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1.
Summary Responses of laboratory population of the azuki bean beetleCallosobruchus chinensis to temperature conditions of 30°C and 32°C are compared. Equilibrium population size was found to be lower at 32°C. A one-generation
process examined by reproduction-curve experiments is divided into two consecutive life stages specified by different habitats,
i.e., outside and inside beans. Modified logistic difference equations are used to describe these population-level responses
at each life stages. Sensitivity analysis is used to determine parameters of importance, thus determining the main cause of
the reduced equilibrium population size at 32°C. The reduction resulted from the decrease in maximum population size of emerged
adults which have experienced inside-bean process. The application and limitation of this population-level analysis to different
levels are discussed. 相似文献
2.
Ishizue Adachi 《Researches on Population Ecology》1989,31(2):343-352
Summary The study was carried out in two (A and B) citrus groves to clarify the spatial distribution patterns of eggs and larvae,
and to analyse the mortality process of eggs. From the analysis by using the mean density and the mean crowding, it was clarified
that the distributions of eggs were contagious and that larvae were more contagiously distributed than eggs. The τ andz indices showed that the operation of egg mortality was inversely density-dependent in both groves, and that the degree of
inverse density-dependence was greater in A than in B grove. The spatial correlations between the emergence holes and the
eggs or larvae in each tree, which were analysed by using ω index, showed that the distributions were more overlapping between
the emergence holes and the larvae than the eggs. As the result of dividing trees into several groups according to the number
of emergence holes, it was clarified that the survival rates of eggs were positively correlated with the number of emergence
holes. In conclusion, inversely density-dependent mortality process was considered to be caused by lower mortality rates of
eggs in the trees with more emergence holes. Especially in A grove, because the trees with more emergence holes were larger
in diameter and more egg oviposition, the inversely density-dependent mortality process was considered to be detected more
conspicuously than in B grove. 相似文献
3.
Midori Tuda 《Researches on Population Ecology》1996,38(2):133-140
The effects of spatial structure in terms of local capacity, or the maximum number of larvae surviving competition at resource
patches, and temporal structure in terms of the period vulnerable to parasitoid attack in host populations on the persistence
of host-parasitoid systems were quantitatively evaluated by laboratory experiments and well-parameterized model analyses.
One of two bruchid beetles,Callosobruchus maculatus andC. phaseoli, were used as a host with Heterospilus prosopidis used as the parasitoid.C. maculatus, in which few larvae survive competition to become adults in each bean, andC. phaseoli, in which many larvae become adults in each bean, along with two kinds of beans, the mung and the azuki, were combined to
construct four (2×2) resource-herbivorous host-parasitoid systems that differed in local capacity and vulnerable period. The
mung-C. maculatus system with the parasitoid was the most persistent, i.e., took the longest time for extinction of either the host or parasitoid
to occur. Since this resource-herbivorous host combination exhibited the lowest local capacity and the shortest vulnerable
period, these two conditions possibly promoted the persistence of the system. A model incorporating the host population structure
supported the observed persistence. Furthermore, the possible contribution of the timing of density-dependent competition
of the host on the host-parasitoid persistence is predicted. 相似文献
4.
Yoichi Shirai 《Researches on Population Ecology》1995,37(2):269-277
Plutella xylostella in the temperate zone shows a clear seasonal change in adult body size. In the laboratory, large and small moths were produced
during immature stages at 15°C and 25°C, respectively. These moths were then used to evaluate longevity, age-specific flight
ability, flight ability of mated and unmated females, and the influence of flight experience on the subsequent reproductive
success. The large moths lived longer and displayed a greater flight ability over 3 weeks. Irrespective of body size, unmated
females flew for a longer time than mated females, and flight experience affected their subsequent reproductive success. Females
of both sizes mated and laid eggs soon after emergence, without any obvious pre-reproductive period. More flight experience
did not delay oviposition, but did reduce egg production. It is likely that large moths with a longer adult life span and
greater flight ability are better fitted for long-distance flight and more fecund than small ones. These experimental results
may explain why long-distance migration ofP. xylostella is mostly seen during cool seasons, when relatively large moths with long forewing appear in the field. 相似文献
5.
