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1.
Summary Population behaviour of adults and 5th-instar nymphs ofNezara viridula L. was analysed by means of the marking-and-recapture method in an early-planted paddy field. The field contained five varieties
of rice which differend in growth states. It was estimated that a total of more, than 7,000 adults of the first generation,
in which at least 3,000 were females, invaded the field from early July to middle August. Egg-mass census data, however, indicated
that only 10 per cent or less of the females participated in egg-laying. This was largely due to the, low rate of adult survival.
The adults preferred younger plants, for both feeding and oviposition.
The method described byIwao
et al. (1966) permitted estimate that 3,300–3,400 of the 5 th-instar nymphs and 1,100–1,200 of the adults of the second generation
were produced from 298 egg-masses (25, 700 eggs); while 95–6 per cent of the individuals were thought to have died before
reaching adulthood. Most of the 5 th-instar nymphs moved less than 4 m in three days as long as the condition of food plants
remained suitable, but they tended to move more towards younger plants when those on which they lived became too mature. The
apparent survival rate of the second generation adults was very low, probably due both to a rapid emigration and a high mortality
of newly-emerged adults. 相似文献
2.
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
3.
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
4.
I Nyoman Widiarta Kenji Fujisaki Fusao Nakasuji 《Researches on Population Ecology》1991,33(2):257-267
Summary The three year (1988–1990) life tables ofNephotettix cincticeps were constructed, and the daily survival rate and longevity of female adults were estimated by Hokyo and Kiritani’s (1967)
method for the overwintering and the first-generations on the foxtail grass in Okayama, southwestern Japan. The life tables
and the population parameter values estimated were compared with those in the other generations on rice. The FARMCOP suction
sampler was employed to survey the population density.
The durations of pre-ovarial maturation of female adults of the 1st generation on foxtail grass and rice seedling were similar.
Longevity of adults of the overwintering and the first generations which emerged on the wild host was longer than that of
the other generations (2nd and 3rd generations) on the rice plants. Fecundity of females decreased successively as the generation
proceeded and it became lowest in the final 3rd generation.
Only about 3.5 percent of first-instar nymphs of the 1st generation emerged as adults in the fallow field. The survival rate
of nymphs on foxtail grass was always lower in comparison with that on rice plants. However, the survival rates of nymphs
on foxtail grass and rice seedling were not significantly different from each other under laboratory conditions. In the fields,
senescence of foxtail grass occurred in the midst of nymphal period of the 1st generation. The survival rate of nymphs on
foxtail grass decreased with the increasing in the nymphal density. Abundance of spiders during the 1st generation was higher
than that in the early stage of rice plants. 相似文献
5.
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
6.
Tatsuto Kajimura I Nyoman Widiarta Kazuya Nagai Kenji Fujisaki Fusao Nakasuji 《Researches on Population Ecology》1995,37(2):219-224
The reproduction ofSogatella furcifera was investigated in a chemically fertilized rice field and an organically farmed field. In the latter, the density of immigrants
was significantly higher, while the settling rate of female adults and the survival rate of immature stages of ensuing generations
were lower. The number of eggs laid by a female of the invading and following generations was smaller, and the percentage
of brachypterous females in the next generation was also lower. Consequently, the density of nymphs and adults in the ensuing
generations decreased in the organically farmed field. For an experimental comparison, potted rice plants were cultivated
using seedlings and soil from the chemically fertilized or the organically farmed fields. WhenSogatella furcifera was reared on these plants, both the reproductive rate and the appearance rate of brachypterous female adults were lower
in the organic treatment. Egg hatchability was also lower in the organic treatment. This experiment suggested that a specific
nutritional condition in rice plants suppressed the population ofS. furcifera in the organically farmed field. 相似文献
7.
Summary We studied the interpecific competition between 2 species of predatory aquatic bugs,Diplonychus japonicus andD. major by conducting a field experiment. We set up 3 types of experimental plots in the paddy fields whereD. major predominated. The two plots contained single species of eitherD. japonicus orD. major, respectively, and one plot had both species in equal number. We compared the development and the reproductive performance
between plots in each species.
