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1.
Syun'iti Iwao 《Researches on Population Ecology》1977,18(2):243-260
Summary and Conclusion The measurement of spatial association between two species is considered on the basis of interspecies mean crowding. Two indices
of overlapping, γ andC
p, are derived as geometric and weighted arithmetic means of the same component ratios related to inter-and intraspecies mean
crowdings. Both indices behave in a similar way, ranging from 1 when the distributions of two species are completely overlapped
to 0 when they are completely exclusive with each other. The former is essentially identical with indices proposed byKuno (1968) andPianka (1973), and the latter is a modified form ofMorisita's (1959)C
σ index. Indices to measure the degree of spatial correlation between species, Ω andR
μ, are then derived for both kinds of overlapping indices, which vary from 1 in complete overlapping, through 0 in independent
occurrence, to −1 in complete exclusion.
Various kinds of interspecies association are analyzed using these indices and an extended form of the
regression graph which provides a convenient way of indicating the spatial interrelation between two species as well as distribution
patterns of respective species.
The method presented in this paper may also be applicable to compare temporal distribution patterns between species, similarity
between communities, etc. For such a wider application which includes continuous as well as discrete distributions, the interpretation
of intra-and interspecies mean crowdings is not necessarily appropriate, and hence the concept of mean concentration with
the symbols
and
for intraspecies relation and
and
for interspecies relation is suggested.
This study was supported by Science Research Fund (No. 148041) from the Ministry of Education. 相似文献
2.
Summary
Taylor's (1984) view that his power law is better measurement of the distribution pattern of animals than 1/k, I
ρ and
relation because almost all the data on means and variances of given species could be fitted by the power low, was critisized.
Changes in values of 1/k, I
ρ and
suggest the change of distribution pattern of the species, but the data can still be fitted by the power law because of the
great linearizing power of log-log plots, and, using the power law only, we shall overlook the information on the meaningful
changes in the distribution pattern. 相似文献
3.
Tsukasa Sunose 《Researches on Population Ecology》1985,27(2):287-300
Summary Yearly population fluctuations ofM. pustulae were investigated at 19 sites in Kyushu. In sites where a platygastrid is the only parasitoid of the midge, the percentage
parasitism was very low in the incipient stage of the outbreak of the midge populations. After the number of midges reached
a peak, the midge populations declined as the percentage parasitism increased, and then the outbreak ceased. On the other
hand, in several populations no outbreak was found and the percentage parasitism was constantly at a high level. Therefore,
the immediate cause for the outbreak seemed to be a decline of the percentage parasitism. Like the midge, the platygastrid
has one generation each year, and its females also emerge in spring to deposit their eggs within host eggs. The decline of
the percentage parasitism seemed to be mainly affected by the time lag between emergence periods ofM. pustulae and the platygastrid.
In the midge populations parasitized by both the platygastrid and a eulophid (Chrysonotomyia sp.), an extinction of the population was observed, resulting from parasitism by the latter,Chrysonotomyia sp. is polyphagous and multivoltine, and is a late parasitoid, as discussed byAskew (1975). When the density of the midges is very low, the platygastrid may leave the host eggs unparasitized, whileChrysonotomyia sp. may not, because the mature galls are conspicuous. 相似文献
4.
Syuniti Iwao 《Researches on Population Ecology》1970,12(1):100-110
Summary The contagiousness in the operation of mortality processes on the colonies of the western tent caterpillar,Malacosoma californicum pluviale, was analyzed from two different aspects: successive changes in the frequency distribution of the number of surviving individuals
per colony in the course of development, and the distribution pattern of the individuals killed by some biotic mortality factors.
Also, for a tachinid parasite,Tachinomyia similis, the analysis was made on the egg-laying pattern on colonies as well as on individual larvae. The methods of these analyses
were all based on the relation of mean crowding (m) on mean
.
A braconid parasite,Rogas sp., tended to kill few individuals together once it attacked a colony, but its effect on host colonies was rather equivalent
to the random removal of individuals from all the colonies. Diseases in the late-stage larvae before cocooning was contagious
in their action. Nuclear polyhedrosis virus seemed to have no basic contagiousness in its action, but it caused highly contagious
distribution of deaths among the colonies when its average incidence was high. A spore-formingBacillus had a tendency to kill several individuals once it appeared in a colony, but the distribution of its incidence (no. of times
it appeared per colony) was considered to be nearly at random.
