny ofAedes togoi was discussed in terms of life-history strategy under fluctuating environmental conditions where relative advantages of autogenous
and anautogenous reproduction alternate seasonally. 相似文献
4.
Three models were constructed for analyzing the population characteristics ofC. chinensis on stored beans; model A describing the whole reproductive process with a single equation, model B describing the three age-specific
processes (oviposition, egg survival and larval survival) with separate equations, and model C which describes all these processes
not for the whole habitat but for the individual beans comprizing it. The logit equation was employed here as a common basis
to describe the density-response relationship involved. All three models showed very good fit to the experimental data obtained
for both laboratory and wild strains of the weevil. The parameter values characterizing the population dynamics were, however,
widely different between the two strains; the laboratory one which had been reared for some 500 generations showed significantly
higher reproductive capacity, less sensitive and gentler response to crowding in both adult and egg stages, and more uniform
egg distribution among individual beans, as compared with the wild strain newly introduced. Sensitivity analyses using these
models suggested that these changes in population characteristics have been attained by the process of domestication or adaptation
to stable laboratory conditions through a long period of time. This process seemed in effect to have optimized the population's
performances in the laboratory environment. Evolutionary significance of such optimization was discussed with reference to
the selection pressure which may have acted upon individuals. 相似文献
5.
K. L. Heong 《Researches on Population Ecology》1981,23(1):177-191
Summary The functional response parameters of the parasitoid,Anisopteromalus calandrae (Howard) to the third instar, the fourth instar and the pupae ofCallosobruchus maculatus (F.) were estimated from the Random Parasitoid Equation. By modifying this equation for a two host situation and using the
parameters estimated above, a no switch model could be obtained. This model was then used to test for switching. In the preference
experiments where two stages of the host were presented to the female parasitoid, a definite preference for the fourth instar
followed by the pupa and the third instar, respectively was shown. There was, however, no evidence of switching. There was
also no evidence that the data fitted the no switch models which suggests that when the parasitoid is searching in an environment
with two or more hosts, its searching behaviour is more complex. 相似文献
6.
Summary Population behaviour of adults and 5th-instar nymphs ofNezara viridula L. was analysed by means of the marking-and-recapture method in an early-planted paddy field. The field contained five varieties
of rice which differend in growth states. It was estimated that a total of more, than 7,000 adults of the first generation,
in which at least 3,000 were females, invaded the field from early July to middle August. Egg-mass census data, however, indicated
that only 10 per cent or less of the females participated in egg-laying. This was largely due to the, low rate of adult survival.
The adults preferred younger plants, for both feeding and oviposition.
The method described byIwao
et al. (1966) permitted estimate that 3,300–3,400 of the 5 th-instar nymphs and 1,100–1,200 of the adults of the second generation
were produced from 298 egg-masses (25, 700 eggs); while 95–6 per cent of the individuals were thought to have died before
reaching adulthood. Most of the 5 th-instar nymphs moved less than 4 m in three days as long as the condition of food plants
remained suitable, but they tended to move more towards younger plants when those on which they lived became too mature. The
apparent survival rate of the second generation adults was very low, probably due both to a rapid emigration and a high mortality
of newly-emerged adults. 相似文献
7.
8.
Natural hybridization among wingless carabid beetles of the subgenusOhomopterus (Carabidae, genusCarabus) is reviewed, and its significance in the evolution of this subgenus discussed. Natural hybridization occurs between parapatric
species of similar size. Two case studies of natural hybridization suggest that natural hybridization could have affected
the evolution of this subgenus in different ways. When there is a large difference in genital morphology between hybridizing
species, interspecific copulation often results in genital injuries that causes mortality of copulating individuals, and hence
reduces the fitness of hybridizing individuals greatly. In such a case, hybridization may be effective in maintaining the
parapatric distribution of the two species, and in the long term, may promote reinforcement selection for traits which are
effective in prezygotic reproductive isolation. When the morphological difference in genitalia is not so large as to cause
genital injury, a hybrid population may be established at the intermediate zone between two parental species, provided that
the immigration rates of the two species into the intermediate zone are small. Thus, natural hybridization may have contributed
to both divergence and reticulate evolution in this subgenus. 相似文献
9.
Summary Interactions ofTyphlodromus mites and their prey, the European red mite, in orchard settings were examined through computer simulation. In particular,
the consequences of very slow dispersal by the predators, compared with the weather-dependent higher rates of prey dispersal,
were elucidated. In simulations of the interactions of the predator and its prey, both dispersal and temperature strongly
affected the available supply of juvenile prey, and thus could determine whether the predators on an individual tree survived
or perished. 相似文献
10.
