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1.
Takahisa Miyatake 《Researches on Population Ecology》1998,40(3):301-310
Quantitative genetic studies for life history and behavioral traits are important in quality control for insect mass-rearing
programs. Firstly, a brief history of quality control in mass-reared insects is described. Next, the differentiation of many
traits of wild and mass-reared melon flies,Bactrocera cucurbitae, in Okinawa is reviewed, and the factors which have caused variation in these traits are considered. As artificial selection
pressures are thought to be more important than inbreeding depression and genetic drift in the mass-reared strain of the Okinawan
melon fly, two artificial selection experiments were conducted to evaluate genetic variations and genetic correlations among
life history and behavioral traits. These are divergent selections for age at reproduction and for developmental period. The
genetic relationship among 5 traits, i.e. longevity, age at reproduction, developmental period, circadian period, and time
of mating was clarified and discussed in relation to genetic changes of traits during the mass-rearing. The results suggest
that the genetic trade-off relationships between traits should be taken into account in mass-rearing programs. 相似文献
2.
Y. Tanaka 《Researches on Population Ecology》1989,31(2):311-324
Summary Quantitative genetic theory indicates that genetic covariance patterns among life history characters should have played an
important role as genetic constraint in life history evolution. Highly positve (and negative) genetic correlations between
larval development time (or larval growth rate) and adult size characters were detected by means of sib analysis for the small
white butterflyPieris rapae crucivora. The genetic associations suggested that evolution of developmental characteristics and adult phenotypic traits were constrained
by pleiotropy. The positive genetic correlations between development time and adult body size may be compatible with the trade-off
between them, but the negative genetic correlations between larval growth rate and adult body size are not predicted from
theories of optimal energy allocation. That phenotypic correlations drastically differed from the genetic correlations indicates
limitations of evolutionary inferences based only on phenotypic variation. 相似文献
3.
Variability in wing form of crickets 总被引:4,自引:0,他引:4
Loss of functional hindwings is observed in most subfamilies of Japanese crickets. Habitat, behaviour, body size and phylogenetic
factors might be involved, but interactions among them may obscure the general trend. Wing dimorphism is common among the
relatively small-sized members of Gryllinae, and the two small-sized subfamilies, Nemobiinae and Trigonidiinae. Both environmental
cues (e. g. photoperiod) and genetic factors affect the wing form. InDianemobius fascipes (Nemobiinae), the percentage macroptery was drastically changed by selection for macroptery or microptery. Crossing experiments
indicated polygenic control of wing form as well asX-chromosomal and maternal effects. Neither the long-winged nor short-winged line bred true after 40 generations of selection.
Full-sib families revealed a large genetic variation in frequency of macropterous forms within a population. The genetic determination
of the propensity for macropterism did not seem to be directly coupled to the mechanism performing the photoperiodic time-measurement. 相似文献
4.
Summary Some relevant traits of a wild (L) and a laboratory (C) strain ofHylemya antiqua (Meigen), determining differences in their pupation ability under experimental conditions have been investigated in relation to genetic
control. The wild strain showed an intrinsic higher pupation ability than the laboratory strain. The minimum feeding period
was 0.6 days longer for the C strain. The minimum larval dry weight was different for the two strains. With a normal feeding
period C larvae pupated on average 1.63 days later than L larvae. By the shortening of the larval feeding period an acceleration
of the larval development of both strains was observed: the acceleration of development was more marked for the wild strain.
This result has been contrasted with published works onDrosphila. The consequences of these differences as far as the competitive ability of each strain is concerned, have been discussed
in relation to genetic control. 相似文献
5.
Midori Tuda 《Researches on Population Ecology》1998,40(3):293-299
In an insect host (the cowpea weevilCallosobruchus maculatus)- parasitoidHeterospilus prosopidis) experimental system, the population densities of the component species oscillated for the first 20 generations and then
abruptly stabilized as the parasitoid density decreased. Examination of the host and parasitoid after the 40th generation
in the long-term experiment showed that (1) host larvae exhibited contest-type competition (killing other larvae inhabiting
the same bean), in contrast to the founder population being scramble-type competitors and (2) the parasitoid attack rate on
the host did not change. There was also an evolutionary trade-off between body size and the rates of larval survival and development,
suggesting a cost of contest competition on larval survivorship and development. I tested model predictions (Tuda and Iwasa
1998) that (1) host equilibrium population size should gradually decrease as the proportion of the contest type increases
and that (2) random attacks of the parasitoid on the host should reduce the rate of increase in proportion of the contest
type, and the effect should become manifest especially during the first 20 generations. Two of three host-only replicates
showed significant decrease in population sizes. Although the density of emerging adults per bean did not differ between replicates
of the host-only and host-parasitoid systems, comparison of the host body size between them on day 270 (at the 13th generation)
showed that the host was more contest-type in the host-only system than in the host-parasitoid system, as the model predicted,
and later on day 650 the effect of the parasitoid had disappeared. 相似文献
6.
