bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of Sitotroga cerealella (olivier) (lepidoptera: gelechiidae) and Sitophilus zeamais motschulsky (Coleoptera: Curculionidae) populations in a small bulk of stored corn
Authors: Arbogast Richard T. , Mullen Michael A. 
Published: October 2006

SummaryThe dynamics of Angoumois grain moth, Sitotroga cerealella (Olivier), and maize weevil, Sitophilus zeamaisMotschulsky, populations breeding in a small bulk (initially 5.36 t) of shelled corn were studied over an 8‐year period by monthly sampling. The weevil population showed wide fluctuations in density superimposed on a general decline with time. The moth population showed no upward or downward trend for the first 60 months, although it fluctuated widely. Following a decline that occurred between 56 and 60 months, the moth population fluctuated within a much narrower range, and there was a general decrease in density with time. The decline of the weevil population paralleled deterioration of the corn as did that of the moth population after ca 60 months, and the decline of both species probably resulted from increasing scarcity of suitable breeding sites. Both populations exhibited seasonal variation in density with minima in late summer and early fall, following periods of adversely high temperatures in the storage shed. The populations increased during the fall, leveled off or declined slightly during the winter months, and then increased to maximum levels in late spring or early summer. It thus appears that high temperatures had a greater adverse effect on the populations than low temperatures. The grain moth and the maize weevil both tended to be randomly dispersed at low population levels and moderately aggregated at intermediate and high levels, although the degree of aggregation was not correlated with population density when low population levels were considered separately, and the maize weevil showed a greater tendency for aggregation than did the grain moth. Analysis of individual samples at fixed points in time showed a conspicuous bias for negative correlation between numbers of the two species within sampling quadrats, suggesting a tendency for the two species to segregate within the grain mass. This process could have resulted from behavioral differences or from the destruction of one species by the other. Competitive displacement of the grain moth by the maize weevil has been demonstrated in laboratory experiments but has rarely been observed under natural conditions, and in our study the two species coexisted for 8 years in a relatively small grain bulk.
The feeding from edge towards inner part in soybean plot in rufous turtle dove, Streptopellia orientalis (Latham) and the estimation of passing rate of the flock
Authors: Nakamura Kazuo , Matsuoka Shigeru 
Published: October 2006

SummaryRufous turtle dove, Streptopelia orientalis, coming to the soybean field entered it from the outer part to eat soybean cotyledons. As a result, the injured plants extended from the outer to inner parts in the field. A model expressing these behaviours was constructed here, by assuming that the amount of food birds can eat in one block determines whether they stay there or move into neighbour block. As the food decrease due to exploitation of them by birds, birds enter into farther parts with the passage of time.The rate of feeding in all visiting birds (an0 where a is the rate of feeding per individual and n0 the number of birds visiting) and the rate of staying at a block, b, was estimated from the field experimental results, using the above model. The value of an0 fluctuated greatly, depending upon the season in which soybean seeds sowed. The value of b also fluctuated inversely with that of an0, suggesting the the staying rate decreases with an increase in the number of doves coming, probably because of interference among individuals.
A preliminary study on quantitative relations among growth, reproduction and mortality in fishes
Authors: Kitahara Takeru , Hiyama Yoshiaki , Tokai Tadashi 
Published: October 2006

SummaryAs a quantitative approach to the life histories of fishes, the present paper attempted to predict a relation among reproduction, growth and mortality numerically with a technique of control theory, the discrete maximum principle. A method for predicting the relation was derived on the postulate that natural selection maximized the net reproductive rate subject to a few constraints. The derived method was applied to Atlantic cod and Atlantic herring populations in the Southern Gulf of St. Lawrence as numerical examples. The examples demonstrated that the theoretical reproductive effort and body weight were well consistent with the observed ones every age but the theoretical survival rates were slightly different from the observed ones. For the reasons mentioned below, however, it should be interpreted that the examples rather support the adopted postulate to a certain degree. First, in general, it is very difficult to obtain good estimates of the rates with traditional methods. Second, intense fishing pressure possibly changes the life history parameters to some extent in fish populations. Moreover, the examples also suggested that, to examine the postulate in further detail, similar analyses had to be made with the data of many fish populations on which intense fishing pressure had not been exerted.
Space partitioning among the wolf spider Pardosa amentata species group in Hokkaido, Japan
Authors: Suwa Masayoshi 
Published: October 2006

