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1.
Sibling cannibalism in the ladybird beetleHarmonia axyridis: Fitness consequences for mother and offspring 总被引:1,自引:0,他引:1
Naoya Osawa 《Researches on Population Ecology》1992,34(1):45-55
Summary The adaptive significance of sibling cannibalism was analyzed in the ladybird beetleHarmonia axyridis at two prey densities. Possible costs and benefits were considered from three points of view: the mother, the cannibal and
the victim. Cannibals ate both infertile and fertile eggs, thereby increasing in body length and survival rate with the intensity
of sibling cannibalism. The cannibalistic trait was clearly beneficial to the cannibal when aphid density was low. However,
it was not always beneficial when aphid density was high and the victims were full siblings. The altruistic behavior of being
a victim was beneficial only when the victim was cannibalized by full siblings at low aphid density. The mother attained almost
equal fitness at low aphid density, regardless of the intensity of sibling cannibalism. This suggests that sibling cannibalism
is not maladaptive for the mother. At high aphid density, however, mother’s fitness decreased with the intensity of sibling
cannibalism, indicating that sibling cannibalism is maladaptive for the mother when larval food availability is high. 相似文献
2.
《Researches on Population Ecology》1983,25(2):336-352
Summary Numerical changes and distribution patterns of the pine needle gall midge,Thecodiplosis japonensis
Uchida etInouye, were studied during the period from 1978 to 1979 in a young plantation ofPinus thunbergii in Shiga Prefecture, Japan. The survivorship curve of this species was characterized by a low mortality of larvae in galls
and two high mortalities before the formation of galls and during the overwintering period in soil.
The within and between-trees distributions of eggs and larvae in galls were examined by using the
regression method. The egg distribution per shoot was aggregative both within and between host plants. The within-tree variations
in numbers of eggs per shoot were related to the differences in the abundance of available needles for oviposition per shoot
among the canopy layers. The between-tree variations reflected the heterogeneous emergence of adult females in the study plot.
The degree of aggregation increased from egg to gall stage in both within- and between-tree distributions and the increase
was explained by the different mortality of larvae within trees and the inversely density-dependent mortality between trees.
The distribution patterns in the soil habitat stages were examined by the patchness index (
). This species showed aggregative distributions in soil stages. There was a correlation in spatial patterns of adult emergence
between the successive generations.
The distribution properties of this species were discussed in connection with the population dynamics and the availability
of host plants in the study plot. 相似文献
3.
Syuniti Iwao 《Researches on Population Ecology》1970,12(1):100-110
Summary The contagiousness in the operation of mortality processes on the colonies of the western tent caterpillar,Malacosoma californicum pluviale, was analyzed from two different aspects: successive changes in the frequency distribution of the number of surviving individuals
per colony in the course of development, and the distribution pattern of the individuals killed by some biotic mortality factors.
Also, for a tachinid parasite,Tachinomyia similis, the analysis was made on the egg-laying pattern on colonies as well as on individual larvae. The methods of these analyses
were all based on the relation of mean crowding (m) on mean
.
A braconid parasite,Rogas sp., tended to kill few individuals together once it attacked a colony, but its effect on host colonies was rather equivalent
to the random removal of individuals from all the colonies. Diseases in the late-stage larvae before cocooning was contagious
in their action. Nuclear polyhedrosis virus seemed to have no basic contagiousness in its action, but it caused highly contagious
distribution of deaths among the colonies when its average incidence was high. A spore-formingBacillus had a tendency to kill several individuals once it appeared in a colony, but the distribution of its incidence (no. of times
it appeared per colony) was considered to be nearly at random.
The female ofTachinomyia tended to lay more than one egg successively on the same colony. It also attacked individual larvae with a definite tendency
for aggregation, which seemed to be resulted from the parasite’s preference to large hosts. When the number of eggs laid on
prefered hosts exceeded a certain threshold, however, the fly seemed to change its attention to less attractive, smaller individuals. 相似文献
4.
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
5.
J. N. Ayertey 《Researches on Population Ecology》1980,22(1):101-116
Summary This paper describes a series of experiments conducted to determine whySitophilus zeamais
Mots. andSitotroga cerealella (Oliv.) could not survive together in maize cultures in the laboratory. The effect ofS. zeamais on different developmental stages ofS. cerealella was investigated. The presence of adultS. zeamais slightly affected moth copulation, egg laying and moth eggs in a mixed culture, but large numbers of developing moths inside
maize grains were killed by the adult weevil through feeding on the grains. The major cause of elimination ofS. cerealella byS. zeamais from mixed cultures was therefore found to be damage to the immature moths in grain and such moth mortality increased as
the developing moths became bigger in the grains. A weevil: grain ratio of approximately 1.4∶1 was found to be the critical
weevil density at which the moth disappeared from the mixed cultures. 相似文献
6.
