排序方式: 共有11条查询结果,搜索用时 46 毫秒
1.
2.
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
3.
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
4.
5.
On an outbreak of the citrus flat-headed borer,Agrilus auriventrisE. Saunders in Nagasaki Prefecture
Ryoh-ichi Ohgushi 《Researches on Population Ecology》1967,9(1):62-74
Summary The process of an outbreak of the citrus flat-headed borer,Agrilus auriventris in Nagasaki Prefecture was described with some ecological considerations on causative factors.
This outbreak which showed a typical “Gradation”, initiated around 1958, and terminated in 1963. The peak year was seen in
1961. At first attack by the borer was restricted to old and weak trees, but it was also found in young and healthy trees
in the peak year.
Some environmental conditions in orchards were examined in relation to the intensity of infestation by the borer. Soil management
and drought seemed to have remarkable correlations with the borer's infestations.
Probably, this outbreak was caused by the weakening of citrus tree by gummosis and abnormal defoliation, aging of orchard
trees, and drought in the summer of 1959∼1960. Interrelation between these causes and processes are shown schematically in
Fig. 12. 相似文献
6.
Takayuki Ohgushi 《Researches on Population Ecology》1988,30(1):57-68
Summary The relationships between egg predation of an herbivorous lady beetleEpilachna niponica (Lewis) and its predator, the earwigAnechura harmandi (Burr), were examined in both time and space. In spite of little annual, changes in egg densities, egg mortality due to predation
varied considerably. There was no, clear relationship between the earwig density and the proportionate predation over the
five years. The seasonal occurrence of earwig nymphs on thistle plants, however, was closely synchronized with that of egg
predation. Predator attacks on the beetle occurred in a time-restricted manner. Thus, later cohorts mostly escape from heavy
predatory pressure. No spatially density-depent egg predation was detected at the level of either thistle plants or thistle
patches. Furthermore, there was no indication of aggregative behaviour of the earwig in response to local egg density. The
earwig density was more likely to be associated with particular localities with sandy deposits available for its nest site. 相似文献
7.
Izumi Washitani Yasushi Okayama Keiko Sato Hitomi Takahashi Takayuki Ohgushi 《Researches on Population Ecology》1996,38(2):249-256
Antagonistic biological interactions with flower consumers and pathogens may influence reproductive success of flowering plants,
affecting population dynamics and natural selection for floral traits. However, ecological and evolutionary consequences of
the interactions may depend on both spatial and temporal patterns of the interactions. In a forest metapopulation ofPrimula sieboldii E. Morren, an endangered clonal plant species, we measured between-subpopulation patterns of seed sets and interactions with
an influential flower consumer, a rove beetle,Eusphalerum bosatsu Watanabe, and a specific smut fungal pathogen,Urocystis tranzschelina (Lavrov) Zundel (Ustilaginales), for three years. Mean female fertility (seed set per flower) for individual subpopulations
fluctuated moderately among years but was highly variable within each year among the five subpopulations studied. In two subpopulations,
the impact ofEusphalerum beetle, was sufficiently large to result in almost complete failure in seed production over eight years including the three
study and five previous preliminary observation years. In the two other subpopulations, seed set failure was caused by infection
by the smut fungus. Infected capsules which constitute 10–30% of the capsules produced in the subpopulations were filled with
ustilospores instead of seeds. In the subpopulation that escaped flower damage byEusphalerum beetles and smut fungal infection, seed sets of both pin and thrum flowers were much higher than in the other subpopulations.
The spatial restriction of individual antagonistic agents to a part of subpopulations suggest that dispersal of the agents,
as well as the mode of spatial subdivision of the plant population would be important for determining the overall effects
of antagonistic interactions on plant performances at the metapopulation level. 相似文献
8.
Demographic attributes of the adults of an introduced herbivorous lady beetleEpilachna niponica (Coleoptera: Coccinellidae) were investigated from 1975 to 1981 in the Botanical Garden of Kyoto University. Population growth
rate varied from 4.8 to 16.8 throughout the study period. Fecundity and mortality in the late larval period contributed most
to annual changes in the population growth rate. Population growth rate was negatively correlated with the density of overwintering
adults. Adult survival from emergence to the reproductive season, which varied from 0.03 to 0.36 throughout the study, was
almost completely determined by survival during the pre-hibernation period. Adult survival to the preproductive season changed
in a size- and sex-dependent manner. Larger adults survived better than smaller individuals; male-biased mortality occurred
from adult emergence to the reproductive age. Severe intraspecific competition among late instar larvae due to host plant
defoliation produced a higher proportion of small-sized adults, resulting in lower adult survival to hibernation. The introduced
population had a higher population growth rate and a lower adult survival to the reproductive season than the source population. 相似文献
9.
10.