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1.
Shefali Begum Ritsuko Tsukuda Kenji Fujisaki Fusao Nakasuji 《Researches on Population Ecology》1996,38(2):257-263
The wild crucifers,Rorippa indica andLepidium virginicum, are known to serve as host plants for the diamondback moth (DBM),Plutella xylostella, but they are less suitable than the preferred cultivated cruciferous plant, cabbage, in terms of adult body size and fecundity.
The life history traits and flight activity of DBM adults grown on various host plants were investigated. The adults thus
reared on each host plant were divided into three size groups (small, medium and large). In general, female adults grown on
the wild crucifers were less fecund and lived longer than those reared on cabbage. Flight activity was higher in adults grown
on wild crucifers than in those reared on cabbage. Male adults flew longer than females. Fecundity, longevity, flight activity
and morphometrical characters of adults were positively correlated with pupal weight in individuals reared on the same host
plant. A negative relationship was found between fecundity and flight activity in females of the same size group, but a positive
one was observed in females reared on the same host plant. 相似文献
2.
Omar Muhamad Ritsuko Tsukuda Yoko Oki Kenji Fujisaki Fusao Nakasuji 《Researches on Population Ecology》1994,36(1):53-62
The larvae ofPlutella xylostella were fed on five wild crucifers,Capsella bursa-pastoris, Lepidium virginicum, Cardamine flexuosa, Rorippa indica, R. islandica and a crop, cabbage. The developmental period of the immature stages, adult longevity, preoviposition period, fecundity and
morphometrical characters of the adults were measured. The flight activity of the adults was also measured by the tethered
flight method. All the wild plants except forR. islandica were less suitable host plants than cabbage, and larvae which were fed on these less suitable plants emerged as smaller adults
with shorter wings. The smaller female adults had lower fecundity but a higher flight activity. Smaller adults measured in
terms of their pupal weight among individuals fed on the same host plant had longer wings. These smaller adults with longer
wing flew more actively. 相似文献
3.
Summary Lifetime mating success of males in a natural population of the papilionid butterfly,Atrophaneura alcinous, was investigated and causes of the variation were examined. The most successful males mated with 5 females, whereas about
73% of the males failed to mate. Body size of males was not correlated with their eclosion date, longevity and lifetime mating
success. There was no trade-off between mating success and longevity, and long-lived males had a disproportionately high mating
success. Although number of available females per male per day was not variable among males with different longevities, long-lived
males had higher mating efficiency. Time interval between matings by non-virgin males was shorter than that from eclosion
to the first mating. High lifetime mating success of long-lived males was strongly related to their mating experience, not
to their ageper se. 相似文献
4.
I Nyoman Widiarta Tsuyoshi Ikeda Kenji Fujisaki Fusao Nakasuji 《Researches on Population Ecology》1993,35(1):23-29
Summary Dispersal propensity of green leafhoppers was compared between a tropical species,Nephotettix virescens, and a temperate species,N. cincticeps. The flight ability was measured with tethered flight technique under laboratory conditions (25°C, 16L-8D). The pre-flight
period was shorter and the flight duration was longer inN. virescens than inN. cincticeps in both sexes. No significant correlations were found between the flight activity and morphometric characters for either
of the two species. The results suggested that dispersal propensity ofN. virescens is higher than that ofN. cincticeps. 相似文献
5.
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
6.
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
7.
T. S. Bellows Jr. 《Researches on Population Ecology》1985,27(1):55-64
Summary The effects of host age on parasitoid reproductive capacity are studied using the pteromalid parasitoidLariophagus distinguendus
F?rster and its bruchid hosts,Callosobruchus chinensis (L.) andC. maculatus (F.). A series of experiments were performed to investigate relationships between age and size of host parasitized and the
developmental period of pre-imaginal progeny, sex ratio, female size, longevity, fecundity and oviposition rate. There was
no effect of host size on preimaginal parasitoid developmental period. Sex ratio varied from less than 5% females from young
(small) hosts to 60% females from mature (large) hosts. Adult size, female longevity, fecundity, and oviposition rate were
also positively related to host age. Females provided mature hosts lived longer than those provided either young hosts or
no hosts, possibly because of an increased ability to host-feed from the larger hosts. The implications of these findings
to parasitoid population reproductive capacity and host-parasitoid synchrony are discussed. 相似文献
8.
