共查询到20条相似文献,搜索用时 15 毫秒
1.
Summary Population dynamics ofHeliothis virescens (F.) andHeliothis zea (Boddie) (Lepidoptera: Noctuidae) eggs and larvae were studied for two years in a small plot of cotton,Gossypium hirsutum (L.). Due to morphological and ecological similarities, the pooledHeliothis population was considered for most of the analyses. Two generations ofHeliothis eggs and larvae were completed during each year. Stage recruitment was estimated for the eggs and larval instars 2–6, and
recruitment variances were estimated by a Monte Carlo method. A modified form of the Weibull distribution was developed and
used as a model to characterize survivorship curves for each of the fourHeliothis generations. A Type I survivorship curve (mortality rate increasing with age) was inferred for both Generation 1 (early season)
data sets, whereas a Type II survivorship curve (mortality rate constant and thus independent of age) was inferred for both
Generation 2 (late season) data sets. The shapes of the survivorship curves for the individualH. virescens andH. zea populations were inferred to be the same as those for the pooled populations. Analysis of the contributions of various factors
toHeliothis stage-specific mortality indicated that natural enemies (predators and parasites) and the availability of food for larvae
were responsible for between-generation differences in survivorship patterns. 相似文献
2.
Summary ‘Predator-foolhardiness’ (Lloyd andDybas, 1966b) in an epidemic population of the sugarcane cicada,Mogannia minuta was tested by counting the number of successful and failed trials of hand-capturing of adults in the centre and periphery
of a heavily infested area. Males frequently failed to escape from capture in the outbreak area but they did not in the peripheral
zone. Females could escape well irrespective of the density. It was considered that the ‘predator-foolhardiness’ of males
is not due to genetic differentiation through the process of outbreak but to the effect of massive chorus on the escape behaviour.
The work was supported in part by Grant-in-Aid No. 439017 from the Ministry of Education, Science and Culture. 相似文献
3.
Summary Life tables for worker honeybees covering all life span, and those for adults, were prepared for three seasonal cohorts,June bees, July bees andwintering bees. Survivorship curves forJune andJuly bees show a convex type being exceptional for insects, with relatively high mortality at egg and feeding larval stages and at
later adult stage after most bees became potential foragers. Adult longevity greatly lengthens inWinteriing bees and survivorship curve drops approximately with the same rate. A remarkable similarity of survivorship curves for men and
honeybees was demonstrated, apparently due to highly developed social care in both. Some comments were given on mortality
factors. The importance of life tables for population researches was shown by applying our result to the population growth
curve made byBodenheimer, based upon the data byNolan. At the asymptote of the uncorrected curve, the ratio of total population estimated by uncorrected curve to that by corrected
curve reaches about 3∶2.
Contribution No. 821 from the Zoological Institute, Faculty of Science, Hokkaido University, Sapporo, Japan.
Contributions from JIBP-PT No. 45. This study was in part supportod by a grant in aid from the Ministry of Education for the
special project research, “Studies on the dynamic status of biosphere.”
Population and bioeconomic studies on the honeybee colonies. II.
We express our sincere thanks to Dr. YosiakiIt?, National Institute of Agricultural Sciences, Tokyo, for his kind stimulation and advices to the present work. 相似文献
4.
S. Akimoto 《Researches on Population Ecology》1995,37(1):81-89
Closely related species of gall-forming aphids are often associated with a single host species. SixTetraneura species coexist on the Japanese elm,Ulmus davidiana, in Sapporo, northern Japan. This paper describes the probabilities of coexistence on macro- and microgeographic scales (i.e.,
on host trees and host leaves) and examines whether coexistence with conspecific or heterospecific galls on leaves or shoots
has any effect on the fecundity of each aphid species using multiple regression. A Monte Carlo simulation showed that the
frequency distribution of the numbers of species on individual host trees differed significantly from that expected from the
null model. There were significantly positive or negative associations between species.Tetraneura radicicola andsorini always coexisted with other species on trees they infested. Multiple regression revealed that the coexistence of conspecific
or heterospecific galls on individual leaves had no influence on the fecundity ofradicicola andsorini, but had a negative influence on that of sp. O. On average,radicicola andsorini produced a smaller number of offspring in galls than sp. O, and obviously consumed only a small part of resources available
on the galled leaves. Evidence available suggests that although amensalism does arise between sp. O and other species, its
influence in not so strong as to exclude sp. O competitively from theTetraneura community. 相似文献
5.
