bluuebunny/crossref_metadata_2025 huggingface dataset:
Variable fortunes in a patchy landscape —The habitat templet of an insect migrant
Authors: Solbreck C.
Published: November 2006

Migration by flight is essential for insects living in patchy landscapes and knowledge about variability in habitat patch structure and quality is important for the development of theory concerning insect dispersal polymorphisms. However, few studies provide more than anecdotal evidence about habitat change in time and space and its effects on insect survival and reproduction. Here I show how habitats and resource density of a lygaied bug, Lygaeus equestris, change in a patchy landscape over a seventeen year period. Although habitat patches per se are very stable, there are large temporal fluctuations in per capita food resources. Food seems to be limiting only in some years, and there may be periods of several years when populations change due to weather disturbance. Between‐patch variation in reproductive success is large. Furthermore, the relative favourability of patches changes between years. There are also distance effects; in some years distances to suitable hibernation sites affect reproductive success. Long fliers experience more variable success, and sometimes extreme success, when compared with short fliers. The importance of movements from outlying areas also changes with time. The insect is thus faced with a habitat templet which varies strongly on many temporal and spatial scales.
Inconstancy of Taylor's b: Simulated sampling with different quadrat sizes and spatial distributions
Authors: Sawyer Alan J.
Published: November 2006

Taylor's power law, s2=amb, provides a precise summary of the relationship between sample variance (s2) and sample mean (m) for many organisms. The coefficient b has been interpreted as an index of aggregation, with a characteristic value for a given species in a particular environment, and has been thought to be independent of the sample unit. Simulation studies were conducted that demonstrate that the value of b may vary with the size of the sample unit in quadrat sampling, and this relationship, in turn, depends on the underlying spatial distribution of the population. For example, simulated populations with hierarchical aggregation on a large scale produced values of b that increased with the size of the sample unit. In contrast, for a simulated population with randomly distributed clusters of individuals, the value of b eventually decreased with increasing quadrat size, as sample counts became more uniform. A single value ofTaylor's b, determined with a particular sample unit, provides neither a fixed index of aggregation nor a complete picture of a species' spatial distribution. Rather, it describes a consistent relationship between sample variance and sample mean over a range of densities, on a spatial scale related to the size of the sample unit. This relationship may reflect, but not uniquely define, density‐dependent population and behavioral processes governing the spatial distribution of the organism. Interpretation ofTaylor'sb for a particular organism should be qualified by reference to the sample unit, and comparisons should not be made between cases in which different sample units were used. Whenever possible, a range of sample units should be used to provide information about the pattern of distribution of a population on various spatial scales.
Inheritance of sex ratio in the Kanzawa spider mite, Tetranychus kanzawai Kishida
Authors: Takafuji Akio , Ishii Toshio
Published: November 2006

The frequency distributions in sex ratios of offspring from 4 field Tetranychus kanzawai populations were examined. No significant difference was observed between average sex ratios of the 4 populations, although there was a great variability within each population, especially in the population from Pueraia lobata. Using the population from P. lobata, inbred lines with high (H) and low (L) sex ratios were selected. Crossing experiments between H and L showed that sex ratio is determined by the genotype of mothers. It seemed that sex ratio is cointrolled by several genes, with no cytoplasmic factor involved.
Phenological studies on the wing dimorphism of a semi‐aquatic bug, Microvelia douglasi (Heteroptera: Veliidae)
Authors: Muraji Masahiko , Miura Tadashi , Nakasuji Fusao
Published: November 2006

Seasonal changes in the percentage of macropterous individuals in natural population of Microvelia douglasi in permanent habitats were investigated in Shimane, western part of Japan. Macropterous forms of 5th instar nymphs occurred most frequently from late June to early July. However, the seasonal appearance of macropterous adults differed between habitats and years. There were significant effects of density, temperature, photoperiod and food availability on the percentage of macropters under laboratory conditions. The percentage of macropterous forms generally increased with density, but the mode of the response was modified by temperature, photoperiod and food availability. When insects were reared under long day photperiod (16L8D) with abundant food (0.5–1.0 g/container/day), the percentage of macroptery varied most among the different density treatments at the intermediate temperature (24°C) and the difference was reduced at higher temperature (28° and 32°C). Effects of temperature were small under the short day photoperiod (12L12D). Under 12L12D photoperiod sensitivity of density responses were higher at 32°C and lower at 24°C than those under 15L8D photoperiod. When the insects were supplied with food every other day, the density response became obscure. Ecological significance of environmental responses in the wing morph determination was discussed in relation to the heterogeneous environment of water surface.
Sibling and non‐sibling cannibalism by larvae of a lady beetle Harmonia axyridisPallas (Coleoptera: Coccinellidae) in the field
Authors: Osawa Naoya
Published: November 2006

Sibling (cannibalism among siblings) and non‐sibling cannibalism (cannibalism among non‐siblings) were studied in a natural population of a lady beetle, Harmonia axyridisPallas.

