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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.
Summary We studied the relationship between the diurnal nectar secretion pattern of flowers ofCayratia japonica and insect visiting patterns to these flowers. Flower morphology ofC. japonica changed greatly for about 12 hours after flower-opening and the maximum duration of nectar secretion was 2 days. The nectar
volume peaked at 11∶00 and 15∶00, and declined at night and at 13∶00 regardless of time elapsed after flower-opening. The
nectar volume at the two peaks was, on average, 0.25 μl on bagged inflorescences and 0.1μl on unbagged inflorescences (both,
sugar concentration=60%). The flower secreted nectar compensatory when the nectar was removed. This means that insects consume
more nectar than the difference of nectar volume between bagged and unbagged flowers.
Apis cerana is a primary visitor of this flower, and was the only species for which we confirmed pollen on the body, among many species
of flower visiting insects to this flower.Apis cerana visited intensively at the two peaks of nectar secretion. Visits of the other insects were rather constant or intensive only
when there was no nectar secretion. Thus flowers ofC. japonica with morphologically unprotected nectaries may increase likelihood that their nectar is used by certain pollinators, by controlling
the nectar secretion time in day. In this study the pattern of nectar secretion allowedA. cerana maximum harvest of nectar.
Contribution to the ecological and bioeconomoical studies of the pollinator community in Kyoto I. 相似文献
3.
Yoshitsugu Ohara Koukichi Nagasaka Naota Ohsaki 《Researches on Population Ecology》1993,35(2):223-230
Summary Green larvae of the butterflyPieris rapae and black larvae of the sawflyAthalia rosae feed on green leaves of the same cruciferous plants. To demonstrate thatP. rapae has concealing coloration and thatA. rosae has warning coloration, the larvae of the two species were supplied to naive chicksGallus gallus on white, green or black backgrounds.P. rapae larvae were palatable and their green body color acted as a concealing coloration. On the other hand,A. rosae larvae were unpalatable and their black body color acted as a warning coloration.
There is a general consensus that warning coloration is an altruistic character which needs victims, and thus can evolve through
kin selection or green beard selection. However, blackA. rosae larvae were seldom injured by chicks' attack, in particular, on the green background. Therefore, the warning coloration ofA. rosae larvae can be a selfish character and hence can evolve through individual selection as well as concealing coloration ofP. rapae. 相似文献
4.
Naota Ohsaki 《Researches on Population Ecology》1980,22(1):163-183
Summary Utilization of patchy habitats by adult populations of threePieris butterflies,P. rapae, P. melete andP. napi was studied throughout the flight season in an area of their coexistence, about 3×1.5 km, in a farm village in the mountains
in Inabu, Aichi Prefecture. Field study was by the mark-recapture method. Results were analyzed by dispersal distances and
recapture duration decay curves for adults of different age-classes estimated on the basis of physical condition of their
wings, together with supplementary information of daliy egg-laying rate of females, obtained in field cages.
Sexually immature, mated femals ofP. rapae after teneral stage showed a migratory flight. On the other hand, reproductive females and all males ofP. rapae were strongly resident within suitable habitats, and reproductive females begun to lay eggs abundantly at sunny places of
newly suitable areas within a short period.P. melete seemed to disperse gradually from emerged stites and females of this species continued to lay some constant numbers of eggs
for more than ten days over a wider area.P. napi appeared more likeP. melete thanP. rapae.
The habitats of the three species can be characterized as follows:P. rapae, temporary, continued for pre-reproductive females but localized for reproductive females and all males, and unstable;P. melete, permanent, widespread, and stable;P. napi, permanent, localized, and stable.
The numbers of generations ofP. rapae, P. melete andP. napi were estimated to be about six, three and three, respectively. Seasonal fluctuations in the number of adults were influenced
by the stability of their habitats, i. e., the population size fluctuated sharply inP. rapae, but it was much more stable inP. melete andP. napi. In view of these results, it can be said thatP. rapae fits the general characteristics of a r-strategist whereasP. melete andP. napi are more K-strategic thanP. rapae. 相似文献
5.
