bluuebunny/crossref_metadata_2025 huggingface dataset:
An interpretive examination of high school chemistry teachers' analogical explanations
Authors: Thiele Rodney B. , Treagust David F.
Published: October 2006

This article reports an interpretive examination of four teachers' use of analogies to teach chemistry. The study describes why the teachers chose to use analogies, how the characteristics of the analogies employed varied from teacher to teacher, and from where the teachers derived their analogies. These teachers used analogies spontaneously, as well as on a planned basis, to explain abstract chemistry concepts both on a whole‐class basis and for individual students who indicated a lack of understanding. The teachers appeared able to ascertain that the students required an alternative representation without overtly seeking evidence to this effect. The presented analogies, especially those that were of the simple‐comparison type, appeared to have a motivational impact on the students. Several analogies were extended to map selected attributes, and these were believed by the teachers to be powerful explanatory devices. Pictorial analogies were frequently used to enhance analog familiarity, and further analog explanation was not uncommon, although the frequency with which the teachers stated the presence of analogical limitations was low. The article concludes by suggesting how science teacher education can be informed by case studies of teaching in context, in this instance of analogy‐inclusive teaching by four experienced chemistry teachers.
Understanding cellular respiration: An analysis of conceptual change in college biology
Authors: Songer Catherine J. , Mintzes Joel J.
Published: October 2006

This study explored and documented the frequencies of conceptual difficulties confronted by college students seeking to understand the basic processes of cellular respiration. Using concept maps, clinical interviews and an open‐ended instrument, viewpoints were elicited from 100 (novice) introductory biology students before and after relevant instruction in cellular respiration and from 100 (experienced) students enrolled in advanced biology courses. Chi‐square analyses revealed significant differences among groups in the frequencies of scientifically acceptable and alternative conceptions. The findings suggest that novices harbor a wide range of conceptual difficulties that constrain their understanding of cellular respiration. Furthermore, many of these difficulties persist after instruction and new ones arise. Often these conceptual problems remain intact among experienced students despite well‐planned, repeated instruction at advanced levels.
Gender differences in science achievement: Do school effects make a difference?
Authors: Young Deidra J. , Fraser Barry J.
Published: October 2006

The problem of the underrepresentation of girls in science in Australian schools is often attributed to their poor performance. Yet the role of both the home and the school in affecting female science achievement is rarely examined empirically. The comprehensiveness of the Second International Science Study database provided an excellent opportunity to investigate the presence of gender differences in science achievement. Although previous studies of gender differences in science achievement have relied on methodology that has not adequately accounted for the school effects, this study used the design effect and hierarchical linear modeling (multilevel analysis) to explore whether there were significant gender differences. The relative contribution of schools to student achievement was examined, and school‐level differences were found to contribute significantly toward explaining variations in student performance. Although statistically significant sex differences were found in physics achievement for 10‐year‐old, 14‐year‐old, and year‐12 students, school effects were much more powerful in explaining student differences (9–19%) when compared with gender (3%).
A window into thinking: Using student writing to understand conceptual change in science learning
Authors: Fellows Nancy J.
Published: October 2006

This study, conducted in an inner‐city middle school, followed the conceptual changes shown in 25 students' writing over a 12‐week science unit. Conceptual changes for 6 target students are reported. Student understanding was assessed regarding the nature of matter and physical change by paper‐and‐pencil pretest and posttest. The 6 target students were interviewed about the goal concepts before and after instruction. Students' writing during lesson activities provided qualitative data about their understandings of the goal concepts across the science unit. The researcher constructed concept maps from students' written statements and compared the maps across time to assess changes in the schema of core concepts, complexity, and organization as a result of instruction. Target students' changes were studied in detail to determine patterns of conceptual change. After patterns were located in target students' maps, the remaining 19 students' maps were analyzed for similar patterns. The ideas that students identified in their writing showed changes in central concepts, complexity, and organization as the lessons progressed. When instructional events were analyzed in relation to students' demonstrated ideas, understanding of the goal conceptions appeared in students' writing more often when students had opportunities to explain their new ideas orally and in writing.
The development of scientific reasoning skills in conjunction with collaborative writing assignments: An interpretive study of six ninth‐grade students
Authors: Keys Carolyn W.
Published: October 2006