Of all the eggs laid (n=2269), 24.76% (n=562) were killed by sibling cannibalism and 36.10% (n=819) were killed by non‐sibling cannibalism. Sibling cannibalism occurred constantly and intensively in most egg batches throughout the entire oviposition period. On the other hand, non‐sibling cannibalism was more intense in the middle and late oviposition periods, and when the egg batches were close to an aphid colony. This may be due to the high density of H. axyridis larvae relative to aphid density in the middle and late oviposition periods and also the larvae searching intensively near an aphid colony.
Frequent successful multiparasitism by five parasitoids attacking the scale insect Nipponaclerda biwakoensis
Authors: Kaneko Shuji
Published: November 2006

Successful multiparasitism by five parasitoid wasps of the scale insect Nipponaclerda biwakoensis was investigated at a reed bed in Lake Biwa. The wasps were gregarious endoparasitoids consuming the entire body of the host. The rate of successful multiparasitism for a parasitoid species was defined as the proportion of the number of individual hosts from which the species emerged with other species to the total number of hosts from which the species emerged. The rates were high for each parasitoid species, ranging from 17 to 82%. Successful multiparasitism frequently involved two species with similar adult size, but rarely involved species with different adult size. For four of the five species, the number of wasps per host was significantly less when wasps emerged from a host with other species relative to when emerged alone. For the other one species, the number of wasps was less, but the difference was not significant. With only one species, female wasps were significantly smaller when they emerged from a host with other species relative to when emerged alone.
Reproductive strategy of the sugi bark borer, Semanotus japonicus (Coleoptera: Cerambycidae) on Japanese cedar, Cryptomeria japonica
Authors: Shibata Ei'ichi
Published: November 2006

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.
Models for mating disruption by means of pheromone for insect pest control
Authors: Barclay Hugh J. , Judd Gary J. R.
Published: November 2006

Models are presented to investigate the population dynamic behavior of a pest population with the release of pheromone for mating disruption. Three mechanisms of mating disruption are considered: (i) confusion of males, (ii) competition with female pheromone trails yielding false trail following, (iii) emigration of males prior to mating. In addition, several refinements to confusion are considered. Confusion and emigration of males were found to be very similar both quantitatively and dynamically; also, a combination of both mechanisms was very little more efficient than either one separately. False trail following is difficult to compare with the other two, since competition with wild females is involved and thus the total population size enters the equations. Density dependence of the action of pheromones results in some cases in which mating disruption cannot control the pest population. Similarly, aggregation of the pest population decreases the efficiency of the method unless the pheromone action is density independent. Delayed mating of females makes control easier, and may constitute one mechanism for mating disruption.
Spatial pattern analysis of the incidence of aster yellows disease in lettuce
Authors: Madden L. V. , Nault L. R. , Murral D. J. , Apelt M. R.
Published: November 2006

The degree of aggregation of lettuce plants infected by aster yellows phytoplasma (AYP) was investigated in 12 fields from three experiments. Position of diseased and healthy plants was mapped in a 6–9×12‐m section of each field; for most analyses, fields were divided into 10‐plant quadrats. Mean disease incidence (p) ranged from 0.01 to 0.30. The frequency of diseased plants was described by the beta‐binomial distribution, with an index of aggregation (θ) ranging from 0 to 0.17, positively correlated withp, and generally increasing over time within a field. Distance‐class analysis revealed a core‐cluster size of only a few plants. However, spatial autocorrelations ofpbetween quadrats were not significant, indicating that the scale of spatial pattern was small, generally less than 10 plants. An overall measure of aggregation was given by the slope parameter of the binary form of the power law, in which the log of the calculated variance is regressed on the log of the theoretical variance for a binomial distribution. The slope was 1.18 and significantly different from 1. Results for this “simple‐interest” disease are interpreted in relation to the persistent transmission of AYP by its aster leafhopper vector.
Population studies based on relative abundance of five different life history stages of Ayu, Plecoglossus altivelis (Pisces, Plecoglossidae), in Lake Biwa
Authors: Miura Taizo
Published: November 2006

Comparison of relative abundance of each two successive life history stages was made for studying population dynamics of ayu, Plecoglossus altivelis, in Lake Biwa.

Number of eggs spawned is proportional primarily to the size of biomass of spawner population although spawning success plainly depends on presence or absence of heavy rain in the spawning period.

