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1.
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
2.
J. N. Ayertey 《Researches on Population Ecology》1980,22(1):101-116
Summary This paper describes a series of experiments conducted to determine whySitophilus zeamais
Mots. andSitotroga cerealella (Oliv.) could not survive together in maize cultures in the laboratory. The effect ofS. zeamais on different developmental stages ofS. cerealella was investigated. The presence of adultS. zeamais slightly affected moth copulation, egg laying and moth eggs in a mixed culture, but large numbers of developing moths inside
maize grains were killed by the adult weevil through feeding on the grains. The major cause of elimination ofS. cerealella byS. zeamais from mixed cultures was therefore found to be damage to the immature moths in grain and such moth mortality increased as
the developing moths became bigger in the grains. A weevil: grain ratio of approximately 1.4∶1 was found to be the critical
weevil density at which the moth disappeared from the mixed cultures. 相似文献
3.
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
4.
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
5.
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
6.
Summary The dynamics of Angoumois grain moth,Sitotroga cerealella (Olivier), and maize weevil,Sitophilus zeamais
Motschulsky, populations breeding in a small bulk (initially 5.36 t) of shelled corn were studied over an 8-year period by monthly sampling.
The weevil population showed wide fluctuations in density superimposed on a general decline with time. The moth population
showed no upward or downward trend for the first 60 months, although it fluctuated widely. Following a decline that occurred
between 56 and 60 months, the moth population fluctuated within a much narrower range, and there was a general decrease in
density with time. The decline of the weevil population paralleled deterioration of the corn as did that of the moth population
after ca 60 months, and the decline of both species probably resulted from increasing scarcity of suitable breeding sites.
Both populations exhibited seasonal variation in density with minima in late summer and early fall, following periods of adversely
high temperatures in the storage shed. The populations increased during the fall, leveled off or declined slightly during
the winter months, and then increased to maximum levels in late spring or early summer. It thus appears that high temperatures
had a greater adverse effect on the populations than low temperatures. The grain moth and the maize weevil both tended to
be randomly dispersed at low population levels and moderately aggregated at intermediate and high levels, although the degree
of aggregation was not correlated with population density when low population levels were considered separately, and the maize
weevil showed a greater tendency for aggregation than did the grain moth. Analysis of individual samples at fixed points in
time showed a conspicuous bias for negative correlation between numbers of the two species within sampling quadrats, suggesting
a tendency for the two species to segregate within the grain mass. This process could have resulted from behavioral differences
or from the destruction of one species by the other. Competitive displacement of the grain moth by the maize weevil has been
demonstrated in laboratory experiments but has rarely been observed under natural conditions, and in our study the two species
coexisted for 8 years in a relatively small grain bulk. 相似文献
7.
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
8.
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
9.
Toshiyuki Nishida 《Researches on Population Ecology》1966,8(1):78-88
Summary This paper is concerned with some aspects of the ecology of the southern green stink bug,Nezara viridula, in Hawaii. Dispersal studies on adults showed an asymetrical dispersal pattern. The rate of plant to plant to movement by
the adults was 3.3–6.7 feet per day. Mortality studies showed that egg predation by ants,Pheidole megancephala, was as high as 80–90 per cent. Egg parasitism byTelenomus basalis was highest during February, 1965, and adult parasitism byTrichopoda pennipes was highest during July, 1964, to January of the following year. The population ofN. viridula declined during May, 1964, to May, 1965. This decline occurred simultaneously with the decline in the number of eggs produced
per female. It has been speculated that this reduction in egg production was caused by parasitism byT. pennipes.
Published with the approval of the Director of the Hawaii Agricultural Experiment Station as Technical Paper No. 816.
It is with great pleasure that I acknowledge with thanks the help that I received in various ways from the following: Dr.
WallaceC. Mitchell, Dr. MervinKamran., Mr HarryKaya and Mr. HitoshiKamasaki. 相似文献
10.