T. H. Chua 《Researches on Population Ecology》1977,19(1):125-139
Summary Studies on populations ofBrevicoryne brassicae (L.), its parasites and hyperparasites were carried out by actual counting in the sprouts field and by sticky and water traps.B. brassicae was found to be attacked by one primary parasite,Diaretiella rapae (McIntosh), which in turn is parasitized byAlloxysta brassicae (Ashm.),Asaphes vulgaris
Walker,A. suspensus (Nees),Pachyneuron minutissimum (F?rster) andDendrocerus carpenterii (Curtis). The aphid population in the field was started by immigrant alates which were found flying too early to be synchronized
with the sprouts plants. SimilarlyD. rapae was not synchronized with the aphids although many individuals could have been carried into a plot through parasitized immigrant
alates, of which less than 30% were found parasitized. Because of high hyperparasitism (especially byA. brassicae)D. rapae was not able to maintain a high rate of parasitism to curb the aphid population growth. The maximum percentage mummies being
27.8%, while the maximum, percentage parasitism being 56.6% recorded only during the early 1974 season (mean=12.9%). The decline
of aphid population from September onwards was largely due to the cold weather, Syrphid predation and occasionally fungal
attack. The high rate of hyperparasitism byA. brassicae is attributed to its better synchronization withD. rapae. The mean percentage of parasite that emerged from mummies collected during 1973–74 wereD. rapae 31.3%,A. brassicae 64.3%,A. vulgaris andA. suspensus 4.3%,D. carpenterii 0.2% andP. minutissimum 0.1%. 相似文献
7.
Duncan A. Mackay 《Researches on Population Ecology》1985,27(1):87-98
Summary OvipositingE. editha butterflies display post-alighting discrimination among patches ofCollinsia torreyi, one of their major hosts in the General's Highway (GH) population at a montane site in California. Females tended to accept
(i.e. oviposit on) dense patches of this host and to reject sparse patches. Possible behavioural mechanisms underlying this
tendency are discussed. The consequences of this non-random pattern of oviposition for egg and larval survivorship were investigated
and no differences were found in the survivorship of larvae on acceptable and unacceptable collinsias. 相似文献
8.
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
9.
Takayuki Ohgushi 《Researches on Population Ecology》1988,30(1):57-68
Summary The relationships between egg predation of an herbivorous lady beetleEpilachna niponica (Lewis) and its predator, the earwigAnechura harmandi (Burr), were examined in both time and space. In spite of little annual, changes in egg densities, egg mortality due to predation
varied considerably. There was no, clear relationship between the earwig density and the proportionate predation over the
five years. The seasonal occurrence of earwig nymphs on thistle plants, however, was closely synchronized with that of egg
predation. Predator attacks on the beetle occurred in a time-restricted manner. Thus, later cohorts mostly escape from heavy
predatory pressure. No spatially density-depent egg predation was detected at the level of either thistle plants or thistle
patches. Furthermore, there was no indication of aggregative behaviour of the earwig in response to local egg density. The
earwig density was more likely to be associated with particular localities with sandy deposits available for its nest site. 相似文献
10.
Tuyosi Sugimoto 《Researches on Population Ecology》1978,19(2):197-208
Summary The present paper studies how the female parasite ofKratochviliana sp. visits and attacks its host larvae of Ranunculus leaf mining fly,P. ranunculi at a single leaf visit. The parasite visited its hosts at random on the leaf. The frequency of host visits was independent
of the host density and the proportion of hosts survived from the parasite attack, in a leaf and its distribution was expressed
as a single straight line. It almost always attacked living hosts at the first host visit after isolated from them for one
day but with the rate of about 0.5 at the subsequent visits. In consequence, the relationships of the number of host attacks
and killed hosts to the host density drew satulated curves in each. A model of host attack by this parasite at its single
leaf visit was formulated by modifyingBakker
et al.'s model (1972) basing upon these observations and the attack avoidance by the parasite to already attacked hosts previously
reported.