The female ofTachinomyia tended to lay more than one egg successively on the same colony. It also attacked individual larvae with a definite tendency
for aggregation, which seemed to be resulted from the parasite’s preference to large hosts. When the number of eggs laid on
prefered hosts exceeded a certain threshold, however, the fly seemed to change its attention to less attractive, smaller individuals. 相似文献
5.
A new method of sequential sampling to classify populations relative to a critical density 总被引:3,自引:0,他引:3
Syuniti Iwao 《Researches on Population Ecology》1975,16(2):281-288
Summary A method of sequential sampling for grading population level in relation to a critical density is proposed. The method is
based on the
relationship and can be used without restrictions on the distribution patterns. The formulae for simple random sampling as
well as for two-stage sampling are given.
This research was suported by science research fund from the Ministry of Education. 相似文献
6.
Hiroshi Takeda 《Researches on Population Ecology》1979,21(1):120-134
Summary The distribution pattern of ten species of Collembola was studied during the four years period from July 1971 to May 1975
in a pine forest soil.
The distribution patterns were analysed for two scales of distribution, i. e., the distribution over the plot of 10×10 m2 and the micro-distribution within a block sample consisting of 36 contigious units each 2×2 cm2 in area, by applying the
-m regression method.
The fundamental pattern which appeared was quite similar for the species examined and individuals were aggregated in response
to the heterogeneity of habitat conditions. The causes of aggregations were discussed with regard to some environmental factors.
The relative abundances of 10 species within the collembolan community was examined in relation to the habitat utilization
and the relative abundance was not related to the degree of aggregation but rather to the area occupied by individuals. This
suggests that the more numerically abundant species tend to occupy broader micro-habitat. Biological meaning of aggregation
was discussed in connection with the population biology and community organization of collembola. 相似文献
7.
Naoya Osawa 《Researches on Population Ecology》1989,31(1):153-160
Summary Sibling (cannibalism among siblings) and non-sibling cannibalism (cannibalism among non-siblings) were studied in a natural
population of a lady beetle,Harmonia axyridis
Pallas.
Of all the eggs laid (n=2269), 24.76% (n=562) were killed by sibling cannibalism and 36.10% (n=819) were killed by non-sibling cannibalism. Sibling cannibalism occurred constantly and intensively in most egg batches
throughout the entire oviposition period. On the other hand, non-sibling cannibalism was more intense in the middle and late
oviposition periods, and when the egg batches were close to an aphid colony. This may be due to the high density ofH. axyridis larvae relative to aphid density in the middle and late oviposition periods and also the larvae searching intensively near
an aphid colony. 相似文献
8.
B. F. J. Manly 《Researches on Population Ecology》1985,27(1):99-109
Summary
Jackson's method for separating death and emigration has been studied by computer simulation. In general this method seems to be
quite effective in producing nearly unbiased survival estimates. However, the correction can cause a substantial increase
in the variance of these estimates. 相似文献
9.
Hiroshi Inoue 《Researches on Population Ecology》1985,27(2):255-264
Summary Nymphs ofAgriosphodrus dohrni
Signoret (Reduviidae) have a strong gregariousness and show group predatory behavior. This study was conducted to clarify adaptive
significance of group predation of this species, including laboratory observations and 6-year field surveys.
In the laboratory, observations on both solitary and group attacking against armyworms were made at varying prey size classes
to compare the capture success rate by solitary predators with that by groups. The efficiency in capturing the prey was significantly
higher in group attacking at any prey size class compared.
Data obtained from the field surveys indicated the tnedency for searching nymphs to feed in group and to increase the number
of predators feeding per prey item with increasing prey size. Average sizes of prey captured were also larger in group feeding
throughout the nymphal stage. In particular, it was remarkable that, when prey were “creeping” types, the upper size limit
of prey eaten was dramatically increased. 相似文献
10.