Koukichi Nagasaka 《Researches on Population Ecology》1991,33(1):115-128
Summary ThreeAthalia sawflies,A. japonica, A. rosae andA. infumata, feeding on cruciferous plants, coexist in Japan. However, it is not known what ecological strategies they use and what environmental
factors are crucial to such strategies. I attempted to explain these questions by examining the relationship between the spatio-temporal
distribution patterns of threeAthalia sawflies and their habitats in three districts (Lowland, Intermediate and Mountain).
The three sawflies have different spatio-temporal distribution patterns, though they usually used common cruciferous plants.A. japonica was abundant in spring and autumn but disappeared during summer in all the districts. In the Lowland, populations ofA. rosae andA. infumata, like that ofA. japonica, crashed in summer. HoweverA. rosae occurred mainly in summer in the Intermediate and Mountain. AlthoughA. infumata occurred in the same seasons asA. rosae in all districts, population levels ofA. infumata were always lower than those ofA. rosae.
The crucial factors controlling their population patterns were the availability of host plants and temperature. Population
crashes ofA. rosae andA. infumata were due to food depletion, and those ofA. japonica were due to heat stress. On the other hand, their population patterns may be interpreted as phenological synchronization
with their original host plants, though they all existed on common cruciferous plants.
The three sawflies may have evolved different strategies to escape from unfavorable habitat conditions. Such strategies are
speculated to be summer diapause inA. japonica, long distance migration inA. rosae, and local dispersal inA. infumata. 相似文献
11.
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
12.
Alan J. Sawyer 《Researches on Population Ecology》1989,31(1):11-24
Summary
Taylor's power law,s
2
=am
b
, provides a precise summary of the relationship between sample variance (s
2
) and sample mean (m) for many organisms. The coefficientb has been interpreted as an index of aggregation, with a characteristic value for a given species in a particular environment,
and has been thought to be independent of the sample unit. Simulation studies were conducted that demonstrate that the value
ofb may vary with the size of the sample unit in quadrat sampling, and this relationship, in turn, depends on the underlying
spatial distribution of the population. For example, simulated populations with hierarchical aggregation on a large scale
produced values ofb that increased with the size of the sample unit. In contrast, for a simulated population with randomly distributed clusters
of individuals, the value ofb eventually decreased with increasing quadrat size, as sample counts became more uniform. A single value ofTaylor'sb, determined with a particular sample unit, provides neither a fixed index of aggregation nor a complete picture of a species'
spatial distribution. Rather, it describes a consistent relationship between sample variance and sample mean over a range
of densities, on a spatial scale related to the size of the sample unit. This relationship may reflect, but not uniquely define,
density-dependent population and behavioral processes governing the spatial distribution of the organism. Interpretation ofTaylor'sb for a particular organism should be qualified by reference to the sample unit, and comparisons should not be made between
cases in which different sample units were used. Whenever possible, a range of sample units should be used to provide information
about the pattern of distribution of a population on various spatial scales. 相似文献
13.
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
14.
Masakazu Shimada 《Researches on Population Ecology》1985,27(2):203-216
Summary Effects of niche shift in ecological time scale on the population dynamics of competing species were studied in the experimental
populations of two parasitoid wasp species,Anisopteromalus calandrae andHeterospilus prosopidis (both are solitary parasites), on a host, the azuki bean weevil,Callosobruchus chinensis. Four resource conditions were set up with combination of kind of bean (azuki or black eye), and host distribution (uniform
or clumped). In each resource condition, four developmental stages of hosts were provided as a resource spectrum for parasitoid
wasps.
