bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial variation in female fertility related to interactions with flower consumers and pathogens in a forest metapopulation of Primula sieboldii
Authors: Washitani Izumi , Okayama Yasushi , Sato Keiko , Takahashi Hitomi , Ohgushi Takayuki 
Published: November 2006

AbstractAntagonistic biological interactions with flower consumers and pathogens may influence reproductive success of flowering plants, affecting population dynamics and natural selection for floral traits. However, ecological and evolutionary consequences of the interactions may depend on both spatial and temporal patterns of the interactions. In a forest metapopulation of Primula sieboldii E. Morren, an endangered clonal plant species, we measured between‐subpopulation patterns of seed sets and interactions with an influential flower consumer, a rove beetle, Eusphalerum bosatsu Watanabe, and a specific smut fungal pathogen, Urocystis tranzschelina (Lavrov) Zundel (Ustilaginales), for three years. Mean female fertility (seed set per flower) for individual subpopulations fluctuated moderately among years but was highly variable within each year among the five subpopulations studied. In two subpopulations, the impact of Eusphalerum beetle, was sufficiently large to result in almost complete failure in seed production over eight years including the three study and five previous preliminary observation years. In the two other subpopulations, seed set failure was caused by infection by the smut fungus. Infected capsules which constitute 10–30% of the capsules produced in the subpopulations were filled with ustilospores instead of seeds. In the subpopulation that escaped flower damage by Eusphalerum beetles and smut fungal infection, seed sets of both pin and thrum flowers were much higher than in the other subpopulations. The spatial restriction of individual antagonistic agents to a part of subpopulations suggest that dispersal of the agents, as well as the mode of spatial subdivision of the plant population would be important for determining the overall effects of antagonistic interactions on plant performances at the metapopulation level.
The effects of wild cruciferous host plants on morphology, reproductive performance and flight activity in the diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae)
Authors: Begum Shefali , Tsukuda Ritsuko , Fujisaki Kenji , Nakasuji Fusao 
Published: November 2006

AbstractThe wild crucifers, Rorippa indica and Lepidium virginicum, are known to serve as host plants for the diamondback moth (DBM),Plutella xylostella, but they are less suitable than the preferred cultivated cruciferous plant, cabbage, in terms of adult body size and fecundity. The life history traits and flight activity of DBM adults grown on various host plants were investigated. The adults thus reared on each host plant were divided into three size groups (small, medium and large). In general, female adults grown on the wild crucifers were less fecund and lived longer than those reared on cabbage. Flight activity was higher in adults grown on wild crucifers than in those reared on cabbage. Male adults flew longer than females. Fecundity, longevity, flight activity and morphometrical characters of adults were positively correlated with pupal weight in individuals reared on the same host plant. A negative relationship was found between fecundity and flight activity in females of the same size group, but a positive one was observed in females reared on the same host plant.
Vertical foodweb structure of freshwater zooplankton assemblages estimated by stable nitrogen isotopes
Authors: France R. , Westcott K. , del Giorgio P. , Klein G. , Kalff J. 
Published: November 2006

AbstractAlthough theoretical foodweb models predict the presence of only three to four trophic categories, estimation of “potential” vertical foodweb structure from species lists and inferred feeding interactions suggest that as many as 7 trophic categories can occur in the pelagic foodwebs of North American glaciated lakes. A compilation of data on the nitrogen isotopic composition of zooplankton from 46 Canadian Shield lakes suggested the average existence of one “realized” trophic category in addition to that of filter‐feeding, herbivorous cladocerans. When phytoplankton, planktivorous invertebrates, and plantivorous and piscivorous fish are included, the vertical foodweb structure in the pelagic zones of these lakes are greater than those hypothesized from some theoretical models.
Dynamics of buried seed population and seedling cohorts of two dominant weeds in a hill agroecosystem of the humid subtropics of India
Authors: Misra J. , Pandey H. N. , Tripathi R. S. , Sahoo U. K. 
Published: November 2006

AbstractDynamics of the buried seeds and plant population of two dominant weeds, viz.,Emilia sonchifolia (Linn.) DC. and Richardsonia pilosa HBK were studied in the crop fields of Meghalaya, north‐east India during radish and maize cropping and intervening fallow periods. The total buried seed population of R. pilosa was always larger than that of E. sonchifolia, but the germinable fraction was invariably greater in the latter. A major portion (39–41%) of the viable (germinable+dormant) seed population in both weeds was confined to the surface soil layer (0–5 cm). The viable seed population of E. sonchifolia peaked during April, while that of R. pilosa showed two peaks (during August and December). The survival pattern and half‐lives of seedling cohorts showed, some differences in the two weed species, but both being summer annuals, their populations behaved in a similar manner by showing higher seedling recruitment (K) and survivorship (p) rates in the summer crop (maize) than in the winter crop (radish). However, the density of plants that could attain adulthood was significantly higher in E. sonchifolia than R. pilosa which might have resulted in greater seed input of the former to the soil leading to its greater abundance in the crop fields.
On the mathematical basis of the variance‐mean power relationship
Authors: Tokeshi Mutsunori 
Published: November 2006

