bluuebunny/crossref_metadata_2025 huggingface dataset:
An analysis of scientific understandings of preservice elementary teacher education students
Authors: Ginns Ian S. , Watters James J.
Published: October 2006

This article reports an investigation of the intuitive scientific ideas and understandings of 321 preservice elementary teacher education students enrolled in the 2nd year of a 3‐year program. The sample completed a physical science concept challenge instrument by responding, in writing, to open‐ended questions about the concepts of floating/sinking, the nature of matter, air pressure and its effects, and the balance beam. Subjects' responses and explanations were analyzed, and response categories established. The results reveal that the majority of subjects, with the exception of a high proportion of those who had a successful senior high school background in physics and chemistry, have misunderstandings in these basic concept areas. It is argued that teachers should have a sound conceptual knowledge base in order to implement effective problem‐solving strategies in the elementary science classroom. The importance of teaching science in elementary schools is widely acknowledged, therefore, teacher educators must identify and implement more effective strategies for science instruction in preservice teacher education courses that will enable all students to construct scientifically accurate concept knowledge.
Relationships between metaphors, beliefs, and actions in a context of science curriculum change
Authors: Tobin Kenneth , Lamaster Sarah Ulerick
Published: October 2006

This study is an interpretive investigation of Sarah, a first‐time teacher of middle‐ and high‐school science who, because of high levels of disruption, was unable to establish and maintain environments favorable to learning. Sarah reflected on her roles as a teacher and identified facilitating learning, management, and assessment as salient, each being associated with defining metaphors and belief sets. Sarah's efforts to improve her teaching began with the construction of a new metaphor, the social director, for her role as manager. She developed coherence between the new metaphor and beliefs about constructivism, teaching, and learning. Sarah then managed her class in accordance with the social director metaphor and, although improvements were apparent, some students were uncooperative. Sarah then changed her metaphor for assessment from the teacher being a fair judge to the teacher looking through a window into a student's mind, an opportunity for students to show what is known. When this metaphor guided Sarah's assessment practices the learning environment improved appreciably. Although the development of new metaphors was a significant part of the process of reconceptualizing her roles as a science teacher, Sarah could not have improved the quality of teaching and learning without substantial assistance from her colleagues and school administrators.
Gender, race, ethnicity, and science education in the middle grades
Authors: Catsambis Sophia
Published: October 2006

This article examines gender differences in science achievements and attitudes during the middle grade, when our nation's scientific pipeline begins to emerge. It uses data from a large, nationally representative sample of eighth‐grade students (NELS‐88). The findings show that in these grades female students do not lag behind their male classmates in science achievements tests, grades, and course enrollments. Actually, some female students have higher probabilities of enrolling in high‐ability classes than males. However, female students have less positive attitudes toward science, participate in fewer relevant extracurricular activities, and aspire less often to science careers than males. Students' science attitudes and career interests vary according to students' gender as well as their racial or ethnic background. These findings emphasize the need to further examine the interrelationships between gender and race or ethnicity in our efforts to understand the processes leading to women's limited participation in science‐related careers.
Analysis of analogies used by science teachers
Authors: Dagher Zoubeida R.
Published: October 2006

Science teachers use analogies that display a rich variety of form and content. An account of science teacher analogies that relies solely on systems of analysis imported from other fields of inquiry tends to obscure the unique features of these analogies as they operate within classroom discourse. This study examines teachers' analogies in context and highlights some of their special characteristics. The purpose of this analysis is to increase our understanding of how analogies operate in naturalistic instructional settings and to generate new research questions about science teaching and learning in view of the broader dimensions of the curriculum.

Science isa very human activity. It involves human actors and judgements, rivalries and antagonisms, mysteries and surprises, the creative use of metaphor and analogy. It is fallible, often uncertain, and sometimes creatively ambiguous [Lemke, 1990, p. 134].
Biology teachers' perceptions of subject matter structure and its relationship to classroom practice
Authors: Gess‐Newsome Julie , Lederman Norman G.
Published: October 2006

The purpose of this investigation was to determine the nature of biology teachers' global content understandings (herein called subject matter structure‐SMS), the sources and formation of SMSs, and the variables that differentially affected teachers' abilities to translate SMSs into classroom practice. Case studies of 5 experienced biology teachers were constructed through interviews, classroom observations, and analysis of instructional materials. The data were qualitatively analyzed to describe the SMS exhibited by the teacher in the classroom and compared to SMSs provided by the teachers in postobservation interviews. The teachers' SMSs for biology were based on discrete content topics rather than conceptually integrated themes. Though most teachers recognized the integrated nature of biology, few used such conceptions to guide practice purposefully. The initial formation of SMSs were typically credited to college content courses and modified by the act of teaching. Opportunities for reflection and reinforcement seemed critical for the formation of coherent SMSs. The relationship of SMSs to classroom practice was complex and varied. The most direct form of translation occurred in the scope of course content. Variables that differentially affected SMS translation (typically through mitigation) included teacher intentions, content knowledge, pedagogical knowledge, students, teacher autonomy, and time.
Talking about science: An interpretation of the effects of teacher talk in a high school science classroom
Authors: Moje Elizabeth B.
Published: October 2006

