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1.
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
2.
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
3.
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
4.
Summary Male and female prairie deermice housed singly from weaning (21 days) until 40 days of age had urine from one of the following
sources applied daily to their nostrils: sexually mature laboratory population males or females, and sexually mature breeder
males or females from our laboratory colony. Other males and females were treated with water. Records were obtained of the
weights of the tests, seminal vesicles and bacula of males and the ovaries and uteri of females at 40 days of age.
The major results of this study were as follow: Female urine from sexually mature and inhibited population or isolated mice
stimulated the development of the male reproductive organs significantly more than water or male urine. Male urine applied
to young males did not differentially affect the weights of their reproductive organs compared with water and thus showed
no inhibition effects.
The reproductive organs of females treated with male urine did not differ significantly in weight from those of females treated
with female urine. Females treated with water developed significantly larger uteri than those treated with urine from sexually
mature population females (P≤0.02), inhibited population females (P<0.001) and inhibited population males (P<0.007). 相似文献
5.
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
6.
Yasuyuki Ishibashi Takashi Saitoh Syuiti Abe Michihiro C. Yoshida 《Researches on Population Ecology》1998,40(1):51-59
Kinship amongClethrionomys rufocanus was investigated during the winter of 1992/93 in a 3-ha enclosure using both molecular and catch-mark-release techniques.
Forty-six adult voles (22 males and 24 females) having high heterozygosities, which were collected from several natural populations,
were released into the enclosure on 29 September 1992. Most fall-born individuals of both sexes stayed in their natal site
during the non-breeding period (December–March), although reproductively active females dispersed during the fall breeding
season (October–November). These philopatric individuals aggregated and formed an maternal family in the winter. Several females
which failed to reproduce were solitary during this season. Some individuals which were derived from several families also
aggregated into a mixed lineage group. Survival rate of fall-born voles from earlier litters was higher than that from later
ones. Maternal families broke up soon after the onset of spring reproduction. Most females established a territory near the
wintering site and made a kincluster, in which close relatives neighbored each other. Maternal families in winter bring about
female kin-clusters in spring, which may influence reproductive output in the breeding season. 相似文献
7.
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
8.
Ei'ichi Shibata 《Researches on Population Ecology》1986,28(2):253-266
Summary Adult populations of the sugi bark borer,Semanotus japonicus
Lacordaire, which attacks the trunks of Japanese cedar and cypress, were studied in two cedar stands in 1981 and 1984, using a band-trapping
method developed by the author.
Adults began to emerge and fly earlier in 1981 than in 1984 because of the higher temperature after hibernation in 1981. Population
size wasestimated by a markrelease-recapture method. The daily survival rate ranged from 0.86 to 0.92 and the mean longevity
from 7.0 to 11.9 days. Females were fewer than males throughout the season, especially early in the flight period, because
males consistently emerged earlier. The mean distances traversed among the cedar trees were 9.2 m for males and 16.3 m for
females; maximum dispersal was 79.5 m for males, 149.5 m for females. There are two different patterns in their dispersal
movement: the small-scale movement which consists of walking at cool temperatures and large-scale flight at warm temperatures.
Adults of this species are somewhat sluggish and between-tree movement is infrequent. This lack of movement resulted in a
contagious distribution pattern of adults. 相似文献
9.
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
10.
Takayoshi Nishida 《Researches on Population Ecology》1989,31(2):211-224
Summary The mating system of the coreid bug,Colpula lativentris, was studied, and compared with those in other hemipteran bugs. Copulating pairs formed a compact aggregation on a shoot
of the Japanese knotweed,Polygonum cuspidatum, and there continued copulation and feeding for more than one day. This aggregation was defined as “a shoot aggregation”.
Other than this aggregation composed of copulating pairs, there were loose aggregations on the ground composed of males and
females not in copula. This loose aggregation was defined as “a ground aggregation”. Males searched for receptive females
mostly in a ground aggregation.
Sex ratio was constant and variance of sex ratio was also very small in any shoot aggregations and in large ground aggregations.
However, in small ground aggregations, sex ratio was strongly male biased and variance of sex ratio was fairly large. This
was because receptive females tended to leave a small ground aggregation and join a large one. These results suggest that
a male can attain higher mating success in a larger ground aggregation. 相似文献
11.
We examined the age structure and sex ratio of a viperid snake,Trimeresurus flavoviridis, based on samples collected by hand by local inhabitants, habu hunters and by baited traps in the middle and south of Okinawa
Island, Japan. Small individuals had a low possibility of capture in all the collecting methods. The age structure was estimated
through summing up the age frequency in each snout-vent length (SVL) class in samples with a similar SVL structure. From the
age structures, annual survival rates of adult females and males were estimated to be 0.7 and 0.8, respectively. In most samples
the sex ratio was biased towards males, especially in March and August and in large individuals. However, the female proportion
increased in June. 相似文献
12.