Takayoshi Nishida 《Researches on Population Ecology》1994,36(2):209-218
Spatio-temporal variations of lifetime reproductive succes (LRS) of both male and female individuals of a coreid bugColpula lativentris were measured and analyzed using the multiple regression method of Arnold and Wade (1984a, b). The standardized variance
of LRS was larger in males than that in females as males often to secure mates for a long period whereas females could easily
find mates and oviposit simply dependent on ovarial maturation. LRS was partitioned into 4 consecutive fitness components:
(1) reproductive lifespan, (2) copulating efficiency, (3) guarding efficiency (for males) or oviposition efficiency (for females),
and (4) number of eggs per clutch. In males copulating efficiency was the largest determining factor of LRS, whereas in females
reproductive lifespan was the most important factor. Such tendencies were stable on both a yearly and local basis. Patterns
of relative contribution of natural selection (reproductive lifespan and number of eggs per clutch) and sexual selection (copulating
efficiency and guarding or oviposition efficiency) to LRS were clearly different between males and females. This sexual difference
is, at least to some extent, thought to be brought about by sexual selection among males for mating opportunity, though no
physical fight was observed among males. Directional selection on body length was found only in relation to the clutch size
of females because large females tended to lay larger clutches. No significant directional selection was found in other fitness
components. 相似文献
9.
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
10.
Takatoshi Ueno 《Researches on Population Ecology》1999,41(1):47-57
Charnov's host-size model explains parasitoid host-size-dependent sex ratio as an adaptive consequence when there is a differential
effect of host size on the offspring fitness of parasitoid males versus females. This article tests the predictions and the
assumptions of the host-size model. The parasitoid wasp Pimpla nipponica Uchida (Hymenoptera: Ichneumonidae) laid more female eggs in larger or fresher host pupae when choice among hosts of different
sizes or ages was allowed. Then, whether an asymmetrical effect of host size and age on the fitness of females versus males
existed in P. nipponica was examined. Larger or fresher host pupae yielded larger wasps. Larger females lived longer, whereas male size did not influence
male longevity. Large males mated successfully with relatively large females but failed with small females, whereas small
males could mate successfully either with small or with large females. Thus, small-male advantages were found, and this held
true even under male–male competition. Ovariole and egg numbers at any one time did not differ among females of different
sizes. Larger females attained higher oviposition success and spent less time and energy for oviposition in hosts. Larger
females produced more eggs from a single host meal. Taken together, females gained more, and males lost more, by being large.
Host size and age thus asymmetrically affected the fitness of offspring males versus females through the relationships between
host size or hast age and wasp size, which means the basic assumption of the host-size model was satisfied. Therefore, sex
ratio control by P. nipponica in response to host size and age is adaptive.
Received: November 13, 1998 / Accepted: January 18, 1999 相似文献
11.
C. Solbreck 《Researches on Population Ecology》1995,37(1):129-134
Migration by flight is essential for insects living in patchy landscapes and knowledge about variability in habitat patch
structure and quality is important for the development of theory concerning insect dispersal polymorphisms. However, few studies
provide more than anecdotal evidence about habitat change in time and space and its effects on insect survival and reproduction.
Here I show how habitats and resource density of a lygaied bug,Lygaeus equestris, change in a patchy landscape over a seventeen year period. Although habitat patches per se are very stable, there are large
temporal fluctuations in per capita food resources. Food seems to be limiting only in some years, and there may be periods
of several years when populations change due to weather disturbance. Between-patch variation in reproductive success is large.
Furthermore, the relative favourability of patches changes between years. There are also distance effects; in some years distances
to suitable hibernation sites affect reproductive success. Long fliers experience more variable success, and sometimes extreme
success, when compared with short fliers. The importance of movements from outlying areas also changes with time. The insect
is thus faced with a habitat templet which varies strongly on many temporal and spatial scales. 相似文献
12.
Masakazu Shiga 《Researches on Population Ecology》1977,18(2):284-301
Summary Stabilizing mechanism in population ofMalacosoma neustria testacea was investigated in a central part of Japan based on eight year survey.