Although density of fry tends to be proportional to that of egg, yearly fluctuation of the fry mortality may be caused by changes in density of food organisms but is not in compensatory way.

From the fry stage to the juvenile one the rate of mortality and/or of growth seem to fluctuate in compensatory way which is supposed to be related to a shortage of food.

Yearly fluctuation of mortality of adult stage is caused by an artificial factor as changes of fishing intensity.

Necessity of studying actual events at each stage of the life history process separately in relation with environmental conditions is discussed through the result of the present analysis.
A statistical model of the competition curve
Authors: Fujii Koichi
Published: November 2006

A theoretical model for the competition curve, which stands on a few simple assumptions, was proposed.

Some applications were done to actual data, and during these applications the validity of the present model and its assumptions was discussed.

From the present model it can be expected that there is a discrete competition mechanism even in the appearently continuous medium.
Interspecific competition between two species of Trichogrammatidae III The analytical study on the competition
Authors: Sasaba Takafumi
Published: November 2006

The experiment was carried out in order to analyze the results of interspecific competition which were mentioned in the previous reports (Sasaba 1964, 1965). The following definite tendencies were obtained and an account was given with regard to the process of competition. (1)T. minutum had a higher reproductive rate than T. japonicum at a lower density of the parent wasps. (2) The parasitic efficiency of T. minutum was high as compared with T. japonicum. (3)T. japonicum was consistently superior to T. minutum in the interspecific competition at larval stage.
Population behaviour of the southern green stink bug, Nezara viridula, with special reference to the developmental stages of early‐planted paddy
Authors: Kiritani Keizi , Hokyo Nobuhiko , Iwao Syun'iti
Published: November 2006

Population behaviour of adults and 5th‐instar nymphs of Nezara viridula L. was analysed by means of the marking‐and‐recapture method in an early‐planted paddy field. The field contained five varieties of rice which differend in growth states. It was estimated that a total of more, than 7,000 adults of the first generation, in which at least 3,000 were females, invaded the field from early July to middle August. Egg‐mass census data, however, indicated that only 10 per cent or less of the females participated in egg‐laying. This was largely due to the, low rate of adult survival. The adults preferred younger plants, for both feeding and oviposition.

The method described byIwaoet al. (1966) permitted estimate that 3,300–3,400 of the 5 th‐instar nymphs and 1,100–1,200 of the adults of the second generation were produced from 298 egg‐masses (25, 700 eggs); while 95–6 per cent of the individuals were thought to have died before reaching adulthood. Most of the 5 th‐instar nymphs moved less than 4 m in three days as long as the condition of food plants remained suitable, but they tended to move more towards younger plants when those on which they lived became too mature. The apparent survival rate of the second generation adults was very low, probably due both to a rapid emigration and a high mortality of newly‐emerged adults.
Application of a marking‐and‐recapture method for the analysis of larval‐adult populations of an insect, Nezara viridula (Hemiptera: Pentatomidae)
Authors: Iwao Syun'iti , Kiritani Keizi , Kokyo Nobuhiko
Published: November 2006

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 (Leslieet al., 1953) has been devised to analyze the capture‐recapture data of the 5th‐instar larvae and adults of Nezara 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.
Preliminary studies for the population estimation of the cryptomeria red mite, Oligonychus hondoensis
Authors: Kobayashi Fujio , Murai Minoru
Published: November 2006

This is the second paper dealing with techniques necessary to the population estimation of the Cryptomeria red mite feeding on a coniferous Cryptomeria tree, with the final object of determining the absolute population. Results are as follows:

The population can be defined as the whole of mites existing on branches with foliage younger than two years old, because more than 95% of individuals are always there.

Optimal sampling unit varies according to mite population. Unless a fixed unit is necessary, seasonal placement of units is recommended.

Since significant variance is associated with crown levels, representative sampling from each level is designed. These calculation should be based on the data transformed to logarithms, as the relation between mean and variance suggests that the population data are of contagious distribution.

A trial to calculate the total length of branches for each age, which is needed for the conversion to absolute population, is described.
Experimental studies on the distribution of the aphid counts
Authors: Shiyomi Masae , Nakamura Kazuo
Published: November 2006

The present paper dealt with the sequential changes of the distribution pattern of apterous females aphid populations, that were artificially settled at the beginning on the experimental barley ‘field'. The aphids were settled at random or even with a fixed denisty per plant. For five or six days after the settling, the number of individuals followed the negative binomial distributions in all cases while the parameters k and p were varying. The estimated values of k were rather small for the first one week after the settling, which may suggest that the number of moving aphids between plants was relatively small and the degree of concentration expressing the intrinsic increase was high. After that, as the number of individuals increased, the number of moving aphids between plants would be considered to be increased. It was found that with the lapse of time the degree of concentration decreased or k became larger.