William K. Reisen Farida Mahmood Tauheeda Parveen 《Researches on Population Ecology》1979,21(1):12-29
Summary A mark-release-recapture experiment to estimate population survivorship and absolute size was performed with wild-caughtAn. subpictus adults at the village of Khano-Harni, Lahore District, Punjab Province, Pakistan during September 1978, the end of the monsoon
rainy season, when temporal population abundance was maximized. Daily survival rate estimated from the recapture sequence
of marked adults was low, males=0.192 and females=0.343. Survivorship for females estimated by several vertical age-grading
procedures ranged from 0.347 to 0.628. Both stage- and age-specific life tables were calculated from vertical age-grading
data determined by the dilatation method. Female and male population size was estimated byBailey’s modification of theLincoln Index and was found to average 4478.4 and 6106.8, respectively. The bionomics, survivorship and population size ofAn. subpictus in the Lahore are indicated that this species was probably not important in the transmission of human malaria. 相似文献
6.
Summary Intra- and interspecific competition between laboratory populations of four green leafhoppers,Nephotettix spp. was studied in the laboratory under three different temperature regimes of 24°C, 27°C and 30°C. For the single-species
population of the three tropical species, the equilibrium density increased as the temperature increased. On the other hand,
for the temperature speciesN. cincticeps, the highest equilibrium density was at the intermediate temperature and the lowest at high temperature.
Interspecific interactions between two tropical (N. virescens vs.N. nigropictus), a tropical and a temperature (N. virescens vs.N. cincticeps) and a rice-feeding and a grass-inhabiting (N. virescens vs.N. malayanus) Nephotettix species were also studied in the laboratory at the three temperature regimes. Temperature differentially affected the outcome
of competition between twoNephotettix species. BetweenN. virescens andN. nigropictus, the latter was more successful over the former at low and intermediate temperatures, while the former was more successful
at high temperature. BetweenN. virescens andN. cincticeps, the temperate species inhibited the growth of the tropical species at low temperature while the tropical species inhibited
the growth of the temperate species at high temperature. At intermediate temperature, the population ofN. virescens persisted at a slightly higher density over the population ofN. cincticeps. Between the rice-feedingN. virescens and the grass-inhabitingN. malayanus, regardless of temperature the population density of the latter was greatly reduced and later became extinct while the population
of the former continued its growth. These consequences of competition between twoNephotettix species conformed fairly well to those predicted by theLotka-Volterra model using demographic parameters specified for each species. 相似文献
7.
T. S. Bellows Jr. 《Researches on Population Ecology》1985,27(1):55-64
Summary The effects of host age on parasitoid reproductive capacity are studied using the pteromalid parasitoidLariophagus distinguendus
F?rster and its bruchid hosts,Callosobruchus chinensis (L.) andC. maculatus (F.). A series of experiments were performed to investigate relationships between age and size of host parasitized and the
developmental period of pre-imaginal progeny, sex ratio, female size, longevity, fecundity and oviposition rate. There was
no effect of host size on preimaginal parasitoid developmental period. Sex ratio varied from less than 5% females from young
(small) hosts to 60% females from mature (large) hosts. Adult size, female longevity, fecundity, and oviposition rate were
also positively related to host age. Females provided mature hosts lived longer than those provided either young hosts or
no hosts, possibly because of an increased ability to host-feed from the larger hosts. The implications of these findings
to parasitoid population reproductive capacity and host-parasitoid synchrony are discussed. 相似文献
8.
Eizi Kuno 《Researches on Population Ecology》1988,30(1):69-82
Summary The influence of spatial distribution pattern on the outcomes of intra- and interspecific competition is studied theoretically.
