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1.
A galling aphid with extra life-cycle complexity: Population ecology and evolutionary considerations 总被引:2,自引:0,他引:2
Summary In most gall-forming aphids, only the fundatrix is able to induce a gall on the host plant. InSmynthurodes betae Westw. (and a few other species), F2 descendants emerge from the mother gall and induce their own, morphologically different galls. This constitutes an added
complexity to the already very complex life cycle of gall-forming aphids.
We investigated the ecology ofS. betae on marked trees and shoots at four sites in Israel. Gall initiation, gall distribution and density, and temporal changes
in clone size within the galls were investigated during two consecutive years. We discuss the possibility that the two-gall
life cycle evolved from the typical one-gall system of most gall aphids, and the possible selective advantage of this added
complexity in the life-history strategy of gall aphids. Although the total reproductive output ofS. betae is not higher than in related species with a single gall per life cycle, there seems to be an advantage in the subdivision
of each aphid clone into several galls, thus reducing the risk of the accidental extinction of the clone (genotype) by environmental
factors, including parasites and predators. 相似文献
2.
Samples of shoots ofPistacia lentiscus carrying galls of the aphid,Aploneura lentisci, were collected at three localities in Israel.
Shoots growing near pruning scars carried more galls than elsewhere on the plant, but these galls weighed less and contained
fewer aphids (smaller clones). The proportion of empty galls increased with gall density. Crowding of galls at such sites
may be due to the early burst of buds at the time of aphid emergence from the overwintering eggs, and not to active search
for preferred sites. 相似文献
3.
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
4.
S. Akimoto 《Researches on Population Ecology》1995,37(1):81-89
Closely related species of gall-forming aphids are often associated with a single host species. SixTetraneura species coexist on the Japanese elm,Ulmus davidiana, in Sapporo, northern Japan. This paper describes the probabilities of coexistence on macro- and microgeographic scales (i.e.,
on host trees and host leaves) and examines whether coexistence with conspecific or heterospecific galls on leaves or shoots
has any effect on the fecundity of each aphid species using multiple regression. A Monte Carlo simulation showed that the
frequency distribution of the numbers of species on individual host trees differed significantly from that expected from the
null model. There were significantly positive or negative associations between species.Tetraneura radicicola andsorini always coexisted with other species on trees they infested. Multiple regression revealed that the coexistence of conspecific
or heterospecific galls on individual leaves had no influence on the fecundity ofradicicola andsorini, but had a negative influence on that of sp. O. On average,radicicola andsorini produced a smaller number of offspring in galls than sp. O, and obviously consumed only a small part of resources available
on the galled leaves. Evidence available suggests that although amensalism does arise between sp. O and other species, its
influence in not so strong as to exclude sp. O competitively from theTetraneura community. 相似文献
5.
Masakado Kawata 《Researches on Population Ecology》1997,39(2):227-237
An individual-based simulation model was used to examine the effect of population subdivision, dispersal distance of offspring,
and migration rates between subpopulations on genetic variability(H
1
H
S
andH
T
) in a continuously distributed population. Some difficulties with mathematical models of a continuously distributed population
have been pointed out. The individual-based model can avoid these difficulties and can be used to examine genetic variability
in a population within which individuals are distributed continuously and in which the dispersal of individuals is disturbed
by geographical or artificial barriers. The present simulation showed that the pattern of decrease inH
1 had three stages. During the first stage,H
1 decreased at the rates predicted by Wright’s neighborhood size. During the second stage,H
1 decreased more rapidly when the migration rate decreased, while during the third stage, it decreased less rapidly when the
migration rate decreased. Increasing the number of subdivisions increased the rate of decrease after the 200th generation.
The pattern of decrease inH
T
was classified into 2 stages. During the first stage, the rates of decrease corresponded with those of a randomly mating
population. During the second stage, a decrease in the migration rates of the subpopulations slowed the rate of decrease inH
T
. A uniform spatial distribution and a reduced total dispersal distance of offspring causedH
1
H
S
, andH
T
to decrease more rapidly. Habitat fragmentation in a continuously distributed population usually was detrimental to the genetic
variability in the early generations. Other implications of the results for conservation are discussed. 相似文献
6.
