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1.
Tadashi Miyashita 《Researches on Population Ecology》1992,34(1):143-153
Summary Field studies were conducted to clarify whether variation in food availability among habitats influences population density,
and whether population density has a negative effect on foraging success in the orb-web spider,Nephila clavata.
Lifetime food consumption per individual (i.e., foraging success) strongly correlated with mean body size of adult females
and mean fecundity in populations. Also, there was a positive correlation between foraging success and population density.
Since foraging success reflected potential prey availability in the habitat, food resource appeared to be a limiting factor
for populations in this spider. Mean fecundity per individual correlated with population density of the following year, suggesting
that decreased reproduction is a major component of food limitation on population density. Consistent defferences in mean
body size between particular sites were observed over years, while such difference was less obvious in density. Thus, ranking
of food abundance among habitats seems to be predictable between years. A field experiment revealed that an artificial increase
in population density had no negative effect on the feeding rate of individuals, suggesting that intraspecific competition
for food is not important in this species. 相似文献
2.
Kazuma Matsumoto Fuminori Ito Yoshitaka Tsubaki 《Researches on Population Ecology》1993,35(2):325-333
Summary Mean egg cluster size ofLuehdorfia puziloi yessoensis varied among habitats. The mean egg cluster size tended to be large when abundance of the larval food leaves expressed as
the fresh weight of leaves per unit area at a given habitat was high. Since this variation was observed among closely located
study plots (butterflies can easily move between study plots), the egg cluster size variation among habitats is likely to
be a result of flexible response by females to varying food abundance for larvae. 相似文献
3.
Koichi Tanaka 《Researches on Population Ecology》1995,37(2):197-202
Within a population of the web-building spiderAgelena limbata, the weight of the first instar nymphs ranged from 1.187 to 6.559 mg. Both intraclutch and interclutch variation were recorded.
The mean weights were different among clutches and the coefficients of variation within a clutch ranged from 3.3 to 29.2%.
Variation in the nymphal weight was certainly derived from variation in the egg weight because there was a high correlation
between the two weights. Factors affecting interclutch variation in nymphal weight were examined by multiple regression analysis.
Nymphal weight was positively correlated with the body size and food conditions of female parents, and negatively correlated
with the clutch size. Among these three factors, the food conditions of female parents had the largest apparent effect on
the interclutch variation. The results suggest that females with larger body size and more food produce larger offspring,
and that there is a trade-off between offspring size and clutch size. Heavier nymphs had larger body size (carapace width)
and may have larger energy reserves. Heavier nymphs survived experimental starvation for a significantly longer period. 相似文献
4.
Summary Effects of starvation on the suryival period and the respiratory rate in adults of a wolf spider,Pardosa astrigera (L. Koch), were investigated. The spiders used were divided into four groups: well-fed, starved and two limited food groups; in the
latter two, each spider was supplied with one leafhopper every second or third day. Adult males and females ofP. astrigera could survive for a long time; 28.8±2.7 days and 54.4±18.9 days, respectively, without any food. The longevities shown here
were 73.8% for males and 78.6% for females of those of well-fed spiders, indicating thatP. astrigera adults have a strong tolerance to starvation. The respiratory rate of well-fed adults showed no tendency to increase or decrease
with their aging; the mean respiratory rates were 4.86×10−4 mg CO2/mg f.w. (fresh body weight)/hr for males and 3.80×10−4 mg CO2/mg f.w./hr for females. The respiratory rates of starved spiders increased during the first two days of starvation but decreased
markedly from the third to the twelfth day, and thereafter retained an almost constant level for each sex. The mean respiratory
rates after the twelfth day of starvation were 2.49×10−4 mg CO2/mg f.w./hr for males and 2.76×10−4 mg CO2/mg f.w./hr for females; these values were respectively 48.4% and 63.0% of those prior to starvation. The fresh body weight
of starved spiders decreased linearly with time but the rate was small. The respiratory rates of the limited food groups tended
to decline with time and thereby their weight losses were minimized. The decrease in the respiratory rate under starvation
was considered not to be due to spider exhaustion or senescence but due to an intrinsic change in behaviour and/or metabolism,
because when the spiders were supplied with ample food for five days after starvation, the respiratory rate and the body weight
rapidly recovered to near the levels prior to starvation. It is suggested that starved spiders use a higher ratio of fat as
catabolic substrate than normally fed or satiated ones. Feeding strategies of poikilo-therm predators are discussed.