This paper builds on research in science education, secondary education, and sociolinguistics by arguing that high school classrooms can be considered speech communities in which language may be selectively used and imposed on students as a means of fostering academic speech community identification. To demonstrate the ways in which a high school teacher's language use may encourage subject area identification, the results of an interactionist analysis of data from a 2‐year ethnographic study of one high school chemistry classroom are presented. Findings indicate that this teacher's uses of language fell into three related categories. These uses of language served to foster identification with the academic speech community of science. As a result of the teacher's talk about science according to these three patterns, students developed or reinforced particular views of science. In addition, talking about science in ways that fostered identity with the discipline promoted the teacher as expert and built classroom solidarity or community. These results are discussed in light of sociolinguistic research on classroom competence and of the assertions of science educators regarding social and ideologic implications of language use in science instruction.
Determining the conceptions of teaching science held by experienced high school science teachers
Authors: Hewson Peter W. , Kerby Holly Walter , Cook Perry A.
Published: October 2006

The article describes the process of analysis for determining a teacher's conception of teaching science using an available interview task. The analytical process provides a transparent link between teachers' spoken words and the different representations of their conceptions of teaching science. Representations of a teacher's conception of teaching science include a grid for analyzing different themes in a teacher's conception, a brief summary of the themes, and a longer written interpretive summary. Because these representations are based on the fundamental components of teaching science, they allow the uniqueness of both specific and structural aspects of teachers' views to emerge, and they facilitate comparisons between teachers. The analysis and its outcomes are exemplified using interviews with several experienced high school science teachers.
Investigation of worldview theory in a south african context
Authors: Lawrenz Frances , Gray Brian
Published: October 2006

This article reports on an exploratory investigation carried out to identify conceptions of some components of worldview, based on logicostructural worldview theory, held by science student teachers in a South African context. It explores relationships among worldviews, student characteristics, and scientific concepts. The sample included 48 final‐year science student teachers. Data were gathered by a questionnaire with follow‐up interviews. Questions were based on Kearney's model of worldview with stimulus items related to each of seven worldview categories. Responses were categorized and examined for possible relationships. Results of the investigation indicated that students' conceptions of time and distance were nonmechanistic and psychologically bound and that authoritarian scientific explanation was considered as sufficient for proof. Some significant relationships were found between items as well as between field of study and scientific conceptions.
Science knowledge and cognitive strategy use among culturally and linguistically diverse students
Authors: Lee Okhee , Fradd Sandra H. , Sutman Frank X.
Published: October 2006

Science performance is determined, to a large extent, by what students already know about science (i.e., science knowledge) and what techniques or methods students use in performing science tasks (i.e., cognitive strategies). This study describes and compares science knowledge, science vocabulary, and cognitive strategy use among four diverse groups of elementary students: (a) monolingual English Caucasian, (b) African‐American, (c) bilingual Spanish, and (d) bilingual Haitian Creole. To facilitate science performance in culturally and linguistically congruent settings, the study included student dyads and teachers of the same language, culture, and gender. Science performance was observed using three science tasks: weather phenomena, simple machines, and buoyancy. Data analysis involved a range of qualitative methods focusing on major themes and patterns, and quantitative methods using coding systems to summarize frequencies and total scores. The findings reveal distinct patterns of science knowledge, science vocabulary, and cognitive strategy use among the four language and culture groups. The findings also indicate relationships among science knowledge, science vocabulary, and cognitive strategy use. These findings raise important issues about science instruction for culturally and linguistically diverse groups of students.
Students' and teachers' misapplication of le chatelier's principle: Implications for the teaching of chemical equilibrium
Authors: Quílez‐Pardo Juan , Solaz‐Portolés Joan Josep
Published: October 2006