In this investigation, three classes of ninth‐grade general science students participated in a collaborative report‐writing intervention. The purpose of this portion of the study was to evaluate students' collaboratively written laboratory reports for evidence of the use of scientific reasoning skills and to document qualitative changes in reasoning skill use over time. The participants in the study were 6 ninth‐grade students, representing three collaborative writing pairs. During the intervention, students wrote 10 laboratory reports over a 4.5‐month period. The author and classroom teacher designed report guideline prompts to scaffold students in the use of relevant scientific reasoning skills. The results indicated that students used reasoning skills to assess their current models of scientific understanding, make observations, interpret the meaning of results, and generate new models based on their data and relevant information. Participants showed the most improvement in writing that reflected the reasoning skills of (a) selecting and processing textbook passages, (b) drawing conclusions and formulating models, and (c) comparing/contrasting. Over time, participants improved their ability to compose explanations that represented a synthesis of prior knowledge, activity observations, and other sources of information. Collaborative writing encouraged students to construct their own understandings of science concepts by creating an environment in which thinking, reasoning, and discussion were valued.
Letting girls speak out about science
Authors: Baker Dale , Leary Rosemary
Published: October 2006

The purpose of this study was to try to determine what influences girls to choose science. Forty girls were interviewed in Grades 2, 5, 8, 11 using a semistructured protocol. The interview focused on feelings about science, science careers, peer and parental support, and how science is taught. To determine whether their responses were based on gender, each girl was asked to respond to questions as if she were a boy. The girls were highly self‐confident and positive about science. All of the girls took a strong equity position and asserted that women can and should do science. The girls liked learning science in an interactive social context rather than participating in activities that isolated them such as independent reading, writing, or note taking. Those who chose science careers were drawn to them because of strong affective experiences with a loved one and a desire to help. The interviews were analyzed through the framework of women's affective and psychological needs.
Subject matter competence and the recruitment and retention of secondary science teachers
Authors: Shugart Sanford S. , Hounshell Paul B.
Published: October 2006

The purpose of this study was to investigate the relationship of subject matter knowledge in science and the patterns of entering, leaving, and remaining in the teaching profession among college graduates trained to be science teachers. To do this, National Teachers Examination (NTE) Biology and General Science test scores served as the proxy for science subject matter knowledge for a sample of 83 individuals initially certified to teach science in North Carolina during a 4‐year period of time. The career patterns of these individuals as science teachers were documented and their work status was identified as nonrecruits, defectors, or career teachers. Using maximum likelihood logistical regression (MLOGIT) analysis, the relationship between career status (the dependent variable) and knowledge of science, race, gender, and the race and status (public or private) of the college from which they graduated was investigated. Of the 83 individuals in the analysis, 30 (36.1%) were identified as nonrecruits, 31 (37.3%) as defectors, and 22 (26.5%) as career teachers. Science subject matter knowledge was found to have a significant (p = .01) effect on the likelihood of being a nonrecruit versus a career teacher. The magnitude of this effect was also important, with the likelihood of being a nonrecruit increasing 120% for every 100‐point increase in score on the NTE Biology and General Science tests. Science subject matter knowledge also had a significant effect (p = .05) on the likelihood of being a defector versus a career teacher, with the likelihood increasing 80% for every 100‐point increase in NTE Biology and General Science scores. No other significant relationships were found.
Two investigations of students' understanding of the mole concept and its use in problem solving
Authors: Staver John R. , Lumpe Andrew T.
Published: October 2006

The authors' purpose in a series of two investigations is to examine the following research questions: (1) How do college students define the mole concept? (2) How do college students explain the numerical identity between the atomic or molecular mass of a substance and its molar mass? (3) Is there a connection between students' definitions of the mole concept and their explanations of the numerical identity between the atomic or molecular mass and the molar mass of a substance? (4) Do the connections in question 3 extend to students' ability to solve mole concept problems? Research questions 1‐3 are examined first through an analysis of students' answers and errors on a chemistry examination question that assesses their knowledge of the mole concept and the numerical identity between the atomic or molecular mass of a substance and its molar mass. Forty‐eight students in the first quarter of first‐year chemistry for scientists and engineers at a large, urban, midwestern research university during summer session are the subjects. One question on the first exam assesses the extent to which students understand the mole concept and the above‐mentioned relation. Results indicate that students' most frequent errors are: (1) failing to define the mole in terms of 12C; (2) defining the mole as Avogadro's number; (3) defining the mole as a mass; and (4) constructing a logical argument in vague terms or by using improper knowledge. The results and limitations of the first investigation prompted a follow‐up study in which the authors add research question 4 and further examine research questions 1‐3 through qualitative methods. In the second study, the subjects are 12 college students enrolled in a chemistry course for students with little or no background in chemistry. Each subject participates in a think‐aloud protocol designed to focus on the research questions. The authors qualitatively analyze the content of written transcripts of the audiotaped think‐aloud sessions. Results of the second investigation indicate that students' definitions of the mole vary and that their definitions are connected to their understanding of the numerical identity issue. Moreover, students' understanding of the numerical identity issue is a major stumbling block in terms of their ability to solve two problems in the think‐aloud protocol. Results of both investigations are discussed in terms of research in chemical education and in cognitive science.
Restraints to reform: The congruence of teacher and student actions in a chemistry classroom
Authors: McRobbie Campbell , Tobin Kenneth
Published: October 2006