The distribution of aphids per blade in a plant was also described briefly.
Natural mortality at different population densities of a pine shoot moth, Evetria cristata
Authors: Kanamitsu Keiji
Published: November 2006

A field population of Evetria cristata was studied in 10 plots in 1962 and in 6 plots in 1963. These plots were divided into 2 or 3 groups of different population levels of the shoot moth in respective years. The survival of the insect was then analysed in these different groups of plots. The survival rate of E. cristata from eggs to adults in the first generation was found always higher in the group with low population density, which indicates the existence of some factors that affect the population more severely when the insect is more abundant. Lissonota evetriae and Pediobius sp. seemed to have killed more proportion of the hosts where the shoot moth density was high. However, the total effect of the all natural enemies was not always great in the plots with high density of the moth. The survival of the second generation of the moth in 1963 was observed to be much higher at any population level than in the other generations.
Studies on interspecies competition between the azuki bean weevil and the southern cowpea weevil
Authors: Fujii Koichi
Published: November 2006

Experimental studies was made on the interspecies competition between the azuki bean weevil, Callosobruchus chinensis and the southern cowpea weevil, C. macultatus. And the following results were obtained.

The reverse result of competition between the two species observed under the air‐tight condition and the air‐free one. That is, the population of the azuki bean weevils destroyedby that of the southern cowpea weevils under the former condition and vice versa under the latter. It is thought that such a reversal is due to the difference of sensibility of each species to the air‐tight condition.

Under the air‐free condition, change of the time interval of food‐supplying had no effect on the result of competition within the limits of this experiment. The population of the southern cowpea weevils was always destroyed by that of the azuki bean weevils. But there was a certain degree of correlation between the duration of co‐existence and the interval of food‐supplying.

From the results, it is possible to say that by changing the degree of air‐tightness, or the time interval of food‐supplying, the co‐existence period and the final result of competition can be changed.

The different mechanism of competition between two species in the present experiment from the experiments ofUtida (1952) andYoshida (1957) were discussed.

A difference in the mechanism of interspecies competition and intraspecies competition was expected from the level of total population numbers of two species and the individual weight of C. chinensis.
A comparative analysis on the distribution of nymphal populations of some leaf‐ and planthoppers on rice plant
Authors: Kuno Eizi
Published: November 2006

The frequency distribution of the number of nymphs per hill of rice plant were analyzed for three species of rice leaf‐ and planthoppers, Nilaparvata lugens, Delphacodes striatella and Nephotettix cincticeps, based on the sampling data obtained during their last generations in the paddy field.

For every species concerned, individual distributions were proved to be contagious and to fit well to the negative binomial distribution. Further, it was found that the value of negative binomial parameter k is so stable for same species that a single value of k is applicable for a series of counts with different means, whereas that k differs remarkably among different species: if the reciprocal of the weighted estimate of common k which is an adequate index measuring degree of contagiousness of the distribution, is compared among different species, it is higher in the order of Nilaparvata, Delphacodes and Nephotettix.

The ecological and practical implication of constancy and heterogeneity within and among species was discussed respectively as to the value of parameter k.
On a method for estimating the rate of population interchange between two areas
Authors: Iwao Syun'iti
Published: November 2006

A method for estimating the rate of population interchange between two areas is described in this paper. It is applicable to the case where the sampling ratios and the survival factors of the populations on two areas are different from each other. From the marking‐and‐recapture data taken at three successive occasions, we can obtain the estimates of emigration factors, total survival factors over two areas and the ratio of surviving migrants to the total survivors over the two areas, for each of two populations initially living on different areas.
Observations on populations of the horseshoe crab Limulus (=Xiphosura) polyphemus
Authors: Sokoloff Alexander
Published: November 2006

Marked populations of Limulus (=Xiphosura) polyphemus reveal that in Cold Spring Harbor, New York, they consisted of 10,000–18,000 adults in 1957 and 1961. The sex ratio in 1957 was about 4 males: 1 female. Pairs may remain attached for as long as 9 days. An undisturbed female may lay as many as 12,000 eggs in one nest.

The Cold Spring Harbor populations appear to be rather sedentary: none of the 1,000 animals marked on the north edge of the sandspit in 1961 were detected in the outer harbor either at Laurel Hollow Beach or the peninsula adjacent to the Cold Spring Harbor Yacht Club 500–800 meters from the tagging site (see Fig. 1), nor were they found in the small beach adjacent to the Biological Laboratory in the inner harbor. Similarly, none of the 300 animals marked at this last site were found at the north edge of the sandspit.

