bluuebunny/crossref_metadata_2025_split huggingface dataset:
Persistence of abnormal females that produce only female progeny with occasional recovery to normal females in Lepidoptera
Authors: Ishihara M. 
Published: October 2006

AbstractIn Lepidoptera, females that produce only female progeny have been found in wild populations of at least 12 species. In some species, recoveries, where abnormal females return to normal females, have been observed. A mathematical model of the population dynamics with recovery was developed to identify the conditions for realizing the persistence of abnormal females. Analysis indicated normal and abnormal females coexist and reach an equilibrium state at certain recovery rate values. The equilibrium values of normal and abnormal females were determined. When a population was in equilibrium it was shown that the ratio of normal to abnormal females and the sex ratio after reproduction are always functions of the recovery rate and the proportion of female offspring from an abnormal female to that from a normal female. Using the simulation it was found that, even when a population fluctuates under variable environmental conditions, the two ratios mentioned above reach equilibrium. Equilibrium relationships were applied to published data, and it was concluded that recovery from abnormal to normal females explains the persistence of abnormal females in some species of Lepidoptera. The model developed in this paper can also be used for analysing the persistence of abnormal females of other insect species.
How is life history variation generated from the genetic resource allocation?
Authors: Tanaka Yoshinari 
Published: October 2006

AbstractA simple quantitative genetic model is proposed to explain the observed genetic correlation structure of a bruchid beetle Callosobruchus chinensis in terms of two underlying variables: the resource acquisition and the resource allocation. Heritabilities and genetic correlations among age‐specific, fecundities are regarded as consequences of genetic variations of the two variables. Genetic correlations are predominantly positive in both predictions and observations. Nonetheless, comparison between observed and predicted values in heritabilities, genetic correlations, and genetic principal components suggested significant genetic variances both of the resource allocation and the resource acquisition. The prediction of the model is discussed in relation, to experimental tests of trade‐off in life history evolution.
Effects of parasitoid community structure upon the population dynamics of the honeysuckle leafminer, Chromatomyia suikazurae (Diptera: Agromyzidae)
Authors: Kato Makoto 
Published: October 2006

AbstractPopulation dynamics of a leafminer, Chromatomyia suikazurae (Agromyzidae, Diptera) and its parasitoid community were studied for ten years at seven natural populations along an altitudinal gradient in Japan. This species which mines leaves of a forest shrub, Lonicera gracilipes (Caprifoliaceae), was attacked by 25 hymenopterous parasitoid species. Annually, the parasitoid community structure varied less within a population than among populations. The seven parasitoid communities were clustered into three groups corresponding to the altitudinal gradient: (a) lowland communities dominated by late‐attacking, generalist pupal idiobiont eulophids and with highest species diversity, (b) hillside communities dominated by an early‐attacking, specialist larval‐pupal koinobiont braconid and (c) highland communities dominated by an early‐attacking, generalist larval idiobiont eulophid. Annual changes of the host larval densities among the local populations were largely synchronous rather than cyclic. Among these populations, host density levels and mortality patterns greatly varied. By analyzing these inter‐populational differences of host mortality patterns, the following conclusions were drawn: (1) The host mortality patterns were determined by the host utilization patterns of the locally dominant species. (2) The host pupal mortality but not larval mortality was related to species diversity but not to species richness itself of each parasitoid community. (3) Density dependence was detected only in pupal mortality at a lowland population dominated by late‐attacking pupal parasitoids. These results suggest that interspecific interactions of parasitoids add additive effects to host population dynamics dissimilarly among local populations with different parasitoid communities.
Modelling selection for resistance to methods of insect pest control in combination
Authors: Barclay Hugh J. 
Published: October 2006