Three models were constructed for analyzing the population characteristics ofC. chinensis on stored beans; model A describing the whole reproductive process with a single equation, model B describing the three age-specific
processes (oviposition, egg survival and larval survival) with separate equations, and model C which describes all these processes
not for the whole habitat but for the individual beans comprizing it. The logit equation was employed here as a common basis
to describe the density-response relationship involved. All three models showed very good fit to the experimental data obtained
for both laboratory and wild strains of the weevil. The parameter values characterizing the population dynamics were, however,
widely different between the two strains; the laboratory one which had been reared for some 500 generations showed significantly
higher reproductive capacity, less sensitive and gentler response to crowding in both adult and egg stages, and more uniform
egg distribution among individual beans, as compared with the wild strain newly introduced. Sensitivity analyses using these
models suggested that these changes in population characteristics have been attained by the process of domestication or adaptation
to stable laboratory conditions through a long period of time. This process seemed in effect to have optimized the population's
performances in the laboratory environment. Evolutionary significance of such optimization was discussed with reference to
the selection pressure which may have acted upon individuals. 相似文献
7.
Summary The mechanism of the genetic control of wing form determination of the small brown planthopperLaodelphax striatellus was analyzed by selection and crossing experiments. The selection experiment for brachypterous and macropterous forms for
13 generations showed that the wing form is under some genetic control. The crossing experiment showed that the wing form
polymorphism was not a simple Mendelian character but was under polygenic control. The data from the crossing experiment were
applied to the liability method for the quantitative genetics by Falconer (1981). The analysis suggested that wing form determination
was a threshold character under polygenic control, and the estimated minimum number of loci concerned was 2.07. The realized
heritability estimated from the data of selection experiment was 0.36 for macroptery. On the other hand, the heritability
in broad sense estimated on the basis of the variance of F1 and F2 in crossing experiment was 0.81. 相似文献
8.
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
9.
Keizi Kiritani 《Researches on Population Ecology》1970,12(1):19-34
Summary Polymorphism in adult colour pattern ofNezara viridula is determined on the genetic basis. The basic colour patterns of adult are classified into four types, i. e. G, O, R and
F. No appreciable differences between these types were observed in respect to various physiological traits of nymphs and adults,
except that type G seems to be superior in reproductive ability but to be inferior in ability of surviving winters at least
to types R and F.
Inter-generation changes in percentage frequency of G type were examined from 1959 to 1967 covering more than 30 generations.
Percentage frequencies of G types prior to the severe winter of 1962–3 fluctuated greatly around a mean of 87.9%, while they
did to a lesser extent than before with a mean of 85.0% after the winter. Unexpected high percentages of G type were recorded
frequently in summer generations, viz. 1st and 2nd. On the other hand, the relative frequencies of G and O types decreased
after hibernation in contrast to the increases in those of F and R. This sort of changes in genetic composition related to
the winter of 1962–3 was observed in several populations segregated from each other.
This seasonal alternation of selective activity in the environments is considered to be responsible for retention of the polymorphism.
Alternative possible causes, i. e. difference in habitat preference, non-random mating and selective predation by predators
among polymorphs, may safely be rejected as irrelevant to the mechanism in maintaining polymorphism.
The polymorphism of this insect seems to be in a transient state rather than balanced one contributing little to population
regulation, but the persistence ofN. viridula in the periphery range may be assisted by retention of the polymorphism. 相似文献
10.
The observed practice of discounting the future should not be rationalised on the grounds of myopia or selfishness. A positive
rate of pure time preference is necessary to ensure that heterogeneous generations are treated in an egalitarian fashion.
A zero social discount rate would yield intertemporal allocations which are biased against the current generations. Endogenous
productivity growth requires that the social discount rate be set above the subjective rate of pure time preference. Positive
social time preference, far from discriminating against future generations, is essential for a fairer intertemporal allocation
of resources.
Received: 3 July 1999/Accepted: 6 October 1999 相似文献
11.