This work was partially supported by the Nippon Life Insurance Foundation Research Fund and Grant-in-Aid (No. 56480039) from
the Ministry of Education, Science and Culture, Japan. 相似文献
5.
Kazuo Nakamura 《Researches on Population Ecology》1982,24(2):302-317
Summary The prey capture tactics of spiders was analyzed, considering the energy gained by the capture of prey and that required for
it. For the purpose of it, a growth model of spiders was constructed, expressing the flow rate of prey biomass to the spider's
body by differential equations. Solving these equations under the differing values of three parameters, growth curves of spiders
was obtained. These three parameters are the amount of prey biomass supplied daily to spiders,x
0, the rate of prey capture of spiders, α, and a coefficient of the respiration rate required for the capture of prey,k. When the value ofk increased, spiders could grow only at high value ofx
0. These results suggest that habitats with small prey biomass are preferred by spiders adopting a sit-and-wait tactics for
prey capture, which requires small values ofk. Wolf spiders are one of these spiders showing that tactics. On the other hand, web-builders which require large amount of
energy for spinning webs (namely, take large value ofk), are able to grow only in the habitats with large prey biomass. Each species of spiders are considered to locate in a certain
point between both extremes of these tactics for the capture of prey. 相似文献
6.
Masayoshi Suwa 《Researches on Population Ecology》1986,28(2):231-252
Summary There are 4 species belonging to the wolf spiderPardosa amentata species group in Hokkaido. The 4 species have separately occurred in Hokkaido in general, but a few species have sometimes
occurred together at the same sites. Their biology at the coexisting sites, with special reference to partitioning of space
was studied.P. agraria mainly inhabited fields and occurred widely in Hokkaido.P. hokkaido, P. brebivulva andP. lugubris inhabited the vicinity of forests and occurred in southern Hokkaido and on the side of the Sea of Japan in Hokkaido, all
over Hokkaido excent the side of the Sea of Japan in central Hokkaido, and the lowlands and highlands in northern and eastern
Hokkaido and mainly the highlands in other regions, respectively. In eastern Hokkaido whereP. brevivulva andP. lugubris have coexisted, as the number of spiders detected and the number of localities of the former were less than those of the
latter, it was concluded that the former occurred mainly in southern Hokkaido and the Hidaka region. In southern Hokkaido
whereP. hokkaido andP. brevivulva have coexisted, few individuals of both species were collected together at the same sites, and they were distributed allotopically.
In short, the partitioning of space among theP. amentata species group occurring in Hokkaido was clear. From investigations on the coexisting sites and some other reports, it was
considered that food, life cycle and diel activity periodicity amongPardosa occurring in Hokkaido were similar to one another. This may be one of the causes of the clear space partitioning amongPardosa. SincePardosa is a raptorial predator that does not weave but wanders on the ground and uses space horizontally, available prey resource
forPardosa would be limited. It was therefore conjectured that the spider would be prone to space segregation, even if the spider could
segregate the other niche dimensions. The partitioning of space betweenP. agraria andP. hokkaido inhabiting distinct habitats was loose when it was compared with that between species inhabiting similar habitats. As most
of the spiders observed in the overlapping areas were females with egg cocoons, which required little food, the reduced feeding
was considered to have allowed the loose partitioning. 相似文献
7.