AbstractThe development of resistance to insecticides is now widespread among insects. Other methods of pest control are also potentially at risk of encountering resistance. A modelling approach is presented here to evaluate the effects of combining methods of insect pest control on the selection for resistance to the control methods. This analysis is based on partitioning the total mortality acting on a population into its constituent components from all known sources, and these are related to selection for resistance. When two control methods are used in combination, selection for resistance against the two is a linear function if the two don't interact, otherwise it may be sublinear or supralinear. A specific example is presented using a model of the Olive fruit fly (Dacus oleae Gmel.) and employing food‐baited and pheromone‐baited traps for control. The control methods that appear least likely to encounter resistance are natural enemies and the use of pheromone traps for male annihilation. These should be integrated into a control program where possible to minimize the development of resistance to other control methods being used.
Predator‐prey system structure in patchy and ephemeral phytotelmata: Aquatic communities in small aroid axils
Authors: Mogi M. , Sembel D. T. 
Published: October 2006

AbstractMechanisms allowing the persistence of an aquatic predator‐prey system in tiny pools (the mean ca. 0.5 ml) held by taro axils were analyzed from the viewpoint of temporal and spatial patterns of habitat use. Predatory larvae of a mosquito Topomyia tipuliformis concentrated in young axils, while 9 other taxa utilized both young and old axils or concentrated more in older axils. The total prey density was lower in axils with the predator but the density of each prey taxon (except for a few cases) and the number of prey taxa did not differ between axils with and without predators. This indicates that T. tipuliformis is a general predator and does not influence prey community organization through selective removal of particular prey taxa. Inter‐axil distribution of T. tipuliformis was aggregated in the first instar but uniform in the third and fourth instars due to intraspecific cannibalism, which assures the survival of a single individual under short food supply. Distributions of prey taxa were mostly aggregated, fitting the negative binomial distribution. Thirty seven out of 45 associations of 10 taxa were independent with 3 negative (between the predator and some late‐colonizing prey) and 5 positive (between some prey taxa) associations. Probabilistic refuges (produced by independent aggregated distributions) reduced interspecific encounters which may result in competition and predation, and thus probably facilitated prey coexistence. There was no evidence for the importance of predation in structuring the prey community. This system may be prey‐dominated in that predator persistence depends on prey community existence but prey community structure depends less on predation.
How an ant decides to prey on or to attend aphids
Authors: Sakata Hiroshi 
Published: October 2006

AbstractThe following results on the behavior decision making of the antLasius nigertoward two species of myrmecophilous aphidsLachnus tropicalisandMyzocallis kuricolaon chestnut trees have been found. (1) An individual worker consistently attended only one aphid species, even if her nestmates attended other aphid species on the same tree. (2) The ants preyed less on the aphid species which they attended than on other myrmecophilous aphid species. (3) The ants preyed less on the aphids which had been attended by their nestmates, even if both aphids were the same species. (4) The ants preyed less on aphids which had provided honeydew to their nestmates. (5) The increased aphid density per ant led to an increase in the rate of predation on the introduced aphids by the ants. These results suggest that each worker ofL. nigerchooses aphid species to attend from her experience. In addition, the workers can recognize whether an aphid has been attended by their nestmates and whether an aphid has given their nestmates honeydew. Through these processes, each worker decides to attend or to prey on the aphid. As a result, they may realize efficient collective foraging dependent on aphid density per worker.
Statistical study of Trichogramma brassicae efficiency in relation with characteristics of the European corn borer egg masses
Authors: Hawlitzky N. , Dorville F. M. , Vaillant J. 
Published: October 2006

AbstractThe efficiency of Trichogramma brassicae inundative releases in biological control of the European corn borer Ostrinia nubilalis was analyzed in seven plots of 504 plants, each situated in a corn field naturally infested by the European corn borer. Different strategies of Trichogramma releases were defined on the seven plots. These inundative releases were concluded to be highly efficient even on plots where there were either no parasitoid release or only one parasitoid release at the beginning of the egg mass laying period.
Survival rate and sex ratio in habu, Trimeresurus flavoviridis (Viperidae), on the subtropical Okinawa Island, Japan
Authors: Nishimura Masahiko , Kamura Takao 
Published: October 2006