InD. japonicus, the number of eggs and early instar nymphs were significantly smaller in the plots containing both species than in the monospecific
plots. However, the numbers of late instar nymphs and newly emerged adults were not significantly different between plots.
The proportions of starved nymphs in both plots were larger than those in theD. japonicus's natural habitats. The final densities of adults in both plots were lower than those in the natural habitats. These results
suggest that lower density ofD. japonicus in these paddy fields is due to the lack of available food for nymphs rather than the effects of interspecific competition
withD. major.
InD. major, significant differences were not found in the number of eggs, each instar nymphs and adults. These results suggest that
the effects of interspecific competition did not affect the reproductive performance ofD. major. 相似文献
8.
Summary Microhabitat of the nymphs and the adults of the rice brown, planthopper,Nilaparvata lugens is known to be the lower parts of rice plants. In this study, possible environmental factors determining the range of the
microhabitat were experimentally analyzed by using the nymphs under laboratory conditions. Thirty individuals of the 1st or
the 3rd instar nymphs were released to a potted rice plant covered with a transparent acrylic cylinder. When the top of the
cylinder was kept opening (open condition), the temperatures in the cylinder were almost constant, and relative humidities
in the cylinder decreased with the increase of the height from the water surface of the pot. In the open condition, most nymphs
and all exuviae were found on the basal parts of rice plants where the humidity was more than ca. 90% r.h. When the top of
the cylinder was kept closing with parafilm (closed condition), the temperatures in the cylinder were almost constant, and
relative humidities in the cylinder were more than 95% r.h. In the closed condition, the nymphs and the exuviae were distributed
sparsely to the whole parts of rice plants. In both of the open and the closed conditions, patterns of nymphal distributions
on rice plants during the dark regime were the same as those during the light regime under 25±2°C and 16L∶8D. Four different
temperatures ranging from 20°C to 35°C did not influence on the microhabitat in the open condition. It was concluded from
the results that relative humidity is the important environmental factor to determine the microhabitat of the nymphs ofN. lugens which showed to prefer very humid condition more than ca. 90% r.h. 相似文献
9.
Summary Two experiments on the nymphal predation ofPodisus maculiventris were conducted usingSpodoptera litura larvae as prey.
First experiment: The predator nymphs divided into three groups were reared individually from second instar to adult in a
small vessel. Each nymph in the groups 1, 2 and 3 was allowed to attack the serially growing larvae (these were supplied at
the rate of one per day) from 3-, 5- and 7-day old after hatching, respectively. The first prey used for the group 1 was so
small that it was not only insufficient to satiate the predator but also was difficult to be searched out. But these disadvantages
were soon recuperated due to the rapid growth of the prey and all nymphs could survive to adults. The survival rate of third
and fourth instar nymphs in the group 3 was severely affected by vigorous counterattack of older prey larvae.
Second experiment: The predator nymphs were individually reared either in a small vessel or in a large one at various rates
of food supply (the prey larvae of 7-day old were used). The functional response curves obtained for each instar of the predator
took a saturation type within a certain range of the prey density. The saturation level specific to each instar was generally
higher for the predator reared in the large vessel than in the small one. The functional response of fourth and fifth instar
nymphs was accelerated at a high prey density,viz. 16 larvae per vessel. Even at the low rate of food supply,viz. one larva per day per predator, the predator nymphs could survive to adults, but the size of resultant adults were abnormally
small. 相似文献
10.
Hiroshi Sakata 《Researches on Population Ecology》1995,37(2):159-164
The antLasius niger was observed collecting honeydew and preying on the two aphid speciesLachnus tropicalis andMyzocallis kuricola on the chestnut treesCastanea crenata. Observation determined how the antL. niger controlled their predation on the aphids in response to the density and honeydew-productivity of the aphids.Lachnus tropicalis was a better honeydew source thanM. kuricola forL. niger in terms of the amount of honeydew collected per unit time by the ants. The number of foraging workers on a tree increased
with the number ofL. tropicalis on the tree, but not with the number ofM. kuricola. The density ofL. tropicalis perL. niger worker on a tree had a positive effect on the predation activity ofL. niger on both aphids, whereas the density ofM. kuricola per ant did not have any significant effect. The predation pressure by the ant which increased withL. tropicalis density, however, directed toM. kuricola rather than toL. tropicalis. These facts suggest (1) thatL. niger control their predation activities on aphids with regards to the densities of the attended aphids per worker, and (2) that
the ants prey on the aphid species producing less honeydew. The effects of the ant predation on aphids and the importance
of these predation effect in antaphids interactions were discussed. 相似文献
11.
