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1.
Summary Studies on the population dynamics of the fall webworm,Hyphantria cunea have been carried out at three survey stations and along selected roads in the urban area of Tokyo since 1966. Twelve survivorship
curves obtained during two years and 8 life tables show that the mortality rate in early developmental stages of the fall
webworm is remarkably low as compared with that of other lepidopterous defoliaters and the mortality rate in later developmental
stages is compensatory high. The low mortality rate in early stages is considered to be due to the protective role of the
nest-web and the lack of egg and larval parasites. All but one parasitic species emerge from prepupae and pupae. Spiders living
in the nest-web of the fall webworm play an important role in reducing the number of young larvae. Direct observations and
caging experiments showed that relatively high mortality during later larval stages is mainly due to predation by birds (in
the first generation) and wasps (in the second generation). The generation mortality in the survey stations always exceeded
the level where the population is kept at the steady state, and the outbreak of this moth is considered to be continued by
the immigration of adults from large trees growing in gardens on which the larvae can escape from predation pressure.
Contributions from JIBP-PT No. 51. A part of this study was supported by the special project research, ‘Studies on the dynamic
status of biosphere’, sponsored by the Ministry of Education. 相似文献
2.
Summary The zygaenidPryeria sinica
Moore and the ichneumonidAgrothereutes minousubae
Nakanishi form a one host—one parasitoid system in nature. Their seasonal life cycles were investigated by laboratory experiments and
field observations, and the life-cycle adaptation of the parasitoid to its host was examined.
The moth is univoltine. The larva hatches from mid-February to mid-March and feeds on leaf buds and young leaves of ever greenEuonymus japonicus
Thunb. The thermal constants for completing the 1st, 2nd, 3rd, 4th larval instars and prepupal stage were 85.6, 80.5, 85.2, 177,0
and 197.6 degree-days, respectively. The prepupa and pupa vulnerable to the attack by the parasitoid occurred from mid-April
to early May and from mid- to late May, respectively.
Diapause in the parasitoid is facultative and occurs in the eonymphal stage. The photoperiodic response for this diapause
was a long-day type with a critical photoperiod of 13 hr 40 min at 20°C, but it was not expressed at 25°C, most larvae entering
diapause irrespective of photoperiod. About 19, 120, 82 and 112 degree-days above 7°C were required to complete the egg, larval,
prepupal and pupal development, respectively. These data were superimposed on the photothermograph of Fukuoka, and it is predicted
that the 1st adult eclosion would occur in late April and the partial 2nd adult eclosion in early June. The prediction was
supported by field observations.
The adult eclosion of the parasitoid synchronized well with the apperance of prepupae and pupae of the moth. The parasitoid
has two types of seasonal life cycle, one generation and two generations a year. Both types have an extremely long dormant
period of 10–11 months due to aestivo-hibernation. This seasonal life cycle enables the parasitoid to maintain its population
when the host is in short supply. 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.
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
5.
Kohji Hirano 《Researches on Population Ecology》1995,37(2):185-195
Temporal changes in the population size of a phytophagous lady-beetle were analyzed to identify mechanisms affecting lady-beetle
population dynamics at different spatial scales. The study area (15 ha) included 18 habitat patches. The major host plants
were potato for first generation larvae and eggplant for second generation larvae. The habitat patches were classified into
three groups according to the major host plants in each patch: P-E patches (both host plants available), P patches (potato
only), and E patches (eggplant only). The winter disappearance of adults in the whole study area, and larval mortality in
E patches were apparently the most important factors disturbing the overall population density. Density-dependent movement
of females appeared to have the greatest stabilizing effect on the yearly fluctuation of population density. Rate of increase
of female adults from the first to the second generation,R, was generally higher on eggplants in E patches than in P-E patches because the adult density of the first generation was
much higher in P-E patches. The yearly fluctuation of adult density in each generation tended to be less in patches with all
habitat components necessary for the full life cycle (P-E patches). However, such patches were not favorable for first generation
females, as indicated by the lower rate of increase from the first to the second generation. The density and stability of
lady-beetle populations is discussed in relation to habitat structure. 相似文献
6.
I Gusti Ngurah Aryawan I Nyoman Widiarta Yoshito Suzuki Fusao Nakasuji 《Researches on Population Ecology》1993,35(1):31-43
Summary Population dynamics ofNephotettix virescens was studied in 17 paddy fields transplanted at intervals of about 1 month in 1988–1990. The adult density was highest either
in the immigrant or the 1st generation and sharply decreased to the 2nd generation. The survival rate of the 1st generation
was lowest in the transition season when areal population density increased. Key factor analysis revealed that the nymphal
and adult mortality of the 1st generation (kn) was the principal source of population fluctuations. No significant correaltion
was found between kn and natural enemy density, natural enemy density/healthy egg density, or the precipitation during the
nymphal period. On these bases adult emigration was suspected to be the key factor. Areal population build-up ofN. virescens in the transition season was considered to occur as a result of increasing immigration to young stages of rice.