Population fluctuation in each developmental stage in the experimental field was rather small, i.e., 5.9 times in egg and
85.0 times in female adult. Pupal weight negatively correlated with the densities of 5th instar larvae and prepupae (cocoons)
and correlation coefficient was highly significant in females. Population density was stabilized by density-dependent dispersal
of female moths in preovipositional period. Comparison between fecundity of emerged moths and that of actually oviposited
ones in the experimental field suggested that density-dependent dispersal took place as the result of density-dependent size
variation, i.e., small-sized female months have higher flying ability. This hypothesis was supported by the experiment in
which flying ability of newly emerged female moth was measured. Similar stabilizing mechanism is expected to occur in semelparous
or pro-ovigenic insects.
Contribution Ser. A, No. 64 from Fruit Tree Research Station, Ministry of Agriculture and Forestry, Japan 相似文献
13.
Kenji Fujisaki 《Researches on Population Ecology》1992,34(1):173-183
Summary A male fitness advantage to wing reduction was investigated for the oriental chinch bug,Cavelerius saccharivorus, which is wing dimorphic. Field surveys for the frequency of matings between wing morphs showed that the mating probability
was much higher in brachypterous males than in macropterous males in the early breeding season. Brachypterous males copulated
with not only brachypterous females but also macropterous females in this season. This led to a considerable rate (30%) of
insemination of macropterous females just before emigration even in the early breeding season. A rearing experiment for the
pre-reproductive period of females revealed that females mated with brachypterous males copulated and oviposited earlier than
females mated with macropterous males. These results indicate that there is a fitness advantage to wing reduction in the males
ofC. saccharivorus in terms of the earlier sexual maturation. 相似文献
14.
Yoshitaka Tsubaki Rowan E. Hooper Michael T. Siva-Jothy 《Researches on Population Ecology》1997,39(2):149-155
The damselflyMnais pruinosa costalis (Odonata: Calopterygidae) is unusual in that males are dimorphic, existing as clear-winged non-territorial ‘sneaks’ and orange-winged
territorial ‘fighters’. Here we report the results of population census data and behavioural observations in the field and
laboratory, and present estimates of emergence period, reproductive period, total lifespan, and reproductive success of each
morph. Clear-winged males are smaller and have lower daily reproductive success than orange-winged males, but live for longer
in the field and laboratory. We accounted for the difference in the ‘operational reproductive life’ of the two morphs and
estimated lifetime reproductive success: there was no difference between clear-winged and orange-winged males. We discuss
possible mechanisms for the maintenance of the two forms. 相似文献
15.
Takayoshi Nishida 《Researches on Population Ecology》1993,35(1):45-56
Summary Spatial relationships of mate acquisition probability for individuals of both sexes of a gregariously-mating coreid bug,Colpula lativentris, were studied in relation to aggregation size. Operational sex ratio was always strongly male biased. Mate acquisition probability
of females was rather constant and independent of aggregation size, as predicted by an ideal free distribution. Moreover laboratory
experiments showed that both multiple mating and rearing density little affected female fecundity, suggesting ideal free distribution
of females in terms of reproductive success. On the other hand, mate acquisition probability of males was higher in larger
aggregations, where more receptive females were available. This male discrepancy from an ideal free distribution was similar
to the patterns predicted by an ideal free distribution under perceptual constraints (Abrahams, 1986), but not by that under
unequal competitive ability. 相似文献
16.
Recruitment and growth of the sardineSardinops melanostictus fluctuated markedly in the Sea of Japan and adjacent waters between 1978 and 1993. Stock size was calculated using Virtual
Population Analysis and average body length in each age class was determined by the number of annual rings on the scales.
There is an inverse correlation between average water temperature at a depth of 50 m in the coastal area of the mainland of
Japan in winter (January to March) and recruitmentR defined as the number of individuals at 1 year old. There is also an inverse correlation between spawning stock sizeE and reproductive success in (R/E). A multiple regression model using spawning stock size and water temperature in winter as independent variables can explain
73% of variance in reproductive success. It suggests that both density-dependent and density-independent factors perform important
roles determining reproductive success. There is an inverse correlation between body length and stock size and this suggests
that there is a density-dependent effect on the growth of the sardine. 相似文献
17.
