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1.
Flower nectar of an autogamous perennialRorippa indica as an indirect defense mechanism against herbivorous insects 总被引:2,自引:0,他引:2
Shuichi Yano 《Researches on Population Ecology》1994,36(1):63-71
This report shows that one of the most important roles of the flower nectar of an autogamous perennialRorippa indica (L.) Hieron is as an attractant for employing some ant species as a defense against herbivorous insects. The plant has flowers
from spring to early winter. Its flower nectar is frequently stolen by some ant species (hereafter cited as ants) which also
feed on small herbivorous insects on the plant. Internations among the tritrophic levels (R. indica, herbivores, ants) were experimentally examined and the followings became clear. (1) Ants were attracted toR. indica in search of its flower nectar. (2) The gradual secretion of flower nectar seemed to detain ants on the plant. (3)Pieris butterfly lavae were the major herbivores onR. indica and were potentially harmful to the plant. (4) The presence of ants reduced the survival rate ofP. rapae larvae onR. indica. (5) The presence of ants reduced the feeding damage toR. indica. (6) The disadvantage of nectar use by ants seemed to be minimal for the plant since the ants did not disturb the other flower
visitors. These facts suggest a mutualistic relationship betweenR. indica and ants. That is, the flower nectar serves as an indirect defense against herbivorous insects. 相似文献
2.
This study examines the role of learning and memory in the butterflyPieris rapae crucivora Boisduval during foraging for flowers. In an outdoor cage with 6 flower species,P. rapae showed various visiting patterns: some visited only one species, while others visited several species in a day. The foraging
process for flowers ofErigeron annuus (L.) Pers. could be divided into two successive steps: (1) landing on the nectaring caputs, and (2) finding the source of
nectar in the caput. Butterflies learned to proceed through the two steps more efficiently with successive attempts: they
gradually decreased landings on nectarless caputs and probings on the nectarless petals of ligulate flowers respectively.
As a result, handling time per unit caputs became shorter, and apparent rewards per unit time, i.e. the efficiency of collecting
nectar, increased. In addition, once learned,P. rapae could remember a rewarding flower color for 3 days, which was not interfered with by learning another flower color. This
indicates thatP. rapae keeps memory for a period longer than 3 days, and that they can remember at least two flower species as suitable flower resources.
Furthermore, data indicated that they sometimes can apply the foraging skills obtained on other flower species to a novel
one. These abilities could enable butterflies to easily switch flower species, or to enhance labile preference. It has been
known thatP. rapae also shows flower constancy, which may be due to memory constraints. Therefore, they may appropriately use two foraging tactics:
visit consistency and labile preference, to get enough nectar according to their circumstances. 相似文献
3.
Takehiko Kakutani Tamiji Inoue Toshiyuki Tezuka Yasuo Maeta 《Researches on Population Ecology》1993,35(1):95-111
Summary To know basic information about the stingless bee,Trigona minangkabau, and the European honey bee,Apis mellifera, as pollinator of strawberry, we set three greenhouse areas: the honey bee introduced area, the stingless bee introduced
area and the control area. Foraging and pollination efficiencies of the two bee species were studied comparatively.
During the experimental period (10 days), the stingless bee foraged well and the nest weight did not change, though the honey
bee often foraged inefficiently and the nest weight decreased by 2 kg. The average nectar volume of a flower was lower in
the honey bee area (0.02 μl) and nearly the same in the other two areas (0.1 μl).
We make a numerical model to describe pollination and fertilization process. This model shows that one visit of the honey
bee pollinated 11% of achenes and one visit of the stingless bee did 4.7% on average and that 11 visits of the honey bee or
30 visits of the stingless bee are required per flower to attain normal berry (fertilization rate, 87%). In this study, the
rate of deformed berries in the stingless bee area (73%) was lower than that of the control area (90%), but higher than that
of the honey bee area (51%). From our numerical model, we conclude the stingless bee could pollinate strawberry as well as
the honey bee if we introduced 1.8 times of bees used in this experiment. 相似文献
4.