Summary Functional responses of the wolf spider,Pardosa pseudoannulata (Boesenberg et Strand) attacking the rice brown planthopper,Nilaparvata lugens (St?l.), and the mirid predatorCyrtorhinus lividipennis Reuter were both those of Holling Type II. The attack rate was higher and handling time lower forC. lividipennis. However, when caged with the two prey, the wolf spider showed a significant preference forN. lugens at a lower prey proportion. Proportions of prey attacked were significantly different from the expected ratios of prey available
as well as from the predicted preferences derived from the functional response parameters. As proportions ofN. lugens attacked changed from greater to less than expected as the proportions ofN. lugens available increased, a “reverse switch” behaviour seems to be evident. 相似文献
12.
Keiji Kanamitsu 《Researches on Population Ecology》1965,7(1):16-22
Summary A field population ofEvetria cristata was studied in 10 plots in 1962 and in 6 plots in 1963. These plots were divided into 2 or 3 groups of different population
levels of the shoot moth in respective years. The survival of the insect was then analysed in these different groups of plots.
The survival rate ofE. cristata from eggs to adults in the first generation was found always higher in the group with low population density, which indicates
the existence of some factors that affect the population more severely when the insect is more abundant.Lissonota evetriae andPediobius sp. seemed to have killed more proportion of the hosts where the shoot moth density was high. However, the total effect of
the all natural enemies was not always great in the plots with high density of the moth. The survival of the second generation
of the moth in 1963 was observed to be much higher at any population level than in the other generations. 相似文献
13.
Sh?ichi F. Sakagami Kazuo Hoshikawa Hiromi Fukuda 《Researches on Population Ecology》1984,26(2):363-378
Summary Overwintering of two social halictine bees,Lasioglossum duplex (Dalla Torre) andL. problematicum (Blüthgen), was studied. InL. duplex many females stay near the old nests, each female preparing a hibernaculum separated from the natal nest. InL. problematicum most females overwinter communally within the natal nest. This difference in overwintering habits relates to the social structure
in the next spring.L. duplex is nearly always solitary in spring although later becoming eusocial, whereas many nests ofL. problematicum are polygynous, beginning in early spring.L. duplex overwinters much deeper (
) in the soil than doesL. problematicum (
), but both species are safe from drops in soil temperature, which is above 0°C even in midwinter, and the bees' supercooling
points are lower than −6°C. This cold resistance and the storage of sufficient food in the crop are reflected in the winter
survival, which is much higher (79%) than the rate of successful nests in the spring active phase (25%).
Bionomics of the eusocial halictine beeLasioglossum duplex VII.
Contribution No. 2654 from the Inst. Low Temp. Sci. 相似文献
14.
Eizi Kuno 《Researches on Population Ecology》1991,33(1):33-39
Summary In some situations the logistic equation in the usual expression, dN/dt=r(1−N/K)N, exhibits properties that are biologically unrealistic. For example, whenr≦0 the population can no longer show any normal, negative response in per-capita growth rate to increasing density. Also,
when the equation is employed in the Volterra's competition model, a familiar but incredible conclusion is derived which says
that the outcome of competition is entirely independent of the reproductive potentialr of each species. It is shown that all such strange properties are mere artifacts arising peculiarly in thisr-K model from its misleading implicit supposition thatK could be independent ofr, and they can be readily removed by alternative use of a plainer, classical form of the model, dN/dt=(r−hN)N. 相似文献
15.
Summary Intraspecies competition in a field population ofGregopimpla himalayensis (Hym.: Ichneumonidae) parasitic on the prepupae ofMalacosoma neustria testacea (Lep.: Lasiocampidae) was investigated.
