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1.
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
2.
Summary Populations of the two-spotted spider mite,Tetranychus urticae Koch collected from various localities and from various host plants in Japan showed wide variations in diapause attribute.
Diapause percentages at 18°C/9L15D varied from nearly 100% in the north to 0% in the south-west. At intermediate latitudes
the mites showed wide inter-population variations. Populations on herbaceous hosts in vinyl- or glass-houses gave significantly
lower incidence of diapause than those on roses and deciduous fruit trees. Presence of winter hosts and better host quality
under protected environments seemed to favour non-diapausing mites.
The temperature threshold for diapause expression also varied widely among local populations. Northern populations consistently
had higher and less variable thresholds than populations at intermediate latitudes with thresholds between 15 and 18°C. Inbred
lines derived from a population in Kyoto exhibited a wide variation in diapause percentage at 18°C. These results show that
diapause inT. urticae is a quantitative threshold trait and that populations in central Japan consist of a variety of genotypes with different
diapause traits. This might provide a genetic source for adaptation to local and temporal variations in environmental conditions. 相似文献
3.
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
4.
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
5.
Density dependence depends on scale; at larval resource patch and at whole population 总被引:1,自引:0,他引:1
Midori Tuda 《Researches on Population Ecology》1993,35(2):261-271
Summary A previous study (Tuda and Shimada, 1993) has shown that the equilibrium population size of the azuki bean beetle was lower
at 32°C than at 30°C and that this difference was due to a reduced maximum population size of emerged progeny through inside-bean
process. In this paper, these results were analyzed further on the scale of the individual bean where interaction among larvae
took place. Per-bean numbers of deposited eggs, hatched eggs, and emerged adults have been recorded at seven different parental
densities under the two temperature conditions.
Three individual-bean-scale process hypotheses that may explain the reduced maximum emergence density on the whole population
scale are suggested: (1) a lower maximum emergence per bean at 32°C than at 30°C, if the bean scale and the wholepopulation
scale share the same density-dependent pattern in adult emergence, (2) a limited range of hatched egg number per bean at 32°C,
resulting from the adult oviposition process outside beans, and (3) different patterns of density-dependent emergence between
the two different scales.
This study showed that the inside-bean pattern of responses on the bean scale was a simple saturated curve at 30°C, but one
with a discontinuous decline at higher hatched egg densities at 32°C. On the contrary, during outside-bean process, the peak
number of hatched eggs decreased on this scale as observed on the wholepopulation scale. I discuss why the extracted factor
of inside-bean process on the whole-population in the previous study could not be applied to the bean-scale pattern. 相似文献
6.
Summary Intra- and interspecific competition between laboratory populations of four green leafhoppers,Nephotettix spp. was studied in the laboratory under three different temperature regimes of 24°C, 27°C and 30°C. For the single-species
population of the three tropical species, the equilibrium density increased as the temperature increased. On the other hand,
for the temperature speciesN. cincticeps, the highest equilibrium density was at the intermediate temperature and the lowest at high temperature.
Interspecific interactions between two tropical (N. virescens vs.N. nigropictus), a tropical and a temperature (N. virescens vs.N. cincticeps) and a rice-feeding and a grass-inhabiting (N. virescens vs.N. malayanus) Nephotettix species were also studied in the laboratory at the three temperature regimes. Temperature differentially affected the outcome
of competition between twoNephotettix species. BetweenN. virescens andN. nigropictus, the latter was more successful over the former at low and intermediate temperatures, while the former was more successful
at high temperature. BetweenN. virescens andN. cincticeps, the temperate species inhibited the growth of the tropical species at low temperature while the tropical species inhibited
the growth of the temperate species at high temperature. At intermediate temperature, the population ofN. virescens persisted at a slightly higher density over the population ofN. cincticeps. Between the rice-feedingN. virescens and the grass-inhabitingN. malayanus, regardless of temperature the population density of the latter was greatly reduced and later became extinct while the population
of the former continued its growth. These consequences of competition between twoNephotettix species conformed fairly well to those predicted by theLotka-Volterra model using demographic parameters specified for each species. 相似文献
7.
Summary We compared the seasonal changes in population density and nymphal development at different water temperatures and under different
food conditions between two giant water bugs,Diplonychus japonicus andD. major, in Okayama, Japan.