Summary Two species of tortoise beetles,Aspidomorpha miliaris (AM) andA. sanctaecrucis (AS) feeding on a shrub-like morning glory,Ipomoea carnea, were reared under laboratory conditions to study their survivorship and fertility schedules. AM and AS required 34–39 days
and 30–37, respectively, for the development of the immature stages. The mean longevity of the males was 88.4 days in AM and
63.8 in AS, and that of females was 87.9 days in AM and 83.3 in AS. The mean length of the pre-reproductive period (27.2 days
in AM and 33.8 in AS) was much longer than that of the post-reproductive period (10.9 days in AM and 14.3 in AS). Females
laid eggs at a nearly constant rate throughout their reproductive period. The reproductive valueV
x
/V
0
of the two species remained high for most of their adult life, as a result of prolonged survivorship and fertility periods.
The total number of eggs produced per female was 442.9 (AM) and 80.1 (AS). The intrinsic rate of natural increaser was 0.070 (AM) and 0.044 (AS) per capita per day. The prolonged reproductive schedules, coupled with strong dispersal power,
of these species no doubt have an adaptive value for living in highly disturbed tropical environments, where rainfall is ample
but unpredictable and food resources are available throughout the year in a wide area, but distributed in widely flung patches.
Contributions to the knowledge of population dynamics of tortoise beetles in Sumatra 3.
Contribution No. 33 of Sumatra Nature Study (Entomology).
Partly supported by Grants from Japan Society for Promotion of Science for JSPS-DGHE Scientific Cooperation (1980, 1982) and
Grants-in-Aid for Overseas Scientific Survey from Ministry of Education, Science and Culture of Japan (Nos. 56041027 and 58041030). 相似文献
7.
Summary Population dynamics ofHeliothis virescens (F.) andHeliothis zea (Boddie) (Lepidoptera: Noctuidae) eggs and larvae were studied for two years in a small plot of cotton,Gossypium hirsutum (L.). Due to morphological and ecological similarities, the pooledHeliothis population was considered for most of the analyses. Two generations ofHeliothis eggs and larvae were completed during each year. Stage recruitment was estimated for the eggs and larval instars 2–6, and
recruitment variances were estimated by a Monte Carlo method. A modified form of the Weibull distribution was developed and
used as a model to characterize survivorship curves for each of the fourHeliothis generations. A Type I survivorship curve (mortality rate increasing with age) was inferred for both Generation 1 (early season)
data sets, whereas a Type II survivorship curve (mortality rate constant and thus independent of age) was inferred for both
Generation 2 (late season) data sets. The shapes of the survivorship curves for the individualH. virescens andH. zea populations were inferred to be the same as those for the pooled populations. Analysis of the contributions of various factors
toHeliothis stage-specific mortality indicated that natural enemies (predators and parasites) and the availability of food for larvae
were responsible for between-generation differences in survivorship patterns. 相似文献
8.
《Researches on Population Ecology》1983,25(2):336-352
Summary Numerical changes and distribution patterns of the pine needle gall midge,Thecodiplosis japonensis
Uchida etInouye, were studied during the period from 1978 to 1979 in a young plantation ofPinus thunbergii in Shiga Prefecture, Japan. The survivorship curve of this species was characterized by a low mortality of larvae in galls
and two high mortalities before the formation of galls and during the overwintering period in soil.
The within and between-trees distributions of eggs and larvae in galls were examined by using the
regression method. The egg distribution per shoot was aggregative both within and between host plants. The within-tree variations
in numbers of eggs per shoot were related to the differences in the abundance of available needles for oviposition per shoot
among the canopy layers. The between-tree variations reflected the heterogeneous emergence of adult females in the study plot.
The degree of aggregation increased from egg to gall stage in both within- and between-tree distributions and the increase
was explained by the different mortality of larvae within trees and the inversely density-dependent mortality between trees.
The distribution patterns in the soil habitat stages were examined by the patchness index (
). This species showed aggregative distributions in soil stages. There was a correlation in spatial patterns of adult emergence
between the successive generations.
The distribution properties of this species were discussed in connection with the population dynamics and the availability
of host plants in the study plot. 相似文献
9.