AbstractWe examined the age structure and sex ratio of a viperid snake, Trimeresurus flavoviridis, based on samples collected by hand by local inhabitants, habu hunters and by baited traps in the middle and south of Okinawa Island, Japan. Small individuals had a low possibility of capture in all the collecting methods. The age structure was estimated through summing up the age frequency in each snout‐vent length (SVL) class in samples with a similar SVL structure. From the age structures, annual survival rates of adult females and males were estimated to be 0.7 and 0.8, respectively. In most samples the sex ratio was biased towards males, especially in March and August and in large individuals. However, the female proportion increased in June.
An experimental study on the foraging behavior of a pit‐building antlion larva, Myrmeleon bore
Authors: Matsura Toshiaki 
Published: October 2006

SummaryForaging behavior of a pit‐building antlion larva, Myrmeleon boreTjeder was investigated experimentally to elucidate the relation between the feeding level and pit relocation.
In artificial sands constructed in the field the 3rd instar larvae of M. bore rarely changed the positions of their pits, though several antlions had moved actively until they constructed pits. The average feeding rate was 0.3 prey/day/pit, and about 60% of prey captured were ants.
To examine whether or not M. bore larvae concentrate into the area where they can capture more prey, 8 antlions were released into each of 6 boxes filled with sand. I divided the sand surface of each box into two half areas, then gave prey to the pits built in a half area and gave no prey to the pits built in the other half. During the 50‐day observation period, nonfed antlions never moved into the area where prey were given.
The 3rd instar larvae were reared separately without food. Even under starved conditions they rarely relocated their pits until dealth. The average duration of survival period was 83.9 days.
The experimental results indicate that M. bore larvae adopt a tactic of sedentary ambushing. These larvae exhibit low movement rates which are independent of prey capture rates.
A laboratory study on the predatory mite Typhlodromus pyri (Acarina: Phytoseiidae): I. The effect of temperature and food consumption on the rate of development of the eggs and immature stages
Authors: Hayes A. J. , McArdle B. H. 
Published: October 2006

SummaryDevelopment periods were determined for eggs and juvenile stages of the predatory phytoseiid mite Typhlodromus pyri at four constant temperatures and three feeding levels. For the non‐feeding stages (eggs and larvae) power curve functions were fitted to development rate in terms of temperature. The results are compared to the general arthropod response to temperature. A non‐linear model was fitted to nymphal development rate in terns of temperature and food, in which the weight gain over an instar is assumed to be a linear function of daily food consumption. Examples of the same shape development rate—food relationship are given for two more phytoseiid mites and for other arthropods. The results are discussed with respect to T. pyri as an integrated control agent.
Morphometric variation within apterous females of Schizaphis graminum biotypes
Authors: Fargo W. S. , Inayatullah C. , Webster J. A. , Holbert D. 
Published: October 2006

SummaryThe occurrence of greenbug, Schizaphis graminum (Rondani), biotypes is a constant threat to the development and stability of pest‐resistant cereal crop varieties. Of the five biotypes (A, B, C, D, E) reported, only biotype B can be differentiated in life from the others by the physical characteristics of color. The other biotypes are differentiated on the basis of their ability to kill certain hosts or to withstand selected insecticides. The purpose of this research was to differentiate biotypes of apterous viviparous female greenbugs by multivariate techniques.Appendages from individuals of biotypes B, C, and E were measured. Some of the characters including the length of first and fourth flagellar segments, profemur, mesofemur, mesotibia, metafemur and metatibia differentiated the biotypes in multiple comparisons in univariate analyses. Using discriminant functions based on within‐group covariance matrices, all greenbugs were classified into their correct group. The shortest Mahalanobis distance was between biotypes B and C. This suggests that biotype B is more closely related to biotype C than it is to biotype E. The coefficients of variation in the body measurements of biotype E were higher as compared to those of the other biotypes, indicating that a new biotype may evolve from biotype E in the future.
Stimuli governing intraspecific egg predation in the flour beetles, Tribolium confusum and T. castaneum
Authors: Craig David M. 
Published: October 2006

