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1.
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
2.
Summary Significantly more females reared on bedding soiled by different populations reproduced by 100 days of age than those reared
on bedding soiled by the same populations (P<.1) or on clean bedding (P<.025) whereas the latter two groups did not differ significantly. Significantly greater percentages of females reproduced
in both treatments maintained on soiled bedding than was true in the populations from which the bedding came. There were no
significant differences between treatments in the weights of the reproductive organs (testes, seminal vesicles, ovaries, uteri)
or in the numbers of corpora lutea or mature follicles in the ovaries of nulliparous females. The data suggest that if there
were reproductively inhibiting pheromones influencing the population animals, they were altered or dissipated immediately
after removal of the bedding from the population enclosures or that they were nonfunctional in the absence of the population
animals. These data further suggest that the reproductive inhibition of population young is due to the presence of the populaton
animals and that sociobiological factors within the populations act to prevent the reproductively stimulating influence of
materials which may be present. 相似文献
3.
Summary Female deermice housed from weaning with groups of five females, five males or five males plus five females had significantly
smaller uteri at 35–38 days of age compared to females reared alone. The uterine weights of females reared in the three grouped
treatments did not differ significantly among themselves nor did those reared alone or with another animal of either sex.
Uterine and ovary weights revealed no significant inhibition or stimulation of sexual maturation dependent upon sex of the
adult conspecific with which young females were housed. The number of conspecifics (five or more of either sex) housed with
young females was of primary importance in the retardation of uterine development observed. 相似文献
4.
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
5.
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
6.
Seiji Arakaki Kazunori Yamahira Mutsunori Tokeshi 《Researches on Population Ecology》1999,41(3):235-242
The patterns of sex change and spatial distribution in an intertidal holothurian, Polycheira rufescens (Chiridotidae; Echinodermata), were investigated on a stony beach in Amakusa, western Kyushu. Field caging experiments revealed
that some individuals of P. rufescens underwent a sequential sex change from male to female via hermaphrodite stages and back to male again within a single reproductive
season. The sex ratio of the population gradually changed from male dominance at first to equal proportions of males and females
as the reproductive season progressed. Toward the end of the reproductive season, immature or spent individuals increased
in proportion. Stone size appeared to be an important factor affecting the occurrence of P. rufescens individuals on a stony beach. Analysis of spatial distribution by means of Morisita's index of dispersion and nearest neighbor
distances indicated that (i) males showed a slightly stronger tendency to aggregate than females, while females had a tendency
toward uniform distribution; (ii) females tended to attract males, as shown by relatively short female-to-male distances;
and (iii) there was a substantial variation in male-to-female distances, such that some males were positioned close to females
while others were not. It may be suggested that spatial distribution of P. rufescens individuals during the reproductive period is partly dictated by the differential needs of individuals of different sexual
states.
Received: January 25, 1999 / Accepted: June 10, 1999 相似文献
7.
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
8.
Yutaka Sait 《Researches on Population Ecology》1987,29(1):57-71
Summary Experimental observations on the arrenotokous reproductive patterns of two spider mite species (Acari: Tetranychidae), the
long-seta form ofSchizotetranychus celarius (Banks) andTetranychus urticae
Koch, revealed that reproduction of unfertilized females of the former is very differnt from that of the latter. Unfertilized
females ofS. celarius, which has a subsocial life, laid a few eggs and then became inactive. In contrast, the fecundity of unfertilizedT. urticae females was only slightly reduced as compared with fertilized females. Mother-son matings may thus sometimes occur in naturalS. celarius populations.
A two-year field survey revealed that, in the absence of males, overwintering females ofS. celarius occasionally remain unfertilized until early spring. Furthermore, nest foundation observed in late spring indicated that
most of the season's first nests were founded by single females. These two sets of observations strongly suggest that motherson
mating takes places in nature, corresponding to the reproductive trait seen in the experiment.
Mother-son mating inevitably increases the relatedness between nest members. The estimated father's relatedness to its offspring
is extraordinarily high under such condition. The possibility that kin-selection in the long seta-form ofS. celarius led to subsociality, especially paternal care, is suggested.
This study was supported in part by Grant-in-Aid No. 61540468 from the Ministry of Education, Science and Culture, Japan. 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.
Masami Hasegawa 《Researches on Population Ecology》1990,32(1):119-133
Summary The demography of the lizardEumeces okadae was studied for 4 years on Miyake-jima, in the Izu Islands, central Japan. Most males matured at 3 years of age with a mean
snout-vent length of 77.5 mm. Females matured at 3–4 years with a mean SVL of 77.8 mm, and reproduced biennially thereafter.
Growth continued after maturity with a decreasing rate. In females, annual growth was negligible in reproductive years, but
resumed markedly in non-reproductive years. Clutch size increased with SVL and was used to construct a fecundity schedule.
Population density (exclusive of hatchlings) was estimated to be ca. 4000 individuals/ha in August, an exceptionally high
density for lizards. Before introduction of the weasel onto Miyake-jima, low predation pressure had allowedE. okadae to maintain a high population density. Estimated annual survival rates were 36% for hatchlings, 56% for yearlings, 80% for
2-year-olds, 63% for adult males and 76% for adult females. The cohort generation time (6.95 years) was so long that theE. okadae population can be characterized by a combination of low natality and slow turnover. 相似文献
11.