Yosiaki It? 《Researches on Population Ecology》1964,6(1):13-21
Summary To elucidate the basic food requirement of spiders, the important polyphagous predators of rice-plant insect pests, an attempt
was made to measure the respiratory energy loss of fasting spiders,Lycosa pseudoannulata.
Relationship between fresh (y) and dry (x) weights of spiders inhabiting the bottom layer of the rice-plant community was represented by the following allometric equation:y=0.428x
0.872.
The carbon dioxide production by previously fed and unfed females under the dark at 29°C 100% R. H. was measured by a titration
technique. The relationship between fresh body weight and CO2 production by unfed animals could be represented by the equationM=aW
b, M being the CO2 output per individual per day andW the fresh body weight. The constantb, which determines the slope of curve, was 0.808. Respiration of the adult female with 100 mg fresh weight was 1.155±0.250
mg CO2/100 g fresh weight/day or 48.69 mg CO2/g dry weight/day. This value corresponds to 35.81 cal/g fresh weight/day or 150.94 cal/g dry weight/day. Supposing the calorific
content of spiders to be 5820 cal/g dry weight, rate of the respiratory energy loss to total energy of the body was estimated
to be 2.60%. This rate did not strongly contradict with the loss of fresh body weight before and after the measurement.
The metabolic rate showed remarkable fluctuation with changing food supply. The CO2 production of starved individuals decreased to 83.63±16.34% as compared with individuals which were fed before the measurement. 相似文献
8.
Summary Development periods were determined for eggs and juvenile stages of the predatory phytoseiid miteTyphlodromus pyri at four constant temperatures and three feeding levels. For the non-feeding stages (eggs and larvae) power curve functions
were fitted to development rate in terms of temperature. The results are compared to the general arthropod response to temperature.
A non-linear model was fitted to nymphal development rate in terns of temperature and food, in which the weight gain over
an instar is assumed to be a linear function of daily food consumption. Examples of the same shape development rate—food relationship
are given for two more phytoseiid mites and for other arthropods. The results are discussed with respect toT. pyri as an integrated control agent. 相似文献
9.
C. Solbreck 《Researches on Population Ecology》1995,37(1):129-134
Migration by flight is essential for insects living in patchy landscapes and knowledge about variability in habitat patch
structure and quality is important for the development of theory concerning insect dispersal polymorphisms. However, few studies
provide more than anecdotal evidence about habitat change in time and space and its effects on insect survival and reproduction.
Here I show how habitats and resource density of a lygaied bug,Lygaeus equestris, change in a patchy landscape over a seventeen year period. Although habitat patches per se are very stable, there are large
temporal fluctuations in per capita food resources. Food seems to be limiting only in some years, and there may be periods
of several years when populations change due to weather disturbance. Between-patch variation in reproductive success is large.
Furthermore, the relative favourability of patches changes between years. There are also distance effects; in some years distances
to suitable hibernation sites affect reproductive success. Long fliers experience more variable success, and sometimes extreme
success, when compared with short fliers. The importance of movements from outlying areas also changes with time. The insect
is thus faced with a habitat templet which varies strongly on many temporal and spatial scales. 相似文献
10.
Kazuo Nakamura 《Researches on Population Ecology》1968,10(1):45-53
Summary An wolf spider,Lycosa pseudoannulata, collected from the field were reared in test tubes supplied with fruit flies as the food, and the number and weight of fruit
flies killed per unit time and the weight of residuum of killed flies were recorded. When the cumulative number of flies killed
by a spider was plotted against time after the beginning of food supply, the angle of the curve obtained decreased gradually
until a constant value. In this time, it seems that the gut of spider had saturated with food and the increase rate of number
of flies killed reflects the rate of food disappeared from gut by assimilation and egestion. The amount of ingestion was obtained
by subtracting the weight of residuum and the gain of live weight of the spider from the weight of killed flies. After the
gut has saturated, the amount of food remained in the gut is considered to be equal to the capacity of gut, which is an essential
factor in the study of predation. The amount of food disappearance from gut was also estimated.