The phenotype of the compound eye varies from black to pigmentless. Samples observed in Cold Spring Harbor and in the Marine Biological Laboratory, Woods Hole, Massachusetts (separated by Long Island Sound and a distance of 150 miles) differ in the frequency of the various phenotypes scored, but the mode of inheritance of eye color remains obscure.

The available evidence indicates Limulus has considerable phenotypic variation in regard to body size, eye color, and other characters believed to be inherited, with the result that demes or physiological races are created. It is argued that the belief that this organism is stable and has not changed since the Triassic 200 million years ago has foundation only in regard to the pattern of the body of Limulus, but not in regard to its genotype. Limulus does not seem to be different from other organisms for which considerable genetic evidence is available, and thus the statement that DNA is fairly stable and has remained so for 200 million years is open to question.
A marking‐and‐recapture analysis of the adult population of a phytophagous lady‐beetle, Epilachna sparsa orientalis
Authors: Iwao Syun'iti , Machida Akisato
Published: November 2006

A marking‐and‐recapture study of a population of overwintered adults of Epilachna sparsa orientalis was carried out in a small farm containing potatoes and egg‐plants. The experiment involved a single release and five recapture samplings during May–June. The data were analysed byLeslie's re‐recapture method. Assumption of randomness of sampling proved to be well satisfied.

Survival rate of the overwintered adult population was maintained as high as 90 per cent per week or more until early June, and then it declined rapidly towards the end of June. Initially overwintered adults exclusively lived on potato plants, but half of the population alive in mid June migrated to nearby egg‐plants. Emigration out of the experimental field, however, seemed not to be occurring.

Recapture data of marked individuals in the potato field indicate that majority of the individuals stayed within a radius of 3 m, at least for 2 weeks. Similar data taken from another field also suggest that their mobility was far restricted as compared with random movement within the field.

Some comparisons were made between the population behaviours of overwintered adults of E. sparsa orientalis and E. vigintioctomaculata.
Local distribution of two swallows of genus Hirundo, and breeding success of H. rustica
Authors: Mizuta Kuniyasu
Published: November 2006

The distribution of nests of the swallows was investigated in 1957, 1962 and 1963 at Koriyama, Nara Prefecture. Roughly speaking, the nest of Hirundo rustica was located in the urban areas, and that of H. daurica in the rural areas. This subdivision of the habitat seems to be due to the traditional system more or less depending on some interactions between them. The trend of the decrease in the nest number has not been found out from the 3‐year studies.

The observation on the breeding success of H. rustica was done in 1963, and it was estimated that 869 youngs in total fledged out from the study area.
Damped oscillation of population density at equilibrium
Authors: Utida Syunro
Published: November 2006

It has been theoretically assumed that the population density at the equilibrium oscillates with damping from generation to generation. In the adult population of the southern cowpea weevil, Callosobruchus maculatus, it was exemplified. But, it was not so clear in the adult population of the azuki bean weevil, C. chinensis as seen in that of C. maculatus. This difference seems to be due to the scramble type of competition that occurs in larval stage in C. maculatus, instead of in the egg stage as C. chinensis. Comparing with the oscillation from generation to generation obtained in the present experiment to that of Lucilia population found byNicholson, the oscillation in Lucilia population is composed of the cycle in a generation and the descending phase of each cycle of it is not regulated density‐dependently. The present result seems to be more appropriate for the demonstration of the theory of self‐adjustment of population.
Quantitative evaluation of predation by spiders on the green rice leafhopper, Nephotettix cincticeps Uhler, by a sight‐count method
Authors: Kiritani Keizi , Kawahara Sachio , Sasaba Takafumi , Nakasuji Fusao
Published: November 2006

A sight‐count method for evaluation of predation by spiders on the green rice leafhopper, Nephotettix cincticeps was proposed and its applicability was tested under natural conditions.

The number (n) of leafhoppers preyed on by spiders per rice hill per day was estimated by the formula:
urn:x-wiley:14383896:pope0187:equation:pope0187-math-0001
where F is the frequency of predation observed per hill:P is given by dividing the time spent feeding on prey by 24 hours; and C refers to the total amount of feeding activity expressed in terms of the activity during the standard time interval. The total number (N) of prey attacked during the specified period can be given as follows:
urn:x-wiley:14383896:pope0187:equation:pope0187-math-0002

With this method, the role of paddy‐inhabiting spiders, Lycosa pseudoannulata, Oedothorax insecticeps, Tetragnatha spp, and Enoplognatha japonica, as predator of N. cincticeps was evaluated with reference to life tables of the prey.