Summary Let us consider a strip-wise habitat of line-segment, like a corridor, to simplify the subject mathematically, and assume
that the length of the habitat is γ and there aren individuals. Here, we assume that the spatial pattern of the individuals is random if then distances from the left end of the habitat to each individual follow a uniform distribution on the strip. Under such an assumption,
the variance of the distances between any two neighbors is represented by the formulanθ
2(n+1)−2(n+2)−1 and the variance betweenn+1 distances betweenn individuals from the left end to the right end to the strip, is represented by the formulanθ
2(n+1)−2(n+2)−1. These two kinds of variances can be used for determining (1) the spatial pattern of a population on the strip and (2) the
spatial structure within the population, by comparison with the variances calculated from the data. Two examples cited from
the literature, a cattle population on a pasture and an aphid population on a sycamore leaf, are presented. 相似文献
13.
InMenida scotti aduts which mate during hibernation, we examined the effect of photoperiod on diapause induction in terms of the developmental
degree of reproductive organs and corpora allata. In a hibernating population, mating season and physiological changes related
to dipause were investigated. When newly emerged adults were reared under long- or short-day conditions, reservoir of the
ectodermal accessory gland and corpora allata in males developed, while the developments of ovary and corpora allata in females
were suppressed under both conditions. This suggests that diapause of this species is induced only in females independently
photoperiodic conditions during adult stage. In a hibernating population, mating was observed from early to late November
and from late March to early May. Observations of the development of reproductive organs and corpora allata suggest that diapause
is induced only in females in the former period, while both sexes are not in diapause in the latter period. 相似文献
14.
Takaki Kondo 《Researches on Population Ecology》1982,24(1):85-96
Summary The role of social behavior on the population regulation of the Japanese wood mouse,Apodemus speciosus, was studied in the Ashu Experimental Forest of Kyoto University by monthly trapping and direct observation on the social
behavior at the artificial feeding site. The census was carried out from May to October in 1974 and 1975, and the direct observation
in June, August and October, 1975.
In the study area, the Japanese wood mouse has two breeding seasons in a year: in spring and in autumn. Minimum survival rate
was high in the non-breeding season and low in the breeding season. It was negatively correlated to the number of sexually
active adults in both sexes.
Home ranges of females tended to be mutually exclusive, and female residents prevented the settlement of female immigrants.
On the other hand, home ranges of males overlapped largely and males had a straight social hierarchy. Subordinate males tended
to disappear more often than dominant males did, but male residents did not hinder the settlement of male immigrants. Males
may regulate their number by driving out the subordinate males, while females by spacing behavior.
Contribution from the Laboratory of Animal Ecology, Department of Zoology, Kyoto University, No. 445. 相似文献
15.
Summary Effects of starvation on the suryival period and the respiratory rate in adults of a wolf spider,Pardosa astrigera (L. Koch), were investigated. The spiders used were divided into four groups: well-fed, starved and two limited food groups; in the
latter two, each spider was supplied with one leafhopper every second or third day. Adult males and females ofP. astrigera could survive for a long time; 28.8±2.7 days and 54.4±18.9 days, respectively, without any food. The longevities shown here
were 73.8% for males and 78.6% for females of those of well-fed spiders, indicating thatP. astrigera adults have a strong tolerance to starvation. The respiratory rate of well-fed adults showed no tendency to increase or decrease
with their aging; the mean respiratory rates were 4.86×10−4 mg CO2/mg f.w. (fresh body weight)/hr for males and 3.80×10−4 mg CO2/mg f.w./hr for females. The respiratory rates of starved spiders increased during the first two days of starvation but decreased
markedly from the third to the twelfth day, and thereafter retained an almost constant level for each sex. The mean respiratory
rates after the twelfth day of starvation were 2.49×10−4 mg CO2/mg f.w./hr for males and 2.76×10−4 mg CO2/mg f.w./hr for females; these values were respectively 48.4% and 63.0% of those prior to starvation. The fresh body weight
of starved spiders decreased linearly with time but the rate was small. The respiratory rates of the limited food groups tended
to decline with time and thereby their weight losses were minimized. The decrease in the respiratory rate under starvation
was considered not to be due to spider exhaustion or senescence but due to an intrinsic change in behaviour and/or metabolism,
because when the spiders were supplied with ample food for five days after starvation, the respiratory rate and the body weight
rapidly recovered to near the levels prior to starvation. It is suggested that starved spiders use a higher ratio of fat as
catabolic substrate than normally fed or satiated ones. Feeding strategies of poikilo-therm predators are discussed.
This work was partially supported by the Nippon Life Insurance Foundation Research Fund and Grant-in-Aid (No. 56480039) from
the Ministry of Education, Science and Culture, Japan. 相似文献
16.
