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1.
Ei''ichi Shibata 《Researches on Population Ecology》1995,37(2):229-237
The inner bark of Japanese cedar,Cryptomeria japonica D. Don., is the main food of the sugi bark borer,Semanotus japonicus Lacordaire, but may also be involved in resistance to attack by the borer. I used newly hatched larvae to inoculate cedar
logs that had been cut 2-weeks to 12-months earlier, and undamaged living cedar trees. On living trees, all larvae were killed
by resin flow from the traumatic resin canals between the outer- and inner bark or between the inner bark and cambium. In
logs that were cut more than 4 months prior to inoculation, larvae were unable to complete development. In logs cut 2 weeks
prior to inoculation, almost all larvae were able to reach the adult stage but they were smaller in size than adults from
living trees damaged by this borer. These results suggest that poor nutrient conditions in the inner bark of logs affected
development and survival of the borer. Because of its nutritional advantage, living cedars provide a better environment for
the sugi bark borer. However, all larvae are killed by resin flow, suggesting that this insect is “in between” being primary
and secondary with respect to living trees, or a “weak” primary insect. The sugi bark borer seems to develop early in the
season so that early instar larvae encounter reduced amounts of resin flow and so that late-instar larvae feed mostly in summer
when nutrient levels in the inner bark are at their highest. 相似文献
2.
Koji Tsuchida 《Researches on Population Ecology》1991,33(2):361-366
Summary Females in hibernation site (FH) were significantly larger than foundresses (FO), suggesting that larger FH were less successful
in founding their nest. Body size of FO did not correlate with two nest characters, i.e., the number of cells at pupal stage
(CP) and the timing of nest foundation (DP). However, CP negatively correlated with DP in 2 of 3 studied years, suggesting
that foundress who founded her nest earlier than others tended to construct larger number of cells irrespective of her body
size. 相似文献
3.
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
4.
Reproductive success, copulation success, and mating success were measured for a population of male dragonflies,Orthetrum japonicum. Copulation success explained the greatest variation in reproductive success. The proportion of copulations followed by oviposition
was positively correlated with the number of oviposited eggs per mating. Directional selection on four morphological characters
was estimated. The effect of selection on correlated traits was comparable to that of direct selection. Directional selection
varied between traits and between episodes in a single trait. The probability that the observed directional selection on the
four morphological traits was expected under the condition of the selective neutrality of traits was not smaller than 5%. 相似文献
5.
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
6.
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
7.
Yoichi Shirai 《Researches on Population Ecology》1995,37(2):269-277
Plutella xylostella in the temperate zone shows a clear seasonal change in adult body size. In the laboratory, large and small moths were produced
during immature stages at 15°C and 25°C, respectively. These moths were then used to evaluate longevity, age-specific flight
ability, flight ability of mated and unmated females, and the influence of flight experience on the subsequent reproductive
success. The large moths lived longer and displayed a greater flight ability over 3 weeks. Irrespective of body size, unmated
females flew for a longer time than mated females, and flight experience affected their subsequent reproductive success. Females
of both sizes mated and laid eggs soon after emergence, without any obvious pre-reproductive period. More flight experience
did not delay oviposition, but did reduce egg production. It is likely that large moths with a longer adult life span and
greater flight ability are better fitted for long-distance flight and more fecund than small ones. These experimental results
may explain why long-distance migration ofP. xylostella is mostly seen during cool seasons, when relatively large moths with long forewing appear in the field. 相似文献
8.
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
9.
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
10.
Summary Functional responses of the wolf spider,Pardosa pseudoannulata (Boesenberg et Strand) attacking the rice brown planthopper,Nilaparvata lugens (St?l.), and the mirid predatorCyrtorhinus lividipennis Reuter were both those of Holling Type II. The attack rate was higher and handling time lower forC. lividipennis. However, when caged with the two prey, the wolf spider showed a significant preference forN. lugens at a lower prey proportion. Proportions of prey attacked were significantly different from the expected ratios of prey available
as well as from the predicted preferences derived from the functional response parameters. As proportions ofN. lugens attacked changed from greater to less than expected as the proportions ofN. lugens available increased, a “reverse switch” behaviour seems to be evident. 相似文献
11.
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
12.
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
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.
Summary We performed multiple-generation competition experiments betweenCallosobruchus analis andC. phaseoli with different bean sizes. In each system, we supplied 5 g of mung beans (Vigna radiata) every 10 days. We examined three types of bean conditions: 5 g of large beans, 5 g of small beans, and a mixture of 2.5
g of large and small beans. In small bean condition,C. analis dominatedC. phaseoli in all three replicates andC. phaseoli was extinct by the 260th day. On the contrary,C. phaseoli overcameC. analis within 250 days in large beans in all three replicates. In mixed beans condition the two bruchid species coexisted more than
500 days in two out of the three replicates. Even in the exceptional case, both species coexisted for 460 days. These results
were examined in the light of the predictions from short-term larval competition experiments and a game theoretical model
by Smith and Lessells (1985). The density and frequency dependent results during larval competition inside a bean was concluded
to be a main factor to produce the above long-term competition results. 相似文献
15.