Frank J. Sonleitner 《Researches on Population Ecology》1977,19(1):10-32
Summary A model is described for investigating the interactions of age-specific birth and death rates, age distribution and density-governing
factors determining the growth form of single-species populations. It employs Monte Carlo techniques to simulate the births
and deaths of individuals while density-governing factors are represented by simple algebraic equations relating survival
and fecundity to population density. In all respects the model’s behavior agrees with the results of more conventional mathematical
approaches, including the logistic model andLotka’s Law, which predicts a relationship betwen age-specific rates, rate of increase and age distribution.
Situations involving exponential growth, three different age-independent density functions affecting survival, three affecting
fecundity and their nine combinations were tested. The one function meeting the assumptions of the logistic model produced
a logistic growth curve embodying the correct values orr
m
andK. The others generated sigmoid curves to which arbitrary logistic curves could be fitted with varying success. Because of
populational time lags, two of the functions affecting fecundity produced overshoots and damped oscillations during the initial
approach to the steady state.
The general behavior of age-dependent density functions is briefly explored and a complex example is described that produces
population fluctuations by an egg cannibalism mechanism similar to that found in the flour beetleTribolium.
The model is free of inherent time lags found in other discrete time models yet these may be easily introduced. Because it
manipulates separate individuals, the model may be combined readily with the Monte Carlo simulation models of population genetics
to study eco-genetic phenomena. 相似文献
10.
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
11.
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
12.
Masahiro Nakaoka 《Researches on Population Ecology》1993,35(2):199-213
Summary Long-term variation in recruitment was estimated by constructing projection matrices for a marine bivalve,Yoldia notabilis, at two stations in Otsuchi Bay, northeastern Japan, and the effects of its variation on population dynamics were examined
using a simple matrix model. The matrix model was developed from the Leslie matrix, in which the population growth rate λ
was expressed as a function of recruitment rater
0. The equilibrium recruitment rater
s, or the recruitment rate required to maintain population at constant size (λ=1), was expressed by the reciprocal of the reproductive
value of a newly recruited individual. The estimates ofr
s for the field population were lower at the shallower station than at the deeper station, reflecting higher survivorship and
fecundity. Past recruitment rate estimated both by the field samplings for 3 years and by the back-calculation from the current
age structure for over 10 years showed large yearly variation, ranging between 0 and 58.6×10−4. The estimates were larger thanr
s, and hence, large enough to increase population size (λ>1) only in approximately one-third of the estimated years. This suggests
that the population has been maintained by occasional successful recruitment occurring once every few years. 相似文献
13.
Berend Aukema 《Researches on Population Ecology》1995,37(1):105-110
A review of data on the background of wing dimorphism in carabid beetles (Coleoptera: Carabidae) and especially of the closely
relatedCalathus cinctus andC. melanocephalus is given. In bothCalathus species wing dimorphism is inherited in a simple Mendelian fashion with the brachypterous condition dominant, but inC. melanocephalus the expression of the long winged genotype is under environmental control as well. The development of long winged phenotypes
in the latter species is favoured by relatively favourable environmental conditions, such as high temperatures and a high
food-supply. The higher fecundity of the larger and heavier long winged females of both species may compensate for losses
of long winged phenotypes by flight activities. The evolutionary significance of both types of inheritance is discussed in
relation to dispersal. The ‘fixed type’ as found inC. cinctus is considered an opportunistic short term ‘between sites strategy’, whereas the ‘dynamic type’ ofC. melanocephalus represents a flexible long term ‘within sites strategy’. 相似文献
14.
Summary Dispersal, immigration and emigration rates, horizontal and vertical survivorship and absolute population size were estimated
for micropopulations ofAn. culicifacies, An. stephensi andAn. subpictus at a series of cattle sheds in rural Punjab Province, Pakistan, during November 1979 and May 1980 using capture-mark-release-recapture
and dissection methods. Dispersal was temperature-related, with populations more vagile during May. Mean dispersal distance
per individual was low for all species. More than 70% of all recaptures were taken at the point of release and the longest
detected flight was 1250 meters.