The aim of this article was to study the reasons, strategies, and procedures that both students and teachers use to solve some chemical equilibrium questions and problems. Inappropriate conceptions on teaching and a lack of knowledge regarding the limited usefulness of Le Chatelier's principle, with its vague and ambiguous formulation and textbook presentation, may be some of the sources of misconceptions about the prediction of the effect of changing conditions on chemical equilibrium. To diagnose misconceptions and their possible sources, a written test was developed and administered to 170 1st‐year university chemistry students. A chemical equilibrium problem, relating to the students' test, was solved by 40 chemistry teachers. First, we ascertained that teacher's conceptions might influence the problem‐solving strategies of the learner. Based on this first aspect, our discussion also concerns students' and teachers' misconceptions related to the Le Chatelier's principle. Misconceptions emerged through: (a) misapplication and misunderstanding of Le Chatelier's principle; (b) use of rote‐learning recall and algorithmic procedures; (c) incorrect control of the variables involved; (d) limited use of the chemical equilibrium law; (e) a lack of mastery of chemical equilibrium principles and difficulty in transferring such principles to new situations. To avoid chemical equilibrium misconceptions, a specific pattern of conceptual and methodological change may be considered.
Effects of concept and vee mappings under three learning modes on students' cognitive achievement in ecology and genetics
Authors: Esiobu Gladys O. , Soyibo Kola
Published: October 2006

This study verified the efficacy of concept and vee mapping heuristics under cooperative (CP), cooperative–competitive (CP‐CM) and individualistic whole (IW) class learning conditions in improving students' achievement in ecology and genetics. A total of 808 tenth‐grade students were involved in the study. The results showed that the experimental groups taught with concept and vee mappings under the three learning modes achieved significantly better than the control groups. Students in the CP‐CM condition in all groups achieved significantly better than their counterparts in the other two groups, whereas the CP‐CM experimental group students achieved significantly best. A significant interaction between treatment and ability suggested that an element of competition, when combined with small group cooperation, favored students of lower ability.
Navigating a sea of ideas: Teacher and students negotiate a course toward mutual relevance
Authors: Flick Lawrence B.
Published: October 2006

Theories of social cognition and verbal communication were used to analyze the science teaching of an experienced fourth‐grade teacher. Her teaching skills in language arts and reading were assets in negotiating the rapid flow of relatively unstructured information typical of inquiry in elementary classrooms, to help students generate relevant information about hands‐on experience. The teacher was a collaborator in this case study of her thinking and instructional planning, and her students' learning in a unit of instruction about space. Implications for elementary science instruction include recognizing the importance of embedded speech in conceptually broad discussions with students. Efforts to reform elementary science instruction should attend to these instructional skills more common to language arts instruction.
Problems in Teaching the Topic of Redox Reactions: Actions and Conceptions of Chemistry Teachers
Authors: De Jong Onno , Acampo Jeannine , Verdonk Adri
Published: October 2006

Although there is growing interest in studies of teachers' actions and conceptions, little is known about content‐related teaching problems arising in science classrooms. This article presents a case study of problems which can occur when teaching the topic of redox reactions to Grade 11 students. Two chemistry teachers, a senior and a junior teacher, were involved in the study. Their reflective comments on the teaching problems were also investigated. Research data were obtained from classroom observations and audiotaped recordings of classroom practice. After the lessons, we conducted semistructured interviews with the teachers. The teaching problems are reported in terms of teaching activities causing difficulties for students in considering new conceptions to be necessary, intelligible, plausible, or fruitful. Analyses of the teachers' comments on these teaching activities clarifies a number of reasons why they acted as they did. It can be concluded that teachers' scientific expertise is an important source of difficulties when teaching redox reactions. Implications for an improvement of current chemistry classroom practice and content‐related teacher training are offered.
Confronting the Evolution Education Abyss
Authors: Zook Douglas
Published: October 2006

This article discusses recent evolution education literature and highlights key themes and perspectives recognized in the scientific community but only minimally exposed within either the science classroom or the science education research agenda. Examples include: macroevolution, expressed as the history of life on earth; the microbial dominance of most of earth time as a learning tool and theme organizer; sym‐biogenesis and frequently accompanying horizontal gene transfer; Lamarck and the roles of others traditionally ridiculed in evolution study; and new views of fundamental evolution topics such as speciation. Several recommendations are given to address these important omissions within the science educator community.
Regulation of reproduction rate in a cyclic population of the red‐backed vole, Clethrionomys rufocanus bedfordiae
Authors: Nakata Keisuke
Published: October 2006