D. japonicus produced 1–2 generations a year, whileD. major was strictly inivoltine. The developmental velocity was higher inD. japonicus than inD. major. The thermal constant ofD. japonicus was less than that ofD. major. These results suggest thatD. japonicus is adapted, to higher water temperature thanD. major. In the field,D. japonicus preyed predominately on Lymnaeidae and Physidae snails, whileD. major preyed on aquatic insects such as dragonfly nymphs. 相似文献
8.
Alois Honk 《Researches on Population Ecology》1995,37(1):111-118
Functional alary polymorphisms have been studied rather extensively in several insect species. This review article deals with
factors controlling wing polymorphism in a flightless species,Pyrrhocoris apterus (L.), and discusses its adaptive significance and mechanisms for their persistence under natural conditions. The macropterous
morph is determined by a recessive allele whose penetrance depends on photoperiod and temperature. Natural populations of
this species contain a small fraction of flightless macropters. The disadvantages of being a macropter (increase of development
time, decrease of fecundity) are minimal, while the benefit may consist in the tendency to prereproductive arrest of ovarian
development in teneral females. It prevents establishing a second generation which would mostly die during the next winter.
The mechanism of alary morph regulation may be an ancestral trait linkingP. apterus with other polymorphic Heteroptera, while its decreased penetrance may be a derivative character. Variation in fitness due
to alary morphs is small compared to the one associated with differences in body size. The latter is environmentally determined,
and not linked to the genetic basis of wing polymorphism. In the “mosaic” of phenotypes of various size the significance of
the genetic macroptery may be close to neutral. 相似文献
9.
L. P. Lefkovitch 《Researches on Population Ecology》1967,9(1):45-52
Summary The mean maximum change in position of larvae ofLasioderma serricorne (F.) at 30°C, 60% RH increased by 0.290 cm/day, their mean position at the end of a 24 hour period increased by 0.245 cm/day.
The linear distance from the point of origin was equal to approximately one third of the total distance moved. Either density
or high numbers increased the rate of movement. 相似文献
10.
Kenji Fujisaki 《Researches on Population Ecology》1993,35(2):317-324
Summary Genetic correlations of the wing form and the relative wing length between females and males were estimated in the oriental
chinch bug,Cavelerius saccharivorus, by calculating the correlation between the sexes of the proportion macropterous or the mean relative wing length in full-sib
families obtained from different wing forms of parents emerged in a high density population. There was a significantly positive
genetic correlation between the sexes in both the proportion macropterous and the mean relative wing length. However, the
appearance rate of macropters tended to be much lower in males than in females under the rearing conditions which promote
the appearance of macropters. This was evident especially in the offspring of brachypterous parents. These indicated that
inC. saccharivorus the wing polymorphism of males is not a simple result of the genetic correlation of wing morphology between the two sexes.
It was considered that both of the female and male fitness advantages to wing reduction, as well as the genetic correlation
between the sexes, would influence the evolution of wing polymorphism in this species. 相似文献
11.
Osamu Imura 《Researches on Population Ecology》1986,28(2):281-293
Summary The population fitness in terms of the intrinsic rate of increaser
m was measured in eight pure (homogenic) strains ofEphestia kühniella
Zeller with different larva color at an optimal temperature of 25°C, and in three strains at unfavorble temperatures of 15, 17,
28, and 30°C, to understand a mechanism of maintenance of a larval color variation found in wild populations. The survival
rate, hatchability, and gross rate of reproduction were poorly correlated with the fitness but the mean generation time and
net reproduction rate were correlated with the fitness significantly at 25°C. Intermediate color (pink) strain(s) grew faster,
initiated reproduction earlier and had shorter longevities than other strain(s) under the range of 15 and 28°C; the fitness
was highest in the intermediate larval color strains except at 30°C in which all strains had a negative rate of increase.
The results were discussed with reference to the relationship between the larval color and fitness along with a maintenance
mechanism of the variation. 相似文献
12.
Kenji Fujisaki 《Researches on Population Ecology》1985,27(1):125-136
Summary The wing polymorphism of the oriental chinch bug,Cavelerius saccharivorus, was studied in relation to its reproductive strategy. The frequency distribution of wing form in terms of the relative wing
length (R.W.L.) changed with increase in the population density from a single modality biased toward the brachypterous form
to bimodality with both macropterous and more extreme brachypterous forms. Since some evidences in the field showed that fliers
are limited to macropters, such a bimodality of wing form indicated thatC. saccharivorus employs a mixed strategy with some portion of adults staying on in the same habitat, whereas the rest disperse. Moreover,
macropters were larger in body size than brachypters emerging in high density populations, although smaller than brachypters
emerging in low density populations. Larger body size as well as the delay of ovarian maturation in macropters was considered
to be a beneficial trait for migratory behaviour. 相似文献
13.
