bluuebunny/crossref_metadata_2025_split huggingface dataset:
Host‐dependent association and its implications on the relative abundance of blue alfalfa aphid and pea aphid (Homoptera: Aphididae) on alfalfa in Oklahoma
Authors: Poswal M. Ashraf , Berberet Richard C. 
Published: October 2006

SummaryField populations of blue alfalfa aphid and pea aphid on alfalfa were sampled during 1985 and 1986 to determine the association of co‐occurrence, interspecific interactions and comparative temporal variations in the spatial dispersion patterns of these species in Oklahoma. Relative abundance of these species is discussed in the light of above analyses.Cole's coefficient revealed a high degree of association between these species in terms of their occurrence on the same alfalfa stems in the field. Regression analyses indicated that the species populations tended to increase in concert on the same stems without evidence of competitive displacement. Spatial dispersion patterns of both species were highly aggregated at low population densities early in the season. Over time, both species tended to disperse and became less aggregated as numbers increased. It was concluded that magnitude of interspecific interactions between the blue alfalfa aphid and the pea aphid were not of a nature that they could be termed as competing species. On the contrary, a concept of an “ecospecies” is proposed for practical applications such as sampling plans and economic threshold determinations.
Estimation of population parameters by optimizing catch effort allocation
Authors: Matsumiya Yoshiharu , Matsuishi Takashi 
Published: October 2006

Summary
In this study, we have developed a new method to estimate population parameters and applied it to a concrete example on the situation that there are two fisheries resources which are depleted only by catch, and that these two resources are not caught equally because of the difference of prices.
Switching function, which is originally used to describe the effort allocation that one predator eats two preys, has been introduced. We have constructed a model of fishery in which each fisherman pursues economical optimum.
The population size of two species at the beginning of the fishing season, catchability coefficient and parameters of switching function are estimated by the criterion of minimum error sum of squares between CPUE (catch per unit effort) of data and that by model.
We have applied it to the diver fishery of abalone in Ojika Island, Nagasaki Prefecture. The model describes well the situation during the season that CPUE of the less expensive species increases gradually as the population of the other species is depleted.
Variability in food consumption rate of natural populations in the spider, Nephila clavata
Authors: Miyashita Tadashi 
Published: October 2006

SummaryMean daily food consumption and total lifetime food consumption of the spider, Nephila clavata, were estimated in natural populations. Daily food consumption in the late adult stage was 27–150 mg wet weight, which was nearly equivalent or slightly larger than that in other large web‐building spiders. Considerable variation in food consumption was found among habitats or years. The largest variation among habitats in the same year was 7 and 5 fold for daily and lifetime consumption, respectively, while that among years in the same habitat was 3.5 and 2.5 for daily and lifetime consumption, respectively. Feeding conditions evaluated from the food consumption per body weight of spiders declined during the period from mid‐July to mid‐September in almost all the populations, which suggested that they faced to severe food limitation in this period.
Sibling cannibalism in the ladybird beetle Harmonia axyridis: Fitness consequences for mother and offspring
Authors: Osawa Naoya 
Published: October 2006

SummaryThe adaptive significance of sibling cannibalism was analyzed in the ladybird beetle Harmonia 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.
A simple evolutionary model of dormancy and dispersal in heterogeneous patches with special reference to phytophagous lady beetles: I. Stable environments
Authors: Tsuji Nobuyuki , Yamamura Norio 
Published: October 2006

SummaryA simple evolutionary model of dormancy and dispersal is presented with special reference to phytophagous lady beetles. In order to investigate spatially heterogeneous environments, we assume the simplest patch structure, that is, there are only two patches, main and sub. Environments are also assumed to be temporally constant. The main patch is superior to the sub patch, but density effect at the main patch is higher than at the sub patch. Optimal dormancy and dispersal are obtained at the same time by the method of evolutionarily stable strategy (ESS). In the univoltine life cycle, dormancy strategy vanishes because dormant individuals do not reproduce at all but suffer from a certain mortality rate during winter hibernation. In the bivoltine life cycle, the dormancy and dispersal rates constitute a trade‐off: the rates change together with a negative correlation when the mortality rate during dispersal or during winter hibernation changes. When suitability of the main patch gradually deteriorates, the optimal strategy changes as follows: neither dormancy nor dispersal is adopted at the most suitable condition, the dispersal rate is increased without dormancy in the intermediate condition, and then the dormancy rate is increased with a constant dispersal rate. We discuss the field observation data of lady beetles in the light of results of our model.
Spatio‐temporal analysis of the population dynamics of the oriental moth, Monema flavescens (Lepidoptera: Limacodidae)
Authors: Yamada Yoshihiro 
Published: October 2006