Population dynamics of the two wasp populations were investigated in each resource condition in Multi-Generation Competitive
Systems (MGCS), in which fresh hosts of four developmental stages were periodically introduced and were parasitized competitively
by the two wasp species. Competitive coexistence of both wasps occurred in the azuki-clumped condition, where the peaks of
the resource utilization curves separated in the two species; pupae inA. calandrae and the early or late fourth instar inH. prosopidis, A. calandrae was eliminated in the azuki-uniform condition andH. prosopidis went extinct in two black eye conditions irrespective of host distributions. The degrees of overlap of the resource utilization
patterns of the two wasp species during population dynamics were not significantly different among resource conditions irrespective
of the results of coexistence or extinction. Even in the azuki-clumped condition, however, extinction ofA. calandrae was observed when resource partitioning could not be realized with only the late fourth instar larvae available to wasps.
Further analytical experiments showed that parasitizing ability ofA. calandrae increased with host density per bean with azuki beans, butA. calandrae could express higher parasitizing ability with black eye beans thanH. prosopidis irrespective of host density per bean.
The flexibility in parasitizing ability byA. calandrae for various host stages under different resource conditions was thought to be the major factor in determining the competitive
coexistence or the extinction of either species under different resource conditions. The present experiments also suggested
that different second-best host stages between competitors could be a major contributing factor to competitive coexistence. 相似文献
15.
Minoru Murai 《Researches on Population Ecology》1977,18(2):147-159
Summary Two adjacent stations (H and L) were set up to study movement ofC. saccharivorus adults in sugarcane fields. At the beginning of the study the density ofC. saccharivorus including all stages of development was quite different between the two. The density of the first generation adult on Station
H was about 5 times that on Station L. The number ofC. saccharivorus on both the stations became almost the same one month after the beginning of the study. At the beginning of the study macropterous
adults were more numerous in Station H than in Station L. However percentage of macropterous adults on Station L increased
after one month whereas that on Station H declined.
About 2,000 marked adults were released on each station during the early period of the emergence of the first generation adult.
Marked insects were recaptured on both the stations one month after the release. The adults released on the dense population
(H) tended to disperse more actively than those on the scarce population (L). Marked macropterous adults moved more actively
than brachypterous ones. The density related dispersal of adults was considered to be an important factor to regulate the
population density. 相似文献
16.
Summary A marking-and-recapture study of a population of overwintered adults ofEpilachna sparsa orientalis was carried out in a small farm containing potatoes and egg-plants. The experiment involved a single release and five recapture
samplings during May–June. The data were analysed byLeslie's re-recapture method. Assumption of randomness of sampling proved to be well satisfied.
Survival rate of the overwintered adult population was maintained as high as 90 per cent per week or more until early June,
and then it declined rapidly towards the end of June. Initially overwintered adults exclusively lived on potato plants, but
half of the population alive in mid June migrated to nearby egg-plants. Emigration out of the experimental field, however,
seemed not to be occurring.
Recapture data of marked individuals in the potato field indicate that majority of the individuals stayed within a radius
of 3 m, at least for 2 weeks. Similar data taken from another field also suggest that their mobility was far restricted as
compared with random movement within the field.
Some comparisons were made between the population behaviours of overwintered adults ofE. sparsa orientalis andE. vigintioctomaculata.
Contribution from the Entomological Laboratory, Kyoto University, No. 371. 相似文献
17.
I Nyoman Widiarta Yoshito Suzuki Hiroichi Sawada Fusao Nakasuji 《Researches on Population Ecology》1990,32(2):319-328
Summary The population dynamics ofNephotettix virescens, a vector of rice tungro virus disease was investigated in a synchronized transplanting area at Jatisari (1984–1986), West
Java and in a staggered transplanting area at Sidan (1986–1988), Bali, Indonesia. The FARMCOP suction sampler was employed
for population censuses ofN. virescens and its natural enemies. The population growth pattern was affected by transplanting pattern: In the staggered transplanting
area, the population density increased from the immigrant generation to the first generation, and sharply decrease thereafter,
while in the synchronized transplanting area the population density often reached the highest peak in the second generation.
The degree of contageousness in the spatial distribution ofN. virescens was negatively correlated with population density of the immigrant generation.