Ecological studies on the relationship between Ranunculus leaf mining fly,Phytomyza ranunculi
Schrank (Diptera; Agromyzidae) and its parasite,Kratochviliana sp. (Hymenoptera; Eulophidae) from the viewpoint of spatial structure II.
This paper constitutes a part of the Doctoral Thesis presented to the College of Agriculture, Kyoto University by the present
author. 相似文献
11.
Summary A series of increasing egg densities was obtained by releasing various numbers of femalePlodia interpunctella (Hübner) in rooms where dishes of moth rearing medium were evenly spaced on the floor. The number of larvae produced in each dish
was taken as an indication of the number of eggs that had been laid. At all egg densities, the eggs were aggregated, and most
of the distributions conformed quite well with the negative binormial, but the degree of aggregation denreased as mean egg
density increased. The implications of the results for the development of ware-house sampling strategies are discussed. 相似文献
12.
Yin Yin May 《Researches on Population Ecology》1978,20(1):61-78
Summary The seasonal and annual fluctuations in a population of the delphacid,Stenocranus minutus (Fab.) onDactylis glomerata L. were studied from March 1968 to September 1970. The study involved the comparison of several sampling methods to estimate
the egg, nymphal and adult numbers and an investigation into causes of mortality within each stage. A population budget was
made for the years 1969 and 1970. 相似文献
13.
Summary A simple experiment of simulation was done to analyze the natural mortality process of young larval colonies and egg masses
of the southern green stink bug. In this experiment, a degree of contagiousness
was allowed in regard to the action of a mortality factor, and
was defined as the mean number killed per a colony or an egg mass by the mortality factor within a unit time and the number
killed per a colony was assumed to follow the Poisson series with the mean
. Thus each component of the Poisson series was opposed to each colony or egg mass which was taken at random from 162 egg
masses, 135 and 117 colonies of the first and the second instar larvae, respectively.
It was revealed that mortality factors in the field did not act with a small degree of contagiosness, e. g.
, on all colonies or egg masses, but acted with a large degree of contagiousness, e. g.
, on some of the colonies or egg masses. Thus differential survival somewhat in all or none way occurred among the insect
colonies irrespective of their initial sizes. These results were well explained by taking actual mortality factors into account. 相似文献
14.
Summary Time-specific life tables were constructed for three pea aphid,Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), populations using a modification ofHughes' analytical procedure. All populations were studied on second-growth alfalfa (mid-June to mid-July) in south central Wisconsin;
data for two populations were collected during 1980, and data for the third population were collected during 1982. The intrinsic
rate of increase (r
m) estimated on a physiological time (day-degree) scale under field conditions but in the absence of natural enemies, provided
a reliable estimate of potential population growth rate and was used in preference toHughes' approach of estimating potential population growth rates directly from stage structure data. Emigration by adult alatae and
fungal disease were the major sources ofA. pisum mortality in each of the three populations studied. These factors were most important because of their impact on reducing
birth rates within the local population. Parasitism was never greater than 9 percent. Mortality attributable to predation
ranged from 0.0 to about 30.0%; however, even at the highest predator densitiesA. pisum populations increased exponentially. 相似文献
15.
T. S. Bellows Jr. 《Researches on Population Ecology》1985,27(1):55-64
Summary The effects of host age on parasitoid reproductive capacity are studied using the pteromalid parasitoidLariophagus distinguendus
F?rster and its bruchid hosts,Callosobruchus chinensis (L.) andC. maculatus (F.). A series of experiments were performed to investigate relationships between age and size of host parasitized and the
developmental period of pre-imaginal progeny, sex ratio, female size, longevity, fecundity and oviposition rate. There was
no effect of host size on preimaginal parasitoid developmental period. Sex ratio varied from less than 5% females from young
(small) hosts to 60% females from mature (large) hosts. Adult size, female longevity, fecundity, and oviposition rate were
also positively related to host age. Females provided mature hosts lived longer than those provided either young hosts or
no hosts, possibly because of an increased ability to host-feed from the larger hosts. The implications of these findings
to parasitoid population reproductive capacity and host-parasitoid synchrony are discussed. 相似文献
16.