AbstractThe mathematical basis of a widely‐known variance‐mean power relationship of ecological populations was examined. It is shown that the log variance (S2)—log mean, (m) plot is virtually delimited by two lines log S2=log n+2 log m and log S2=log m, thus increasing the chance that a linear regression line can be successfully fitted, without a profoundly behavioural background. This makes difficult the task of interpreting a successful fit of the power law regression and its parameter b in a biologically meaningful manner. In comparison with the power law regression, Iwao'sm*‐m regression is structurally less constrained, i.e. has a wider spatial region in which data points can scatter. This suggests that a comparison between the two methods in terms of how good a fit is achieved for a particular data set is largely meaningless, since the power law regression may inherently produce a better fit due to its constrained spatial entity. Furthermore, it could be argued that a successful fit in Iwao's method, when found, is less taxed with mathematical arterfacts and perhaps more clearly linked to some biological mechanisms underlying spatial dispersion of populations.
The evolutionary significance of wing dimorphism in carabid beetles (Coleoptera: Carabidae)
Authors: Aukema Berend 
Published: November 2006

AbstractA review of data on the background of wing dimorphism in carabid beetles (Coleoptera: Carabidae) and especially of the closely related Calathus cinctus and C. melanocephalus is given. In both Calathus species wing dimorphism is inherited in a simple Mendelian fashion with the brachypterous condition dominant, but in C. melanocephalus the expression of the long winged genotype is under environmental control as well. The development of long winged phenotypes in the latter species is favoured by relatively favourable environmental conditions, such as high temperatures and a high food‐supply. The higher fecundity of the larger and heavier long winged females of both species may compensate for losses of long winged phenotypes by flight activities. The evolutionary significance of both types of inheritance is discussed in relation to dispersal. The ‘fixed type’ as found in C. cinctus is considered an opportunistic short term ‘between sites strategy’, whereas the ‘dynamic type’ of C. melanocephalus represents a flexible long term ‘within sites strategy’.
Variability in wing form of crickets
Authors: Masaki Sinzo , Shimizu Toru 
Published: November 2006

AbstractLoss of functional hindwings is observed in most subfamilies of Japanese crickets. Habitat, behaviour, body size and phylogenetic factors might be involved, but interactions among them may obscure the general trend. Wing dimorphism is common among the relatively small‐sized members of Gryllinae, and the two small‐sized subfamilies, Nemobiinae and Trigonidiinae. Both environmental cues (e. g. photoperiod) and genetic factors affect the wing form. In Dianemobius fascipes (Nemobiinae), the percentage macroptery was drastically changed by selection for macroptery or microptery. Crossing experiments indicated polygenic control of wing form as well as X‐chromosomal and maternal effects. Neither the long‐winged nor short‐winged line bred true after 40 generations of selection. Full‐sib families revealed a large genetic variation in frequency of macropterous forms within a population. The genetic determination of the propensity for macropterism did not seem to be directly coupled to the mechanism performing the photoperiodic time‐measurement.
Losses of workers and reproductives in colonies of the paper wasp Polistes riparius (Hymenoptera: Vespidae) due to the parasitic wasp Latibulus sp.
Authors: Makino Shun'ichi 
Published: November 2006

Summary
Losses in workers and reproductives due to the ichneumonid parasitoid Latibulus sp. were determined in a haplometrotic, temperate paper wasp, Polistes riparius, during a 5‐year study.
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.
Seventy‐eight to 100% of nests were parasitized on reproductive brood, and lost 10–34% of reproductives.
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.
Spatio‐temporal distribution patterns of two tachinid flies, Epicampocera succincta and Compsilura concinnata parasitizing Pieris
Authors: Iwao Keisuke , Sato Yoshibumi , Ohsaki Naota 
Published: November 2006