Changes of the components of reproduction were analyzed quantitatively in a two‐year cyclic population (which has two peaks in alternate years during a five‐year census) of the red‐backed vole, Clethrionomys rufocanus bedfordiae, with reference to its regulatory mechanism: (1) Variation in sex ratios was not associated with population phase or density, although a higher percentage of females in mature individuals was observed in the increase phase. (2) Females attained to sexual maturity at younger age and at lighter body weight than did males. All the youngest mature individuals were found in the low and the increase phases. Age and size at maturity became older and larger as the population went toward the peak phase. (3) Maturation rate was strongly associated with population phase and density; this component is an important and good parameter to predict population trend. Maturation rates were in the order, the low phase>the increase phase>the peak phase>the decline phase; the differences in the rates among these phases were significant. Maturation rate was somewhat depressed when the population density exceeded about 40 individuals/ha. Changes in age at maturity and in maturation rate are interpreted as derivative phenomena related to the population density and the capacity of the number of mature voles per unit area. (4) The maximum number of mature individuals were 26 males/ha and 29 females/ha; there was almost no increase of the number of mature voles at higher population densities over about 40 individuals/ha. The number of exclusive home ranges per hectare calculated from the observed range lengths did not differ much from the maximum number of mature voles of either sex. (5) Length of breeding period was shorter in the high‐density years than in the low‐density years; the breeding started earlier and ended earlier in the former than that in the latter. In the increase phase a few voles reproduced in winter. (6) The percentage of pregnant females was significantly lower in the peak phase than those in the other phases.
Genetic variance and covariance patterns of larval development in the small white butterfly Pieris rapae crucivora Boisduval
Authors: Tanaka Y.
Published: October 2006

Quantitative genetic theory indicates that genetic covariance patterns among life history characters should have played an important role as genetic constraint in life history evolution. Highly positve (and negative) genetic correlations between larval development time (or larval growth rate) and adult size characters were detected by means of sib analysis for the small white butterfly Pieris rapae crucivora. The genetic associations suggested that evolution of developmental characteristics and adult phenotypic traits were constrained by pleiotropy. The positive genetic correlations between development time and adult body size may be compatible with the trade‐off between them, but the negative genetic correlations between larval growth rate and adult body size are not predicted from theories of optimal energy allocation. That phenotypic correlations drastically differed from the genetic correlations indicates limitations of evolutionary inferences based only on phenotypic variation.
The screw‐worm fly Chrysomya bezziana villeneuve (Diptera: Calliphoridae) in a sterile insect release trial in Papua New Guinea
Authors: Spradbery J. P. , Tozer R. S. , Robb J. M. , Cassells P.
Published: October 2006

The feasibility of the sterile insect release method (SIRM) was tested against natural populations of the Old World screw‐worm fly, Chrysomya bezziana in the Musa Valley, Papua New Guinea. Sterile mating frequencies were determined from egg masses laid by native females on wounded, sentinel cattle. The aerial release of sterilised puparia resulted in low frequencies of sterile matings and few trap recaptures of released material. The release of chilled adult flies resulted in higher frequencies of sterile matings and many trap recaptures. The mean density of males released was 230 males per km2 per week over a target area of 361 km2 (48% of the valley). Sterile masses were first detected 2 weeks after the release of chill flies commenced, reaching a weekly peak of 33% after 5 weeks of releases with 15% of egg masses found to be sterile during the final month. The levels of sterile matings achieved in this trial were similar to comparable SIRM studies made in the USA, Mexico and Guatemala to control the New World screw‐worm fly, Cochliomyia hominivorax.
Nectar secretion pattern of the dish‐shaped flower, Cayratia japonica (Vitaceae), and nectar utilization patterns by insect visitors
Authors: Kakutani Takehiko , Inoue Tamiji , Kato Makoto
Published: October 2006

We studied the relationship between the diurnal nectar secretion pattern of flowers of Cayratia japonica and insect visiting patterns to these flowers. Flower morphology of C. japonica changed greatly for about 12 hours after flower‐opening and the maximum duration of nectar secretion was 2 days. The nectar volume peaked at 11∶00 and 15∶00, and declined at night and at 13∶00 regardless of time elapsed after flower‐opening. The nectar volume at the two peaks was, on average, 0.25 μl on bagged inflorescences and 0.1μl on unbagged inflorescences (both, sugar concentration=60%). The flower secreted nectar compensatory when the nectar was removed. This means that insects consume more nectar than the difference of nectar volume between bagged and unbagged flowers.

Apis cerana is a primary visitor of this flower, and was the only species for which we confirmed pollen on the body, among many species of flower visiting insects to this flower. Apis cerana visited intensively at the two peaks of nectar secretion. Visits of the other insects were rather constant or intensive only when there was no nectar secretion. Thus flowers of C. japonica with morphologically unprotected nectaries may increase likelihood that their nectar is used by certain pollinators, by controlling the nectar secretion time in day. In this study the pattern of nectar secretion allowed A. cerana maximum harvest of nectar.
Impact of lek mating on the sterile insect technique: A modeling study
Authors: Horng Shwu‐Bin , Plant Richard E.
Published: October 2006