B. Leroi 《Researches on Population Ecology》1972,13(2):201-215
Summary The study of the population dynamics of the celery leaf-miner,Philophylla heraclei, must take into account the fact that the host-plant is not present permanently and that it develops between the two annual
generations of the insect. This development affects in particular the quality and quantity of the leaves fed upon by the mining
larvae. It is possible to know the numerical change of the populations from one annual generation to the next (bivoltine insect)
and from one year to the next by counting the populations in the various larval instars, responsible for the injury caused
to celery.
An accurate method of counting of larval numbers, taking into account their change parallel with that of the host-plant, is
described in this text. It makes it possible to know with accuracy the duration and importance of the infestations in relation
to external factors and to factors inherent to the host-plant itself. Certain traits of larval behaviour, particularly the
transfer of a larva from its original mine to a secondary mine as a result of food shortage can thus be established and estimated
quantitatively. 相似文献
11.
Summary Using a relationship between prey consumption and growth rate, field prey consumption of adults ofParatenodera angustipennis (S.) in a paddy field was estimated. Since a great number of grasshoppers (Oxya japonica) lived in the research area and the mantids had frequently eatenO. japonica, we presumed that they consumed onlyO. japonica. As a result, it was estimated that average prey consumptions for 6 days were 406 mg for the females and 23 mg for the males.
From the result of this estimation and the feeding rhythm of the mantids, it is concluded that each female captured one grasshopper
on average every a few days.
By comparing this actual feeding level ofP. angustipennis with those of other predacious arthropods, characteristics ofP. angustipennis as a predator were discussed. 相似文献
12.
Kazuo Nakamura Yosiaki It? Kazuyoshi Miyashita Akira Takai 《Researches on Population Ecology》1967,9(2):113-129
Summary The population parameters of green rice leafhopper,Nephotettix cincticeps in hibernated generation was estimated by the capture-recapture method on the gramineous weeds of resting paddy field from
late in April to mid-May, 1962–1965.
The difficulty of applying the capture-recapture method to this insect is caused from the low density and the low activity
of the leafhopper, so that it is necessary to make the suitable plan of capture-recapture series and to construct the special
method to detect the population parameters.
The number of adults differed greatly among the years and among the plots in the same year. But, in general, the density was
relatively high late in April, and decreased rapidly in May. The number of males was higher than that of females late in April,
but decreased rapidly to become lower in May.
The sampling efficiency with sweep-net depends upon the many factors, such as weather and floristic conditions; especially
the atmospheric temperature and the force of wind are considered to affect greatly to the efficiency. In general, low temperature
and strong wind are the cause of low sampling efficiency.
Contribution from JIBP-PT No. 20. 相似文献
13.
Samples of shoots ofPistacia lentiscus carrying galls of the aphid,Aploneura lentisci, were collected at three localities in Israel.
Shoots growing near pruning scars carried more galls than elsewhere on the plant, but these galls weighed less and contained
fewer aphids (smaller clones). The proportion of empty galls increased with gall density. Crowding of galls at such sites
may be due to the early burst of buds at the time of aphid emergence from the overwintering eggs, and not to active search
for preferred sites. 相似文献
14.
Yosiaki It? 《Researches on Population Ecology》1985,27(2):333-349
Summary More than 50% of nests ofRopalidia fasciata were founded by association of foundresses (multifemale nests). The multifemale nests were generally initiated earlier and
grew faster than the single-female nests. The survival rate of the multifemale nests was significantly higher than that of
single-female nests, and the productivity as measured by the number of cells produced per foundress had a peak at a foundress-group
size from 6 to 10. The number of marked foundresses which were seen on their original nest decreased as the colony cycle proceeded,
but some of them continued to coexist on the original nests after emergency of many female progeny. Except in the case where
a large number of foundresses attended a young nest so that some foundresses could not sit on the nest, the dominance interactions
among cofoundresses were mild. More than twothirds (71.4%) of nests (including those at the post-emergence stage) had multiple
egg-layers. The foundress association in this species is considered to be beneficial for every foundress because it raises
ability to avoid predation or to reconstruct their nests when the nests are destroyed by typhoons.
This work was supported in part by a Grant-in-Aid for Special Project Research on Biological Aspect of Optimal Strategy and
Social Structure from the Japan Ministry of Education, Science and Culture. 相似文献
15.
16.