SummaryThe present research has not identified all of the factors that interact to produce the observed egg cannibalism rates in Tribolium. It has, however, shown that some physical and chemical properties of the egg and environment play an important role in determining cannibalistic activity in a population. Of general interest is the observation that cannibalism is not solely the result of the biological characteristics of the cannibal. While it is generally acknowledged that the quality and quantity of food may influence the intensity of cannibalism, it is not generally recognized that the environment can affect cannibalism in as complex a manner as is suggested by the current research. That two such closely related species, and even two life‐stages of the same species, may respond so differently to the same environmental cues is impressive. Predicting the intensity and hence the importance of cannibalism in natural populations may be difficult without detailed empirical studies.
One‐host one‐parasitoid system: Population dynamics of a zygaenid moth Pryeria sinica Moore in an undisturbed habitat
Authors: Shiotsu Yoshifumi , Tsubaki Yoshitaka 
Published: October 2006

SummaryThe population dynamics of Pryeria sinica was investigated in an undisturbed area in 1976–1979. We analyzed the process stabilizing the local population by the life table approach for immature stages and the mark‐recapture method for the adult stage. Females usually layed about 130 eggs in an egg‐mass. The shape of the survivorship curve was convex and was characterized by a relatively low mortality in the egg and larval stages and by a relatively high mortality in the prepupal and pupal stages. The low mortality in the early stage seemed to be not only due to the peculiar life cycle of this species (larvae develop in early spring when natural enemies are not active) but due to their protective nest‐webs, larval warning coloration and repellent smell. The high mortality after cocooning was caused by severe parasitization by Agrothereutes minousubae. The number of adult in the population varied by 2.10‐fold, which was less than that of other gregarious moths. The life table data and field observations suggest that adult female dispersal would have acted as a stabilizing factor, and A. minousubae as a conditioning factor on the dynamics of the moth population.
Arthropod predation limits the population density of an herbivorous lady beetle, Henosepilachna niponica (Lewis)
Authors: Ohgushi Takayuki , Sawada Hiroichi 
Published: October 2006

Summary
The possible impact of arthropod predation on inter‐population variation in adult density of a thistle‐feeding lady beetle, Henosepilachna niponica (Lewis) was evaluated by means of predator exclusion experiments conducted in the field.
The population density of newly‐emerged adults at one habitat in the upstream area (site F) was significantly lower than at another in the downstream area (site A) although the egg density was nearly identical in the two habitats.
In the habitat with lower adult density, egg mortality was higher due to higher levels of predation. A predator exclusion experiment demonstrated that arthropod predation was the main factor causing high mortality during the immature stages, and physical factors such as heavy rains were unlikely to influence larval survivals.
Earwigs, ground beetles, predaceous stink bugs, and spiders were identified as the main predators in the study area. Of these, an earwig, Anechura harmandi (Burr) was more predominant than other predators and was significantly more abundant in the habitat with low adult densities.
Foraging behavior of individual workers and foraging dynamics of colonies of three Sumatran stingless bees
Authors: Inoue Tamiji , Salmah Siti , Abbas Idrus , Yusuf Erniwati 
Published: October 2006