SummaryThe comparative analysis of life tables of the oriental moth, Monema flavescens, obtained in 6 patches for 8 generations in 4 years revealed the following:
The ratio of maximum to minimum of cocoon density for each patch ranged from 5.34 to 22.50, each value being more than 3.20, the ratio for the whole study area.
The density change from adult to cocoon in the next generation caused most of the spatial variation in density change per patch. The rate of adult‐to‐cocoon population change showed spatial density dependence in some generations but not in others. When the change rate lacked spatial density dependence, it was the key‐factor for spatial variation in adult density for the following few generations till the change rate recovered spatial density dependence. This was because of flooding, which killed the spatial density dependence existing potentially in the adult‐to‐cocoon change rate and damaged the same patches during the few successive generations.
The rate of population change from overwintered generation adults (summer ones) to first generation cocoons was not only the key‐factor for the rate of throughout‐the‐year change but temporally density dependent in each patch. Therefore, the density for the whole study area is considered to fluctuate within a range. However, the strong equilibrium seen in the cocoon density for the whole study area was due to the floods that happened to occur when the density was near and at its maximum, and it is considered that such a strong equilibrium does not always occur.
In the population change from summer adults to first generation cocoons, temporal density dependence was found in all the patches, but it was found only in one patch in the population change from autumn adults to second generation cocoons. This was because the spatial density dependence seen in the former corresponded to the absolute density of adults, while that in the latter corresponded to the relative density.
A Simulation model for the arrowhead scale (Hemiptera: Diaspididae) population dynamics on citrus trees in relation to pest‐management programs
Authors: Adachi Ishizue , Korenaga Ryoji 
Published: October 2006

Summary
A mathematical model was constructed describing population dynamics of the arrowhead scale, Unaspis yanonensis Kuwana. The population occurrence patterns simulated by the model from 1971 to 1976 were relatively consistent with the actual findings in the field.
The effects of control tactics for this pest were examined on the basis of the model.
Effective timing of insecticide (petroleum oil and organophosphorous insecticide) application was indicated to be 40 days after the initial appearance of 1st‐instar nymphs in both the 1st and 2nd generations of the host.
The number of overwintering adult females in May of the next year (i.e., the starting point of the next year's population) decreased linearly with the increment in the degree of insecticide coverage. The pest populations were expected to be kept to low densities by petroleum oil sprays alone for the 1st generation when overall, complete coverage was accomplished.
Examination of the effects of two introduced parasitoids, Aphytis yanonensis and Coccobius fulvus, showed that they were able to control the scale population by themselves when more than 70% parasitism was achieved. When petroleum oil was applied to overwintering adults (termed winter petroleum oil) at the degree of coverage of 0.8, host populations were reduced by ca. 60% parasitism. When the winter petroleum oil was combined either with additional petroleum oil 40 days after the initial appearance of 1st‐instar nymphs of the 1st generation or with an organophosphorous insecticide 40 days after the initial appearance of 1st‐instar nymphs of the 2nd generation (degree of coverage=0.8 in each case), 40% parasitism led the reduction of the pest population.
The most desirable control program was considered to be one in which winter petroleum oil was used every year and additional petroleum oil or an organophosphorous insecticide was also used in those years when host density was high.
A male fitness advantage to wing reduction in the oriental chinch bug, Cavelerius saccharivorus okajima (heteroptera: Lygaeidae)
Authors: Fujisaki Kenji 
Published: October 2006

SummaryA 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 of C. saccharivorus in terms of the earlier sexual maturation.
Principal component analysis of interrelations in stored‐wheat ecosystems infested with multiple species of insects
Authors: White N. D. G. , Sinha R. N. 
Published: October 2006