The advantages and limitation of the sight‐count method were discussed as compared with other methods so far proposed.
A study of natural populations of the celery leaf‐miner Philophylla heraclei L. (Diptera, Tephritidae)
Authors: Leroi B.
Published: November 2006

The study of the population dynamics of the celery leaf‐miner, Philophylla heraclei, must take into account the fact that the host‐plant is not present permanently and that it develops between the two annual generations of the insect. This development affects in particular the quality and quantity of the leaves fed upon by the mining larvae. It is possible to know the numerical change of the populations from one annual generation to the next (bivoltine insect) and from one year to the next by counting the populations in the various larval instars, responsible for the injury caused to celery.

An accurate method of counting of larval numbers, taking into account their change parallel with that of the host‐plant, is described in this text. It makes it possible to know with accuracy the duration and importance of the infestations in relation to external factors and to factors inherent to the host‐plant itself. Certain traits of larval behaviour, particularly the transfer of a larva from its original mine to a secondary mine as a result of food shortage can thus be established and estimated quantitatively.
Sampling error as a misleading artifact in “key factor analysis”
Authors: Kuno Eizi
Published: November 2006

The influences of sampling error in key factor analysis are investigated statistically. The error involved in the data distorts the results in various misleading ways. In the course of detecting key factors by correlation analysis, the distortion arises in the following two ways: (1) the contributions made by the first and the last components of population trend index (log I or K) to the total variation are overrated as compared with the others; and (2) spurious negative correlation arises between successive two components. The risk of misinterpretation due to such disturbance is usually increased further if the error is concentrated on any particular developmental stages. In the tests to detect density‐dependence by using regression analysis, the error consistently acts as if it were a density‐dependent factor: under the effect of sampling error, the slope b for the regression of log Ni+1 on log Ni, for example, is expected to become<1 even where there is no density‐dependent factor at all. A set of formulas are derived which may serve to check and correct these misleading distortions caused by the error. It is also shown that such undesirable influences can be avoided, at least to a considerable extent, if appropriate sampling plans are adopted for the study. The validity of key factor analysis is discussed in reference to this and some related problems.
Biological control of Pacific mites and Willamette mites in San Joaquin Valley vineyards: part III. Role of tydeid mites
Authors: Flaherty Donald L. , Hoy Marjorie A.
Published: November 2006

In the absence of spider mites, tydeids (Pronematus anconaiBaker and Pronematus ubiquitus [Mc Gregor]) may serve as alternate prey to maintain good numbers of the predatory mite, Metaseiulus occidentalis (Nesbitt) (Acarina, Phytoseiidae), late in the season. This late‐season predator and alternate prey relationship is necessary to stabilize Pacific mite populations and perpetuate balance in San Joaquin Valley vineyards.

Thriving laboratory colonies of tydeids were reared on a diet of windblown pollens, including cattail pollen (Typha sp., Typhaceae) and bottlebrush pollen (Melaleuca sp., Myrtaceae).M. occidentalis was successfully reared on a diet of tydeids and ovipositing predator females were obtained. In addition, pollen dusted on grapevines significantly increased both tydeid and indirectly M. occidentalis populations late in the season. These studies suggest that artificially disseminating cattail pollen or manipulating good pollen producing flora in and around vineyards may be used to correct situations where Pacific mites have become serious pests.
Colony genetic structure in the mono‐ and polygynous sibling species of the ants Camponotus nawai and Camponotus yamaokai: DNA fingerprint analysis
Authors: Satoh Toshiyuki , Masuko Keiichi , Matsumoto Tadao
Published: November 2006

Using the ant‐derived probe (pMY7), we performed DNA fingerprinting in monogynous and polygynous sibling ant species Camponotus nawai and Camponotus yamaokai. In monogynous C. nawai, band‐sharing probabilities were low between unrelated individuals (mean 0.09), but those and relatedness estimates were consistently high between workers of the same nest (mean 0.85 and 0.74–0.83, respectively), suggesting that the queen mated once and nestmate workers are super‐sisters. It also suggested monoandry: that is, that all nestmate workers shared most of the bands which were considered to have derived from a male. In polygynous C. yamaokai, band‐sharing probabilities were low between queens of different populations (mean 0.13), moderate between queens of different nests in the same population (mean 0.25), but very high between queens of the same nest (within‐nest means were 0.84–0.96). These results suggest that nestmate queens are genetically closely related with each other. Relatedness estimates between colony members sometimes reached 1. This might result from successive intranidal mating (inbreeding or large Wahlund effect) and adoption of new queens into the natal nests.
Modelling canopy photosynthesis using parameters determined from simple non‐destructive measurements
Authors: Anten Niels P. R.
Published: November 2006