Contribution from Indonesia-Japan Joint Program on Food Crop Protection (ATA 162), which was implemented by the Directorate
of Food Crop Protection, Ministry of Agriculture, Indonesia and Japan International Cooperation Agency, Japan. 相似文献
7.
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
8.
Takao Itino 《Researches on Population Ecology》1986,28(2):185-199
Summary I compared life tables between the solitary eumenid waspAnterhynchium flavomarginatum
Smith and the subsocial eumenid waspOrancistrocerus drewseni
Saussure in Kyoto, Japan, during 1980–1983. The subsocial eumenid is parthenogenetic in this study area. There were 9 identified mortality
factors in the solitary eumenid and 7 in the subsocial eumenid, 6 of which were common to the two eumenids. The important
differences of mortality between the two eumenids were seen in the egg, larval, and prepupal stages. In the egg stage, mortality
by the phorid flyMegaselia sp. was much lower in the subsocial eumenid (1.4%) than in the solitary eumenid (15.0%) likely because of the matenal care
of the subsocial eumenid (progressive provisioning and other related behavior), which reduced predation pressure. In the larval
stage, mortality by the miltogrammine flyAmobia distorta was also lower in the subsocial eumenid (8.1%) than in the solitary eumenid (23.8%) also probably because of the maternal
care of the subsocial eumenid. A comparison of mortality in the two eumenids between the stable, long continuing natural nest
sites and the additional temporal ones showed that the phorid fly remained near its birth place and parasitized stable nest
sites. The miltogrammine fly followed returning eumenid wasps and parasitized those nest sites that have a high host density.
In the prepupal stage, mortality by endogenous death was higher in the subsocial eumenid than in the solitary eumenid. Mortality
due to the rhipiphorid beetle was also higher in the subsocial eumenid probably due to more frequent flower-visits by the
subsocial eumenid.
The defense mechanism of the subsocial eumenid was discussed in relation to the evolution of subsociality.
Contribution to the ecological studies of the eumenid wasps. I. 相似文献
9.
Makoto Kato 《Researches on Population Ecology》1996,38(1):27-40
Population dynamics of a leafminer,Chromatomyia suikazurae (Agromyzidae, Diptera) and its parasitoid community were studied for ten years at seven natural populations along an altitudinal
gradient in Japan. This species which mines leaves of a forest shrub,Lonicera gracilipes (Caprifoliaceae), was attacked by 25 hymenopterous parasitoid species. Annually, the parasitoid community structure varied
less within a population than among populations. The seven parasitoid communities were clustered into three groups corresponding
to the altitudinal gradient: (a) lowland communities dominated by late-attacking, generalist pupal idiobiont eulophids and
with highest species diversity, (b) hillside communities dominated by an early-attacking, specialist larval-pupal koinobiont
braconid and (c) highland communities dominated by an early-attacking, generalist larval idiobiont eulophid. Annual changes
of the host larval densities among the local populations were largely synchronous rather than cyclic. Among these populations,
host density levels and mortality patterns greatly varied. By analyzing these inter-populational differences of host mortality
patterns, the following conclusions were drawn: (1) The host mortality patterns were determined by the host utilization patterns
of the locally dominant species. (2) The host pupal mortality but not larval mortality was related to species diversity but
not to species richness itself of each parasitoid community. (3) Density dependence was detected only in pupal mortality at
a lowland population dominated by late-attacking pupal parasitoids. These results suggest that interspecific interactions
of parasitoids add additive effects to host population dynamics dissimilarly among local populations with different parasitoid
communities. 相似文献
10.
Syunro Utida 《Researches on Population Ecology》1967,9(1):1-9
Summary It has been theoretically assumed that the population density at the equilibrium oscillates with damping from generation to
generation. In the adult population of the southern cowpea weevil,Callosobruchus maculatus, it was exemplified. But, it was not so clear in the adult population of the azuki bean weevil,C. chinensis as seen in that ofC. maculatus. This difference seems to be due to the scramble type of competition that occurs in larval stage inC. maculatus, instead of in the egg stage asC. chinensis. Comparing with the oscillation from generation to generation obtained in the present experiment to that ofLucilia population found byNicholson, the oscillation inLucilia population is composed of the cycle in a generation and the descending phase of each cycle of it is not regulated density-dependently.