Masakazu Shiga 《Researches on Population Ecology》1977,18(2):284-301
Summary Stabilizing mechanism in population ofMalacosoma neustria testacea was investigated in a central part of Japan based on eight year survey.
Population fluctuation in each developmental stage in the experimental field was rather small, i.e., 5.9 times in egg and
85.0 times in female adult. Pupal weight negatively correlated with the densities of 5th instar larvae and prepupae (cocoons)
and correlation coefficient was highly significant in females. Population density was stabilized by density-dependent dispersal
of female moths in preovipositional period. Comparison between fecundity of emerged moths and that of actually oviposited
ones in the experimental field suggested that density-dependent dispersal took place as the result of density-dependent size
variation, i.e., small-sized female months have higher flying ability. This hypothesis was supported by the experiment in
which flying ability of newly emerged female moth was measured. Similar stabilizing mechanism is expected to occur in semelparous
or pro-ovigenic insects.
Contribution Ser. A, No. 64 from Fruit Tree Research Station, Ministry of Agriculture and Forestry, Japan 相似文献
6.
Summary The effects of egg cannibalism, conditioned medium and the presence of quinone secretions on oviposition rate were studied
using single pairs of adults to eliminate any direct crowding effects. Most measurements were made on beetles confined to
the surface of the flour medium in plastic towers. Oviposition rate was decreased by about 58% when pairs were transferred
from fresh to conditioned medium; lowered about 25% when only quinones were present and the medium was still fresh; and enhanced
35% in dry conditions when beetles were provided with eggs to eat. Both the lowered oviposition rate in confined cultures
and egg-eating may be explained by natural selection at the individual level. Cannibalizing eggs boosts a female's oviposition
rate. The presence of quinones or conditioned medium indicates high population densities and acts as a signal for ceasing
oviposition and dispersing to avoid high egg mortality. In confined populations, this results in population regulation, while
in open populations, this strategy is a mechanism to avoid competition. It implies that the resource shortages normally experienced
by such organisms are relative, not absolute. 相似文献
7.
K. Tanaka T. Watanabe H. Higuchi K. Miyamoto Y. Yusa T. Kiyonaga H. Kiyota Y. Suzuki T. Wada 《Researches on Population Ecology》1999,41(3):253-262
To examine density dependence in the survival, growth, and reproduction of Pomacea canaliculata, we conducted an experiment in which snail densities were manipulated in a paddy field. We released paint-marked snails of
15–20 mm shell height into 12 enclosures (pens) of 16 m2 at one of five densities – 8, 16, 32, 64, or 128 snails per pen. The survival rate of released snails was 95% and was independent
of snail density. The snail density had a significant effect on the growth and egg production of individual snails. This density
dependence may have been caused by reduced food availability. The females at high density deposited fewer and smaller egg
masses than those at low density, and consequently produced fewer eggs. The females at densities 8 and 16 deposited more than
3000 eggs per female, while the females at density 128 oviposited only 414 eggs. The total egg production per pen was, however,
higher at higher snail density. The survival rates of juvenile snails were 21%–37% and were independent of adult density.
The juvenile density was positively correlated with the total egg production per pen and hence was higher at higher adult
density. However, the density of juveniles larger than 5 mm in shell height, i.e., juveniles that can survive an overwintering
period, was not significantly different among density treatments. These results suggest that snail density after the overwintering
period is independent of the density in the previous year. Thus, density dependence in growth and reproduction might regulate
the population of P. canaliculata in paddies.
Received: October 23, 1998 / Accepted: July 16, 1999 相似文献
8.
Myron P. Zalucki 《Researches on Population Ecology》1981,23(2):318-327
Summary The effects of age and weather conditions on egg laying inD. plexippus were determined for caged females. Age (measured in physiological time), temperature and solar radiation influence egg laying
in this species of butterfly. An algorithm taking these factors into account in presented and accounts for 88% of the daily
variation in egg laying. CagedD. plexippus begin to lay eggs six—seven days after emergence, peak egg production (about 60 eggs/♀) occurs about 15 days later. Females
continue to lay eggs throughout their adult life, which in a flight cage was about 40 days. This egg laying pattern is compared
with other published fecundity schedules. The effect and importance of a female being prevented from laying her eggs, on her
life-time egg production, is also discussed. 相似文献
9.