There was a linear relationship between the log body weight of spiders and the log capacity of gut. The linear relationship
was also seen between the log total amount of ingestion and the log total amount of food disappeared from gut. 相似文献
11.
Takayuki Ohgushi 《Researches on Population Ecology》1987,29(1):147-154
Summary Size variation in newly-emerged adults was examined in two different local populations of an herbivorous lady beetle,Henosepilachna niponica, for 1976–80. Mean adult size of both sexes changed rather synchronously in the two populations over 5 years. Body size of
adult beetles apparently decreased with increasing leaf damage of the plants on which they developed. Adult beetles which
emerged late in the season, associated with increasing food deterioration, were smaller than those which emerged early. Ecological
consequences of adult size variation is discussed in terms of oviposition site selection. 相似文献
12.
The relationship between size, budding rate, and growth efficiency in three species of hydra 总被引:1,自引:0,他引:1
Alan E. Stiven 《Researches on Population Ecology》1965,7(1):1-15
Summary Three species of the fresh water carnivore hydra,H. littoralis, H. pseudoligactis, andC. viridissima present a graduation in size with the first species the largest and albinoChlorohydra the smallest. When presented with a daily overabundance of food (artemia), considerable variation in food intake and gross
efficiency of growth (proportion of food energy consumed that is turned into new protoplasm or buds) existed among the species.
The degree of association between size of species and food intake was highly significant. However, budding efficiency among
the species was found to be independent of food intake (when the effects of species size were eliminated) and of species size
(when the effects of food intake were removed). However, species with high (low) efficiencies have significantly higher (lower)
reproductive rates.
A lowering of the temperature from 25° to 15° C. increased the size of the species, increased food intake, but decreased reproductive
rate. In all species exceptH. pseudoligactis a corresponding increase in the production of bud energy with no change in efficiency also occurred. On the other hand, lowering
of the temperature forH. pseudoligactis significantly lowered reproductive efficiency but had no effect on the total calorific output of buds. This species, in constrast
to the others, appears to have a compensatory ability to adjust its efficiency to maintain a high calorific output when temperature
increases.
It was also found that albinoChlorohydra have budding efficiencies of around 35 percent which are not influenced by changes in food intake or light. Normal green
hydras, however, have efficiencies which range from 40 to 62 percent above their albino counterparts when fed once a day and
once every two days in light respectively. It it concluded first, that the symbiotic algae in the gastrodermals cells of green
hydra contribute quantitatively in the order of the above amounts to the growth process in this species, and second, that
green hydras have the ablity to increase their growth efficiency when food intake is reduced thus reducing the drop in calorific
but output that normally occurs in the albino (control) form.
This study was supported by a National Science Foundation Grant (GB-912) 相似文献
13.
C. David Rollo 《Researches on Population Ecology》1984,26(1):150-187
Summary Activity (to food, water and shelter) and resource allocation (mass budget, and size of various body components) were examined
in populations of adultPeriplaneta americana subjected to periods of starvation or sugar feeding. Following 13 days of starvation, roaches ate 5 times their normal daily
ration and feeding required about 20 days to return to pre-starvation levels. When sucrose was substituted for the usual dog-food
diet for 13 days, there was also a large increase in feeding initially. When the dog food was re-established, however, there
was very little feeding for about one week. Although reproduction was markedly curtailed by starvation, females fed sucrose
continued reproducing for at least 59 days. The results suggested that the roaches were mainly energy limited.
Although the consumption of roaches was strongly affected by reserve depletion, eating was a small component of the time budget,
and overall activity was relatively unchanged by starvation or sugar-feeding. There was a slight decrease in activity during
starvation, but the circadian pattern remained unchanged. Females carrying o?thecae were highly active and were apparently
attracted to food (even though they ate little). Thus the activity of the population was dominated by circadian rhythmicity
and the reproductive cycle. 相似文献
14.