SummaryPrincipal component analysis (PCA) was used to determine the effects of infestation of bulk stored wheat by multiple species of insects at 30±2°C for 60 wk. Eight 204‐liter drums containing wheat at 15.5% moisture content were used as three distinct man‐made ecosystems: (a) Control system (2 drums), insect‐free; (b) RST system (3 drums), artificially infested with Rhyzopertha dominica (F.),Sitophilus oryzae (L.), and Tribolium castaneum (Herbst); and (c) COT system (3 drums), infested with Cryptolestes ferrugineus (Stephens),Oryzaephilus surinamensis (L.), and Tribolium castaneum. The variables measured tri‐weekly within each system included carbon dioxide, oxygen, temperature, grain moisture, seed damage, grain weight and volume, dust weight and volume, fat acidity values (FAV) of the wheat, seed germination, microflora including Alternaria alternata(Fr.) Keissler,Aspergillus glaucus group, Aspergillus candidusLink, and bacteria, insects and the mite Tarsonemus granariusLindquist. PCA provided multivariate synopsis of the data quantifying several important relationships among the variables monitored. Tri‐weekly and cumulative 60‐wk analyses of each system showed that high bacterial counts were associated with high FAV levels;Tarsonemus numbers were positively related to Aspergillus; Alternaria and seed germination were negatively related to FAV, bacteria and grain damage; and that the number of insects was related to the presence of Aspergillus and negatively related to the presence of bacteria. Seed germination and Alternaria infection often decrease rapidly presumably because of infection by fungi of the Aspergillus glaucus group. The combined action of R. dominica and Aspergillus spp. enhanced seed damage and increased grain moisture content thus promoting bacterial growth which in turn inhibited insect and mold growth. Fat acidity values increased with time unless seed damage and bacterial infection were extensive as in the RST system.
Analysis of factors affecting bird predation on gypsy moth egg masses by using Holling's disc‐equation
Authors: Higashiura Yasutomo 
Published: October 2006

Summary
Birds’ predation on gypsy moth egg masses deposited on tree trunks was quantitatively evaluated in a birch forest at Bibai, Hokkaido during the four winter seasons from 1974 to 1978.
Holling's disc‐equation could be successfully applied to describe the relationship between the total egg consumption by birds and the density of egg masses. A rapid method for fitting the disc‐equation to observed data was proposed based on the study byShinozaki andKira (1961).
Appreciable amounts of predation were observed only during the period when the depth of snow cover on the ground exceeded 1 m, while the egg masses deposited on lower parts of tree trunk below 1 m level suffered from only slight predation. It was therefore presumed that deep snow cover made the predator birds to change their feeding place from ground vegetation to tree trunks.
The duration of the period with snow accumulation deeper than 1 m was introduced into the disc‐equation as an additional parameter. The values calculated by the resultant formulation agreed with the observed values in respective years satisfactorily.
There were circumstantial evidences that the great tit, Parus major, was one of the important predators concerned.
Distribution patterns of and sampling plans for Tetranychus urticae Koch (Acarina: Tetranychidae) on roses
Authors: So Ping‐Man 
Published: October 2006

SummaryI sampled Tetranychus urticae Koch (Acarina: Tetranychidae) regularly from four rose gardens in Kyoto and Nara Prefectures in 1988–1990. When mite density was low, T. urticae showed an uneven vertical distribution, being more abundant in the lower third and absent from the upper third of the plants. Mite density was less variable within than between plants, suggesting that a sampling plan which includes more leaves from different plants rather than from different levels of a plant is favourable. Spatial distribution of T. urticae was nonrandom and followed the negative binomial distribution. In addition, both the Taylor's power law and the Iwao's patchiness regression described the distribution well. An empty‐sample method for estimating mite density from the proportion of empty sampling units was developed. Sampling plans for determining the sample size required to reach a predetermined precision level, based on this method and by directly counting the mites, were designed. The counting method was more accurate than the empty‐sample method. However, when the time factor was taken into account, the latter was more favourable, because it was faster than the former at a density range of 1.5–300 mites leaf−1, which was most commonly encountered in the field.
Combining pheromone‐baited and food‐baited traps for insect pest control: Effects of additional control by parasitoids
Authors: Barclay Hugh J. 
Published: October 2006

SummaryTwo age‐structured population dynamic models are analyzed in which pheromone‐baited trapping and food‐baited trapping are used simultaneously to eradicate an insect pest. The pest species is assumed to be under partial control by a host‐specific parasitoid species. The two models assume that density‐dependent population regulation is accomplished either by host larval competition or by means of oviposition interference among the parasitoids. The two trap types interact in a positive synergistic manner and this combination appears to be very promising as a useful combination of pest control methods. Several features of the system are examined; the feature which appears to cause the greatest problem is the possibility of the parasitoids being attracted to the pheromone or the food traps. In either case, the degree of attraction does not have to be very great to undermine the control effort. It is seen that food trapping becomes indispensible if host pheromone is used by the parasitoids as a host‐locating kairomone. If odor in the food traps is used by the parasitoids as kairomone, then the situation appears more optimistic, as the reduction in efficiency of the food traps appears much less than with the pheromone traps when pheromone acts as kairomone.
Interspecific relations in forest floor coleopteron assemblages: Niche overlap and guild structure
Authors: Kobayashi Shiro 
Published: October 2006