An interpretive methodology was employed to examine interrelations between teacher and student actions in a context of teaching and learning in an urban high school in Australia, a teacher of 20 years' experience, and a Grade 11 chemistry class. Data sources included teacher and student interviews, direct observation and videotapes of 4 weeks of lessons, and responses to a classroom environment survey. Three narratives were constructed for a typical lesson, the perspectives of the teacher, and the perspectives of a composite student. These narratives were used to describe what happened and communicate what we learned from the study. Initially, the teacher and students had difficulty describing their beliefs; however, as the study progressed they used language to describe their practices and construct mental models that fit with their practices and beliefs about learning. Teacher and student goals, beliefs about teacher and learner roles, and constructions of the context were coherent to such an extent that there was little impetus for change. These findings are discussed in terms of the difficulties of initiating and sustaining reform when the teacher and students are satisfied with what is happening and other sociocultural factors tend to support the status quo.
Students' coding orientation and school socializing context in their relation with students' scientific achievement
Authors: Fontinhas Fernanda , Morais Ana M. , Neves Isabel P.
Published: October 2006

The study described in this article is part of a broader research developed by the Project ESSA‐Socio‐logical Studies of the Classroom‐whose main aim is to find out pedagogic practices more appropriate to all children. The study is mainly based on Bernstein's theory (1977, 1990; Domingos et al., 1986) and uses his concept of code as instrument of analysis. It intends to analyze the relation between general coding orientation and school achievement of socially differentiated children (social class, race, gender). It also intends to study the influence of differential modalities of school pedagogic practice on children's coding orientation. The results show that there is a mutual influence of family and school factors on students' coding orientation and science achievement. Specific characteristics of a pedagogic practice seem to be favourable to the development of the elaborated coding orientation required by the school.
How does biological knowledge grow? a study of life scientists' research practices
Authors: Abrams Eleanor , Wandersee James H.
Published: October 2006

In his book entitled Restructuring Science Education: The Importance of Theories and Their Development (1990), science educator Richard A. Duschl presented an equiposed triadic model of the growth of scientific knowledge that is based upon the work of philosopher of science, Larry Laudan (1984). Stage 1 of our study tested that model against the research practices of 10 accomplished life scientists employed at a Carnegie Research 1 university, via purposive sampling, a carefully sequenced model‐based interview schedule, face‐to‐face questioning, and propositional analysis of the interview transcripts. In Stage 2, a revised research‐based graphic version of Laudan's model was presented to two experts on the nature of science (Drs. Richard Duschl and Nancy Nercessian) during an extended interview. From that interview, further data collection and analysis, and an extensive literature search, our Stage 1 graphic was elaborated. In response to the interview, 5 novice graduate students and 5 advanced graduate students or new Ph.D's of the original 10 life scientists were interviewed, using the same methods, to ascertain if their research perceptions and practices will differ from that of their mentors. Implications for the teaching of biological science were derived from the research findings.
Gender‐inclusive science teaching: A feminist‐constructivist approach
Authors: Roychoudhury Anita , Tippins Debora J. , Nichols Sharon E.
Published: October 2006