Body masses of wild-caught habu,Trimeresurus flavoviridis, were measured with known error range. Habu larger than mature female size had steeper slope in length-mass regression than
smaller individuals. Females outweighed males in most snout-ventlength classes and in early summer. Gravid females outweighed
non-gravid ones by about 20% on the average, but the body mass ranges of the two groups overlapped. Through the body mass
change in mature females, the proportion of gravid females was estimated to be about 0.5. 相似文献
18.
Tock H. Chua 《Researches on Population Ecology》1992,34(2):285-292
Summary The effect of body size, as measured by the head width, of the femaleBactrocera sp. Malaysian A (kept separately in sexual pairs) on the demographic parameters was investigated in the laboratory under
ambient conditions of 28–30°C, 78–85% RH and natural photoperiod. Body size was shown to influence significantly all the demographic
parameters. The expectation of life of females at eclosion from pupae was respectively for head widths of 1.6, 1.8, 1.9, 2.0
and 2.1 mm: 76.2, 73.4, 73.8, 102.4 and 115.2 days. The mean number of eggs laid per female in its life time was respectively:
86.4±48.7, 181.8±56.1, 229.7±72.6, 364.3±69.4 and 477.5±109.3 which was significantly different from one another (F=3.73,P<0.05) especially the two smaller sizes from the two larger sizes. The regression line for total eggs laid (Y) against head width (X) wasY=785.2X−1208.7 (R
2=0.35,P<0.001). The net reproductive rate (R
0) was respectively 15.8, 34.0, 43.5, 66.9 and 88.8 eggs, while the intrinsic rate of increase (r) was respectivley 0.0435, 0.0538, 0.0670, 0.0665 and 0.0711. The results confirm that for mass rearing purposes, larger females
which produce more offspring are to be preferred. 相似文献
19.
In May 1971, 45 adults of an herbivorous lady beetleEpilachna niponica (Coleoptera: Coccinellidae) from Asiu Experimental Forest were introduced into a botanical garden of Kyoto University, where
is 10 km south of the southern limits of its distribution with being 3–5°C warmer than the original site. The introduced population
of the lady beetle was thus investigated from 1975 to 1981. Mark-release-recapture experiments were applied to individual
adult beetles, to estimate population size and daily survival rate. Overwintering adults emerged from hibernation around early
April, reaching peak numbers in late April to early May, then gradually declined to late June. No adults remained at the end
of June. Adult survival was maintained at a high level to early May, and declined consistently until late in the reproductive
season. New adults began to emerge in late June and quickly reached a peak in early July; thereafter they decreased in number
and had entered hibernation by late October. In spite of seasonally deteriorating food resources and heat stress in summer,
new adults showed moderately high survival during the inimical period. New adults which emerged later in the season tended
to be smaller in body size than those that emerged early. The proportion of females in the new adult population gradually
increased throughout the pre-hibernating period, suggesting that male-biased mortality occurred during this period. When compared
to the source population, the introduced population had a higher rate of population growth. Coupled with the improved population
growth, heavy leaf damage during the larval period suggested that intensive intraspecific competition was most likely to occur
among larvae in the introduced population. 相似文献
20.
Tadashi Miyashita 《Researches on Population Ecology》1992,34(1):143-153
Summary Field studies were conducted to clarify whether variation in food availability among habitats influences population density,
and whether population density has a negative effect on foraging success in the orb-web spider,Nephila clavata.
Lifetime food consumption per individual (i.e., foraging success) strongly correlated with mean body size of adult females
and mean fecundity in populations. Also, there was a positive correlation between foraging success and population density.
Since foraging success reflected potential prey availability in the habitat, food resource appeared to be a limiting factor
for populations in this spider. Mean fecundity per individual correlated with population density of the following year, suggesting
that decreased reproduction is a major component of food limitation on population density. Consistent defferences in mean
body size between particular sites were observed over years, while such difference was less obvious in density. Thus, ranking
of food abundance among habitats seems to be predictable between years. A field experiment revealed that an artificial increase
in population density had no negative effect on the feeding rate of individuals, suggesting that intraspecific competition
for food is not important in this species. 相似文献