Shiro Kobayashi 《Researches on Population Ecology》1965,7(2):109-117
Summary To investigate the relation between the distribution pattern of eggs and the parental density in the common cabbage butterfly,Pieris rapae crucivora, the countings of egg number per plant were made on both cabbage plants cultivated in the farm and planted in the net house
in which the female butterflies were released at various densities.
The frequency distribution of eggs fits well to the negative binomial excepting the cases where they agree withPoisson series, and the degree of aggregation expressed as the reciprocal of the parameter, 1/k, tends to decrease as the egg or parental density increases. At the same parental density, however, the distribution of eggs
can be described by the negative binomial with a common parameter,k
c, regardless of the difference in the density of laid eggs.
In the case where a single female butterfly lays eggs, the spatial pattern of egg distribution is always lean, while its frequencies
conform toPoisson or the negative binomial series. This lean changes toward patchy with increasing the parental density.
From these results, it is concluded that the degree of aggregation in the distribution of eggs decreases with the increase
of the parental density. 相似文献
10.
Summary The consequences of infestation of stored wheat by the rusty grain beetle,Cryptolestes ferrugineus (Stephens) was determined for 222 d at 30°C in 70-1 drums containing wheat at 13.5% moisture content. Temperature, grain
moisture, seed damage, germination and weight, dust weight, fat acidity values (FAV), published data on growth, reproduction,
survival and cannibalism rates and energy budget were used to develop a computer simulation model to simulate the population
dynamics ofC. ferrugineus at 30°C. In the insect-free control system, the fungi,Alternaria alternata decreased,Aspergillus glaucus group andPenicillium spp. increased, probably causing a rise in FAV of the grain. In the insect-infested system,C. ferrugineus could only eat the wheat germ of kernels that had a broken bran layer; 35.7% of the wheat germ or 914.6 J per 100 kernels
was consumed. Within two generations after initial introduction,C. ferrugineus reached a peak in numbers and biomass polluting the ecosystem with excreta and remains, and accelerating the deteriorative
process observed in the insect-free control system by increasing respiration temperature, FAV and reducing grain germination.
After 87 d, the insect population declined to low levels. The simulation model provided a close match between the observed
and predicted numbers of insect life stages and bioenergetic variables during the insect population growth phase. Simulation
trials suggested that cannibalism of larger compared with smaller immature stages would be more wasteful of developmental
time and energy, reducing the number of individuals reaching reproductive age, and that density-dependent fecundity was probably
not an important regulatory mechanism ofC. ferrugineus population dynamics in this study.
Contribution No. 1314 from Agriculture Canada Research Station, Winnipeg, Manitoba, R3T 2M9, Canada 相似文献
11.
Contest competition inDrosophila subobscura 总被引:1,自引:0,他引:1
T. H. Jones ?. Langefors M. B. Bonsall M. P. Hassell 《Researches on Population Ecology》1996,38(1):105-110
The role of larval intraspecific competition in laboratory populations ofDrosophila subobscura was investigated. Mortality is density-independent during the first 3 days after hatching but becomes density dependent as
development proceeds to pupation. Although total biomass per patch was independent of initial egg density, competition betweenDrosophila larvae leads to the formation of smaller pupae. This resulted in a population that was dominated by suppressed individuals.
Development rate ofD. subobscura larvae was not affected by high larval densities. Smaller pupae give rise to females with fewer eggs in their ovarioles.
A simple simulation model, predicting the effects of intraspecific competition on the fecundity of the nextDrosophila generation is described. 相似文献
12.