The underrepresentation of women in science is an extensively studied yet persistent concern of our society. Researchers have identified numerous educational and social factors thought to be responsible for this underrepresentation (Kahle, 1990a; Kelly, 1987). One of the dominant explanations, used by many researchers for years to discuss gender differences in science and mathematics achievement as well as interest, has been the differences in the cognitive abilities of men and women. This explanation, however, has been discarded in recent years (Linn & Hyde, 1989; Linn 1990). On the basis of their meta‐analyses of various studies. Linn and Hyde (1989) concluded that gender differences in cognitive skills have declined and those that remain are largely explained by experiential differences. Women may not have different cognitive abilities, but they may have a different way of learning rooted in their role in society. The epistemic differences between men and women stemming from their standpoint in life can help us understand their differential interaction with the nature of science, and hence their participation in the field. In the following section, we will briefly discuss the feminist critique of science and extend the implication to science education.
Sex differences in science museum exhibit attraction
Authors: Greenfield Teresa AráMbula
Published: October 2006

This study examines the relative attraction of hands‐on, interactive science museum exhibits for females and males. Studies have demonstrated that such exhibits can be effective learning experiences for children, with both academic and affective benefits. Other studies have shown that girls and boys do not always experience the same science‐related educational opportunities and that, even when they do, they do not necessarily receive the same benefits from them. These early differences can lead to more serious educational and professional disparities later in life. As interactive museum exhibits represent a science experience that is‐readily available to both girls and boys, the question arose as to whether they were being used similarly by the two groups as well as by adult women and men. It was found that both girls and boys used all types of exhibits, but that girls were more likely than boys to use puzzles and exhibits focusing on the human body; boys were more likely than girls to use computers and exhibits illustrating physical science principles. However, this was less true of children accompanied by adults (parents) than it was of unaccompanied children on school field trips who roamed the museum more freely.
Reasoning about Interactions between Variables
Authors: Zohar Anat
Published: October 2006

Thinking about interactions between variables is a necessary condition for accurate scientific thinking. The purpose of this study was to investigate difficulties in thinking about interactions between variables and to suggest remedial educational means. A conceptual analysis distinguishes between valid interaction inferences, invalid interaction inferences, and limited inferences which can be seen as a partial or a primitive interaction inference. Empirical findings show that expert thinkers demonstrate thinking about interactions at both an operational and a metastrategic level. Some lay‐adults however, although able to draw many limited inferences, encounter substantial difficulties in drawing valid interaction inferences while engaged in an investigation of a scientific sort. Four types of difficulties were identified in this study: lack of a “double set of controlled comparisons” strategy that is necessary for valid inferences about interacting variables; lack of the conceptual framework for interacting factors; diversion of attention to other features; and difficulty in maintaining the necessary control of other variables. The implications of the findings to science curriculum are discussed.
Effectiveness of Using Computer‐Assisted Supplementary Instruction for Teaching the Mole Concept
Authors: Yalçinalp Serpil , Geban Ömer , Özkan Ilker
Published: October 2006

This study examined the effect of computer‐assisted instruction (CAI), used as a problem‐solving supplement to classroom instruction, on students' understanding of chemical formulas and mole concept, their attitudes toward chemistry subjects, and CAI. The objective was to assess the effectiveness of CAI over recitation hours when both teaching methods were used as a supplement to the traditional chemistry instruction. We randomly selected two classes in a secondary school. Each teaching strategy was randomly assigned to one class. The experimental group received supplementary instruction delivered via CAI, while the control group received similar instruction through recitation hours. The data were analyzed using two‐way analysis of variance and t‐test. It was found that the students who used the CAI accompanied with lectures scored significantly higher than those who attended recitation hours, in terms of school subject achievement in chemistry and attitudes toward chemistry subjects. In addition, there was a significant improvement in the attitudes of students in the experimental group toward the use of computers in a chemistry course. There was no significant difference between the performances of females versus males in each treatment group.
Simple mathematical models to describe the rate of mating in insect populations
Authors: Kuno Eizi
Published: October 2006

Simple models are constructed to describe the rate of mating in insect populations. The models are based on the assumption of random mate‐searching in a closed habitat, including four parameters, i.e., population size, sex ratio, searching efficiency and male's capacity on mating frequency. The modes of effects of these parameters on the rate of mating are analyzed and some principles deduced are discussed in relation to the mating process in natural populations.
Asymptotic methods for modeling biological processes
Authors: Wollkind D. J. , Logan J. A. , Berryman A. A.
Published: October 2006

The technique of matched asymptotic expansions is discussed as a means for derivation of uniformly valid functions describing population processes. Use of the technique is then illustrated through quantitative description of a rate‐temperature model, development of a functional model relating survival to attack density in bark beetles, and finally for derivation of a generalized competition function. It is concluded that the technique has potentially wide application for development of descriptive models in population ecology.
Two fish species competition model with nonlinear interactions and equilibrium catches
Authors: Shirakihara Kunio , Tanaka Syoiti
Published: October 2006

Two species competition model is built up by assuming the hypothetical second order interactions in order to consider effects of exploitation on two competing fish species with non‐linear interactions. Most important characteristic of this model, compared withLotka‐Volterra type linear competition model, is that this model can possess multiple stable equilibrium points. Therefore there is a possibility that two species keeping the equilibrium state at one stable equilibrium point will be attracted to the other stable equilibrium point after a heavy perturbation.