SummaryThere are 4 species belonging to the wolf spider Pardosa amentata species group in Hokkaido. The 4 species have separately occurred in Hokkaido in general, but a few species have sometimes occurred together at the same sites. Their biology at the coexisting sites, with special reference to partitioning of space was studied. P. agraria mainly inhabited fields and occurred widely in Hokkaido. P. hokkaido, P. brebivulva and P. lugubris inhabited the vicinity of forests and occurred in southern Hokkaido and on the side of the Sea of Japan in Hokkaido, all over Hokkaido excent the side of the Sea of Japan in central Hokkaido, and the lowlands and highlands in northern and eastern Hokkaido and mainly the highlands in other regions, respectively. In eastern Hokkaido where P. brevivulva and P. lugubris have coexisted, as the number of spiders detected and the number of localities of the former were less than those of the latter, it was concluded that the former occurred mainly in southern Hokkaido and the Hidaka region. In southern Hokkaido where P. hokkaido and P. brevivulva have coexisted, few individuals of both species were collected together at the same sites, and they were distributed allotopically. In short, the partitioning of space among the P. amentata species group occurring in Hokkaido was clear. From investigations on the coexisting sites and some other reports, it was considered that food, life cycle and diel activity periodicity among Pardosa occurring in Hokkaido were similar to one another. This may be one of the causes of the clear space partitioning among Pardosa. Since Pardosa is a raptorial predator that does not weave but wanders on the ground and uses space horizontally, available prey resource for Pardosa would be limited. It was therefore conjectured that the spider would be prone to space segregation, even if the spider could segregate the other niche dimensions. The partitioning of space between P. agraria and P. hokkaido inhabiting distinct habitats was loose when it was compared with that between species inhabiting similar habitats. As most of the spiders observed in the overlapping areas were females with egg cocoons, which required little food, the reduced feeding was considered to have allowed the loose partitioning.
Time‐specific life tables for the pea aphid, Acyrthosiphon pisum (Harris), on alfalfa
Authors: Hutchison William D. , Hogg David B. 
Published: October 2006

SummaryTime‐specific life tables were constructed for three pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), populations using a modification ofHughes' analytical procedure. All populations were studied on second‐growth alfalfa (mid‐June to mid‐July) in south central Wisconsin; data for two populations were collected during 1980, and data for the third population were collected during 1982. The intrinsic rate of increase (rm) estimated on a physiological time (day‐degree) scale under field conditions but in the absence of natural enemies, provided a reliable estimate of potential population growth rate and was used in preference toHughes' approach of estimating potential population growth rates directly from stage structure data. Emigration by adult alatae and fungal disease were the major sources of A. pisum mortality in each of the three populations studied. These factors were most important because of their impact on reducing birth rates within the local population. Parasitism was never greater than 9 percent. Mortality attributable to predation ranged from 0.0 to about 30.0%; however, even at the highest predator densities A. pisum populations increased exponentially.
Population regulation of the euonymus gall midge Masakimyia pustulaeYukawa andSunose (Diptera: Cecidomyiidae) by hymenopterous parasitoids
Authors: Sunose Tsukasa 
Published: October 2006

SummaryYearly population fluctuations of M. pustulae were investigated at 19 sites in Kyushu. In sites where a platygastrid is the only parasitoid of the midge, the percentage parasitism was very low in the incipient stage of the outbreak of the midge populations. After the number of midges reached a peak, the midge populations declined as the percentage parasitism increased, and then the outbreak ceased. On the other hand, in several populations no outbreak was found and the percentage parasitism was constantly at a high level. Therefore, the immediate cause for the outbreak seemed to be a decline of the percentage parasitism. Like the midge, the platygastrid has one generation each year, and its females also emerge in spring to deposit their eggs within host eggs. The decline of the percentage parasitism seemed to be mainly affected by the time lag between emergence periods of M. pustulae and the platygastrid.In the midge populations parasitized by both the platygastrid and a eulophid (Chrysonotomyia sp.), an extinction of the population was observed, resulting from parasitism by the latter, Chrysonotomyia sp. is polyphagous and multivoltine, and is a late parasitoid, as discussed byAskew (1975). When the density of the midges is very low, the platygastrid may leave the host eggs unparasitized, while Chrysonotomyia sp. may not, because the mature galls are conspicuous.
Polygyny and the breeding success of the great reed warbler Acrocephalus arundinaceus
Authors: Urano Eiichiro 
Published: October 2006