Summary Time-specific life tables were constructed for three pea aphid,Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), populations using a modification ofHughes' analytical procedure. All populations were studied on second-growth alfalfa (mid-June to mid-July) in south central Wisconsin;
data for two populations were collected during 1980, and data for the third population were collected during 1982. The intrinsic
rate of increase (r
m) estimated on a physiological time (day-degree) scale under field conditions but in the absence of natural enemies, provided
a reliable estimate of potential population growth rate and was used in preference toHughes' approach of estimating potential population growth rates directly from stage structure data. Emigration by adult alatae and
fungal disease were the major sources ofA. pisum mortality in each of the three populations studied. These factors were most important because of their impact on reducing
birth rates within the local population. Parasitism was never greater than 9 percent. Mortality attributable to predation
ranged from 0.0 to about 30.0%; however, even at the highest predator densitiesA. pisum populations increased exponentially. 相似文献
11.
Summary A simple experiment of simulation was done to analyze the natural mortality process of young larval colonies and egg masses
of the southern green stink bug. In this experiment, a degree of contagiousness
was allowed in regard to the action of a mortality factor, and
was defined as the mean number killed per a colony or an egg mass by the mortality factor within a unit time and the number
killed per a colony was assumed to follow the Poisson series with the mean
. Thus each component of the Poisson series was opposed to each colony or egg mass which was taken at random from 162 egg
masses, 135 and 117 colonies of the first and the second instar larvae, respectively.
It was revealed that mortality factors in the field did not act with a small degree of contagiosness, e. g.
, on all colonies or egg masses, but acted with a large degree of contagiousness, e. g.
, on some of the colonies or egg masses. Thus differential survival somewhat in all or none way occurred among the insect
colonies irrespective of their initial sizes. These results were well explained by taking actual mortality factors into account. 相似文献
12.
Yin Yin May 《Researches on Population Ecology》1978,20(1):61-78
Summary The seasonal and annual fluctuations in a population of the delphacid,Stenocranus minutus (Fab.) onDactylis glomerata L. were studied from March 1968 to September 1970. The study involved the comparison of several sampling methods to estimate
the egg, nymphal and adult numbers and an investigation into causes of mortality within each stage. A population budget was
made for the years 1969 and 1970. 相似文献
13.
Summary Spatial distribution pattern of the brown planthopper (BPH) was analyzed at 9 experimental fields in the northern part of
West Java during two consecutive rice cropping seasons, i.e., wet and dry seasons.
The population of each developmental stage and wing form of BPH at each location showed consistent departure from the random
(Poisson) distribution, the variances of the densities in most cases exceeding their means. Namely, the distribution pattern
of BPH per hill of rice plant was found to have a general tendency to be aggregated or contagious and to fit fairly well to
the negative binomial model. The tendency for aggregation was further confirmed by both the β-values of
-m regression being larger than unity and theC
A
-values being larger than zero for each developmental stage.
Although significant variations in the distribution pattern as measured by β- orC
A
-value were observed between different developmental stages, between wing forms and among locations, the degree of aggregation
for a given developmental stage at each experimental field remained fairly stable throughout the crop period, despite wide
temporal changes in population density.
Possible factors to explain these characteristics of the spatial distribution pattern of the BPH in West Java were discussed
with reference to the process generating it. 相似文献
14.
Sh?ichi F. Sakagami Kazuo Hoshikawa Hiromi Fukuda 《Researches on Population Ecology》1984,26(2):363-378
Summary Overwintering of two social halictine bees,Lasioglossum duplex (Dalla Torre) andL. problematicum (Blüthgen), was studied. InL. duplex many females stay near the old nests, each female preparing a hibernaculum separated from the natal nest. InL. problematicum most females overwinter communally within the natal nest. This difference in overwintering habits relates to the social structure
in the next spring.L. duplex is nearly always solitary in spring although later becoming eusocial, whereas many nests ofL. problematicum are polygynous, beginning in early spring.L. duplex overwinters much deeper (
) in the soil than doesL. problematicum (
), but both species are safe from drops in soil temperature, which is above 0°C even in midwinter, and the bees' supercooling
points are lower than −6°C. This cold resistance and the storage of sufficient food in the crop are reflected in the winter
survival, which is much higher (79%) than the rate of successful nests in the spring active phase (25%).
Bionomics of the eusocial halictine beeLasioglossum duplex VII.
Contribution No. 2654 from the Inst. Low Temp. Sci. 相似文献
15.