In this model reversible change of the fishing pressure does not always results in that of the equilibrium catch. In this sence MSY concept for single species can not be extended to this model. If there are multiple stable equilibrium points, the change of the dominant fish species, catastrophic and irreversible change of each equilibrium catch may be observed when the perturbation by the exploitation is added. This phenomenon immediately reminds us of the change of the dominant fish species between Japanese common mackerel and Pacific saury in the northwest Pacific Ocean.

In case of the management of two competing fish species with nonlinear interactions, the consideration on the balance between the fishing pressure for each species may be as important as the decision on the catch limit for each species. MSY level for each species based on the single‐species theory could be quite erroneous.
Host‐dependent association and its implications on the relative abundance of blue alfalfa aphid and pea aphid (Homoptera: Aphididae) on alfalfa in Oklahoma
Authors: Poswal M. Ashraf , Berberet Richard C.
Published: October 2006

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

In this study, we have developed a new method to estimate population parameters and applied it to a concrete example on the situation that there are two fisheries resources which are depleted only by catch, and that these two resources are not caught equally because of the difference of prices.

Switching function, which is originally used to describe the effort allocation that one predator eats two preys, has been introduced. We have constructed a model of fishery in which each fisherman pursues economical optimum.

The population size of two species at the beginning of the fishing season, catchability coefficient and parameters of switching function are estimated by the criterion of minimum error sum of squares between CPUE (catch per unit effort) of data and that by model.

We have applied it to the diver fishery of abalone in Ojika Island, Nagasaki Prefecture. The model describes well the situation during the season that CPUE of the less expensive species increases gradually as the population of the other species is depleted.
Variability in food consumption rate of natural populations in the spider, Nephila clavata
Authors: Miyashita Tadashi
Published: October 2006

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

The adaptive significance of sibling cannibalism was analyzed in the ladybird beetle Harmonia axyridis at two prey densities. Possible costs and benefits were considered from three points of view: the mother, the cannibal and the victim. Cannibals ate both infertile and fertile eggs, thereby increasing in body length and survival rate with the intensity of sibling cannibalism. The cannibalistic trait was clearly beneficial to the cannibal when aphid density was low. However, it was not always beneficial when aphid density was high and the victims were full siblings. The altruistic behavior of being a victim was beneficial only when the victim was cannibalized by full siblings at low aphid density. The mother attained almost equal fitness at low aphid density, regardless of the intensity of sibling cannibalism. This suggests that sibling cannibalism is not maladaptive for the mother. At high aphid density, however, mother's fitness decreased with the intensity of sibling cannibalism, indicating that sibling cannibalism is maladaptive for the mother when larval food availability is high.
A simple evolutionary model of dormancy and dispersal in heterogeneous patches with special reference to phytophagous lady beetles: I. Stable environments
Authors: Tsuji Nobuyuki , Yamamura Norio
Published: October 2006

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

The comparative analysis of life tables of the oriental moth, Monema flavescens, obtained in 6 patches for 8 generations in 4 years revealed the following:

The ratio of maximum to minimum of cocoon density for each patch ranged from 5.34 to 22.50, each value being more than 3.20, the ratio for the whole study area.

The density change from adult to cocoon in the next generation caused most of the spatial variation in density change per patch. The rate of adult‐to‐cocoon population change showed spatial density dependence in some generations but not in others. When the change rate lacked spatial density dependence, it was the key‐factor for spatial variation in adult density for the following few generations till the change rate recovered spatial density dependence. This was because of flooding, which killed the spatial density dependence existing potentially in the adult‐to‐cocoon change rate and damaged the same patches during the few successive generations.

The rate of population change from overwintered generation adults (summer ones) to first generation cocoons was not only the key‐factor for the rate of throughout‐the‐year change but temporally density dependent in each patch. Therefore, the density for the whole study area is considered to fluctuate within a range. However, the strong equilibrium seen in the cocoon density for the whole study area was due to the floods that happened to occur when the density was near and at its maximum, and it is considered that such a strong equilibrium does not always occur.