The models developed are the generalized logistic andVolterra equations, whereLloyd’s indices of intra- and interspecies mean crowding were incorporated with their assumed linear relationship to mean density
in order to express the intensity of crowding which is really effective to the existing individuals. It is shown that while
the increasing patchiness of distribution has a pronounced effect of promoting the intraspecific competition and lowering
the equilibrium density for individual populations, it generally relaxes the interspecific competition, making it easy for
different species sharing the same niche, which would otherwise be incompatible, to coexist stably. These models thus provide
a simplest theoretical basis to explain why many insect populations in nature are kept relatively rare in number and why a
number of allied species often coexist freely sharing the same resource, against the “competitive exclusion principle” deduced
from the originalVolterra equations. 相似文献
9.
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
10.
Summary Experiments are described showing the long-term dynamics of two species of bruchid beetles (Callosobruchus chinensis andC. maculatus) in arenas in which the resource of 50 black-eyed beans is divided between 5, 10 or 50 ‘patches’. Both species of adult beetles
exhibit clumped distributions between patches. Within a patch there is a tendency for a density dependent reduction in (1)
eggs laid per female, (2) the proportion of eggs hatching per bean (C. chinensis only) and (3) larval survival which is strongly overcompensating (particularly inC. maculatus). A discrete generation model is used as a framework to draw these results together and show how the different factors affecting
natality and mortality can influence the population dynamics. Finally, the importance of the resource renewal interval in
influencing the period of the population cycles is discussed. 相似文献
11.
Estimation of vital rates by means of monte carlo simulation 总被引:1,自引:0,他引:1
Monte Carlo simulation has been used to estimate age-specific fertility and mortality rates for a small population,the French-derived isolate of Northside on St. Thomas, U. S. Virgin Islands. Estimates were based on data collected in a household census and genealogical survey and on birth, death, and marriage records for the years 1916to 1966. During this 50-year period (in which the population size increased from 202 to 657), the numbers of births and deaths were too, small to estimate age-specific rates directly, and in addition, death registration was incomplete. Mortality rates were estimated using a simulation program in which mortality was the only stochastic variable. A model mortality schedule was chosen which most accurately reproduced the growth pattern of the population over the 50-year period. To estimate fertility rates, a more complex simulation model was used in which fertility, nuptiality, and mortality were random variables with probability distributions. Preliminary estimates of fertility were made from the birth records and used as input to this simulation program. Birth probabilities were adjusted empirically from one set of simulation runs to the next, until population growth rates, as well as other demographic characteristics, were similar in the real and simulated populations. The birth rates which produced the best fit to the real population data were taken as the estimated age-specific fertility schedule. To reproduce the real population age structure more closely, secular changes in birth probabilities were applied. 相似文献
12.
Summary A series of experiments were carried out with the endophagous egg parasiteTelenomus fariai on its hostTriatoma phyllosoma pallidipennis to determine the possible role of intraspecific competition by the parasite progeny in population regulation of the parasite.
Eight parasite densities (1, 3, 5, 10, 20, 30, 40, and 50 individuals per vial) were used, and the design of sequentially
sacrificed replicates applied. Survivorship curves for each density indicated smaller number of progeny per host at higher
densities, and the shapes of the curves suggested a relatively early mortality process.Morris' linear regression technique for determining within-generation density-dependence was used, and the results showed that only
larval mortality could be identified as density dependent. The same technique applied within the larval stage proved that
only mortality of larvae in their second, third, and fourth day of development were responsible for population regulation.
The applicability of the technique, as well as the relevance of the results for natural population, is discussed. 相似文献
13.
In this article, we show how stochastic diffusion models can be used to forecast demographic cohort processes using the Hernes, Gompertz, and logistic models. Such models have been used deterministically in the past, but both behavioral theory and forecast utility are improved by introducing randomness and uncertainty into the standard differential equations governing population processes. Our approach is to add time-series stochasticity to linearized versions of each process. We derive both Monte Carlo and analytic methods for estimating forecast uncertainty. We apply our methods to several examples of marriage and fertility, extending them to simultaneous forecasting of multiple cohorts and to processes restricted by factors such as declining fecundity. 相似文献
14.