Most models for canopy photosynthesis require a large number of parameters as input which have to be determined by means of direct measurements. Such measurements are usually expensive, time consuming and destructive. The objective of the present study was, therefore, to develop a simple but accurate canopy photosynthesis model based on a minimum number of parameters that can be determined non‐destructively. The results from previous studies were used to derive an empirical expression which describes the variation in leaf photosynthetic capacity (Pm) as a function of the light distribution in the canopy. The light distribution itself was calculated with a simple model which assumes only three leaf angle classes (0–30°, 30–60° and 60–90°). The leaf area index was determined indirectly from measurements of direct radiation below the canopy. The result was a model for canopy photosynthesis that requires only a few parameters. These parameters are the leaf photosynthetic capacity at the top of the canopy, the relative frequency of leaves in each of the three leaf angle classes, and the fraction of direct radiation below the canopy. Each of these parameters can be determined by means of simple non‐destructive measurements. The model was applied to dense stands of two monocotyledonous species: rice (Oryza sativa L.) and pearl millet (Pennisetum americanum (L.) K. Schum.). The rates of canopy photosynthesis thus calculated were compared to those obtained with a more elaborate reference model. The differences between the values obtained with the two models were small. The present photosynthesis model can, therefore, be considered to be a suitable alternative for the more elaborate model. It was further discussed that, since the model is based on purely non‐destructive measurements, it will be particularly useful in cases where it is required to estimate canopy photosynthesis at regular intervals over a length of time or in stands of vegetation that cover large areas of land.
Dry matter production, population structure and environmental conditions of the spring ephemeral Erythronium japonicum growing in various habitats differing in sunlight exposure in cool temperate Japan
Authors: Sawada Shinichi , Chida Saori , Sawaguchi Yuuki , Nagasawa Nobutaka
Published: November 2006

Phenology, dry matter production, population structure and environmental conditions were examined in Erythronium japonicum Decne plants growing on the floor of a deciduous broad‐leaved Quercus mongolica forest (Q. m. stand), an evergreen coniferous Cryptomeria japonica plantation (C. j. stand) and bare ground left for 3 years after the clearing of a forest composed of young Q. mongolica and Pinus densiflora trees (bare stand) in the cool temperate zone of Japan. The average population density of the plants growing at the Q.m. stand was much higher than that observed at the bare stand, whereas the average number of flowering plants at the former stand was less than half of that at the latter. The population density and number of flowering plants growing at the C. j. stand were both less than 30% of those at the Q. m. stand. The number of seedlings at the Q. m. stand was much more than that at the bare and C. j. stands. Their survivorship rate over 1 year at the former stand also seems to be significantly higher than those at the other stands. Their aboveground and belowground parts at the bare stand were exposed to more severe heat and water stress than those at the other two stands. The net production per leaf area of the plants growing at the Q. m. stand was two and six times larger than those at the bare and C. j. stands, respectively. The plants at the bare stand did not use the available solar radiation as efficiently for dry matter production through photosynthesis as those growing at the Q. m. stand, whereas those at the C. j. stand are strongly restricted in their photosynthetic process by the significantly limited light condition on the floor of the evergreen coniferous plantation. The differences in the number of plants reaching sexual maturity, the density and structure of the population and the net production between their three habitats are discussed here from the standpoint of differences in environmental conditions.
The impact of changing irrigation practices in rice fields on frog populations of the Kanto Plain, central Japan
Authors: Fujioka Masahiro , Lane Simon J.
Published: November 2006

Rice fields are important substitute wetlands for frogs. Traditionally, rice fields in Japan were supplied with water and drained via shallow earth ditches (old‐style). In the last 30 years, however, more than 80% of rice fields have been converted to a new irrigation system in which water is typically supplied through underground pipes via taps and is drained into deep, concrete‐sided ditches (new‐style). We compared the occurrence of frogs in paired areas of old‐ and new‐style rice fields at six locations in Ibaraki Pref., central Japan, from May to August 1995. The Japanese tree frog (Hyla japonica) did not differ in abundance between the two types of rice fields, but the Japanese brown frog (Rana japonica) and the Tokyo daruma pond frog (Rana porosa porosa) preferred the old‐style rice fields. These findings suggest that the status of Rana species has been adversely affected by the conversion of rice fields to the new irrigation system. Modification of the deep, U‐shaped concrete ditches and the water management regime during the spawning season is needed to safeguard these species.
Myrmecofauna of lucidophyllous forests in different developmental stages in south‐western Japan
Authors: Touyama Yoshifumi , Nakagoshi Nobukazu , Yamamoto Tetsuya
Published: November 2006