In the population change from summer adults to first generation cocoons, temporal density dependence was found in all the patches, but it was found only in one patch in the population change from autumn adults to second generation cocoons. This was because the spatial density dependence seen in the former corresponded to the absolute density of adults, while that in the latter corresponded to the relative density.
A Simulation model for the arrowhead scale (Hemiptera: Diaspididae) population dynamics on citrus trees in relation to pest‐management programs
Authors: Adachi Ishizue , Korenaga Ryoji
Published: October 2006

A mathematical model was constructed describing population dynamics of the arrowhead scale, Unaspis yanonensis Kuwana. The population occurrence patterns simulated by the model from 1971 to 1976 were relatively consistent with the actual findings in the field.

The effects of control tactics for this pest were examined on the basis of the model.

Effective timing of insecticide (petroleum oil and organophosphorous insecticide) application was indicated to be 40 days after the initial appearance of 1st‐instar nymphs in both the 1st and 2nd generations of the host.

The number of overwintering adult females in May of the next year (i.e., the starting point of the next year's population) decreased linearly with the increment in the degree of insecticide coverage. The pest populations were expected to be kept to low densities by petroleum oil sprays alone for the 1st generation when overall, complete coverage was accomplished.

Examination of the effects of two introduced parasitoids, Aphytis yanonensis and Coccobius fulvus, showed that they were able to control the scale population by themselves when more than 70% parasitism was achieved. When petroleum oil was applied to overwintering adults (termed winter petroleum oil) at the degree of coverage of 0.8, host populations were reduced by ca. 60% parasitism. When the winter petroleum oil was combined either with additional petroleum oil 40 days after the initial appearance of 1st‐instar nymphs of the 1st generation or with an organophosphorous insecticide 40 days after the initial appearance of 1st‐instar nymphs of the 2nd generation (degree of coverage=0.8 in each case), 40% parasitism led the reduction of the pest population.

The most desirable control program was considered to be one in which winter petroleum oil was used every year and additional petroleum oil or an organophosphorous insecticide was also used in those years when host density was high.
A male fitness advantage to wing reduction in the oriental chinch bug, Cavelerius saccharivorus okajima (heteroptera: Lygaeidae)
Authors: Fujisaki Kenji
Published: October 2006

A male fitness advantage to wing reduction was investigated for the oriental chinch bug, Cavelerius saccharivorus, which is wing dimorphic. Field surveys for the frequency of matings between wing morphs showed that the mating probability was much higher in brachypterous males than in macropterous males in the early breeding season. Brachypterous males copulated with not only brachypterous females but also macropterous females in this season. This led to a considerable rate (30%) of insemination of macropterous females just before emigration even in the early breeding season. A rearing experiment for the pre‐reproductive period of females revealed that females mated with brachypterous males copulated and oviposited earlier than females mated with macropterous males. These results indicate that there is a fitness advantage to wing reduction in the males of C. saccharivorus in terms of the earlier sexual maturation.
Principal component analysis of interrelations in stored‐wheat ecosystems infested with multiple species of insects
Authors: White N. D. G. , Sinha R. N.
Published: October 2006

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

Birds’ predation on gypsy moth egg masses deposited on tree trunks was quantitatively evaluated in a birch forest at Bibai, Hokkaido during the four winter seasons from 1974 to 1978.

Holling's disc‐equation could be successfully applied to describe the relationship between the total egg consumption by birds and the density of egg masses. A rapid method for fitting the disc‐equation to observed data was proposed based on the study byShinozaki andKira (1961).

Appreciable amounts of predation were observed only during the period when the depth of snow cover on the ground exceeded 1 m, while the egg masses deposited on lower parts of tree trunk below 1 m level suffered from only slight predation. It was therefore presumed that deep snow cover made the predator birds to change their feeding place from ground vegetation to tree trunks.

The duration of the period with snow accumulation deeper than 1 m was introduced into the disc‐equation as an additional parameter. The values calculated by the resultant formulation agreed with the observed values in respective years satisfactorily.

There were circumstantial evidences that the great tit, Parus major, was one of the important predators concerned.
Distribution patterns of and sampling plans for Tetranychus urticae Koch (Acarina: Tetranychidae) on roses
Authors: So Ping‐Man
Published: October 2006

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

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

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

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

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