Toshiya Masumoto Shintaro Nomakuchi Kouji Sawada 《Researches on Population Ecology》1993,35(2):241-250
Summary We investigated how the distribution pattern of eggs and larval on the host plant,Turritus glabra, was influenced by the oviposition behavior of the pierid butterflyAnthocharis scolymus. Females searched for the host plants visually and they frequently approached taller host plants with sparse surrounding
vegetation. After encountering host plants, oviposition behavior of females was independent of host plant characteristics
such as height, density, and type of surrounding vegetation. A female laid eggs singly on a host plants. Most females appeared
to lay their eggs regardless of the presense of eggs on the host plant. Consequently egg and larva tended to be abundant on
conspicuous host plants as measured by height or relative isolation from other plants. However, overcrowding of eggs on an
individual host decreased the survival rate of larvae. 相似文献
13.
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
14.
Summary A series of increasing egg densities was obtained by releasing various numbers of femalePlodia interpunctella (Hübner) in rooms where dishes of moth rearing medium were evenly spaced on the floor. The number of larvae produced in each dish
was taken as an indication of the number of eggs that had been laid. At all egg densities, the eggs were aggregated, and most
of the distributions conformed quite well with the negative binormial, but the degree of aggregation denreased as mean egg
density increased. The implications of the results for the development of ware-house sampling strategies are discussed. 相似文献
15.
Somchai Isichaikul Koichi Fujimura Toshihide Ichikawa 《Researches on Population Ecology》1994,36(1):23-28
Nymphs ofNilaparvata lugens were experimentally reared from the 2nd instar in a cage covering part of the leaf sheath of an individual rice plant grown
in a Wagner pot. Plants were covered with the cage from the water surface of the pot to 10 cm above the surface (lower cage-group)
or from 10 cm to 20 cm above the surface (upper cage-group). Temperatures measured at three different parts of the cage remained
fairly constant in both groups at around 25°C (23.7–25.2°C in mean value). In the lower cage-group, relative humidities measured
at the three heights in the cage in (76.3–90.5% in mean value) markedly increased with the approach to the water surface.
The nymphs of this group, particularly during the molting period, aggregated close to the surface. Eighty-two percent of the
released nymphs emerged in this group. Relative humidities measured at three heights of the upper cage-group were 69.5–72.7%
in mean value, and all the nymphs in this group died within 3 days after their release although half of them stayed on the
rice plants within 6 h after their release. The role of relative humidity as a limiting factor on the range of the microhabitat
and the population density ofN. lugens in rice fields was discussed on the basis of the results. 相似文献
16.
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
17.
《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
18.
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
19.
Katsuyuki Kohno 《Researches on Population Ecology》1997,39(1):11-16
The possible influences of life history and habitat characteristics on the evolution of semelparity and cannibalism in the
hump earwigAnechura harmandi were studied. This species is univoltine and overwinters as an adult. Females laid single egg-batches during winter in nests
under stones at a riverside in a valley. They took care of the eggs which hatched in early spring and the offspring ate their
mother before dispersing. The valley was sometimes flooded in summer. Nymphs emerged as adults and dispersed to elsewhere
before the rainy season arrived. They returned to the riverside after the rainy season. The flooding and/or summer heat seemed
to be the selective force for the evolution of dispersal behavior and semelparity in this species. The cannibalism of the
female parent by her offspring seemed to have readily evolved after the evolution of semelparity. The unfavorable environmental
conditions seemed to have a large effect on the evolution of semelparity and cannibalism in this species. 相似文献
20.
Summary Optimal clutch size of the chestnut gall-wasp,Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), was examined in galls on wild and resistant chestnut trees in 1988 and 1989. The rate
of escape success of newly-emerged adults from galls was an average of 60%, irrespective of cell numbers per gall. Dry mass
per cell of a gall (as an index of nutritive condition) decreased with increasing cell number per gall, but was proportional
to the mean number of mature eggs of new adults per gall. The number of cells per gall that occurred most frequently did not
agree with that attained by the maximum survival rate from young larva to adult emergence of the gall-wasp. This discrepancy
was examined from the viewpoint of three factors: 1) quality of offspring, 2) defensive response of the host plant causing
mortality of the gall-wasp before cell formation, and 3) fitness per gall vs. fitness per egg. It is concluded that the third
factor is most likely to be the one best in explaining the discrepancy. 相似文献