SummaryLarvae of genus Pieris in the northern part of Kyoto City are parasitized by two tachinid flies:Epicampocera succincta, a specialist on genus Pieris, and Compsilura concinnata, a generalist with very wide host‐range. We surveyed the parasitism rates of Pieris by both flies for two years at six study areas. In these study areas, there lived three host species in the genus Pieris: P. rapae, P. melete, and P. napi, but neither tachinid parasitized P. napi to any significant extent. In the mountainous district, P. rapae and P. melete coexisted and their populations were relatively continuous, while in the lowland, only P. rapae larvae were abundant in spring and autumn, but even they disappeared in summer. Parasitisms by E. succincta occurred mainly in mountainous district and never in the lowland. C. concinnata parasitized Pieris in all the areas, but its parasitisms occurred mainly in autumn.We analyzed the factors affecting the spatial and temporal patterns of parasitism rates and presumed that the temporal discontinuity of host population restricted the distribution of the specialist parasitoid.
Modelling and analyzing density‐dependent population processes: Comparison between wild and laboratory strains of the bean weevil, Callosobruchus chinensis (L.)
Authors: Kuno Eizi , Kozai Yoshitake , Kubotsu Koji 
Published: November 2006

AbstractThree models were constructed for analyzing the population characteristics of C. 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.
Interannual fluctuations in recruitment and growth of the sardine, Sardinops melanostictus, in the sea of Japan and adjacent waters
Authors: Hiyama Yoshiaki , Nishida Hiroshi , Goto Tsuneo 
Published: November 2006

AbstractRecruitment and growth of the sardine Sardinops melanostictus fluctuated markedly in the Sea of Japan and adjacent waters between 1978 and 1993. Stock size was calculated using Virtual Population Analysis and average body length in each age class was determined by the number of annual rings on the scales. There is an inverse correlation between average water temperature at a depth of 50 m in the coastal area of the mainland of Japan in winter (January to March) and recruitment R defined as the number of individuals at 1 year old. There is also an inverse correlation between spawning stock size E and reproductive success in (R/E). A multiple regression model using spawning stock size and water temperature in winter as independent variables can explain 73% of variance in reproductive success. It suggests that both density‐dependent and density‐independent factors perform important roles determining reproductive success. There is an inverse correlation between body length and stock size and this suggests that there is a density‐dependent effect on the growth of the sardine.
Effect of organic rice farming on planthoppers 4. Reproduction of the white backed planthopper, Sogatella furcifera Horváth (Homoptera: Delphacidae)
Authors: Kajimura Tatsuto , Widiarta I Nyoman , Nagai Kazuya , Fujisaki Kenji , Nakasuji Fusao 
Published: November 2006

AbstractThe reproduction of Sogatella furcifera was investigated in a chemically fertilized rice field and an organically farmed field. In the latter, the density of immigrants was significantly higher, while the settling rate of female adults and the survival rate of immature stages of ensuing generations were lower. The number of eggs laid by a female of the invading and following generations was smaller, and the percentage of brachypterous females in the next generation was also lower. Consequently, the density of nymphs and adults in the ensuing generations decreased in the organically farmed field. For an experimental comparison, potted rice plants were cultivated using seedlings and soil from the chemically fertilized or the organically farmed fields. When Sogatella furcifera was reared on these plants, both the reproductive rate and the appearance rate of brachypterous female adults were lower in the organic treatment. Egg hatchability was also lower in the organic treatment. This experiment suggested that a specific nutritional condition in rice plants suppressed the population of S. furcifera in the organically farmed field.
Accumulation of phyllodulcin in sweet‐leaf plants of Hydrangea serrata and its neutrality in the defence against a specialist leafmining herbivore
Authors: Ujihara Mami , Shinozaki Masateru , Kato Makoto 
Published: November 2006

AbstractAmong wild plants of Hydrangea serrata (Hydrangeaceae) in Japan, there are sweet plants whose leave contain a kind of isocoumarin, phyllodulcin, which happens to be 350 times as sweet as sucrose to the human tongue. In a primary beech forest in Ashu, Kyoto, the spatial distribution of sweet plants and temporal and the spatial distribution of phyllodulcin within and among plants were investigated using a high performance liquid chromatograph. The distribution of sweet plants was confined within a valley and was parapatric with non‐sweet plants. A plant's characteristic phyllodulcin accumulation did not change, even when transplanted into the different habitats. The phyllodulcin content of the sweet plants varied greatly among plants, and the population mean peaked in July when the plants flowered. Within a plant, phyllodulcin content was elevated by partial defoliation. We examined the possible effect of phyllodulcin on herbivory by a specialist leafmining herbivore, Antispila hydrangifoliella (Lepidoptera: Heliozelidae). We transplanted sweet and nonsweet plants reciprocally between their original habitats, excluded attacks by parasitoids, and compared performance of the leafminer. Leafminer colonization and larval survivorship on transplanted and in situ plants was not significantly different between sites. The fact that accumulation of phyllodulcin did not augment a defensive function, at least against herbivory by the leafminer, and the sporadic distribution of phyllodulcin‐accumulating plants, suggest that the genotypes synthesizing phyllodulcin emerged independently at separate localities by mutation, and that the genotypes are almost adaptively neutral in defence against the specialist herbivore.
Influence of parental density on the distribution pattern of eggs in the common cabbage butterfly, Pieris rapae crucivora
Authors: Kobayashi Shiro 
Published: November 2006