SummaryIn six different environments of the Towada‐Hachimantai National Park, the forest floor coleopterons were sampled by means of pitfall traps with five different baits. Their niche breadths and niche overlaps were assessed for the electivity of habitat, bait, and habitat × bait, and compared with those expected from neutral models constructed randomly. The niche breadths in the observed assemblages were smaller than those expected from the neutral model, while the niche overlaps were more widely distributed than those expected from the neutral model. Mean overlaps between species neighbors in niche space, cluster analyses, and ordinations of species revealed a guild for habitat, bait and habitat × bait. Lawlor's (1979) gamma matrices concerning the habitat electivity show that the rates of mutualism resulted from indirect interspecific competitions are significantly smaller in the guild than in the whole assemblage. This suggests that the interspecific competition among the guild members is mitigated or even converted into mutualism by joining of the species which do not belong to the guild. The rates of mutualism were also significantly larger in the resource state of two dimensions (habitat × bait) than in that of either one. Therefore, if niche overlaps are measured on the basis of resource state of multi‐dimensions, the rates of mutualism may increase further.
The effects and limits of territoriality on population regulation in grey red‐backed voles, Clethrionomys rufocanus bedfordiae
Authors: Saitoh Takashi 
Published: October 2006

SummaryThe effects of breeding territoriality on the stability of grey red‐backed vole (Clethrionomys rufocanus bedfordiae) populations were investigated on a control grid and a grid on which the voles were fed, in an outdoor enclosure in Hokkaido, Japan. Vole populations were monitored by live trapping from 1984 to 1986: (1) Population density was 2–7 times greater on the experimental grid to which food was added than on the control grid. Reproductive output was more closely associated with the difference in density between grids than survival or dispersal (immigration and emigration) rates. (2) The number of adult females and pregnancy rate of the experimental population were significantly greater than those of the control one. The difference in the number of adult females between the populations was greater than that in pregnancy rate. (3) The proportion of successful litters and the number of weanlings per litter were not significantly different between the control and experimental population. (4) Adult females held territories on both the control and experimental grid; they were spaced out more than would be expected from random occupation. The territories overlapped more on the experimental grid than on the control grid. (5) Mean territory size of adult females on the experimental grid was about half of that on the control grid. The territory size was correlated negatively with population density. (6) The proportion of trap sites that were used by adult females was significantly greater on the experimental grid than on the control grid. This suggests that adult females on the experimental grid used the area more extensively. This factor, in association with territory size and overlapping of territory, was also important in causing the difference in the number of adult females between the grids. (7) These results call into question the hypothesis that territoriality stabilizes the density in populations of Clethrionomys.
The phenology and intrinsic quality of wild crucifers that determine the community structure of their herbivorous insects
Authors: Yano Shuichi , Ohsaki Naota 
Published: October 2006

SummaryThis report examines the plant traits that effect the community structure of herbivorous insects on wild crucifers. Wild crucifers were classified into 4 types (A, B, C, D) according to their phenology. Type A and B plants had a pausing phenology, disappearing in the middle of the insects' active season, while type C and D plants had a continual phenology, existing all year long. The intrinsic quality of the plants as food, which was assessed by measuring the performance of herbivores, was superior in type A, B and D plants, while it was inferior in type C. The phenology and intrinsic quality were the alternative means of direct defense mechanisms against herbivorous insects: The plants with a pausing phenology were intrinsically superior (A, B), while the plants with a continual phenology were intrinsically inferior (C). However, there were a few plants with continual phenology and superior intrinsic quality (D, the type B plants that remained in the summer). Within the community of the herbivorous insects on the plants with direct defense mechanisms, the number of species and individuals was small and most of the community members were specialists of the plants. On the other hand, within the community on plants without direct defense mechanisms, the number of species was large and the proportion of generalists was high. In addition, the number of individuals was very large on the remaining type B plants, but it was small on type D plants, which were inferred to have indirect defense mechanisms.