T. S. Bellows Jr. 《Researches on Population Ecology》1985,27(1):65-76
Summary Oviposition rates and related behaviours were quantified forLariophagus distinguendus
F?rster attackingCalosobruchus chinensis (L.) andC. maculatus (F.). Oviposition rates varied with parasitoid age; parasitoids aged 1–7 days laid approximately twice as many eggs per day
as those aged 8–14 days. Similar differences were noted in search rates and handling times; younger parasitoids had higher
attack rates and lower handling times than older parasitoids. Search rates and handling times also varied with the host stage
available for attack. Search rates were higher and handling times were lower on larger stages. The results are discussed with
reference to their impact on the dynamical behavior of insect parasitoid-host populations. 相似文献
16.
Summary Reproductive compatibility was studied among populations of different types of the citrus red mite,Panonychus citri (McGregor), i.e., the diapausing type from pear (DP), the non-diapausing type from citrus (C) and that from pear (NP).
Copulation was also observed between mates of different types (DP and C). Only in crosses between C ♀ and DP ♂, was copulation
occasionally broken off prematurely; duration of copulation varied considerably between pairs and the average duration was
much shorter than that between DP ♀ and C ♂ and than that in crosses between mates of the same types.
No F1 adult females were produced at all from crosses between DP and C, showing that there was a complete reproductive isolation
between the two types. There was a significant reciprocal difference in the egg hatchability and survival rate of immatures
in the F1 progeny; mortality in the eggs and that in the immature stage were significantly higher in crosses between DP ♀ and C ♂,
as compared to those in the reciprocal cross. This suggested that fertilization may have occurred in the former cross, whereas
it seemed that eggs were not fertilized in crosses between the C ♀ and DP ♂.
The NP was compatible with the C, whereas it was completely incompatible with the DP. Thus, there was a complete reproductive
incompatibility between the diapausing and non-diapausing type ofP. citri.
This work was supported in part by Grant-in-Aid No. 60560049 from the Ministry of Education, Science and Culture, Japan. 相似文献
17.
Kenichi Ozaki 《Researches on Population Ecology》1993,35(2):273-284
Summary The number of larvae reaching maturity within the gall ofAdelges japonicus was positively related to gall volume, and the relationship between the number of mature larvae and gall volume did not change
with different densities of colonized larvae.
The population changes in the bud galls ofA. japonicus were surveyed by collecting the galls, which did not suffer predation or parasitism within the galls, from young artificial
plantations ofPicea jezoensis over two years. In the year when the density of colonized larvae was high, they suffered a 42% mortality within the galls,
whereas mortality was nearly zero in the low density year. The numbers of larvae per gall were positively correlated with
gall volume. The regression lines of the number of colonized larvae on gall volume did not differ significantly in the regression
coefficients between the two years, whereas the intercept was significantly higher in the year when the density of colonized
larvae was higher. However, different within-gall mortality nullified this difference, and the regression lines of the number
of mature larvae on gall volume had no significant difference both in the regression coefficients and the intercepts. This
suggests that the number of mature larvae per gall was limited by available resources within the gall which were positively
related to gall volume. In 25% of the galls in which mature larvae inhabited, the space within the galls were completely filled
by the larvae, indicating that space was one of the limiting resources. Gall volume also affected the number of adults that
emerged from the gall and the potential number of their progeny. 相似文献
18.
L. P. Lefkovitch 《Researches on Population Ecology》1966,8(2):89-92
Summary The index
, which takes the value of −1 for a perfectly regular distribution, +1 for a highly aggregated distribution and 0 for the
distribution implied by the theoretical varianceσ
2, is proposed and a significance table provided. 相似文献
19.
Summary A five-year study on the microgeographical distribution pattern of a sugarcane cicada,Mogannia minuta (=iwasakii), in the Island of Okinawa revealed that the trapezoid type distribution was an unique feature of the distribution of this
species. The rate of expansion of the distribution range was remarkably small despite the continuous occurrence of sugarcane
plants. These facts can be explained well by the theory of escape. That is, the epidemic cicada populations should be free
from predation pressure in the infested area, but those in peripheral zones could be eradicated by predators. The possible
role of regulatory factor(s) which suppress further increase in the density in the infested area was suggested. 相似文献
20.
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