Lucidophyllous forest is the climax vegetation of the lowland and foothill areas of south‐western Japan. We investigated the myrmecofauna of lucidophyllous forests in different developmental stages in relation to the intensity of disturbance. The less‐disturbed lucidophyllous forests contained a greater variety of myrmecofauna. This pattern was explained by the condition of the habitat. Richness in epigeal and/or hypogeal ant species is related to habitat structure, especially vegetation structure expressed as summed vegetation cover, and the proportion of evergreen trees was a better predictor of ant species richness than the depth of the soil organic layer. In disturbed stands, habitat conditions have deteriorated; subsequently, some silvicolous ant species have disappeared.
Intraspecific nest parasitism in the grey starling (Sturnus cineraceus)
Authors: Yamaguchi Yasuhiro , Saitou Takashi
Published: November 2006

We studied intraspecific nest parasitism in the grey starling (Sturnus cineraceus) in 1992 and 1993. We used three criteria to detect nest parasitism: (i) the appearance of more than one egg per day while the host was laying; (ii) the appearance of extra eggs after the host completed its clutch; and (iii) the appearance of eggs which were of a different shape, size and color to other eggs in the clutch. There were 290 nests (157 nests in 1992; 133 nests in 1993) in which the clutch was completed early (clutches initiated before May 10). Twenty‐nine (1992) and 32 (1993) nests contained at least one parasitic egg. Parasitic eggs hatched if they were laid during the laying period and early in the incubation period of their host, and a few of them fledged. Fledging success of parasitic eggs was not different from that of eggs in non‐parasitized nests if parasitic eggs were laid during the host's laying period. However, fledging success of all parasitic eggs was fewer than that of eggs in non‐parasitized nests. By comparison, fledging success of parasitized nests was not a great as that of non‐parasitized nests.
Competitive influence of isaza, Chaenogobius isaza, on ayu, Plecoglossus altivelis, in Lake Biwa
Authors: Miura Taizo
Published: November 2006

Competitive influence of the isaza population on the ayu population was studied in Lake Biwa.

The results of comparison of ecology of the two species suggest that interaction of ayu and isaza possibly occurs in cold season when there is no other important competitor.

The significance of interspecific competition between them is evaluated as a factor controlling the rate of recruitment of juvenile through analysis of the Pre‐war catch statistics.

Presence of the compensation between the juvenile stage and the adult one relieve the ayu population of influence of interspecific competition which they will suffer in the stage of juvenile.

Competitive processes which will be responsible for increase of mortality and reduction of individual growth are discussed.
Behavior and mortality of the southern stink bug Nezara viridula in Hawaii
Authors: Nishida Toshiyuki
Published: November 2006

This paper is concerned with some aspects of the ecology of the southern green stink bug, Nezara viridula, in Hawaii. Dispersal studies on adults showed an asymetrical dispersal pattern. The rate of plant to plant to movement by the adults was 3.3–6.7 feet per day. Mortality studies showed that egg predation by ants, Pheidole megancephala, was as high as 80–90 per cent. Egg parasitism by Telenomus basalis was highest during February, 1965, and adult parasitism by Trichopoda pennipes was highest during July, 1964, to January of the following year. The population of N. viridula declined during May, 1964, to May, 1965. This decline occurred simultaneously with the decline in the number of eggs produced per female. It has been speculated that this reduction in egg production was caused by parasitism by T. pennipes.
Comparative analysis of breeding rates of rural and urban grey starling colonies in Tokyo area: The second report (Part 2)
Authors: Kuroda Nagahisa
Published: November 2006

The rates of clutch size, brood size and brood‐size fledged recorded during the period 1956≈63 (2 years interrupted) in the rural and the urban colony of the grey starling were analysed comparatively.

The clutch size was significantly larger in the urban than in the rural one and the brood size was also larger significantly in the urban population. But, the difference in brood‐size fledged was insignificant.

This reflected that the hatching rate was similar in both colonies (the rates in total differed but possible unusual rate was included in the clutch size of 5 eggs) and this may be determined physiologically but not depending upon food supply since smaller clutches showed higher hatching rate.

However, the fledging rate was higher in the rural and lower and more variable in the urban colony. This is apparently due to food which was nutritive animal food in the rural but largely mixed with fruits in the urban.

The fledging rate was rather irregularly variable with brood size suggesting that this is dependent upon parents' adaptability in feeding. However, the rate of 100% fledging becomes higher from brood sizes of 6 and less chicks.

Thus, in general larger clutch and brood sizes produced larger absolute numbers of chicks and chicks fledged respectively. But, 5 was the most frequent size in the clutch and brood sizes and 4 in the brood‐size fledged.

From the above, the ecological evolution of urban population was discussed.