Variability in wing form of crickets 总被引:4,自引:0,他引:4
Loss of functional hindwings is observed in most subfamilies of Japanese crickets. Habitat, behaviour, body size and phylogenetic
factors might be involved, but interactions among them may obscure the general trend. Wing dimorphism is common among the
relatively small-sized members of Gryllinae, and the two small-sized subfamilies, Nemobiinae and Trigonidiinae. Both environmental
cues (e. g. photoperiod) and genetic factors affect the wing form. InDianemobius fascipes (Nemobiinae), the percentage macroptery was drastically changed by selection for macroptery or microptery. Crossing experiments
indicated polygenic control of wing form as well asX-chromosomal and maternal effects. Neither the long-winged nor short-winged line bred true after 40 generations of selection.
Full-sib families revealed a large genetic variation in frequency of macropterous forms within a population. The genetic determination
of the propensity for macropterism did not seem to be directly coupled to the mechanism performing the photoperiodic time-measurement. 相似文献
14.
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
15.
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
16.
Kenji Fujisaki 《Researches on Population Ecology》1992,34(1):173-183
Summary A male fitness advantage to wing reduction was investigated for the oriental chinch bug,Cavelerius saccharivorus, which is wing dimorphic. Field surveys for the frequency of matings between wing morphs showed that the mating probability
was much higher in brachypterous males than in macropterous males in the early breeding season. Brachypterous males copulated
with not only brachypterous females but also macropterous females in this season. This led to a considerable rate (30%) of
insemination of macropterous females just before emigration even in the early breeding season. A rearing experiment for the
pre-reproductive period of females revealed that females mated with brachypterous males copulated and oviposited earlier than
females mated with macropterous males. These results indicate that there is a fitness advantage to wing reduction in the males
ofC. saccharivorus in terms of the earlier sexual maturation. 相似文献
17.
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
18.
Summary This report examines the plant traits that effect the community structure of herbivorous insects on wild crucifers. Wild crucifers
were classified into 4 types (A, B, C, D) according to their phenology. Type A and B plants had a pausing phenology, disappearing
in the middle of the insects' active season, while type C and D plants had a continual phenology, existing all year long.
The intrinsic quality of the plants as food, which was assessed by measuring the performance of herbivores, was superior in
type A, B and D plants, while it was inferior in type C. The phenology and intrinsic quality were the alternative means of
direct defense mechanisms against herbivorous insects: The plants with a pausing phenology were intrinsically superior (A,
B), while the plants with a continual phenology were intrinsically inferior (C). However, there were a few plants with continual
phenology and superior intrinsic quality (D, the type B plants that remained in the summer). Within the community of the herbivorous
insects on the plants with direct defense mechanisms, the number of species and individuals was small and most of the community
members were specialists of the plants. On the other hand, within the community on plants without direct defense mechanisms,
the number of species was large and the proportion of generalists was high. In addition, the number of individuals was very
large on the remaining type B plants, but it was small on type D plants, which were inferred to have indirect defense mechanisms. 相似文献
19.
T. Burnett 《Researches on Population Ecology》1979,20(2):227-234
Summary WhenPhytoseiulus persimilis was reared withTetranychus urticae, infesting roses propagated in a greenhouse at controlled daily temperatures of 24°C (12 hrs) and 18°C (12 hrs), prey numbers
fluctuated with peaks of increasing amplitude. Differential dispersal of prey and predator species was one factor contributing
to the inability of the natural enemy to control the pest population. 相似文献
20.
Chobei Imai 《Researches on Population Ecology》1984,26(2):353-362
Summary The population dynamics of the housefly,Musca domestica, on patchy and unstable habitats consisting of refuse was investigated at a waste disposal site by using sticky flypaper
and mark-release-recapture technique (Jolly-Seber's method). The newly disposed garbage was favorable for breeding of the flies for about one month after being disposed, while
a mixture of garbage and ash from incinerated refuse was less favorable. On the garbage under favorable conditions, the rates
of population increase was 1.25–2.82 per day, and approximately 1300–1500 flies were produced per square meter within the
available period of one month. The rapid decrease in the fly density was observed just after the appearance of high density
peaks. The mark-release-recapture study suggested that this rapid decrease would be mainly due to the density-dependent emigration
of adult flies from the patchy habitats. The emigration was also activated when the time after garbage disposition became
long. 相似文献