Summary Dispersal, immigration and emigration rates, horizontal and vertical survivorship and absolute population size were estimated
for micropopulations ofAn. culicifacies, An. stephensi andAn. subpictus at a series of cattle sheds in rural Punjab Province, Pakistan, during November 1979 and May 1980 using capture-mark-release-recapture
and dissection methods. Dispersal was temperature-related, with populations more vagile during May. Mean dispersal distance
per individual was low for all species. More than 70% of all recaptures were taken at the point of release and the longest
detected flight was 1250 meters.
Horizontal survivorship was greater during November and was always less than vertical survivorship calculated from dissection
agegrading data. Survivorship during the nulliparous period was greater than survivorship throughout total life, indicating
the survivorship curve may be slightly sigmoid. Daily population sizes of endemic and immigrating females and males were calculated
usingBailey's (1952) modification of the Lincoln Index, with the daily captures adjusted for immigration which was highest in May. Daily
additions to the indoor resting population exclusive of immigrants were estimated using the method ofManly andParr (1968). The relationship of the present findings to malaria transmission and genetic control were discussed. 相似文献
15.
B. F. J. Manly 《Researches on Population Ecology》1985,27(2):325-332
Summary An iterative procedure for correcting stage-frequency data is described to allow for situations where the period during which
a population is sampled begins after some individuals have entered stage 2 or ends before all individuals are dead. The reason
for correcting data in this way is to enableKiritani andNakasuji's method for estimating stage-specific survival rates, with extensions proposed byManly (1976, 1977), to be used to analyse the data.
The proposed procedure is illustrated on data obtained by sampling a population of the grasshopperChorthippus brunneus passing through four instar stages to reach the adult stage. 相似文献
16.
Summary A statistical and graphic study is presented of the wastage of eggs byVenturia (=Nemeritis) canescens when searching singly and in groups of 10 among hosts at four different host densities in laboratory universes as described
byHuffaker andMatsumoto (preceding paper of this journal). The host insect was the fluour mothAnagasta kühniella and the host densities used were 10, 30, 100 and 200 per universe. Intensity of egg wastage due to superparasitim varied
significantly according to host density, and between the two parasite densities employed, 1 and 10, using bothF-tests and chi-square tests. Plots ofk-factor analysis on this egg wastage showed high negative correlations with host density, and the raw data for single parasites
was well represented by a parabola while that for the grouped parasites departed from this relationship only at the lowest
host density.
These studies were conducted as a part of a general investigation into the processes operating in the population dynamics
of arthropods under grants from the National Institutes of Health, U. S. Public Health Service (#A10-1611), and the National
Science Foundation and Environmental Protection Agency (NSF DEB7504223) to the University of California. The findings, opinions
and recommendations expressed herein are those of the authors and not necessarily those of the University of California, the
National Institutes of Health, the National Science Foundation or the Environmental Protection Agency. 相似文献
17.
Alkema L Raftery AE Gerland P Clark SJ Pelletier F Buettner T Heilig GK 《Demography》2011,48(3):815-839
We describe a Bayesian projection model to produce country-specific projections of the total fertility rate (TFR) for all
countries. The model decomposes the evolution of TFR into three phases: pre-transition high fertility, the fertility transition,
and post-transition low fertility. The model for the fertility decline builds on the United Nations Population Division’s
current deterministic projection methodology, which assumes that fertility will eventually fall below replacement level. It
models the decline in TFR as the sum of two logistic functions that depend on the current TFR level, and a random term. A
Bayesian hierarchical model is used to project future TFR based on both the country’s TFR history and the pattern of all countries.
It is estimated from United Nations estimates of past TFR in all countries using a Markov chain Monte Carlo algorithm. The
post-transition low fertility phase is modeled using an autoregressive model, in which long-term TFR projections converge
toward and oscillate around replacement level. The method is evaluated using out-of-sample projections for the period since
1980 and the period since 1995, and is found to be well calibrated. 相似文献
18.