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
12.
Koichi Tanaka 《Researches on Population Ecology》1995,37(2):197-202
Within a population of the web-building spiderAgelena limbata, the weight of the first instar nymphs ranged from 1.187 to 6.559 mg. Both intraclutch and interclutch variation were recorded.
The mean weights were different among clutches and the coefficients of variation within a clutch ranged from 3.3 to 29.2%.
Variation in the nymphal weight was certainly derived from variation in the egg weight because there was a high correlation
between the two weights. Factors affecting interclutch variation in nymphal weight were examined by multiple regression analysis.
Nymphal weight was positively correlated with the body size and food conditions of female parents, and negatively correlated
with the clutch size. Among these three factors, the food conditions of female parents had the largest apparent effect on
the interclutch variation. The results suggest that females with larger body size and more food produce larger offspring,
and that there is a trade-off between offspring size and clutch size. Heavier nymphs had larger body size (carapace width)
and may have larger energy reserves. Heavier nymphs survived experimental starvation for a significantly longer period. 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.
Tamito Sakurai 《Researches on Population Ecology》1998,40(1):167-172
This study examines the relationship between the number of sperm in the seminal receptacle (spermatheca) and the receptivity
of female remating in the bean bugRiptortus clavatus Thunberg. On the 21 st day after the first mating when receptivity to remating was > 70%, females receptive to remating had
significantly fewer sperm ( < 40 on average) in the spermathecae than females reluctant to do (about 150 on average). However,
averages of the number of eggs laid by receptive and reluctant females within 21 days were almost same. The proportion of
fertilized eggs for receptive females at 15–21 days after copulation was significantly lower than that for reluctant females.
Spermatozoa transferred from a male to a female’s spermatheca were detected 5 min after copulation and then increased continuously
to about 500 with the first hour. When copulation durations were manipulated artificially, the shorter the copulation period
(=females had less sperm in their spermathecae), the higher the remating rate became. Females may perceive the number of sperm
in their seminal receptacles and then determine whether they copulate or not. These results support the hypothesis that females
mate multiply in order to replenish inadequate sperm supplies to fertilize all eggs produced. 相似文献
16.
Yozo Koshiyama Hisaaki Tsumuki Kenji Fujisaki Fusao Nakasuji 《Researches on Population Ecology》1996,38(1):51-56
Menida scotti (Puton) males have been shown to transfer secretions from their bulbus ejaculatorius and reservoir of ectodermal accessory
gland to females by mating during hibernation. In the present study, the major components of the secretions were found to
be proteins and lipids. To specify the female organ incorporating the male secretions, a radiotracer experiment in which the
male secretions were labeled by [14C]valine was conducted in nine tissues of females collected in the fall and spring of the hibernation period. Relatively high
radioactivities were detected in the haemolymph and the residual carcass (head, legs, air-sacs, exoskeleton, etc.) in the
fall females, and in CO2 gas evolved and carcasses in the spring females. The radioactivities in the fat body were significantly higher in the fall
mating females than in the spring mating females, and vice versa in the ovary. The radioactivities in six fractions (lipids,
proteins, glycogen, sugars, free amino acids and the residues) were also assayed in the five organs of females that had a
relatively high radioactivity. The highest radioactivity was detected in the protein fraction of the haemolymph in fall and
spring females. There were significant differences in the radioactivities incorporated into the lipid fractions of the carcass
between fall and spring females. 相似文献
17.
Summary Individual differences in several reproductive parameters of femalePieris rapae were investigated in a controlled laboratory condition. Lifetime and age-specific fecundity showed considerable variability
between individuals. Larger females began oviposition at an earlier age than smaller ones, and larger females were more fecund
than smaller ones. Larger females laid a larger proportion of their eggs in the early stages of their reproductive lifetime,
whilst smaller females laid the larger proportion of their eggs later in their reproductive lifetime. The significance of
the variance in age-specific fecundity associated with female size is discussed with respect to the seasonal change in size
and habitat utilization of this species. 相似文献
18.
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
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.
Reproductive behavior of the foam-nesting treefrog,Rhacophorus arboreus, is described. Oviposition was made either by an amplectant pair (a female, and an amplectant male) alone or by an amplectant
pair and other males (joiners). The snout-vent length of males and females was negatively correlated with the date of the
first appearance in the pond. The period of staying in the pond in males was longer than that in females. Physical body contacts
of other males, and encounter calls by ampletant males were frequently observed before oviposition with joiners. Snout-vent
length of the female and an amplectant male were positively correlated. Encounter calls by amplectant males were likely to
precede movement of females. There was no difference of snout-vent length between amplectant males and joiners. Females moved
the hindlimbs more frequently than males during oviposition. Amplectant males made encounter cells more frequently in oviposition
with joiners, than oviposition without joiners. The patterns of transitions between acts of females and amplectant males were
similar between oviposition with and without joiners. Females more frequently responded to amplectant males than joiners.
Both the duration of a bout of the movements of hindlimbs of females and the interval between the bouts were longer in oviposition
without joiners than that with joiners. The number of the movements per bout in oviposition without joiners was smaller than
that with joiners. Encounter calls by amplectant males during oviposition tended to precede the hindlimb movements of females. 相似文献