Modelling studies are presented which describe the effect of lek mating on the control of a wild population by sterile male release. The mixed leks are assumed to follow a Poisson‐binomial distribution and the system includes three parts: territory defense, matings inside a lek and matings outside a lek. The effects of parameters on the hatchability are discussed. Among the parameters, sterile type effect (Ws), female choice (fs) and mating competitiveness (Cm) are the most important. The application to determining the effects of sterile male release and on the proportion of sterile males required for eradication are also discussed.
Differential diet breadths and species coexistence in leafroller‐hunting eumenid wasps
Authors: Itino Takao
Published: October 2006

There are, at least, three possible ways in which similar species coexist; resource partitioning, interference competition, and exploitation competition. Here, I investigated which way contributed to the coexistence of leafroller‐hunting eumenid wasp species. Resource partitioning and, in addition, differential diet breadths proved to promote species coexistence in this case.

First, I analyze the prey records and diet overlap of four eumenid species in a local area. The larger two eumenids hunted similar‐sized prey items and had similar potential taxonomic prey uses. But the diet breadth of the subsocial eumenid was much wider than that of the solitary one. As a result, the diet overlap between the two large eumenids decreased. This was because the solitary eumenid attend repeatedly to the same hunting site inhabited by one abundant prey species, while the subsocial one made random hunting. On the other hand, the two medium‐sized eumenids partitioned resources according to prey size.

Secondly, I related these results to prey choice by several other species of eumenid obtained from literature sources. Ten Japanese common eumenids were divided into four groups according to their prey size. In each of the four groups, 2 to 3 wasp species differentiated the habitat (1 group) or coexisted by means of differential diet breadths (parallel with differential sociality, 2 groups).
A model of the species rank‐abundance relation for a community in an open habitat
Authors: Kobayashi Shiro
Published: October 2006

A mathematical model is proposed to describe the relationship between the abundance and the rank of species in order from the most abundant to the least in a community in an open habitat. This model is derived as a corollary of a species‐area equation (Kobayashi, 1975) which could be expected in the case where the individuals of each species are uniformly distributed over a habitat area. Numerical simulation reveals that a rank‐abundance curve for a universe results in different species‐area or species‐individual curves according to the spatial distribution of individuals, and that the relative abundance of each species in a sample varies with sample size unless the spatial distribution of individuals is uniform. A species‐individual curve obtained bySanders's (1968) rarefaction method agrees with that observed actually only for the spatially uniform distribution. Change in the pattern of rank‐abundance curve with species diversity and with sample size is discussed in relation to the present model.
Effects of sterile insect releases on a population under predation or parasitism
Authors: Barclay H. , Mackauer M.
Published: October 2006

A continuous‐time differential equation model was constructed which describes the population dynamics of a predator prey system in which sterile prey are released in a program designed to eradicate or reduce the prey population. It was found that the dynamics of the system behave quite differently when predators are present.

Two conditions were found which have differing implications for the control program. If the predators still exist when the wild prey population declines to extinction, then the SIRM is assisted by the predators, sometimes to a considereble extent. If the predators decline to extinction before the wild prey population goes extinct, then the predators may or may not assist the SIRM depending on the parameters of the system. If the predators do assist the SIRM, then a potentially dangerous situation exists in which an explosion of the prey population could occur after the predators go extinct. Predator polyphagy would probably minimize this danger of an explosion since it would stabilize the predator population.
Prey preference of the wolf spider, Pardosa pseudoannulata (Boesenberg et Strand)
Authors: Heong K. L. , Bleih Saad , Rubia Elsa G.
Published: October 2006

Functional responses of the wolf spider, Pardosa pseudoannulata (Boesenberg et Strand) attacking the rice brown planthopper, Nilaparvata lugens (Stål.), and the mirid predator Cyrtorhinus lividipennis Reuter were both those of Holling Type II. The attack rate was higher and handling time lower for C. lividipennis. However, when caged with the two prey, the wolf spider showed a significant preference for N. lugens at a lower prey proportion. Proportions of prey attacked were significantly different from the expected ratios of prey available as well as from the predicted preferences derived from the functional response parameters. As proportions of N. lugens attacked changed from greater to less than expected as the proportions of N. lugens available increased, a “reverse switch” behaviour seems to be evident.
Contest and scramble competitions in two bruchid species, Callosobruchus analis and C. Phaseoli (Coleoptera: Bruchidae)
Authors: Toquenaga Yukihiko , Fujii Koichi
Published: October 2006