SummaryTo investigate the relation between the distribution pattern of eggs and the parental density in the common cabbage butterfly, Pieris rapae crucivora, the countings of egg number per plant were made on both cabbage plants cultivated in the farm and planted in the net house in which the female butterflies were released at various densities.The frequency distribution of eggs fits well to the negative binomial excepting the cases where they agree withPoisson series, and the degree of aggregation expressed as the reciprocal of the parameter, 1/k, tends to decrease as the egg or parental density increases. At the same parental density, however, the distribution of eggs can be described by the negative binomial with a common parameter, kc, regardless of the difference in the density of laid eggs.In the case where a single female butterfly lays eggs, the spatial pattern of egg distribution is always lean, while its frequencies conform toPoisson or the negative binomial series. This lean changes toward patchy with increasing the parental density.From these results, it is concluded that the degree of aggregation in the distribution of eggs decreases with the increase of the parental density.
Application of Iδ‐index to sampling techniques
Authors: Morisita Masaaki 
Published: November 2006

Conclusion and SummaryAn advantage in the Iδ method which utilizes the Iδ‐index for the description and analysis of population structure is that the values obtained through the use of this method indicated the degrees of non‐randomeness of the distribution of individuals so that they are comparable directly with each other. In this paper, equations representing some basic relations between the Iδ‐values of sample and population and those between the inter‐group Iδ and intra‐group Iδ were described and an example of their application to the field data was presented. Though the equations and methods may still have such a weakness as to be supplemented or corrected from mathematical point of view, they seem to be useful at least as the basis for the the future study for the development of the Iδ method.
The fitting of the logistic equation to the rate of increase of population density
Authors: Morisita Masaaki 
Published: November 2006

Conclusion and SummaryThough there are many problems on the usefulness of the logistic curve, it may be necessary to examine before discussing these problems whether or not the actual data fit to the theoretical values. It has been clarified in this paper that the relation between the population density and its rate of increase per individual described by the differential equation (1) is represented by a straight line on a finite difference diagram on which Ni+1−Ni/Ni values are plotted against Ni+1. Utilizing this linear relation we may examine the fittness of the logistic curve to the actual data and when it is fitted we may estimate the parameters of the logistic equation by (5) and (6). The result of the application of this method to the experimental populations of azuki bean weevil indicates that the relation between parent and progeny densities fits well to the logistic type as has been proved byFujita andUtida (1953) who utilized the linear reltion between 1/R+2σ and parent density where R is the apparent rate of reproduction and σ is a constant dependent primarily upon the length of adult life (0≦σ≦1).
Adaptive parental feeding as a factor influencing the reproductive rate in the grey starling
Authors: Kuroda Nagahisa 
Published: November 2006

Summary
Adaptive parental feeding of chicks is one of the factors influencing the reproductive rate of a local population.
The food resources in the rural and urban colonies in Tokyo were entirely different as proved by collar experiments of the chicks.
In the rural habitat the mole‐cricket of fair size (1 g) and of a high nutritive value was the ‘key food' to all broods and only a few other items were added for larger broods.
In the urban habitat the food consisted of both animal and plant (fruits) items of various kinds, but the animal matter was mostly small and of poor nutritive value, and fruits are much less nutritive than animal matters as experimentally proved with captive chicks by using cherries which are the most abundant and favoured fruit.
Thus the food preference and the feeding ability of parents had more important effect upon growth rate and flying success of chicks in the urban colony than in the rural, especially in larger broods.
In the rural colony, the adaptive reaction of parents to a large brood size (experimentally increased) was evident in a pair which adequately switched the normal food, the secretive mole‐cricket, to an easily obtainable kind, the small white pupae and caterpillars.
Such focussed or concentrated foraging was also shown to some other food items to be found in clustered condition and selection for large size was also suggested, since such large foods as the gecko or lizard were brought though they were disgorged by chicks in some cases.
Subject to various factors, there is the maximum possible feeding frequency for the parents and therefore, however hard the parents might work, there were limits of brood size they could successfully raise.
Such limits were 6 chicks for some parents or 7 for others, and a single parent could raise not more than 3 chicks.
Thus in the grey starling the broods of 5–6 chicks are of the most efficient size in reproductive rate and are most common, though are subject to difference of local food situation.