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1.
The deme formation hypothesis in herbivorous insects states that herbivores differentiate genetically into small demes, each
specialized in the idiosyncratic traits of individual plants. We examined this hypothesis in gall-forming aphids,Adelges japonicus, by reciprocal transfers of aphids among three susceptible clones ofPicea jezoensis standing in proximity. Performance of aphids transferred to their natal clone was compared with that of aphids transferred
to other novel clones. ANCOVA showed no significant donor (source of aphids) by receptor (recipient of aphids) interactions
for both total aphid performance on the host tree over a life cycle and its three subdivisions(q
1,q
2 andq
3). In addition, the total performance on the natal clone was lowest among those in the three clones, which was explicitly
against the prediction from the local adaptation. In contrast, there were significant receptor effects onq
1 (fecundity of gallicolae multiplied by survivorship of fundatrices while feeding on needles) andq
3 (fecundity of fundatrices multiplied by survivorship of gallicolae before emergence from the galls), suggesting genetic differences
in resistance among clones. The two-fold difference inq
3 among clones was due to different gall size, which was highly correlated with the number of gallicolae that emerged from
the gall. The two-fold difference inq
1 seemed to be caused by different survivorship of larval fundatrices while feeding on needles. 相似文献
2.
Following four hypotheses on the production of soldiers were tested in thePheidole fervida colonies collected in the natural field:
The present test suggested that the last idea was most likely to the wild colonies ofP. fervida. 相似文献
1. | The proportion of new soldiers is primarily dependent on the population size of old workers. |
2. | The abundance of old soldiers reduces the proportion of new soldiers. |
3. | The production of sexuals reduces the proportion of new soldiers. |
4. | The number of soldiers is correlated with the size of defense zone. |
3.
Harunobu Shibao 《Researches on Population Ecology》1998,40(3):325-333
A complete understanding of the evolution of sociality in aphids requires a detailed knowledge of the patterns of soldier investment in their ecology. The eusocial bamboo aphidPseudoregma bambucicola has a morphologically specialized first-instar soldier caste. The proportion of soldiers was positively correlated with colony size. Within a colony, soldiers were evenly distributed among subcolonies; within each subcolony, however, their distribution was biased toward peripheries which were exposed to many predators. Field experiments introducing natural enemies such asEupeodes confrater (Diptera: Syrphidae) andSynonycha grandis (Coleoptera: Coccinellidae) revealed that the survival rate of these predators was negatively correlated with the density of soldiers, suggesting that soldiers can more or less defend their colonies by killing or removing a range of natural enemies. Observations suggest that large mature colonies attract more predators than newly established small colonies and that, within a colony, the predators attack each subcolony regardless of its position on bamboo shoots. This implies the presence of a positive correlation between colony size and predation risk. Thus, the investment in soldiers seems to reflect the attacking pattern of predators within a colony. These results agree with the defence-optimization hypothesis in soldier investment ofP. bambucicola colonies. 相似文献
4.
Shun'ichi Makino Seiki Yamane Tsukasa Sunose Shigeyuki Aoki 《Researches on Population Ecology》1987,29(1):111-117
Summary Dispersion capabilities of new queens were studied in the two haplometrotic paper waspsPolistes riparius andP. snelleni. New queens were marked on the nests in the late summer and located in the next spring. Dispersion distances greatly varied
among queens: although a large part of recovered queens nested in close proximity to their natal sites, some did disperse
over 100–300 m. This suggests that queens' emigration from and immigration into the censused areas occurred to a substantial
extent. On the whole, these species exhibited a weaker “philopatric” tendency than those so far studied for dispersion distance,
and seem to have the potential for a long-distance dispersion. 相似文献
5.
Mun Il Ryoo 《Researches on Population Ecology》1986,28(1):17-26
Summary The basic components of the predation ofPhytoseiulus persimilis
Athias-Henriot feeding upon eggs ofTetranychus urticae
Koch were studied in an open system where the predator could disperse freely.
The type of the functional response of the predator to the density of its prey was the same as that studied so far in a closed
system, i.e.,Holling's Type 2. The search rate of the predator, however, was much lower in comparison with the result from a closed system. The
oviposition of the predator per day was only weakly related to prey densities higher than 10 per leaf disc. But the emigration
rate was inversely dependent upon the initial prey density up to 60 per leaf disc. The searching behaviour of the predator
was influenced by both the web density spun byT. urticae and the density of the prey: the predator searched for its prey intensively only after it had contact with web. Mutual interference
was observed in prey consumption, but not in the emigration rate. The emigration rate was largely dependent upon the prey
density available per predator. 相似文献
6.