We performed multiple‐generation competition experiments between Callosobruchus analis and C. phaseoli with different bean sizes. In each system, we supplied 5 g of mung beans (Vigna radiata) every 10 days. We examined three types of bean conditions: 5 g of large beans, 5 g of small beans, and a mixture of 2.5 g of large and small beans. In small bean condition, C. analis dominated C. phaseoli in all three replicates and C. phaseoli was extinct by the 260th day. On the contrary, C. phaseoli overcame C. analis within 250 days in large beans in all three replicates. In mixed beans condition the two bruchid species coexisted more than 500 days in two out of the three replicates. Even in the exceptional case, both species coexisted for 460 days. These results were examined in the light of the predictions from short‐term larval competition experiments and a game theoretical model by Smith and Lessells (1985). The density and frequency dependent results during larval competition inside a bean was concluded to be a main factor to produce the above long‐term competition results.
Spatial pattern of pine wilt disease caused by Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) within a Pinus thunbergii stand
Authors: Togashi Katsumi
Published: October 2006

To understand the mechanism of spread of pine wilt disease caused by the pinewood nematode, Bursaphelenchus xylophilus, which is vectored by a cerambycid, Monochamus alternatus, the spatial distribution of trees weakened by the nematode was examined within a Pinus thunbergii stand from June to October for 4 years. The weakened trees were distributed in a clumped pattern in 1980 and 1981, at an early stage of infestation. In many cases, they showed a double‐clumped pattern. The degree of aggregation was higher in June or July than after August. They were uniformly distributed in June or July 1982 and in June 1983 whereas they showed a double‐clumped pattern after August. The trees were frequently weakened in June or July when they were near the trees weakened during the previous year. At quadrat sizes of more than 25 m2, spatial overlapping was pronounced between trees weakened during June–July of the current year and those weakened in the previous year. The seasonal changes in spatial distribution of weakened trees were explained by the interaction among M. alternatus, B. xylophilus and Pinus trees.
Inter‐ and intra‐population variations in diapause attribute of the two‐spotted spider mite, Tetranychus urticae Koch, in Japan
Authors: Takafuji Akio , So Ping‐Man , Tsuno Nobuko
Published: October 2006

Populations of the two‐spotted spider mite, Tetranychus urticae Koch collected from various localities and from various host plants in Japan showed wide variations in diapause attribute. Diapause percentages at 18°C/9L15D varied from nearly 100% in the north to 0% in the south‐west. At intermediate latitudes the mites showed wide inter‐population variations. Populations on herbaceous hosts in vinyl‐ or glass‐houses gave significantly lower incidence of diapause than those on roses and deciduous fruit trees. Presence of winter hosts and better host quality under protected environments seemed to favour non‐diapausing mites.

The temperature threshold for diapause expression also varied widely among local populations. Northern populations consistently had higher and less variable thresholds than populations at intermediate latitudes with thresholds between 15 and 18°C. Inbred lines derived from a population in Kyoto exhibited a wide variation in diapause percentage at 18°C. These results show that diapause in T. urticae is a quantitative threshold trait and that populations in central Japan consist of a variety of genotypes with different diapause traits. This might provide a genetic source for adaptation to local and temporal variations in environmental conditions.
Yearly variation in recruitment and its effect on population dynamics in Yoldia notabilis (Mollusca: Bivalvia), analyzed using projection matrix model
Authors: Nakaoka Masahiro
Published: October 2006

Long‐term variation in recruitment was estimated by constructing projection matrices for a marine bivalve, Yoldia notabilis, at two stations in Otsuchi Bay, northeastern Japan, and the effects of its variation on population dynamics were examined using a simple matrix model. The matrix model was developed from the Leslie matrix, in which the population growth rate λ was expressed as a function of recruitment rate r0. The equilibrium recruitment rate rs, or the recruitment rate required to maintain population at constant size (λ=1), was expressed by the reciprocal of the reproductive value of a newly recruited individual. The estimates of rs for the field population were lower at the shallower station than at the deeper station, reflecting higher survivorship and fecundity. Past recruitment rate estimated both by the field samplings for 3 years and by the back‐calculation from the current age structure for over 10 years showed large yearly variation, ranging between 0 and 58.6×10−4. The estimates were larger than rs, and hence, large enough to increase population size (λ>1) only in approximately one‐third of the estimated years. This suggests that the population has been maintained by occasional successful recruitment occurring once every few years.
Population‐level analysis on reduction in equilibrium population size of the azuki bean beetle
Authors: Tuda Midori , Shimada Masakazu
Published: October 2006

Responses of laboratory population of the azuki bean beetle Callosobruchus chinensis to temperature conditions of 30°C and 32°C are compared. Equilibrium population size was found to be lower at 32°C. A one‐generation process examined by reproduction‐curve experiments is divided into two consecutive life stages specified by different habitats, i.e., outside and inside beans. Modified logistic difference equations are used to describe these population‐level responses at each life stages. Sensitivity analysis is used to determine parameters of importance, thus determining the main cause of the reduced equilibrium population size at 32°C. The reduction resulted from the decrease in maximum population size of emerged adults which have experienced inside‐bean process. The application and limitation of this population‐level analysis to different levels are discussed.
Index of intensity of sexual selection: A comment on Nishida's article
Authors: Kasuya Eiiti
Published: October 2006