The parasite oviposits the sufficient number of progeny (5 individuals/0.1 g dry weight of host) to exhaust a single host
in a single attack. However, at the intensity less than 22–26 individuals/0.1 g d.w. of host, all individuals can emerge,
i.e. density-dependent mortality does not occur. Within this range of intensity, survival of parasite larvae is guaranteed
by diminution in body size and decreasing sex ratio. In contrast, total biomass of parasites showed a peak at 5 individuals/0.1
g d.w. of host at which a single host is exhausted.
Above the intensity of 22–26, extraordinary minute individuals appeared and they died before maturation.
If intraspecies competition play a role in regulation ofG. himalayensis population in the field, the process is usually not through density-dependent mortality but through decreasing reproductive
rate caused by decrease in the sex ratio, adult longevity and fecundity.
Contribution Ser. 2, No. 275. Entomological Laboratory, Faculty of Agriculture, Kyushu University. 相似文献
16.
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
17.
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
18.
I Gusti Ngurah Aryawan I Nyoman Widiarta Yoshito Suzuki Fusao Nakasuji 《Researches on Population Ecology》1993,35(1):31-43
Summary Population dynamics ofNephotettix virescens was studied in 17 paddy fields transplanted at intervals of about 1 month in 1988–1990. The adult density was highest either
in the immigrant or the 1st generation and sharply decreased to the 2nd generation. The survival rate of the 1st generation
was lowest in the transition season when areal population density increased. Key factor analysis revealed that the nymphal
and adult mortality of the 1st generation (kn) was the principal source of population fluctuations. No significant correaltion
was found between kn and natural enemy density, natural enemy density/healthy egg density, or the precipitation during the
nymphal period. On these bases adult emigration was suspected to be the key factor. Areal population build-up ofN. virescens in the transition season was considered to occur as a result of increasing immigration to young stages of rice.
Contribution from Indonesia-Japan Joint Program on Food Crop Protection (ATA 162), which was implemented by the Directorate
of Food Crop Protection, Ministry of Agriculture, Indonesia and Japan International Cooperation Agency, Japan. 相似文献
19.
Summary The effects of food supply and population density on the nocturnal behaviour ofArion ater andAriolimax columbianus were investigated. Density did not significantly affectA. ater's level of activity or short-term movement, resting, or feeding.A. columbianus was more active and moved, rested, and fed more frequently when slug density was high.A. ater foraged and rested more often, but fed less when good food was unavailable.Ariolimax's only response to the food regime was to feed more when good food was available. Seasonal changes in the level of activity
and behaviour ofArion were evident, whereasAriolimax's activity and behavioural repertoire were not similarly affected.Arion ater's nightly activity appeared to be mainly food oriented, whileAriolimax columbianus seemed most responsive to slug density during its nocturnal activity periods. 相似文献
20.
Preference and performance linkage in aPhyllocolpa sawfly on the willow,Salix miyabeana, on Hokkaido
A leaf-folding sawfly in the genusPhyllocolpa (Hymenoptera: Tenthredinidae) attackingSalix miyabeana (Salicaceae) was studied near Sapporo, Hokkaido, along the Ishikari River in 1993. Host plant individuals were young trees
4–7 years old which were growing rapidly, producing some long shoots with large leaves. On a gradient of shoot length classes
from 0–5 cm long to over 80 cm long, shoots were much more abundant in the shorter shoot length classes. However, attacks
by ovipositing females increased as shoot length increase from 0 attacks on the shortest shoots to 5.17 attacks per shoot
on the longest shoots. The frequency of attack per leaf increased from 0 to 0.13 over the same range of shoot lengths. This
pattern of attack resulted in a high frequency of larval establishment in feeding sites, between 0.96 and 1.00, in all attacked
shoot length categories. However, probability of survival to a late instar larva increased with shoot length and corresponded
to the attack pattern, indicating a preference-performance linkage between female ovipositional decisions and larval survival.
The patterns found for thisPhyllocolpa species are similar for galling sawflies in North America and Europe, especially in the genusEuura, members of which make stem, bud and leaf midrib galls. Extending the pattern to aPhyllocolpa species broadens identification of pattern and ultimately the generality of the emerging theory on populations of galling
sawflies. 相似文献