Koukichi Nagasaka 《Researches on Population Ecology》1992,34(2):383-395
Summary This report assesses the primary factor for the evolution of summer diapause of the three species of sawfly,Athalia japonica, A. rosae andA. infumata that feed on cruciferous plants and coexist in the same area.A. japonica has two discrete spring and autumn generations, butA. rosae andA. infumata 5–6 generations. OnlyA. japonica enters summer diapause in response to the long daylengths in spring. Although these three sawflies usually feed on the same
cultivated crucifers, they differ markedly in the utilization of wild crucifers. They oviposit only on young leaves.A. japonica mainly usesCardamine plants which sprout in spring and autumn.A. rosae andA. infumata primarily use hosts with new leaves all the year round, i.e. cultivated crucifers andRorippa indica, respectively. The thermal threshold for development is lower inA. japonica than in the other two species. The low heat tolerance ofA. japonica is adapted only to cool shady habitats whereCardamine grows. Presumably, summer diapause ofA. japonica is adaptation to the deterioration of the primary host plants rather than unfavorable climatic conditions. This interpretation
is supported by the movement patterns of the threeAthalia sawflies, alternative means to escape from deteriorated habitat conditions. 相似文献
5.
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
6.
T. Nagamitsu Kuniyasu Momose Tamiji Inoue David W. Roubik 《Researches on Population Ecology》1999,41(2):195-202
Floral resource partitioning among stingless bees (Trigona, Meliponini, Apidae) in a lowland rain forest in Sarawak, Malaysia, was investigated using tree towers and walkways in a
4-year study that included a general flowering period. We obtained 100 collections of insect visitors to flowers of varying
floral location and shape representing 81 plant species. The tendency of 11 species of stingless bees to visit specific flowers
with a particular floral location and shape was analyzed by logistic regression analysis. This analysis showed that the proportion
of flower visitor collections containing Trigona fuscobalteata and T. melanocephala differed according to floral location. The former was frequently collected at canopy and gap flowers, whereas the latter
was most often collected at understory flowers. The analysis also suggested that T. erythrogastra was more rarely collected at shallow flowers than at deep flowers. Analysis of the pollen diets of T. collina, T. fuscobalteata, T. melanocephala, and T. melina revealed that similarity of pollen sources differed among the six permutated pairs of the four species. The lowest mean rank
of similarity found was between T. fuscobalteata and T. melanocephala. This result supports the hypothesis that preference in visiting flowers in different locations leads to pollen resource
partitioning.
Received: May 14, 1997 / Accepted: April 23, 1999 相似文献
7.
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
8.
M. Kato Akihiro Shibata Takaya Yasui Hidetoshi Nagamasu 《Researches on Population Ecology》1999,41(2):217-228
The Bonin (Ogasawara) Islands are oceanic islands located in the northwest Pacific, and have ten native (nine endemic) bee
species, all of which are nonsocial. The European honeybee (Apis mellifera), which was introduced to the islands for apiculture in the 1880s, became naturalized in a few islands shortly after introduction.
To detect the impact of the honeybees upon native bee diversity, we analyzed pollen harvest by honeybees and surveyed the
relative abundance of honeybees and native bees on flowers on several islands. Both hived and feral honeybee colonies were
active throughout the year, harvesting pollen of both native and alien flowers and from both entomophilous and anemophilous
flowers. Honeybees strongly depended on the alien plants, especially during winter to spring when native melittophilous flowers
were rare. From June to November, honeybees exhaustively utilized native flowers, which had originally been utilized and pollinated
by native bees. On Chichi and Haha Islands, where human disturbance of forests has been severe, both native and alien flowers
were dominated by honeybees, and native bees were rare or extinct even in well-conserved forests. In contrast, on Ani Island
and Haha's satellite islands where primary forests were well conserved and honeybees were still uncommon or absent, native
bees remained dominant. These results suggest that competition for nectar and pollen of the native flowers between honeybees
and native bees favors honeybees on the disturbed islands, which are thoroughly invaded by alien nectariferous, sometimes
aggressive, weedy plants.
Received: May 8, 1998 / Accepted: May 6, 1999 相似文献
9.
Summary Using a relationship between prey consumption and growth rate, field prey consumption of adults ofParatenodera angustipennis (S.) in a paddy field was estimated. Since a great number of grasshoppers (Oxya japonica) lived in the research area and the mantids had frequently eatenO. japonica, we presumed that they consumed onlyO. japonica. As a result, it was estimated that average prey consumptions for 6 days were 406 mg for the females and 23 mg for the males.