An index of intensity of sexual selection proposed by Nishida (1992: Res. Popul. Ecol. 34: 373–382) was examined. Two examples were presented to show that Nishida's index was not free from confounding effect of mortality schedule. Importance of removing the phylogenetic effects in comparative analyses was also discussed.
Density dependence depends on scale; at larval resource patch and at whole population
Authors: Tuda Midori
Published: October 2006

A previous study (Tuda and Shimada, 1993) has shown that the equilibrium population size of the azuki bean beetle was lower at 32°C than at 30°C and that this difference was due to a reduced maximum population size of emerged progeny through inside‐bean process. In this paper, these results were analyzed further on the scale of the individual bean where interaction among larvae took place. Per‐bean numbers of deposited eggs, hatched eggs, and emerged adults have been recorded at seven different parental densities under the two temperature conditions.

Three individual‐bean‐scale process hypotheses that may explain the reduced maximum emergence density on the whole population scale are suggested: (1) a lower maximum emergence per bean at 32°C than at 30°C, if the bean scale and the wholepopulation scale share the same density‐dependent pattern in adult emergence, (2) a limited range of hatched egg number per bean at 32°C, resulting from the adult oviposition process outside beans, and (3) different patterns of density‐dependent emergence between the two different scales.

This study showed that the inside‐bean pattern of responses on the bean scale was a simple saturated curve at 30°C, but one with a discontinuous decline at higher hatched egg densities at 32°C. On the contrary, during outside‐bean process, the peak number of hatched eggs decreased on this scale as observed on the wholepopulation scale. I discuss why the extracted factor of inside‐bean process on the whole‐population in the previous study could not be applied to the bean‐scale pattern.
A population dynamic model of Batesian mimicry
Authors: Yamauchi Atsushi
Published: October 2006

A population dynamic model of Batesian mimicry, in which populations of both model and mimetic species were considered, was analyzed. The probability of a predator catching prey on each encouter was assumed to depend on the frequency of the mimic. The change in population size of each species was considered to have two components, growth at the intrinsic growth rate and carrying capacity, and reduction by predation. For simplicity in the analyses, three assumptions were made concerning the carrying capacities of each population: (1) with no density effects on the mimic population growth rate; (2) with no density effects on the model species; and (3) with density effects on both species. The first and second cases were solved analytically, whereas the last was, for the most part, investigated numerically. Under assumption (1), two stable equilibria are possible, in which both species either coexist or go to extinction. Under assumption (2), there are also two stable equilibria possible, in which either only the mimic persists or both go to extinction. These results explain the field records of butterflies (Pachliopta aristolochiae and its mimic Papilio polytes) in the Ryukyu Islands, Japan.
Intervening in pest outbreaks: Simulation studies with the western tent caterpillar
Authors: Thompson W. A. , Vertinsky I. B. , Wellington W. G.
Published: October 2006

A stochastic model mimicking the behavior of the western tent‐caterpillar populations on Vancouver Island was used to study methods of suppressing an outbreak. Since many forest defoliators often receive only one treatment during their outbreak period, we applied a hypothetical single treatment at different times during a simulated outbreak, to assess the influence of timing.

Intervening early in the cycle was the best method of suppressing numbers below a tolerable threshold during a particular outbreak. Treatment during the most rapid period of increase was less effective, and treatments at or beyond the peak provided little relief during that particular outbreak. For longer‐term protection, however, treating the refugia of a declining population was far superior to less selective intervention. Concentrating the treatment within these refuges decimated the breeding stock surviving there at a time when the population could least afford such injury. Timing and focussing the intervention to obtain that maximal impact thus prolonged the period of suppression during the next outbreak.
Some risks and causes of mortality in mountain pine beetle populations: A long‐term analysis
Authors: Cole Walter E.
Published: October 2006

The interpretation of the probabilities presented in this paper is that none of the competing biological risks, acting in the presence of other risks, offers much, if any, regulatory influence upon a mountain pine beetle population. Consequently, if no single risk, or combination of these risks, offers much help, then the contention that mountain pine beetle populations are food‐regulated is once again strengthened (Cole andAmman, 1969). The evidence remains (or continues) that the mountain pine beetle is food‐regulated at optimum temperature conditions and temperature‐regulated at optimum food conditions. Reducing and/or minimizing tree loss to the mountain pine beetle is thus dependent upon manipulating the food supply or management of the tree (stand) growth.
Some beneficial effects of aggregation in young larvae of Pryeria sinica moore (Lepidoptera: Zygaenidae)
Authors: Tsubaki Yoshitaka
Published: October 2006

The effects of group size on the survival and development of young larvae of Pryeria sinicaMoore were investigated by laboratory and field experiments.