We examined the female-biased sex ratio of a trap-nesting wasp Trypoxylon malaisei considering the following factors: (1) local mate competition (LMC), (2) resource quality, (3) partial bivoltinism, and (4)
presence of constrained females. The sex ratio (expressed as male ratio) at emergence was strongly female biased, i.e., 0.30
and 0.19, in terms of the number and investment, respectively. To evaluate the primary sex ratio, we analyzed the data from
nests where all the offspring successfully emerged, excluding nests composed of single-sex offspring. The primary sex ratio
was also female biased, at 0.33 and 0.21, in terms of the number and investment, respectively. LMC was highly responsible
for the female-biased sex ratio because both the nonrandom oviposition sequence [females at inner cells and male(s) at outer
cells] and earlier emergence of males allowed sib-matings to occur. In contrast, the other three factors little affected the
female-biased sex ratio: the sex ratio was fairly constant when resource quality (nest size) varied, partial bivoltinism was
extremely rare or absent, and constrained females were absent or did not reproduce at all.
Received: June 19, 1998 / Accepted: January 18, 1999 相似文献
17.
Koh-ichi Takakura 《Researches on Population Ecology》1999,41(3):269-273
Mating behavior and the male's contribution to female fecundity were studied in the bean weevil Bruchidius dorsalis (Fahraeus) (Coleoptera: Bruchidae) in comparison with two other species, Callosobruchus chinensis (which infests stored beans) and Kytorhinus sharpianus (which feeds on wild legumes). Only females of B. dorsalis showed multiple mating and characteristic precopulatory behavior that appeared to solicit the male's nutritious secretion.
In contrast, all females of the other two species did not copulate multiply and did not show such precopulatory behavior.
In B. dorsalis, the decrement of male body weight just after copulation indicated that seminal fluid weighing as much as approximately 7%
of the male's body weight was transferred to the female. Fecundity was more than eight times higher in females that had copulated
ten times than in females that had copulated only once, indicating that males paid most of the nutritional cost of egg production.
These facts suggest that the sex role is reversed in B. dorsalis.
Received: May 22, 1998 / Accepted: July 19, 1999 相似文献
18.
Adult, male white-footed mice (Peromyscus leucopus) were subjected to a variety of social situations ranging from isolation during the 20 day experimental period to constant
contact with both females and other adult males. Contacts included grouping (three or four males per cage) and exposure to
fighters (once daily for 20 minutes). The following measurements were recorded: weights of the body, testes, epididymides,
vesicular glands, vesicular gland tissue (wet and dry), seminal fluid of the vesicular gland, adrenal glands, and baculum;
spermatozoan reserves of the testes and epididymides. Grouping significantly affected both the weight and spermatozoan reserves
of the testes and epididymides, as well as both the tissue and seminal fluid weight of the vesicular glands. The results suggested
a graded effect of all treatments on the reproductive tract. In order of magnitude of the associated response, from none to
greatest, the treatments may be ranked as follows: pairing with females, isolating, handling, fighting, and grouping. All
reproductive parameters measured showed this general ranking, suggesting that the response to the various treatments was similar
and differed only quantitatively. The results further suggested decreased secretion of LH and testosterone, although measurements
of testosterone did not substantiate this conclusion. The lack of significant effects of grouping on adrenal gland weights
strengthened the argument that adrenal involvement is not a necessary adjunct to the suppression of the reproductive tract
in groupedPeromyscus, but the adrenal may be involved if contacts between males result in overt fighting. 相似文献
19.
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
20.
Kazuyuki Fujita Koji Hirano Michiharu Kawanishi Naota Ohsaki Makoto Ohtaishi Eizi Yano Makoto Yasuda 《Researches on Population Ecology》1978,19(2):209-221
Summary Adult population of a dragonflyNannophya pygmaea
Ramber inhabited in a damp ground was investigated with mark-and-recapture method in 1975. The following results about the seasonal
changes of the population size and distribution in the habitat were obtained.
Adults emerged from late May to mid August. The number of the adults was most abundant in early June, but that of matured
males in early July. From the recapture data, the estimate of daily survival rate was 0.82, and the length of immature stage
in males was estimated as 5 days or so. Total number of post-teneral adults emerged in the habitat was estimated as about
9,000. The mean crowding-mean density regression method was applied for the analysis of the distribution pattern of the adults.
Matured males showed a spaced-out distribution, while females and immatured males distributed themselves rather aggregatively.
Such a distribution pattern of the matured male would be attributed to their territorial behaviour. The territorial behaviour
was considered to force the matured males to extend the distribution area in July when they were most abundant.
From the above-mentioned results and some observations, the meaning of the territoriality in this species was discussed. 相似文献