Summary
Luehdorfia butterflies lay eggs in clusters. Clones of their host plants (Asiasarum andHeterotropa) are distributed pacthily among the understory of deciduous forests. Groups ofLuehdorfia larvae often exhaust the clones and may wander over the forest floor seeking new clones. The highest mortality observed is
during this wandering period. To elucidate whyLuehdorfia butterflies lay eggs in clusters, a simulation experiment was made for hypothetical populations which lay eggs in clusters
or singly. Field data on larval mortality, consumption, density of host clones and leaf weight forLuehdorfia japonica were incorporated into the model. The predictions of the simulation were: (1) When the egg density is low, the single egg
type could leave many more pupae than the egg clustering type, but when the egg density is high, the former might leave smaller
number of pupae than the latter; and (2) There are optimal sizes of egg clusters for different egg densities and the optimal
size becomes larger as the egg density increased.
This work was supported in part by Grant-in-Aid No. 439017 and No. 56480039 from the Ministry of Education, Science and Culture,
Japan. 相似文献
15.
Takashi Saitoh 《Researches on Population Ecology》1991,33(2):367-386
Summary The effects of breeding territoriality on the stability of grey red-backed vole (Clethrionomys rufocanus bedfordiae) populations were investigated on a control grid and a grid on which the voles were fed, in an outdoor enclosure in Hokkaido,
Japan. Vole populations were monitored by live trapping from 1984 to 1986: (1) Population density was 2–7 times greater on
the experimental grid to which food was added than on the control grid. Reproductive output was more closely associated with
the difference in density between grids than survival or dispersal (immigration and emigration) rates. (2) The number of adult
females and pregnancy rate of the experimental population were significantly greater than those of the control one. The difference
in the number of adult females between the populations was greater than that in pregnancy rate. (3) The proportion of successful
litters and the number of weanlings per litter were not significantly different between the control and experimental population.
(4) Adult females held territories on both the control and experimental grid; they were spaced out more than would be expected
from random occupation. The territories overlapped more on the experimental grid than on the control grid. (5) Mean territory
size of adult females on the experimental grid was about half of that on the control grid. The territory size was correlated
negatively with population density. (6) The proportion of trap sites that were used by adult females was significantly greater
on the experimental grid than on the control grid. This suggests that adult females on the experimental grid used the area
more extensively. This factor, in association with territory size and overlapping of territory, was also important in causing
the difference in the number of adult females between the grids. (7) These results call into question the hypothesis that
territoriality stabilizes the density in populations ofClethrionomys. 相似文献
16.
This article attempts to explain that parasitoids provide the evolutionary pressure responsible for relationships between
habitat use and larval food plant use in herbivorous insects. Three species of butterflies of the genus Pieris, P. rapae, P. melete, and P. napi use different sets of cruciferous plants. They prefer different habitats composed of similar sets of cruciferous plants.
In our study, P. rapae used temporary habitats with ephemeral plants, P. melete used permanent habitat with persistent plants, although they also used temporary habitats, and P. napi used only permanent habitat. The choice experiment in the field cages indicated that each of the three butterfly species
avoided oviposition on plants usually unused in its own habitat, but accepted the unused plants which grew outside its own
habitat. Their habitat use and plant use were not explained by intrinsic plant quality examined in terms of larval performance.
Pieris larvae collected from persistent plants or more long lasting habitats were more heavily parasitized by two specialist parasitoids,
the braconid wasp Cotesia glomerata and the tachinid fly Epicampocera succincta. The results suggest that Pieris habitat and larval food plant use patterns can be explained by two principles. The evolution of habitat preference may have
been driven by various factors including escape from parasitism. Once habitat preference has evolved, selection favors the
evolution of larval food plant preferences by discriminating against unsuitable plants, including those which are associated
with high parasitism pressures.
Received: December 3, 1998 / Accepted: January 20, 1999 相似文献
17.