Under laboratory conditions, about 20% of isolated larvae died of unsuccessful feeding in the first instar, however, larvae survived successfully in aggregations of four or more individuals.

In the field, larvae emerge in early spring and wait for new leaves to open before feeding. In this period, the larger the group size of hatchlings the survival rate became higher. The nest‐web spun by hatchlings was considered to play an important role in protecting them from desiccation. In the period that larvae began to feed on leaves, more than 36 larvae are necessary to aggregate for the successful establishment of feeding groups. The nest‐web played an important role also in the establishment of feeding group. However, the natural group size of the first instar larvae was larger than the minimum group size to spin a sound nest‐web in the field experiment.

On the other hand, in later stage, larvae in a large group did not have an excess advantage in survival or developmental rate over larvae in a small group. It was found that the experiments on survival and developmental rates could not explain the reason that this species maintain large compact groups in the most part of larval period.
The effect of larval age range on survival of two Tribolium castaneum strains in mixed cultures, through pupal cannibalism
Authors: Wool David
Published: October 2006

The effect of larval age range on survival of two Tribolium castaneum strains in mixed cultures was studied in an experimental situation in which other selective forces were reduced to a minimum. Increasing the difference in larval age setween the strains by one day resulted in a reduction of survival of the faster‐developing mutant strain, because more of its earlier pupae were cannibalized by the larvae. General aspects of the effects of pupal cannibalism by larvae on the outcome of intra‐specific competition (sensu lato) in Tribolium are discussed.
Studies on the interspecies competition between the azuki bean weevil and the southern cowpea weevil IV. Competition between strains
Authors: Fujii Koichi
Published: October 2006

This study analyzes results of interspecies competition between the azuki bean weevil, Callosobruchus chinensis and the southern cowpea weevil, C. maculatus using the four geographical strains of each species.

Fifteen combinations of one strain from each species were set up to compete. The strains of C. chinensis, rather than of C. maculatus, characteristically determine the eventual outcomes of competition. Some strains of C. chinensis (jC and kC) invariably won every encounter with C. maculatus. Another strain (nC) always lost its encounters, while one other strain (iC) won some encounters (:cQ and :cQ) and lost others (:tQ and :bQ). For any combination the competition results were deterministic and no reversal in outcome was observed among the replicates.

The weakness of strain nC in competition is explained by its characteristics in single species populations, different greatly from other strains of C. chinensis, although it had the similar primary (individual) characteristics as other strains of C. chinensis. Strain iC had the shortest adult longevity in the four strains of C. chinensis although it behaved similar to strain jC at the single species population level. Especially under the food supply schedule of the present experiment the shortness of adult longevity might be the important factor determining the outcome.

The relationship of the eight strains based on the individual and single species population characteristics, and that based on the competition results were very similar. Even when the competition results could not be explained by any one or two of these characteristics alone, the outcome would be largely decided by the overall biotic profile made by several characteristics.
Host‐feeding and oviposition strategies of parasitoids in relation to host stage
Authors: Kidd N. A. C. , Jervis M. A.
Published: October 2006

Until now, mathematical models of parasitoid‐host interactions have not incorporated the tendency for destructively host‐feeding parasitoids to partition their feeding and oviposition behaviour in relation to different host stages. A literature survey reveals a trend for female parasitoids to feed preferentially or exclusively on earlier host stages and to oviposit preferentially or exclusively in/or later ones.

We explore the relative advantages to host‐feeding parasitoids of a number of possible host stage selection strategies. We develop hypotheses, formalizing and testing them using modifications to our earlier simulation model of host‐feeding strategies (Jervis and Kidd, 1986).

We conclude from our modelling that the advantage to be gained from feeding on early host stages and ovipositing in late ones is likely to be associated with: 1) reduced handling times when feeding on early stage hosts; 2) reduced wastage of progeny from mortality factors other than host‐feeding by the parent parasitoid, achieved by confining oviposition to late host stages; and 3) reduced probability of progeny mortality resulting from the parent's host‐feeding activities.
Verifying zero‐infestation in pest control: A simple sequential test based on the succession of zero‐samples
Authors: Kuno Eizi
Published: October 2006

A simple sequential test based on the succession of ‘zero's or uninfested sampling units is proposed for use in verifying zero‐infestation in pest control surveys. The method is applicable efficiently to both finite and infinite populations. Problems concerning its efficiency on application are discussed.