Myron P. Zalucki 《Researches on Population Ecology》1981,23(2):318-327
Summary The effects of age and weather conditions on egg laying inD. plexippus were determined for caged females. Age (measured in physiological time), temperature and solar radiation influence egg laying
in this species of butterfly. An algorithm taking these factors into account in presented and accounts for 88% of the daily
variation in egg laying. CagedD. plexippus begin to lay eggs six—seven days after emergence, peak egg production (about 60 eggs/♀) occurs about 15 days later. Females
continue to lay eggs throughout their adult life, which in a flight cage was about 40 days. This egg laying pattern is compared
with other published fecundity schedules. The effect and importance of a female being prevented from laying her eggs, on her
life-time egg production, is also discussed. 相似文献
17.
ABSTRACTNonparametric Bayes and empirical Bayes estimators of the population median are provided under Dirichlet process priors. The finite-population sampling is used to estimate the finite-population median under Dirichlet process priors. The asymptotic properties of the estimators are obtained from a frequentist perspective. 相似文献
18.
T. H. Chua 《Researches on Population Ecology》1977,19(1):125-139
Summary Studies on populations ofBrevicoryne brassicae (L.), its parasites and hyperparasites were carried out by actual counting in the sprouts field and by sticky and water traps.B. brassicae was found to be attacked by one primary parasite,Diaretiella rapae (McIntosh), which in turn is parasitized byAlloxysta brassicae (Ashm.),Asaphes vulgaris
Walker,A. suspensus (Nees),Pachyneuron minutissimum (F?rster) andDendrocerus carpenterii (Curtis). The aphid population in the field was started by immigrant alates which were found flying too early to be synchronized
with the sprouts plants. SimilarlyD. rapae was not synchronized with the aphids although many individuals could have been carried into a plot through parasitized immigrant
alates, of which less than 30% were found parasitized. Because of high hyperparasitism (especially byA. brassicae)D. rapae was not able to maintain a high rate of parasitism to curb the aphid population growth. The maximum percentage mummies being
27.8%, while the maximum, percentage parasitism being 56.6% recorded only during the early 1974 season (mean=12.9%). The decline
of aphid population from September onwards was largely due to the cold weather, Syrphid predation and occasionally fungal
attack. The high rate of hyperparasitism byA. brassicae is attributed to its better synchronization withD. rapae. The mean percentage of parasite that emerged from mummies collected during 1973–74 wereD. rapae 31.3%,A. brassicae 64.3%,A. vulgaris andA. suspensus 4.3%,D. carpenterii 0.2% andP. minutissimum 0.1%. 相似文献
19.
Summary Rufous turtle dove,Streptopelia orientalis, coming to the soybean field entered it from the outer part to eat soybean cotyledons. As a result, the injured plants extended
from the outer to inner parts in the field. A model expressing these behaviours was constructed here, by assuming that the
amount of food birds can eat in one block determines whether they stay there or move into neighbour block. As the food decrease
due to exploitation of them by birds, birds enter into farther parts with the passage of time.
The rate of feeding in all visiting birds (an
0 wherea is the rate of feeding per individual andn
0 the number of birds visiting) and the rate of staying at a block,b, was estimated from the field experimental results, using the above model. The value ofan
0 fluctuated greatly, depending upon the season in which soybean seeds sowed. The value ofb also fluctuated inversely with that ofan
0, suggesting the the staying rate decreases with an increase in the number of doves coming, probably because of interference
among individuals. 相似文献
20.
Reproductive behaviors related to habitat utilization were studied in males of the damsefly,Mnais nawai, which has two male forms, territorial orange-winged males (nawai) and non-territorial pale-orange-winged males (sahoi), at the upper part of a mountain stream where they partiallycoexist with a related species,Mnais pruinosa, which also has two male forms, territorial orange-winged males (esakii) and non-territorial hyaline-winged males (strigata). These two species showed parapatric distribution; the lower part of the stream was occupied byM. nawai, and the upper part byM. pruinosa. In the present study, cross-matings occurred between bothMnais species, although normal intraspecific matings occurred more frequently than cross-matings. Territorial males of both species copulated
with conspecific females that entered their territory and guarded the ovipositing females, probably to avoid sperm displacement
resulting from subsequent copulations. Severe competition for oviposition sites by territorial males even occurred between
the two species. On the other hand, non-territorial males of both species have alternative mating strategies (including several
tactics such as sneaking, takeover and interception). The possible benefits from conflict among territorial males of both
species is discussed. 相似文献