Horizontal survivorship was greater during November and was always less than vertical survivorship calculated from dissection
agegrading data. Survivorship during the nulliparous period was greater than survivorship throughout total life, indicating
the survivorship curve may be slightly sigmoid. Daily population sizes of endemic and immigrating females and males were calculated
usingBailey's (1952) modification of the Lincoln Index, with the daily captures adjusted for immigration which was highest in May. Daily
additions to the indoor resting population exclusive of immigrants were estimated using the method ofManly andParr (1968). The relationship of the present findings to malaria transmission and genetic control were discussed. 相似文献
15.
1. | The effects of larval rearing density and species relative proportions on life-history parameters of two necrophagous Diptera,Hemipyrellia ligurriens (Wiedemann) (Calliphoridae) andBoettcherisca formosensis Kirner and Lopes (Sarcophagidae), were investigated in mixed cultures. Larval rearing density had a significant effect on larval to adult survivorship, duration of immature development, adult size and relative performance (measured by the composite index of performance,r′) of both species. However, species relative proportions affected adult size of both flies and the duration of immature development ofB. formosensis only. |
2. | B. formosensis had a higher survivorship thanH. ligurriens in all mixed cultures and showed a similar survivorship pattern to that in pure cultures. By contrast, survivorship ofH. ligurriens was lower in mixed than in pure cultures. |
3. | H. ligurriens adults reared from mixed cultures were smaller than those from pure cultures of comparable density, butB. formosensis adults from pure and mixed cultures were of similar size. |
4. | The results suggest that competition betweenB. formosensis andH. ligurriens larvae was asymmetric and the former was the superior competior. |
5. | At low larval densities in mixed cultures, the presence ofH. ligurriens enhanced the performance (as measured byr′) ofB. formosensis, a consequence of suspected interspecific facilitation of larval growth. |
16.
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
17.
Dynamics of the buried seeds and plant population of two dominant weeds, viz.,Emilia sonchifolia (Linn.) DC. andRichardsonia pilosa HBK were studied in the crop fields of Meghalaya, north-east India during radish and maize cropping and intervening fallow
periods. The total buried seed population ofR. pilosa was always larger than that ofE. sonchifolia, but the germinable fraction was invariably greater in the latter. A major portion (39–41%) of the viable (germinable+dormant)
seed population in both weeds was confined to the surface soil layer (0–5 cm). The viable seed population ofE. sonchifolia peaked during April, while that ofR. pilosa showed two peaks (during August and December). The survival pattern and half-lives of seedling cohorts showed, some differences
in the two weed species, but both being summer annuals, their populations behaved in a similar manner by showing higher seedling
recruitment (K) and survivorship (p) rates in the summer crop (maize) than in the winter crop (radish). However, the density of plants that could attain adulthood
was significantly higher inE. sonchifolia thanR. pilosa which might have resulted in greater seed input of the former to the soil leading to its greater abundance in the crop fields.
Supported by the University Grants Commission, New Delhi (Grants No. F. 3-37/87 SR II) 相似文献
18.
Summary The present paper dealt with the sequential changes of the distribution pattern of apterous females aphid populations, that
were artificially settled at the beginning on the experimental barley ‘field’. The aphids were settled at random or even with
a fixed denisty per plant. For five or six days after the settling, the number of individuals followed the negative binomial
distributions in all cases while the parametersk andp were varying. The estimated values ofk were rather small for the first one week after the settling, which may suggest that the number of moving aphids between plants
was relatively small and the degree of concentration expressing the intrinsic increase was high. After that, as the number
of individuals increased, the number of moving aphids between plants would be considered to be increased. It was found that
with the lapse of time the degree of concentration decreased ork became larger.
The distribution of aphids per blade in a plant was also described briefly. 相似文献
19.
Shun'ichi Makino Seiki Yamane Tsukasa Sunose Shigeyuki Aoki 《Researches on Population Ecology》1987,29(1):111-117
Summary Dispersion capabilities of new queens were studied in the two haplometrotic paper waspsPolistes riparius andP. snelleni. New queens were marked on the nests in the late summer and located in the next spring. Dispersion distances greatly varied
among queens: although a large part of recovered queens nested in close proximity to their natal sites, some did disperse
over 100–300 m. This suggests that queens' emigration from and immigration into the censused areas occurred to a substantial
extent. On the whole, these species exhibited a weaker “philopatric” tendency than those so far studied for dispersion distance,
and seem to have the potential for a long-distance dispersion. 相似文献
20.
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