From the result of this estimation and the feeding rhythm of the mantids, it is concluded that each female captured one grasshopper
on average every a few days.
By comparing this actual feeding level ofP. angustipennis with those of other predacious arthropods, characteristics ofP. angustipennis as a predator were discussed. 相似文献
10.
Koukichi Nagasaka 《Researches on Population Ecology》1991,33(1):115-128
Summary ThreeAthalia sawflies,A. japonica, A. rosae andA. infumata, feeding on cruciferous plants, coexist in Japan. However, it is not known what ecological strategies they use and what environmental
factors are crucial to such strategies. I attempted to explain these questions by examining the relationship between the spatio-temporal
distribution patterns of threeAthalia sawflies and their habitats in three districts (Lowland, Intermediate and Mountain).
The three sawflies have different spatio-temporal distribution patterns, though they usually used common cruciferous plants.A. japonica was abundant in spring and autumn but disappeared during summer in all the districts. In the Lowland, populations ofA. rosae andA. infumata, like that ofA. japonica, crashed in summer. HoweverA. rosae occurred mainly in summer in the Intermediate and Mountain. AlthoughA. infumata occurred in the same seasons asA. rosae in all districts, population levels ofA. infumata were always lower than those ofA. rosae.
The crucial factors controlling their population patterns were the availability of host plants and temperature. Population
crashes ofA. rosae andA. infumata were due to food depletion, and those ofA. japonica were due to heat stress. On the other hand, their population patterns may be interpreted as phenological synchronization
with their original host plants, though they all existed on common cruciferous plants.
The three sawflies may have evolved different strategies to escape from unfavorable habitat conditions. Such strategies are
speculated to be summer diapause inA. japonica, long distance migration inA. rosae, and local dispersal inA. infumata. 相似文献
11.
The relationship between the infestation rate of carambola fruits byBactrocera carambolae Drew and Hancock was investigated in a carambola orchard. Phenology of the fruits was found to influence percentage infestation
of fruits byB. carambolae. The proportion of unbagged or susceptible fruits infested varied with time of year and tended to decrease with the increase
of unbagged fruits available on the tree. The number of ovipunctures per fruit varied with fruit size and was also found to
be indicative of the number of adult insects (B. carambolae and parasitoids) that will emerge from each fruit. Higher number of susceptible fruits available on each tree also decreased
both the number of ovipunctures per fruit and the number of eggs laid per fruit, which could possibly be due to the strategy
of spreading the risk adopted by the femaleB. carambolae or a result of random selection with more hosts available. The main parasitoids recorded wereBiosteres vandenboschi (Fullaway) andB. arisanus (Sonan). The mean percentage of parasitism was 38.3% and it followed roughly that of infestation of fruits. 相似文献
12.
Summary We studied settling-site selection and the resulting survival of two sessile scale insects,Ceroplastes rubens andC. ceriferus, in the citrus tree,Citrus unshiu, in central Japan.
C. rubens preferred 0-year-old twigs most as a settling-site; the density of nymphs settling on 0-year-old twigs was significantly
higher than those on ≥1-year-old twigs, and few nymphs settled on ≥3-year-old twigs. The mean survival rates from settling
until reproduction in the next year were significantly higher on more preferred twigs than on less preferred ones. InC. ceriferus, nymphs significantly preferred 1- and 2-year-old twigs to 0- and ≥3-year-old ones, and the mean survival rates on the more
preferred 1- and 2-year-old twigs were significantly higher than those on less preferred ≥3-year-old twigs. However, the survival
rate on less preferred 0-year-old twigs was slightly higher than those on 1- and 2-year-old ones. Thus, in both species of
scale, it was the preferred twigs which were more profitable sites for survival after settling, except for less preferred
0-year-old twigs forC. ceriferus.
In both scale species, most mortality was due to growth cessation, which is believed to be related to the twig quality as
a food source. Predators and parasitoids were minor mortality factors.
Both species showed constant survival rates until the density of settled nymphs exceeded double the “upper-limit” density,
whereupon they decreased drastically.
Nymphs ofC. rubens settling on twigs of high scale density showed a spacing-out distribution, those ofC. ceriferus did not. InC. rubens, an increase in preference for originally less profitable twigs at the later stage of the settling season was observed, but
not inC. ceriferus. Accordingly, individuals ofC. rubens showed a stronger tendency to avoid conspecifics than didC. ceriferus.