The present result seems to be more appropriate for the demonstration of the theory of self-adjustment of population.
Contribution from the Entomological Laboratory, Kyoto University, No. 404.
Supported by a grant in aid for Scientific Research from the Ministry of Education. 相似文献
11.
Summary The population growth of the green rice leafhopper,Nephotettix cincticeps, in the paddy field was analyzed based on the life table data accumulated for six years.
The paddy field population, which stems from the invading adults of the first generation (G-I), repeats two complete generations,
and the hatchlings of the fourth generation (G-IV) enter diapause and overwinter as the fourth instar nymphs in fallow paddy
fields. It was clarified that the density dependent reduction in the mean longevity and oviposition rate of adult females
in G-II and III played a primary role in stabilizing the annual population densities. The annual average of the mean longevity
of G-II females (3.9 days) was much shorter than that of G-III ones (7.7 days) and thus the density dependent reduction in
the mean longevity induced a more prompt regulatory effect on the oviposition of G-II females compared with G-III ones. As
the result, two equilibrium densities of eggs were obtained,e.g., ca 100 and 700 eggs per hill in G-III and IV, respectively. Density dependent decrease in the proportion of mature females in
the adult population was especially conspicuous in G-II, and this was closely associated with the density dependent reduction
in the mean longevity and fecundity. Thus, the density dependent dispersal (emigration) of the adult females by flight in
G-II and III was the most convincing factor in the process of population regulation. The density dependent dispersal of the
adult females is effective in avoiding the deleterious effects of nymphal crowding in a breeding habitat unit (a paddy field),
and may result in a more even distribution of the population over a continuous habitat units in a locality than otherwise. 相似文献
12.
Fusao Nakasuji 《Researches on Population Ecology》1982,24(1):157-173
Summary Survival rates and mortality factors of a migrant skipperParnara guttata were censused in paddy fields in 4 localities of central and western Japan during 1975–1980, and 10 life tables were developed
for 3 generations. Mortality rates of eggs, older larvae and pupae were high but those of younger larvae were very low. The
high mortality rate was caused by parasitoids. Ten primary and 6 secondary parasitoids were recorded. Out of three egg parasitoids,Telenomus sp. was predominant. Larval parasitoids,Apanteles baoris andPediobus mitsukurii which are specific to genusParnara were predominant in wet land habitat, i.e. paddy land. On the other hand, tachinid flies which have a wide host range and
a high searching ability were predominant in dry land habitats. Mortalities of eggs and pupae contribute more to the change
in the total mortality of immature stages than those of other stages. egg parasitoids which are the major mortality factor
of eggs acted density-dependently but larval and pupal parasitoids did not do so. The total mortality of immature stages occurred
more or less density-dependently. Larval density on rice plants scarecely affected the survival rate of larvae. 相似文献
13.
Demographic attributes of the adults of an introduced herbivorous lady beetleEpilachna niponica (Coleoptera: Coccinellidae) were investigated from 1975 to 1981 in the Botanical Garden of Kyoto University. Population growth
rate varied from 4.8 to 16.8 throughout the study period. Fecundity and mortality in the late larval period contributed most
to annual changes in the population growth rate. Population growth rate was negatively correlated with the density of overwintering
adults. Adult survival from emergence to the reproductive season, which varied from 0.03 to 0.36 throughout the study, was
almost completely determined by survival during the pre-hibernation period. Adult survival to the preproductive season changed
in a size- and sex-dependent manner. Larger adults survived better than smaller individuals; male-biased mortality occurred
from adult emergence to the reproductive age. Severe intraspecific competition among late instar larvae due to host plant
defoliation produced a higher proportion of small-sized adults, resulting in lower adult survival to hibernation. The introduced
population had a higher population growth rate and a lower adult survival to the reproductive season than the source population. 相似文献
14.
Masaya Matsumura 《Researches on Population Ecology》1996,38(1):19-25
A population census was conducted to describe the effects of the growth stage of rice on the population dynamics ofS. furcifera, in particular, on immigration, seasonal abundance, population growth rate, and wing-form expression. The number of immigrants
was highest on rice plants 17 to 30 days after transplanting (DAT), which suggested that immigrants prefer to settle or remain
more on rice plants at the tillering stage (approximately 20–30 DAT). Population growth rate from immigration to the 1st generation
decreased with an increase in rice plant age. In contrast, population growth rate from the 1st to 2nd generation was not influenced
by rice plant age and was negatively density-dependent. The percentage of macropters (flyers) was positively related to the
growth stage of rice when rice was in the vegetative or early part of the reproductive stage, and reached 100% at about 10
days before heading (booting stage). Threafter, most adult females molted into macropters regardless of population density.