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
16.
Katsumi Togashi 《Researches on Population Ecology》1991,33(2):245-256
Summary To understand the mechanism of spread of pine wilt disease caused by the pinewood nematode,Bursaphelenchus xylophilus, which is vectored by a cerambycid,Monochamus alternatus, the spatial distribution of trees weakened by the nematode was examined within aPinus thunbergii stand from June to October for 4 years. The weakened trees were distributed in a clumped pattern in 1980 and 1981, at an
early stage of infestation. In many cases, they showed a double-clumped pattern. The degree of aggregation was higher in June
or July than after August. They were uniformly distributed in June or July 1982 and in June 1983 whereas they showed a double-clumped
pattern after August. The trees were frequently weakened in June or July when they were near the trees weakened during the
previous year. At quadrat sizes of more than 25 m2, spatial overlapping was pronounced between trees weakened during June–July of the current year and those weakened in the
previous year. The seasonal changes in spatial distribution of weakened trees were explained by the interaction amongM. alternatus, B. xylophilus andPinus trees. 相似文献
17.
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
18.
Summary We studied the interpecific competition between 2 species of predatory aquatic bugs,Diplonychus japonicus andD. major by conducting a field experiment. We set up 3 types of experimental plots in the paddy fields whereD. major predominated. The two plots contained single species of eitherD. japonicus orD. major, respectively, and one plot had both species in equal number. We compared the development and the reproductive performance
between plots in each species.
InD. japonicus, the number of eggs and early instar nymphs were significantly smaller in the plots containing both species than in the monospecific
plots. However, the numbers of late instar nymphs and newly emerged adults were not significantly different between plots.
The proportions of starved nymphs in both plots were larger than those in theD. japonicus's natural habitats. The final densities of adults in both plots were lower than those in the natural habitats. These results
suggest that lower density ofD. japonicus in these paddy fields is due to the lack of available food for nymphs rather than the effects of interspecific competition
withD. major.
InD. major, significant differences were not found in the number of eggs, each instar nymphs and adults. These results suggest that
the effects of interspecific competition did not affect the reproductive performance ofD. major. 相似文献
19.
Toshiya Masumoto Shintaro Nomakuchi Kouji Sawada 《Researches on Population Ecology》1993,35(2):241-250
Summary We investigated how the distribution pattern of eggs and larval on the host plant,Turritus glabra, was influenced by the oviposition behavior of the pierid butterflyAnthocharis scolymus. Females searched for the host plants visually and they frequently approached taller host plants with sparse surrounding
vegetation. After encountering host plants, oviposition behavior of females was independent of host plant characteristics
such as height, density, and type of surrounding vegetation. A female laid eggs singly on a host plants. Most females appeared
to lay their eggs regardless of the presense of eggs on the host plant. Consequently egg and larva tended to be abundant on
conspicuous host plants as measured by height or relative isolation from other plants. However, overcrowding of eggs on an
individual host decreased the survival rate of larvae. 相似文献
20.
Preference and performance linkage in aPhyllocolpa sawfly on the willow,Salix miyabeana, on Hokkaido
A leaf-folding sawfly in the genusPhyllocolpa (Hymenoptera: Tenthredinidae) attackingSalix miyabeana (Salicaceae) was studied near Sapporo, Hokkaido, along the Ishikari River in 1993. Host plant individuals were young trees
4–7 years old which were growing rapidly, producing some long shoots with large leaves. On a gradient of shoot length classes
from 0–5 cm long to over 80 cm long, shoots were much more abundant in the shorter shoot length classes. However, attacks
by ovipositing females increased as shoot length increase from 0 attacks on the shortest shoots to 5.17 attacks per shoot
on the longest shoots. The frequency of attack per leaf increased from 0 to 0.13 over the same range of shoot lengths. This
pattern of attack resulted in a high frequency of larval establishment in feeding sites, between 0.96 and 1.00, in all attacked
shoot length categories. However, probability of survival to a late instar larva increased with shoot length and corresponded
to the attack pattern, indicating a preference-performance linkage between female ovipositional decisions and larval survival.
The patterns found for thisPhyllocolpa species are similar for galling sawflies in North America and Europe, especially in the genusEuura, members of which make stem, bud and leaf midrib galls. Extending the pattern to aPhyllocolpa species broadens identification of pattern and ultimately the generality of the emerging theory on populations of galling
sawflies. 相似文献