Although nymphs of the two scales clearly preferred more profitable sites, their settling-site selection did not agree with
the predictions from the ideal free distribution theory (Fretwell and Lucas, 1970). The discrepancies were (1) frequent settling
on less profitable sites at the early stage of the settling season, (2) insufficient utilization of the most profitable twigs,
and (3) virtually 100% mortality on overcrowded twigs under conditions where unoccupied profitable twigs still remained. These
discrepancies are thought due to the limited dispersal time of nymphs.
Contribution to the ecological studies of scale insects 2. 相似文献
13.
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
14.
Summary Life tables for worker honeybees covering all life span, and those for adults, were prepared for three seasonal cohorts,June bees, July bees andwintering bees. Survivorship curves forJune andJuly bees show a convex type being exceptional for insects, with relatively high mortality at egg and feeding larval stages and at
later adult stage after most bees became potential foragers. Adult longevity greatly lengthens inWinteriing bees and survivorship curve drops approximately with the same rate. A remarkable similarity of survivorship curves for men and
honeybees was demonstrated, apparently due to highly developed social care in both. Some comments were given on mortality
factors. The importance of life tables for population researches was shown by applying our result to the population growth
curve made byBodenheimer, based upon the data byNolan. At the asymptote of the uncorrected curve, the ratio of total population estimated by uncorrected curve to that by corrected
curve reaches about 3∶2.
Contribution No. 821 from the Zoological Institute, Faculty of Science, Hokkaido University, Sapporo, Japan.
Contributions from JIBP-PT No. 45. This study was in part supportod by a grant in aid from the Ministry of Education for the
special project research, “Studies on the dynamic status of biosphere.”
Population and bioeconomic studies on the honeybee colonies. II.
We express our sincere thanks to Dr. YosiakiIt?, National Institute of Agricultural Sciences, Tokyo, for his kind stimulation and advices to the present work. 相似文献
15.
Chobei Imai 《Researches on Population Ecology》1987,29(1):129-146
Summary Susceptible houseflies,Musca domestica, were released at a waste disposal site to control insecticide resistance in a field housefly population. In the first experiment,
a total of 163,000 pupae of the susceptible Takatsuki strain were released in October–November 1977. LD50 values to fenitrothion and diazinon decreased to about one-sixth in April 1978, five months after the releases, of those
before the releases. For the second experiment, a susceptible colony was derived by cross and backcross between a white-eyed
substrain of the Takatsuki and a field colony. This susceptible colony consisted of whiteeyed flies with low activity and
normal-eyed flies bearing no or one white eye gene. The results of large cage experiments suggested that the normal-eyed males
of the susceptible colony had half the mating competitiveness of wild males. Approximately 31,000–46,000 susceptible pupae
were used in each of five releases from October to November 1980. The population number of each sex, estimated by a mark-release-recapture
method, increased from 12,000 in late September to 35,000–43,000 in middle November and then decreased to 5,000–8,000 in early
December. The frequency of field-collected males bearing one white eye gene and those bearing one male determining factor,
which were characteristics of the susceptible colony released, increased gradually during the period of releases. The susceptibility
of the field population to fenitrothion and diazinon was examined five times in the period from September to December 1980.
With time, the dosage-mortality regression gradually shifted towards that of the susceptible colony after starting the releases.
LD50 values to fenitrothion and diazinon decreased to about one-sixth and one-fifth, respectively, in June 1981, six months after
the second series of susceptible fly releases, of those before the releases. Ratios of the wild flies to the released fiies
were estimated to be between 4.7∶1 and 9.8∶1 in males and between 3.0∶1 and 3.9∶1 in females by taking the quality of the
released colony and the population parameters of the field houseflies into consideration. Under several assumptions, the manner
of resistant phenotype reduction was discussed, based on the dosage-mortality regressions and the ratios of released flies.
These results showed that the releases of susceptible flies were successful in suppression of insecticide resistance in the
field housefly population. 相似文献
16.
Summary The functional response ofPseudogonatopus flavifemur E & H (Hym., Dryinidae) was investigated by offering hosts (brown planthopper) at densities ranging from 8 to 160 per cage.