An individual-based model forDrosophila is formulated, based on competition amongst larvae consuming the same batch of food. The predictions of the model are supported
by data for single speciesDrosophila populations reared in the laboratory. The model is used to build a simple discrete model for the dynamics ofDrosophila populations that are kept over a number of generations. The dynamics of a single species is shown to give either a stable
equilibrium or fluctuations which can be periodic or chaotic. When the dynamics of a species in the absence of the other is
periodic or chaotic, we found coexistence or two alternative states, on neither of which the species can coexist. 相似文献
18.
Summary Seasonal changes in the percentage of macropterous individuals in natural population ofMicrovelia douglasi in permanent habitats were investigated in Shimane, western part of Japan. Macropterous forms of 5th instar nymphs occurred
most frequently from late June to early July. However, the seasonal appearance of macropterous adults differed between habitats
and years. There were significant effects of density, temperature, photoperiod and food availability on the percentage of
macropters under laboratory conditions. The percentage of macropterous forms generally increased with density, but the mode
of the response was modified by temperature, photoperiod and food availability. When insects were reared under long day photperiod
(16L8D) with abundant food (0.5–1.0 g/container/day), the percentage of macroptery varied most among the different density
treatments at the intermediate temperature (24°C) and the difference was reduced at higher temperature (28° and 32°C). Effects
of temperature were small under the short day photoperiod (12L12D). Under 12L12D photoperiod sensitivity of density responses
were higher at 32°C and lower at 24°C than those under 15L8D photoperiod. When the insects were supplied with food every other
day, the density response became obscure. Ecological significance of environmental responses in the wing morph determination
was discussed in relation to the heterogeneous environment of water surface. 相似文献
19.
Kazuo Nakamura 《Researches on Population Ecology》1972,14(1):82-96
Summary To express the degree of hunger during both of feeding and unfeeding periods of spiders, equations for the amount of ingestion
and food disappearance from the gut were presented using three components: capacity of gut, rate of ingestion and rate of
food disappearance. The degree of hunger was expressed by the rate of unfilled capacity of gut to the capacity of gut based
on these equations.
The rates of ingestion and food disappearance were estimated from the results of experiment with a wolf spider,Pardosa laura. The equations obtained well applied to the experimental result. By changing values of these rates, it was revealed that
the ratio of rates of ingestion to food disappearance determine the amount of ingestion. 相似文献
20.
R. N. Coulson P. E. Pulley D. N. Pope W. S. Fargo L. J. Edson 《Researches on Population Ecology》1980,22(1):117-135
Summary Infestations ofDendroctonus frontalis
Zimm. are often observed to enlarge continuously by the colonization of new hosts in a pattern similar to a forest fire. This pattern
of infestation growth presents unique problems in quantitatively estimating populations ofD. frontalis. Beetle populations on each infested tree in an infestation go through five processes: attack, oviposition, reemergence,
survivorship, and emergence. These processes, which have been described mathematically in the literature, each take several
days for completion. In order to follow the distribution and abundance ofD. frontalis throughout the course of development of a spot, we need a daily estimate of the number of beetles involved in each process
on every tree. Since it is not practical to sample each tree daily, we developed a procedure whereby quantitative estimation
procedures for within-tree populations were used in combination with the mathematical models for the life processes to produce
a daily record of the number of adults successfully attacking trees, the number of eggs oviposited, the number of beetles
reemerging, number of beetles surviving within the trees, and the number of beetles emerging. These daily estimates were then
summarized for all trees in the spot for the duration of the infestation.
The daily record of populations ofD. frontalis, used with information on infestation geometry, were suggested to be of value in describing and elucidating several important
facets of population dynamics including dispersal patterns within infestations, between tree beetle loss (mortality), and
time lags among the various population processes. The information reported can be used to develop simulation models of population
dynamics or to validate existing models.
Texas Agric. Experiment Stn. TA No. 14689. 相似文献