B. Leroi 《Researches on Population Ecology》1972,13(2):201-215
Summary The study of the population dynamics of the celery leaf-miner,Philophylla heraclei, must take into account the fact that the host-plant is not present permanently and that it develops between the two annual
generations of the insect. This development affects in particular the quality and quantity of the leaves fed upon by the mining
larvae. It is possible to know the numerical change of the populations from one annual generation to the next (bivoltine insect)
and from one year to the next by counting the populations in the various larval instars, responsible for the injury caused
to celery.
An accurate method of counting of larval numbers, taking into account their change parallel with that of the host-plant, is
described in this text. It makes it possible to know with accuracy the duration and importance of the infestations in relation
to external factors and to factors inherent to the host-plant itself. Certain traits of larval behaviour, particularly the
transfer of a larva from its original mine to a secondary mine as a result of food shortage can thus be established and estimated
quantitatively. 相似文献
12.
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
13.
Osamu Imura 《Researches on Population Ecology》1986,28(2):281-293
Summary The population fitness in terms of the intrinsic rate of increaser
m was measured in eight pure (homogenic) strains ofEphestia kühniella
Zeller with different larva color at an optimal temperature of 25°C, and in three strains at unfavorble temperatures of 15, 17,
28, and 30°C, to understand a mechanism of maintenance of a larval color variation found in wild populations. The survival
rate, hatchability, and gross rate of reproduction were poorly correlated with the fitness but the mean generation time and
net reproduction rate were correlated with the fitness significantly at 25°C. Intermediate color (pink) strain(s) grew faster,
initiated reproduction earlier and had shorter longevities than other strain(s) under the range of 15 and 28°C; the fitness
was highest in the intermediate larval color strains except at 30°C in which all strains had a negative rate of increase.
The results were discussed with reference to the relationship between the larval color and fitness along with a maintenance
mechanism of the variation. 相似文献
14.
We studied seasonal changes in the larval population structure, adult size, and autogeny (egg production without a bloodmeal)
of the mosquitoAedes togoi on the seacoast of northern Kyushu, Japan. The effects of temperature, photoperiod and food conditions on larval development,
adult size and autogeny were studied in the laboratory.Aedes togoi overwintered in both the egg and larval stages and was multivoltine. Adult size was greater in spring and autumn and smaller
in summer. Autogeny occurred in spring and autumn but not in summer. Autogenous females were larger than anautogenous females,
and larger autogenous females produced more eggs. Laboratory experiments showed that autogeny was promoted under low temperature
and short-day conditions which corresponded with spring/autumn conditions in the field. Experimental food limitation in the
larval stage greatly reduced adult size and autogenous egg production. In the field, large inter-pool variations in adult
size and autogeny rate probably resulted from variations in nutrient and crowding conditions. Seasonal autogeny ofAedes togoi was discussed in terms of life-history strategy under fluctuating environmental conditions where relative advantages of autogenous
and anautogenous reproduction alternate seasonally. 相似文献
15.
Michael F. Antolin 《Researches on Population Ecology》1999,41(1):29-37
Parasitoid sex ratios are influenced by mating systems, whether complete inbreeding, partial inbreeding, complete inbreeding
avoidance, or production of all-male broods by unmated females. Population genetic theory demonstrates that inbreeding is
possible in haplodiploids because the purging of deleterious and lethal mutations through haploid males reduces inbreeding
depression. However, this purging does not act quickly for deleterious mutations or female-limited traits (e.g., fecundity,
host searching, sex ratio). The relationship between sex ratio, inbreeding, and inbreeding depression has not been explored
in depth in parasitoids. The gregarious egg parasitoid, Trichogramma pretiosum Riley, collected from Riverside, CA (USA) produced a female-biased sex ratio of 0.24 (proportion of males). Six generations
of sibling mating in the laboratory uncovered considerable inbreeding depression (∼ 20%) in fecundity and sex ratio. A population
genetic study (based upon allozymes) showed the population was inbred (F
it = 0.246), which corresponds to 56.6% sib-mating. However, average relatedness among females emerging from the same host egg
was only 0.646, which is less than expected (0.75) if ovipositing females mate randomly. This lower relatedness could arise
from inbreeding avoidance, multiple mating by females, or superparasitism. A review of the literature in general shows relatively
low inbreeding depression in haplodiploid species, but indicates that inbreeding depression can be as high as that found in
Drosophila. Finally, mating systems and inbreeding depression are thought to evolve in concert (in plants), but similar dynamic models
of the joint evolution of sex ratio, mating systems, and inbreeding depression have not been developed for parasitoid wasps.
Received: November 13, 1998 /Accepted: January 8, 1999 相似文献
16.