Summary The biology of the veliid bugM. d. atrolineata, its predatory behavior, and the effects of plural hunting were studied to evaluate its role as a predator of the brown planthopperNilaparvata lugens in the Philippines. The probability of planthoppers falling onto the water surface and provision of habitat continuity was
measured by a sticky trap placed at the base of rice hills in a greenhouse and in paddy fields.
The developmental period of immature stages combined was 21 days. If given prey, females laid 25 eggs on the average during
an adult life span of 18 days. Starved adults could survive for only 3–5 days.
The functional response to prey density was sigmoid, and the maximum number of prey killed was 7 per day. Prey feeding was
completed in 12–36 min. The percentage of successful prey attacks averaged 5–8%, decreasing with higher (and larger) developmental.
stages of prey, but adult prey were found the soonest. Plural hunting increased the probability of capturing prey by as much
as 2.5 times that by individual hunting.
Late-instar nymphs, which may be more active, fell from rice hills in a greenhouse more than early-instar nymphs, and the
number falling increased with density. In the field the percentage of planthoppers falling to the water in 1 day varied considerably,
from 1% for nymphs in one field to 67% for adults in another field.
On the basis of work described above and given the high density of veliid predators in flooded paddy fields of tropical Asia,M. d. atrolineata is considered one of the most important natural enemies of the brown planthopper. 相似文献
7.
Kenichi Ozaki 《Researches on Population Ecology》1993,35(2):273-284
Summary The number of larvae reaching maturity within the gall ofAdelges japonicus was positively related to gall volume, and the relationship between the number of mature larvae and gall volume did not change
with different densities of colonized larvae.
The population changes in the bud galls ofA. japonicus were surveyed by collecting the galls, which did not suffer predation or parasitism within the galls, from young artificial
plantations ofPicea jezoensis over two years. In the year when the density of colonized larvae was high, they suffered a 42% mortality within the galls,
whereas mortality was nearly zero in the low density year. The numbers of larvae per gall were positively correlated with
gall volume. The regression lines of the number of colonized larvae on gall volume did not differ significantly in the regression
coefficients between the two years, whereas the intercept was significantly higher in the year when the density of colonized
larvae was higher. However, different within-gall mortality nullified this difference, and the regression lines of the number
of mature larvae on gall volume had no significant difference both in the regression coefficients and the intercepts. This
suggests that the number of mature larvae per gall was limited by available resources within the gall which were positively
related to gall volume. In 25% of the galls in which mature larvae inhabited, the space within the galls were completely filled
by the larvae, indicating that space was one of the limiting resources. Gall volume also affected the number of adults that
emerged from the gall and the potential number of their progeny. 相似文献
8.
9.
Summary Optimal clutch size of the chestnut gall-wasp,Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), was examined in galls on wild and resistant chestnut trees in 1988 and 1989. The rate
of escape success of newly-emerged adults from galls was an average of 60%, irrespective of cell numbers per gall. Dry mass
per cell of a gall (as an index of nutritive condition) decreased with increasing cell number per gall, but was proportional
to the mean number of mature eggs of new adults per gall. The number of cells per gall that occurred most frequently did not
agree with that attained by the maximum survival rate from young larva to adult emergence of the gall-wasp. This discrepancy
was examined from the viewpoint of three factors: 1) quality of offspring, 2) defensive response of the host plant causing
mortality of the gall-wasp before cell formation, and 3) fitness per gall vs. fitness per egg. It is concluded that the third
factor is most likely to be the one best in explaining the discrepancy. 相似文献
10.
Three models were constructed for analyzing the population characteristics ofC. chinensis on stored beans; model A describing the whole reproductive process with a single equation, model B describing the three age-specific
processes (oviposition, egg survival and larval survival) with separate equations, and model C which describes all these processes
not for the whole habitat but for the individual beans comprizing it. The logit equation was employed here as a common basis
to describe the density-response relationship involved. All three models showed very good fit to the experimental data obtained
for both laboratory and wild strains of the weevil. The parameter values characterizing the population dynamics were, however,
widely different between the two strains; the laboratory one which had been reared for some 500 generations showed significantly
higher reproductive capacity, less sensitive and gentler response to crowding in both adult and egg stages, and more uniform
egg distribution among individual beans, as compared with the wild strain newly introduced. Sensitivity analyses using these
models suggested that these changes in population characteristics have been attained by the process of domestication or adaptation
to stable laboratory conditions through a long period of time. This process seemed in effect to have optimized the population's
performances in the laboratory environment. Evolutionary significance of such optimization was discussed with reference to
the selection pressure which may have acted upon individuals. 相似文献
11.