Summary Population dynamics ofHeliothis virescens (F.) andHeliothis zea (Boddie) (Lepidoptera: Noctuidae) eggs and larvae were studied for two years in a small plot of cotton,Gossypium hirsutum (L.). Due to morphological and ecological similarities, the pooledHeliothis population was considered for most of the analyses. Two generations ofHeliothis eggs and larvae were completed during each year. Stage recruitment was estimated for the eggs and larval instars 2–6, and
recruitment variances were estimated by a Monte Carlo method. A modified form of the Weibull distribution was developed and
used as a model to characterize survivorship curves for each of the fourHeliothis generations. A Type I survivorship curve (mortality rate increasing with age) was inferred for both Generation 1 (early season)
data sets, whereas a Type II survivorship curve (mortality rate constant and thus independent of age) was inferred for both
Generation 2 (late season) data sets. The shapes of the survivorship curves for the individualH. virescens andH. zea populations were inferred to be the same as those for the pooled populations. Analysis of the contributions of various factors
toHeliothis stage-specific mortality indicated that natural enemies (predators and parasites) and the availability of food for larvae
were responsible for between-generation differences in survivorship patterns. 相似文献
17.
David M. Craig 《Researches on Population Ecology》1986,28(2):173-183
Summary The present research has not identified all of the factors that interact to produce the observed egg cannibalism rates inTribolium. It has, however, shown that some physical and chemical properties of the egg and environment play an important role in determining
cannibalistic activity in a population. Of general interest is the observation that cannibalism is not solely the result of
the biological characteristics of the cannibal. While it is generally acknowledged that the quality and quantity of food may
influence the intensity of cannibalism, it is not generally recognized that the environment can affect cannibalism in as complex
a manner as is suggested by the current research. That two such closely related species, and even two life-stages of the same
species, may respond so differently to the same environmental cues is impressive. Predicting the intensity and hence the importance
of cannibalism in natural populations may be difficult without detailed empirical studies. 相似文献
18.
Summary Difficulty arises in applying marking-and-recapture methods to insects when the probability of recapture of marked individuals
is changed with advancing age, either due to detachment of the mark by moulting (in the case of larvae) or to changes in their
survival rate or their behaviour. A modification of the re-recapture method (Leslie
et al., 1953) has been devised to analyze the capture-recapture data of the 5th-instar larvae and adults ofNezara viridula L. Estimation of the rate of moulting to the adult stage is made with the aid of additional information on larval survival.
Migration rates of the larvae between the two halves of the census field is estimated byIwao's (1963) method. Through these analyses, the dynamic feature of the population during transition from the 5th instar to, adult
is revealed. Several problems involved in the application of marking-and-recapture methods to insect populations are discussed.
Contribution from the Entomological Laboratory, Kyoto University No. 392. 相似文献
19.
Tock H. Chua 《Researches on Population Ecology》1979,20(2):179-187
Summary The searching efficiencies of a primary parasite (Diaeretiella rapae (McIntosh)) and a hyperparasite (Alloxysta brassicae (Ash.)) were investigated and compared. In both species, at all parasite densities, there was a curvilinear relationship (P<0.001) between the number of hosts parasitised and the host density. A linear regression (loga=logQ−m logP) was fitted for log area of discovery against log parasite density (P<0.001). The area of discovery for its immediate (i.e. primary) host (viz.Diaeretiella for the hyperparasite and aphid forDiaeretiella) is lower in the hyperparasite than in the primary parasite. InDiaeretialla both the searching efficiency and the mutual interference constant increased (but not significantly,P>0.05) in the presence of its males. 相似文献
20.
Ishizue Adachi 《Researches on Population Ecology》1989,31(2):343-352
Summary The study was carried out in two (A and B) citrus groves to clarify the spatial distribution patterns of eggs and larvae,
and to analyse the mortality process of eggs. From the analysis by using the mean density and the mean crowding, it was clarified
that the distributions of eggs were contagious and that larvae were more contagiously distributed than eggs. The τ andz indices showed that the operation of egg mortality was inversely density-dependent in both groves, and that the degree of
inverse density-dependence was greater in A than in B grove. The spatial correlations between the emergence holes and the
eggs or larvae in each tree, which were analysed by using ω index, showed that the distributions were more overlapping between
the emergence holes and the larvae than the eggs. As the result of dividing trees into several groups according to the number
of emergence holes, it was clarified that the survival rates of eggs were positively correlated with the number of emergence
holes. In conclusion, inversely density-dependent mortality process was considered to be caused by lower mortality rates of
eggs in the trees with more emergence holes. Especially in A grove, because the trees with more emergence holes were larger
in diameter and more egg oviposition, the inversely density-dependent mortality process was considered to be detected more
conspicuously than in B grove. 相似文献