Summary Principal component analysis (PCA) was used to determine the effects of infestation of bulk stored wheat by multiple species
of insects at 30±2°C for 60 wk. Eight 204-liter drums containing wheat at 15.5% moisture content were used as three distinct
man-made ecosystems: (a) Control system (2 drums), insect-free; (b) RST system (3 drums), artificially infested withRhyzopertha dominica (F.),Sitophilus oryzae (L.), andTribolium castaneum (Herbst); and (c) COT system (3 drums), infested withCryptolestes ferrugineus (Stephens),Oryzaephilus surinamensis (L.), andTribolium castaneum. The variables measured tri-weekly within each system included carbon dioxide, oxygen, temperature, grain moisture, seed
damage, grain weight and volume, dust weight and volume, fat acidity values (FAV) of the wheat, seed germination, microflora
includingAlternaria alternata
(Fr.) Keissler,Aspergillus glaucus group,Aspergillus candidus
Link, and bacteria, insects and the miteTarsonemus granarius
Lindquist. PCA provided multivariate synopsis of the data quantifying several important relationships among the variables monitored.
Tri-weekly and cumulative 60-wk analyses of each system showed that high bacterial counts were associated with high FAV levels;Tarsonemus numbers were positively related toAspergillus; Alternaria and seed germination were negatively related to FAV, bacteria and grain damage; and that the number of insects was related
to the presence ofAspergillus and negatively related to the presence of bacteria. Seed germination andAlternaria infection often decrease rapidly presumably because of infection by fungi of theAspergillus glaucus group. The combined action ofR. dominica andAspergillus spp. enhanced seed damage and increased grain moisture content thus promoting bacterial growth which in turn inhibited insect
and mold growth. Fat acidity values increased with time unless seed damage and bacterial infection were extensive as in the
RST system.
Contribution No. 903, Agriculture Canada, Research Station, 195 Dafoe Road, Winnipeg, Manitoba, R3T 2M9. 相似文献
19.
Yutaka Sait 《Researches on Population Ecology》1987,29(1):57-71
Summary Experimental observations on the arrenotokous reproductive patterns of two spider mite species (Acari: Tetranychidae), the
long-seta form ofSchizotetranychus celarius (Banks) andTetranychus urticae
Koch, revealed that reproduction of unfertilized females of the former is very differnt from that of the latter. Unfertilized
females ofS. celarius, which has a subsocial life, laid a few eggs and then became inactive. In contrast, the fecundity of unfertilizedT. urticae females was only slightly reduced as compared with fertilized females. Mother-son matings may thus sometimes occur in naturalS. celarius populations.
A two-year field survey revealed that, in the absence of males, overwintering females ofS. celarius occasionally remain unfertilized until early spring. Furthermore, nest foundation observed in late spring indicated that
most of the season's first nests were founded by single females. These two sets of observations strongly suggest that motherson
mating takes places in nature, corresponding to the reproductive trait seen in the experiment.
Mother-son mating inevitably increases the relatedness between nest members. The estimated father's relatedness to its offspring
is extraordinarily high under such condition. The possibility that kin-selection in the long seta-form ofS. celarius led to subsociality, especially paternal care, is suggested.
This study was supported in part by Grant-in-Aid No. 61540468 from the Ministry of Education, Science and Culture, Japan. 相似文献
20.
W. S. Fargo T. L. Wagner R. N. Coulson J. D. Cover T. McAudle T. D. Schowalter 《Researches on Population Ecology》1982,24(1):123-131
Summary Detailed investigation of the within-tree population system ofDendroctonus frontalis
Zimmermann has resulted in a large data base consisting of abundance estimates for various life stages. This data base was used to construct
histograms for transformed estimates and several life stage indices. Histograms were also constructed for transformed values
of adult residence time, brood development time, and several host-tree characteristics.
Probability and cumulative density functions of the Weibull distribution were fitted, in tandem, to the scaled frequencies
and interval means for each histogram. The inverse cumulative function is known, and with a uniform random number generator,
allows the selection of random deviates from each distribution.
This technique can be used for generating initial (starting) values inD. frontalis population models.
Texas Agricultural Experiment Station Paper No. TA 16628 相似文献