The plastic reproductive allocation of the cruciferous perennialRorippa indica in response to different degrees of feeding damage 总被引:1,自引:0,他引:1
Shuichi Yano 《Researches on Population Ecology》1993,35(2):349-359
Summary The degree of feeding damage in the wild to the cruciferous perennialRorippa indica (L.) Hieron ranged from 0% (not damaged) to 100% (heavily damaged). However, “not damaged” and “heavily damaged” individuals
did not differ in the relative suitability of their intrinsic traits forP. rapae, which caused the heaviest damage on the plant. Therefore, the different degrees of feeding damage may be due to variability
in the extrinsic traits of the plant, that is, it may be determined by the habitat conditions where individual plants exist.
Furthermore,R. indica allocated more resource to seed production at the expense of the roots when it was experimentally subjected to heavy leaf
damage. The result suggested thatR. indica individuals may escape, by means of seed dispersal and seed dormancy, from unfavorable habitats where they are heavily damaged
by herbivores. 相似文献
6.
Summary Larvae of genusPieris in the northern part of Kyoto City are parasitized by two tachinid flies:Epicampocera succincta, a specialist on genusPieris, andCompsilura concinnata, a generalist with very wide host-range. We surveyed the parasitism rates ofPieris by both flies for two years at six study areas. In these study areas, there lived three host species in the genusPieris: P. rapae, P. melete, andP. napi, but neither tachinid parasitizedP. napi to any significant extent. In the mountainous district,P. rapae andP. melete coexisted and their populations were relatively continuous, while in the lowland, onlyP. rapae larvae were abundant in spring and autumn, but even they disappeared in summer. Parasitisms byE. succincta occurred mainly in mountainous district and never in the lowland.C. concinnata parasitizedPieris in all the areas, but its parasitisms occurred mainly in autumn.
We analyzed the factors affecting the spatial and temporal patterns of parasitism rates and presumed that the temporal discontinuity
of host population restricted the distribution of the specialist parasitoid. 相似文献
7.
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
8.
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
9.
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
10.
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
11.
How an ant decides to prey on or to attend aphids 总被引:3,自引:0,他引:3
Hiroshi Sakata 《Researches on Population Ecology》1994,36(1):45-51
The following results on the behavior decision making of the antLasius niger toward two species of myrmecophilous aphidsLachnus tropicalis andMyzocallis kuricola on chestnut trees have been found. (1) An individual worker consistently attended only one aphid species, even if her nestmates
attended other aphid species on the same tree. (2) The ants preyed less on the aphid species which they attended than on other
myrmecophilous aphid species. (3) The ants preyed less on the aphids which had been attended by their nestmates, even if both
aphids were the same species. (4) The ants preyed less on aphids which had provided honeydew to their nestmates. (5) The increased
aphid density per ant led to an increase in the rate of predation on the introduced aphids by the ants. These results suggest
that each worker ofL. niger chooses aphid species to attend from her experience. In addition, the workers can recognize whether an aphid has been attended
by their nestmates and whether an aphid has given their nestmates honeydew. Through these processes, each worker decides to
attend or to prey on the aphid. As a result, they may realize efficient collective foraging dependent on aphid density per
worker. 相似文献
12.
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
13.
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
14.
Summary We studied the stopping rule obeyed by the female parasitoid,Chrysocharis pentheus, in deciding when to leave the leaflet on which she is searching for larvae ofPhytomyza ranunculi. She seemed not to employ some stopping rules that have been suggested; i.e., a fixed-number rule and a fixed-time rule and
others. The stopping model formulated forDapsilarthra rufiventris parasitic on the same host species fitted well to the results. The model assumes that the searching female will deposit a
marking pheromone on the leaflet at a rate proportional to the search speed and will leave the leaflet when the amount of
the pheromone that has accumulated on the leaflet reaches the threshold,L. In this model,L denotes the amount of search effort spent on the leaflet. A comparison of the observed results with the predictions from
the model suggested thatL increased markedly at the first encounter with the mine (host), but less at later encounters.C. pentheus appears to employ a mixed strategy of a fixed search-effort and an area-concentrated search. This would confer an adaptive
advantage in foraging forP. ranunculi larvae, which are distributed in clumps among leaflets in the field. 相似文献
15.