Pierre-Alexandre Landry Fran?ois-Joseph Lapointe 《Researches on Population Ecology》1999,41(3):263-268
A survey of the genetic variability in deer mouse populations was performed using specimens collected from six different
islands on a lake covering approximately 50 km2. Random amplified polymorphic DNA (RAPD) was used to measure the extent of the genetic differences in this insular system.
An analysis of molecular variance (AMOVA) revealed that populations are clearly separated at this microgeographic scale (F
st
= 0.13863; P < 0.001). The homogeneity of molecular variance test (HOMOVA) indicated that within-population levels vary greatly (B
p
= 0.76831; P < 0.001). The within-population molecular variance was found to be mainly correlated with the accessibility of the islands,
computed as the inverse of the geographic distance separating an island from the lakeshore (r = 0.916; P < 0.003).
Received: March 5, 1999 / Accepted: July 16, 1999 相似文献
17.
Hideki Ueno 《Researches on Population Ecology》1994,36(1):121-124
Heritabilities and genetic correlations for body size characters and development period in a coccinellid beetle,Harmonia axyridis were estimated by a sib-analysis experiment. Positive genetic correlations were detected between size characters and development
rate. If this is upheld in the field, genetic variation would be eliminated, as the loci affecting the characters are supposed
to be fixed. However, the results indicated moderate heritabilities for all characters. Possible explanations for the results
are discussed. 相似文献
18.
Yukihiko Toquenaga 《Researches on Population Ecology》1993,35(1):57-68
Summary Competition between contest and scramble strategists was examined using two strains ofCallosobruchus maculatus, the contest strain (iQ) and the scramble strain (tQ). The direct larval interference experiment within each strain showed
that the contest strain performed strong direct interference throughout its larval stage against the conspecific opponent(s).
The scramble strain also performed its interference, but only during the 3rd and the 4th larval stages. The inter-strain larval
competition experiments inside a large and small mung bean (Vigna radiata) showed that the contest strain was, in general, superior to the scramble strain in competition, but the competition results
were density- and frequency-dependent. In the large beans, the proportion of adult emergence of the contest strain increased
with the increase of its own initial density but decreased as the initial density of the scramble strain increased. The shape
of the proportion of adult emergence became nonlinear in the small beans. The cause of the complexity of inter-strain competition
results was discussed in the light of the difference in larval interference ability between the two strains. 相似文献
19.
Motomi Ito 《Researches on Population Ecology》1998,40(2):205-212
The Bonin Islands are typical oceanic islands, located at the western part of the North Pacific Ocean and approximately 1,000
km south of mainland Japan. This archipelago consists of about 20 small islands. Although floristic diversity is low due to
the small area and limited environmental diversity, the Bonin Islands harbor unique endemic flora as in other well-known oceanic
islands. This paper presents a brief summary of the results obtained from recent studies on the endemic flora of the Bonin
Islands. The results are reviewed in relation to the four stages of the evolution of endemic flora in the oceanic islands;
migration, establishment, enlargement and diversification. The ancestors of the flora originated mostly from tropical and
subtropical Southeast Asia or mainland Japan by rare events of long distance dispersal. The proportion of bird-dispersed species
is relatively high as for other oceanic islands. Genetic data sets obtained from allozyme variation in some endemic species
suggest that migration occurred several million years ago and genetic diversity is correlated with current population size.
At the time of establishment, self-compatible plants are expected to have an advantage. However, the percentage of dioecious
plants is relatively high. This is partly due to evolutionary changes from hermaphroditic ancestors to dioecy which occurred
in two genera in the Bonin Islands. In addition, there are some examples of evolutionary changes from herbaceous ancestors
to woody endemics. Adaptive radiation is found in some genera, although the number of congeneric endemic species is less than
five. Studies of allozyme variation inPittosporum, Symplocos andCrepidiastrum showed that genetic identity is generally very high between congeneric species in spite of their distinct morphologies. This
result suggests that divergence of these species occurred rather recently and distinct morphological differences are based
on a limited number of genetic changes. 相似文献
20.
Kazuma Matsumoto Fuminori Ito Yoshitaka Tsubaki 《Researches on Population Ecology》1993,35(2):325-333
Summary Mean egg cluster size ofLuehdorfia puziloi yessoensis varied among habitats. The mean egg cluster size tended to be large when abundance of the larval food leaves expressed as
the fresh weight of leaves per unit area at a given habitat was high. Since this variation was observed among closely located
study plots (butterflies can easily move between study plots), the egg cluster size variation among habitats is likely to
be a result of flexible response by females to varying food abundance for larvae. 相似文献