Contribution from Indonesia-Japan Joint Program on Food Crop Protection 相似文献
18.
Among many stabilizing factors for community dynamics, nonlinear biological interactions such as type III functional response
have been widely considered to be major characteristics. However, most experimental biological communities employed so far
had quite simple structures. Therefore, the possibility that the conclusions in earlier studies were dependent on simple community
structure is undeniable. In this study, using a multiple-species experimental community, we evaluated which combinations of
component species and what kinds of interspecific interactions allow communities to persist and how these contribute to community
persistence. We conducted experimental communities using two species of beans, the adzuki bean (Vigna angularis) and the red kidney bean (Phaseolus vulgaris), two species of bean weevils, the Mexican bean weevil (Zabrotes subfasciatus, Coleoptera: Bruchidae) and adzuki bean weevil (Callosobruchus chinensis, Coleoptera: Bruchidae), and two species of parasitic wasp, Heterospilus prosopidis (Hymenoptera: Braconidae) and Anisopteromalus calandrae (Hymenoptera: Pteromalidae). The outcome of multiple-generation experimental communities was explained by the characteristics
of component species obtained from short-term experiments. In our two resources–two herbivores–one carnivore system, the strong
density-dependent attack ability of one parasitic wasp species (A. calandrae) led to the extinction of C. chinensis. On the other hand, the weak density-dependent attack ability of the other parasitic wasp species (H. prosopidis) led to system persistence. Our overall results show that, in a multiple-species community, the combination of species itself
is more important for community persistence than are the characteristics of the particular species.
Received: September 29, 1997 / Accepted: October 5, 1998 相似文献
19.
Idrus Abbas Koji Nakamura Haruo Katakura Hiroyuki Sasaji 《Researches on Population Ecology》1988,30(1):43-56
Summary Geographical variation in the elytral spot patterns of a phytophagous ladybird,Epilachna vigintioctopunctata, was studied in the Province of Sumatera Barat, Indonesia. Populations ofE. vigintioctopunctata were divided into four major groups (I–IV) by the incidence of spot pattern variations. Group I, occurring in the coastal
plains and inland lowlands, and Group IV, confined to the highlands, were the extremes of the spot pattern variations, the
latter had many more non-persistent spots and confluences with larger body size and advanced melanism than the former. These
two groups were connected with each other via the intermediate groups. A positive relationship was detected between the elevations
of sample sites and the average number of non-persistent spots per elytron. Consequently, present results favor the view that
the two previously recognized forms ofE. vigintioctopunctata (formae A and B inKatakura et al., 1988) represent a complicated intraspecific variation rather than two distinct sibling species. Elytral spot pattern
variations were not different between the sexes or between the beetles collected from different kinds of host plants.
Contribution No. 30 of Sumatra Nature Study (Entomology).
Supported in part by grants from Japan Society for the Promotion Science for JSPS-DGHE Scientific Cooperation (1980, 1982)
and for the RONPAKU program (toI. Abbas, 1984) and Grants-in-Aid for Overseas Scientific survey from the Ministry of Education, Science and Culture of Japan (Nos.
56041027 and 58041030). 相似文献
20.
Summary Difficulty arises in applying marking-and-recapture methods to insects when the probability of recapture of marked individuals
is changed with advancing age, either due to detachment of the mark by moulting (in the case of larvae) or to changes in their
survival rate or their behaviour. A modification of the re-recapture method (Leslie
et al., 1953) has been devised to analyze the capture-recapture data of the 5th-instar larvae and adults ofNezara viridula L. Estimation of the rate of moulting to the adult stage is made with the aid of additional information on larval survival.
Migration rates of the larvae between the two halves of the census field is estimated byIwao's (1963) method. Through these analyses, the dynamic feature of the population during transition from the 5th instar to, adult
is revealed. Several problems involved in the application of marking-and-recapture methods to insect populations are discussed.
Contribution from the Entomological Laboratory, Kyoto University No. 392. 相似文献