The roles of host plant age and crowding effect on the population dynamics ofS. furcifera are discussed. 相似文献
15.
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
16.
Yukihiko Toquenaga 《Researches on Population Ecology》1993,35(1):57-68
Summary Competition between contest and scramble strategists was examined using two strains ofCallosobruchus maculatus, the contest strain (iQ) and the scramble strain (tQ). The direct larval interference experiment within each strain showed
that the contest strain performed strong direct interference throughout its larval stage against the conspecific opponent(s).
The scramble strain also performed its interference, but only during the 3rd and the 4th larval stages. The inter-strain larval
competition experiments inside a large and small mung bean (Vigna radiata) showed that the contest strain was, in general, superior to the scramble strain in competition, but the competition results
were density- and frequency-dependent. In the large beans, the proportion of adult emergence of the contest strain increased
with the increase of its own initial density but decreased as the initial density of the scramble strain increased. The shape
of the proportion of adult emergence became nonlinear in the small beans. The cause of the complexity of inter-strain competition
results was discussed in the light of the difference in larval interference ability between the two strains. 相似文献
17.
In May 1971, 45 adults of an herbivorous lady beetleEpilachna niponica (Coleoptera: Coccinellidae) from Asiu Experimental Forest were introduced into a botanical garden of Kyoto University, where
is 10 km south of the southern limits of its distribution with being 3–5°C warmer than the original site. The introduced population
of the lady beetle was thus investigated from 1975 to 1981. Mark-release-recapture experiments were applied to individual
adult beetles, to estimate population size and daily survival rate. Overwintering adults emerged from hibernation around early
April, reaching peak numbers in late April to early May, then gradually declined to late June. No adults remained at the end
of June. Adult survival was maintained at a high level to early May, and declined consistently until late in the reproductive
season. New adults began to emerge in late June and quickly reached a peak in early July; thereafter they decreased in number
and had entered hibernation by late October. In spite of seasonally deteriorating food resources and heat stress in summer,
new adults showed moderately high survival during the inimical period. New adults which emerged later in the season tended
to be smaller in body size than those that emerged early. The proportion of females in the new adult population gradually
increased throughout the pre-hibernating period, suggesting that male-biased mortality occurred during this period. When compared
to the source population, the introduced population had a higher rate of population growth. Coupled with the improved population
growth, heavy leaf damage during the larval period suggested that intensive intraspecific competition was most likely to occur
among larvae in the introduced population. 相似文献
18.
Mathematical procedures are given to estimate infestation totals and daily life stage arrivals, departures, and mortality
ofDendroctonus frontalis
Zimmermann for an infested tree in the field. These estimates are based on minimal sample data and are designed to utilize all available
information. Daily arrival estimates for larvae, pupae, and callow adults are obtained by indirect analysis without direct
observation of these stages. The procedures are applied to 147 infested trees, and the results are transformed to a common
time basis to obtain daily expectations by life stage for an “average” tree. These expectations suggest optimal times for
field sampling or relative times of sampling when optimal times are missed. Expected daily arrival distributions by life stage
for a single egg and a single attacking adult are given. Procedures are given for utilizing collateral information to obtain
an infestation total and daily arrival estimates for a boundary life stage. The results of this study are applicable to anyD. frontalis field study, and the procedures given are applicable to any bark inhabiting insect having similar habits. 相似文献
19.
《Researches on Population Ecology》1983,25(2):336-352
Summary Numerical changes and distribution patterns of the pine needle gall midge,Thecodiplosis japonensis
Uchida etInouye, were studied during the period from 1978 to 1979 in a young plantation ofPinus thunbergii in Shiga Prefecture, Japan. The survivorship curve of this species was characterized by a low mortality of larvae in galls
and two high mortalities before the formation of galls and during the overwintering period in soil.
The within and between-trees distributions of eggs and larvae in galls were examined by using the
regression method. The egg distribution per shoot was aggregative both within and between host plants. The within-tree variations
in numbers of eggs per shoot were related to the differences in the abundance of available needles for oviposition per shoot
among the canopy layers. The between-tree variations reflected the heterogeneous emergence of adult females in the study plot.
The degree of aggregation increased from egg to gall stage in both within- and between-tree distributions and the increase
was explained by the different mortality of larvae within trees and the inversely density-dependent mortality between trees.
The distribution patterns in the soil habitat stages were examined by the patchness index (
). This species showed aggregative distributions in soil stages. There was a correlation in spatial patterns of adult emergence
between the successive generations.
The distribution properties of this species were discussed in connection with the population dynamics and the availability
of host plants in the study plot. 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