SummaryThe foraging behavior of three stingless bees, Trigona (Tetragonula) minangkabau, T. (Trigonella) moorei and T. (Heterotrigona) itama, was studied to describe patterns of resource harvest in disturbed forest areas in Sumatra, Indonesia.
Average daily total number of foraging flights per colony was 1200 in T. minangkabau, 2400 in T. moorei and 7000 in T. itama and it was proportional to colony population size. Foragers collecting nectar, pollen or plant resin were respectively 70–80%, 10–20% and <10% in the three species. Pollen was collected most in the morning. Nectar collection peaked in midday in T. itama but continued almost evenly until dusk in T. minangkabau and T. moorei. Resin was collected evenly throughout day.
In all the three species the volume of a nectar load carried by a returning forager did not decrease until 1600, followed by slight decline. In the morning the sugar concentration of nectar was almost constantly 30%, and in the afternoon its maximum value reached 60% although some remained 30%. As a result, the mean sugar weight in a nectar load gradually increased until dusk.
In T. minangkabau, resin was collected by specialized foragers. Nectar foragers switched to collect pollen and vice versa. There were two types of foraging: “exploitatory” flights, the repitition of short, rather constant flights bringing back full resource loads, and “exploratory” flights, prolonged flight and/or reduction in amount of resources carried. Exploitatory flights followed the exploratory flights which led to discovery of rich sources. Mean duration of exploitatory flights was 7 min during nectar collection, 12 min for pollen and 23 min for resin. Sites of exploited flowers were estimated to be 84–434 m distant from the nest site. Mean duration of flights for nectar collection was 13 min in the morning and 6 min in the late afternoon.
Simulation model of a predator‐prey system comprised ofPhytoseiulus persimilisandTetranychus urticae. II. Model sensitivity to variations in the life history parameters of both species and to variations in the functional response and components of the numerical response
Authors: Shaw Peter B. 
Published: October 2006

SummaryA detailed sensitivity analysis of a model of a predator‐prey system comprised ofTetranychus urticaeandPhytoseiulus persimiliswas performed. The aim was to assess the relative importance of the life history parameters of both species, the functional response, and the components of the numerical response. In addition, the impact of the initial predator‐prey ratio and the timing of predator introduction were tested. Results indicated that the most important factors in the system were relative rates of predator and prey development, the time of onset of predator oviposition, and the mode of the predator's oviposition curve. The total oviposition of the predator, the effect of prey consumption on predator oviposition, and predator searching were important under some conditions. Factors of moderate importance were the adult female predator's functional response, total prey oviposition, the mode of the prey's oviposition curve, abiotic mortality of the pre‐adult predator, and the effect of prey consumption on predator development and on the immature predator's mortality. Factors of least importance were the variances of the predator's and prey's oviposition curves, the abiotic mortality of the adult predator, the abiotic mortality of the pre‐adult and adult prey, the functional response of the nymphal and adult male predators, and the effect of prey consumption on adult predator mortality. The sex ratios had little effect, except when the proportion of female predators was very low. The initial predator‐prey ratio and time of predator introduction had significant impacts on system behavior, though the patterns of impact were different.
Why small hermit crabs have large shells
Authors: Spight Tom M. 
Published: October 2006

SummaryFrequent shell exchanges among hermit crabs imply the enigmatic circumstance that large crabs frequently obtain large shells from smaller crabs. This seeming anomaly is explored as a key to the shell resource system. It is hypothesized to reflect how, where, and how often shells become available to the crabs. Shells become available infrequently, as snails die, and are available to the crabs for only a brief time before they become inaccessible. The standing crop of empty shells is almost always low and is irrelevant to rates of shell turnover in the crab population. Crabs are most likely to encounter shells of the wrong size, and the chance of encountering a shell of the desired size decreases as a crab grows. Snails and crabs are usually found on different portions of the shore; thus, crabs must make “foraging trips” for shells. Under this regime of shell supply, a crab will get a suitable shell the fastest when it accepts any fresh shell that is larger than its initial shell. It can then trade with other crabs to improve its shell fit. This behavior will make small crabs into a regular source of large shells for large crabs, and a shell exchange ritual will be strongly favored because both participants will benefit. Shells are an unusual resource because they are the object of both competitive and mutualistic interactions. This ambiguous quality is revealed in the intraspecific and interspecific responses of crabs to each other and to shells.