Reproductive behaviors related to habitat utilization were studied in males of the damsefly,Mnais nawai, which has two male forms, territorial orange-winged males (nawai) and non-territorial pale-orange-winged males (sahoi), at the upper part of a mountain stream where they partiallycoexist with a related species,Mnais pruinosa, which also has two male forms, territorial orange-winged males (esakii) and non-territorial hyaline-winged males (strigata). These two species showed parapatric distribution; the lower part of the stream was occupied byM. nawai, and the upper part byM. pruinosa. In the present study, cross-matings occurred between bothMnais species, although normal intraspecific matings occurred more frequently than cross-matings. Territorial males of both species copulated
with conspecific females that entered their territory and guarded the ovipositing females, probably to avoid sperm displacement
resulting from subsequent copulations. Severe competition for oviposition sites by territorial males even occurred between
the two species. On the other hand, non-territorial males of both species have alternative mating strategies (including several
tactics such as sneaking, takeover and interception). The possible benefits from conflict among territorial males of both
species is discussed. 相似文献
16.
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
17.
T. H. Chua 《Researches on Population Ecology》1977,19(1):125-139
Summary Studies on populations ofBrevicoryne brassicae (L.), its parasites and hyperparasites were carried out by actual counting in the sprouts field and by sticky and water traps.B. brassicae was found to be attacked by one primary parasite,Diaretiella rapae (McIntosh), which in turn is parasitized byAlloxysta brassicae (Ashm.),Asaphes vulgaris
Walker,A. suspensus (Nees),Pachyneuron minutissimum (F?rster) andDendrocerus carpenterii (Curtis). The aphid population in the field was started by immigrant alates which were found flying too early to be synchronized
with the sprouts plants. SimilarlyD. rapae was not synchronized with the aphids although many individuals could have been carried into a plot through parasitized immigrant
alates, of which less than 30% were found parasitized. Because of high hyperparasitism (especially byA. brassicae)D. rapae was not able to maintain a high rate of parasitism to curb the aphid population growth. The maximum percentage mummies being
27.8%, while the maximum, percentage parasitism being 56.6% recorded only during the early 1974 season (mean=12.9%). The decline
of aphid population from September onwards was largely due to the cold weather, Syrphid predation and occasionally fungal
attack. The high rate of hyperparasitism byA. brassicae is attributed to its better synchronization withD. rapae. The mean percentage of parasite that emerged from mummies collected during 1973–74 wereD. rapae 31.3%,A. brassicae 64.3%,A. vulgaris andA. suspensus 4.3%,D. carpenterii 0.2% andP. minutissimum 0.1%. 相似文献
18.
The lifetime mating frequency of female butterflies is believed tobe dependent on the reproductive status of the males which
they have mated. This report assesses those status usingPieris rapae L. Multiple mating females mated males with a short time interval after the last mating or males with many mating records.
Such males, like small ones, produced small spermatophores during copulation, which may have resulted in high mating frequency
of those females. The males with short time interval after the last mating or those with many mating records also showed a
long mating duration. Alternative interpretations of the adaptive significance of this behavior for males are discussed. 相似文献
19.
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
20.
Morio Tsukada 《Researches on Population Ecology》1994,36(2):219-224
I studied the seasonal occurrence of the andromeda lace bug,Stephanitis takeyai, on its two main host-plant species. In a secondary forest in Kyoto, this bug altered its hosts seasonally, i.e., from an
evergreen shrub,Pieris japonica, in winter to a deciduous shrub,Lyonia elliptica, in summer. In contrast, in Nara park where fewL. elliptica were available, the bug exploited onlyP. japonica. Thus, seasonal host alternation by this bug is not obligate. A comparison of adult longevity and fecundity on the two host-plant
species demonstrated the higher quality ofL. elliptica as a food resource. Corresponding to this difference in host quality, there was a dramatic difference in the seasonal population
growth in the two study sites. In Nara, the population size at the beginning of the 2nd generation was almost the same as
in the overwintered generation, whereas in Kyoto the population size in the 2nd generation was approximately one hundred times
as large as in the overwintered generation. Thus seasonal host alternation is adaptive for the bug. In a previous study, I
reported that overwintering as eggs in living leaves of their hosts is likely to be common among all the related species of
this bug. Thus, this trait can be considered to be a phylogenetic constraint to the group. I speculate that host alternation
by this bug has been derived because it is more adaptive from autoecy on an evergreen plant, similar to the pattern currently
found in Nara, and that this bug can not only exploit deciduous host due to a phylogenetic constraint. 相似文献