The response curve was found to be sigmoid, i. e.Holling's (1959) Type III curve. In experiments involving 310 hosts per cage distributed unevenly in 5 densities (10, 20, 40, 80
and 160 per hill), and a different female parasite density each time (viz. 1, 2, 4, 8 or 16 per cage), the behavioral response
was described well by the “random predator equation” ofRoyama (1971) andRoger (1972), which is a convex exponential curve. The area of discovery (a) decreased with an increase in female parasite density (P), and the relationship was described by the equation: loga=−1.0099−0.3638 logP. There was an apparent increase in handling time per host as the number of female parasites increased. Superparasitism, a
rare phenomenon under natural conditions, was often observed in the laboratory. The potential ofP. flavifemur as a biocontrol agent of the brown planthopper is discussed. 相似文献
17.
Summary Rufous turtle dove,Streptopelia orientalis, coming to the soybean field entered it from the outer part to eat soybean cotyledons. As a result, the injured plants extended
from the outer to inner parts in the field. A model expressing these behaviours was constructed here, by assuming that the
amount of food birds can eat in one block determines whether they stay there or move into neighbour block. As the food decrease
due to exploitation of them by birds, birds enter into farther parts with the passage of time.
The rate of feeding in all visiting birds (an
0 wherea is the rate of feeding per individual andn
0 the number of birds visiting) and the rate of staying at a block,b, was estimated from the field experimental results, using the above model. The value ofan
0 fluctuated greatly, depending upon the season in which soybean seeds sowed. The value ofb also fluctuated inversely with that ofan
0, suggesting the the staying rate decreases with an increase in the number of doves coming, probably because of interference
among individuals. 相似文献
18.
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
19.
Akio Tamaki 《Researches on Population Ecology》1994,36(2):225-236
On an intertidal sandflat in western Kyushu, Japan in 1979, the trochid gastropod,Umbonium (Suchium) moniliferum (Lamarck), and the thalassinidean ghost shrimp,Callianassa japonica Ortmann, densely inhabited the lower and upper zones, respectvely.Callianassa japonica subsequently expanded its distribution range considerably, having occupied almost the entire sandflat by 1983. Concurrently,
theU. moniliferum population gradually declined, becoming extinct in 1986. Furthermore, the populations of 9 species associated withU. moniliferum (predators, an ectoparasite, and subsequent inhabitants of emptyU. moniliferum shells) had disappeared by the end of 1992. The extinction processes ofU. moniliferum and the two other most numerically dominant species, the ectoparasitic gastropod,Odostomia sp., and the hermit crab,Diogenes nitidimanus Terao, were described in detail. It is believed that the bioturbation of sediments byC. japonica was responsible for the extinctions, possible mechanisms involved being discussed. This is the first documented record of
the extinction of a large part of a macrobenthic assemblage centering on a filter-feedingUmbonium species which is characteristic of the benthic communities on many intertidal sandflats extending from Japanese to Southeast-Asian
waters. 相似文献
20.
Pollination and factors limiting fruit set of chasmogamous flowers of an amphicapric annual,Polygonum thunbergii (Polygonaceae) 总被引:1,自引:0,他引:1
Summary We observed phenology and insect visitors of chasmogamous flowers of an amphicarpic annual,Polygonum thunbergii (Polygonaceae) in Kyoto, Japan, and clarified limiting factors for fruit set by bagging and hand-pollination experiments.
Flowering season was one month from late September. Flowers were visited by various insect groups (total 30 families and 64
species) and effective pollinators were lower bees (Halictidae) and wasps (Vespidae) in the early flowering season, and middle-sized
flies (Syrphidae and Calliphoridae) in the later season. Nectar was secreted at a constant rate (0.013mg sugar/hour) throughout
a day and >90% of it was consumed by insects. The average number of flowers per ramet was 122, of which 95% were pollinated
in the natural conditions. Bagging experiments showed that 47% of flowers were self-pollinated even under no pollinator visits.
Despite of a high probability of cross pollination, the probability of fruit set within the ramet was 0.30 due to resource
limitation. We discussed possible adaptive significance of cleistogamous flowers under the condition that seeds could be produced
by chasmogamous flowers through self-pollination even under pollinator limited conditions. 相似文献