Shun'ichi Makino 《Researches on Population Ecology》1989,31(1):1-10
1. | Losses in workers and reproductives due to the ichneumonid parasitoidLatibulus sp. were determined in a haplometrotic, temperate paper wasp,Polistes riparius, during a 5-year study. |
2. | Fifty-four to 79% of pre-emergence nests were parasitized on worker brood, resulting in a worker loss of 25–31% on average. Worker brood reared in outer cells were much more often parasitized than those in central ones, possibly because outer cells are more accessible to the parasitoid. Infestation of worker brood was not random but aggregated among nests. |
3. | Seventy-eight to 100% of nests were parasitized on reproductive brood, and lost 10–34% of reproductives. |
4. | The number of emerged workers positively correlated with that of reproductives produced and that of cells made during the season. This suggests that worker loss reduces reproductive output of colonies. Hence, the parasitoid can reduce colonial reproductive output not only by killing reproductive brood but by reducing worker force. |
12.
13.
Somchai Isichaikul Koichi Fujimura Toshihide Ichikawa 《Researches on Population Ecology》1994,36(1):23-28
Nymphs ofNilaparvata lugens were experimentally reared from the 2nd instar in a cage covering part of the leaf sheath of an individual rice plant grown
in a Wagner pot. Plants were covered with the cage from the water surface of the pot to 10 cm above the surface (lower cage-group)
or from 10 cm to 20 cm above the surface (upper cage-group). Temperatures measured at three different parts of the cage remained
fairly constant in both groups at around 25°C (23.7–25.2°C in mean value). In the lower cage-group, relative humidities measured
at the three heights in the cage in (76.3–90.5% in mean value) markedly increased with the approach to the water surface.
The nymphs of this group, particularly during the molting period, aggregated close to the surface. Eighty-two percent of the
released nymphs emerged in this group. Relative humidities measured at three heights of the upper cage-group were 69.5–72.7%
in mean value, and all the nymphs in this group died within 3 days after their release although half of them stayed on the
rice plants within 6 h after their release. The role of relative humidity as a limiting factor on the range of the microhabitat
and the population density ofN. lugens in rice fields was discussed on the basis of the results. 相似文献
14.
Summary Microhabitat of the nymphs and the adults of the rice brown, planthopper,Nilaparvata lugens is known to be the lower parts of rice plants. In this study, possible environmental factors determining the range of the
microhabitat were experimentally analyzed by using the nymphs under laboratory conditions. Thirty individuals of the 1st or
the 3rd instar nymphs were released to a potted rice plant covered with a transparent acrylic cylinder. When the top of the
cylinder was kept opening (open condition), the temperatures in the cylinder were almost constant, and relative humidities
in the cylinder decreased with the increase of the height from the water surface of the pot. In the open condition, most nymphs
and all exuviae were found on the basal parts of rice plants where the humidity was more than ca. 90% r.h. When the top of
the cylinder was kept closing with parafilm (closed condition), the temperatures in the cylinder were almost constant, and
relative humidities in the cylinder were more than 95% r.h. In the closed condition, the nymphs and the exuviae were distributed
sparsely to the whole parts of rice plants. In both of the open and the closed conditions, patterns of nymphal distributions
on rice plants during the dark regime were the same as those during the light regime under 25±2°C and 16L∶8D. Four different
temperatures ranging from 20°C to 35°C did not influence on the microhabitat in the open condition. It was concluded from
the results that relative humidity is the important environmental factor to determine the microhabitat of the nymphs ofN. lugens which showed to prefer very humid condition more than ca. 90% r.h. 相似文献
15.
Samples of shoots ofPistacia lentiscus carrying galls of the aphid,Aploneura lentisci, were collected at three localities in Israel.
Shoots growing near pruning scars carried more galls than elsewhere on the plant, but these galls weighed less and contained
fewer aphids (smaller clones). The proportion of empty galls increased with gall density. Crowding of galls at such sites
may be due to the early burst of buds at the time of aphid emergence from the overwintering eggs, and not to active search
for preferred sites. 相似文献
16.
17.
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
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.
Summary We compared the seasonal changes in population density and nymphal development at different water temperatures and under different
food conditions between two giant water bugs,Diplonychus japonicus andD. major, in Okayama, Japan.
D. japonicus produced 1–2 generations a year, whileD. major was strictly inivoltine. The developmental velocity was higher inD. japonicus than inD. major. The thermal constant ofD. japonicus was less than that ofD. major. These results suggest thatD. japonicus is adapted, to higher water temperature thanD. major. In the field,D. japonicus preyed predominately on Lymnaeidae and Physidae snails, whileD. major preyed on aquatic insects such as dragonfly nymphs. 相似文献
20.
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