SummarySettlement date, mating status, and breeding success of individually marked great reed warblers, Acrocephalus arundinaceus, were studied during the 1980–84 breeding seasons in Kahokugata, Ishikawa Prefecture, Japan. Twenty‐five per cent of the territorial males were polygynous, of which the majority were bigamous. The settling periods of both sexes were long, extending for 65 days in males and 49 days in females. About 80% of males and females settled in the first half of the settling period, and the settlement date of 28–54% males overlapped with that of females. Many of the late settlers were bachelors and the males which mated earlier tended to be polygynous. The timing of a male's settlement is important in acquiring mates. Fifty‐five per cent of eggs laid were lost before fledging, mainly due to predation. The mean number of fledglings was 3.19 per primary female, 2.41 per secondary female, and 2.80 per monogamous female. Comparison of the number of fledglings of females which mated during the same period showed that the presence of another female in the same territory did not adversely affect the breeding success of either of the polygynous females. Polygynous males have the advantage of decreasing the risk of breeding failure under high predation pressure.
Population biology of the broad‐horned flour beetle, Gnathocerus cornutus (F.) II. Crowding effects of larvae on their survival and development
Authors: Tsuda Yoshio , Yoshida Toshiharu 
Published: October 2006

SummaryCrowding effects of larvae on survival and development were examined for the broad‐horned flour beetle, Gnathocerus cornutus (F.). The larvae matured about 3 weeks after hatching regardless of their densities, but pupation was severely hindered by crowding. There existed an upper limit for the number of the pupae produced and its mechanism was studied by a statistical analysis of the distribution patterns of pupal cells and the experiment in which glass tubes were artificially supplied in addition as pupation site. These studies show that G. cornutus larvae have a habit to construct cells for pupation and this habit leads to a contest competition for pupation site at high densities. The significance of the contest competition for population regulation was discussed comparing the results on Tribolium confusumJacqueline duVal.
Conspecific host discrimination by ovipositing Euphydryas editha butterflies: Its nature and its consequences for offspring survivorship
Authors: Mackay Duncan A. 
Published: October 2006

SummaryOvipositing E. editha butterflies display post‐alighting discrimination among patches of Collinsia torreyi, one of their major hosts in the General's Highway (GH) population at a montane site in California. Females tended to accept (i.e. oviposit on) dense patches of this host and to reject sparse patches. Possible behavioural mechanisms underlying this tendency are discussed. The consequences of this non‐random pattern of oviposition for egg and larval survivorship were investigated and no differences were found in the survivorship of larvae on acceptable and unacceptable collinsias.
Ecological significance of the wing polymorphism of the oriental chinch bug, Cavelerius saccharivorusOkajima (Heteroptera: Lygaeidae)
Authors: Fujisaki Kenji 
Published: October 2006

SummaryThe wing polymorphism of the oriental chinch bug, Cavelerius saccharivorus, was studied in relation to its reproductive strategy. The frequency distribution of wing form in terms of the relative wing length (R.W.L.) changed with increase in the population density from a single modality biased toward the brachypterous form to bimodality with both macropterous and more extreme brachypterous forms. Since some evidences in the field showed that fliers are limited to macropters, such a bimodality of wing form indicated that C. saccharivorus employs a mixed strategy with some portion of adults staying on in the same habitat, whereas the rest disperse. Moreover, macropters were larger in body size than brachypters emerging in high density populations, although smaller than brachypters emerging in low density populations. Larger body size as well as the delay of ovarian maturation in macropters was considered to be a beneficial trait for migratory behaviour.
Resource utilization pattern of two species of tetranychid mites (Acarina: Tetranychidae)
Authors: Kondo Akira , Takafuji Akio 
Published: October 2006

SummaryLife history and resource utilization pattern were compared between two closely related mite species of the genus Tetranychus.
Tetranychus urticae developed more quickly and had a higher oviposition rate than T. kanzawai. Consequently, the potential for population increase was greater for T. urticae than for T. kanzawai but the difference was slight.
T. urticae was more tolerant of a deteriorating food resource and/or over‐crowding. T. kanzawai responded more sensitively to food deterioration and dispersed more quickly.
There was a considerable difference between injury patterns by the two species. T. kanzawai damaged host plants more severely, causing earlier and more extensive defoliation of the plants.
The maximum population size achieved by T. urticae was 2 to 3 times greater than that of T. kanzawai on potted host plant. This showed that the former could utilize a food resource much more efficiently.
Pheromone trapping models for pest control: Effects of mating patterns and immigration
Authors: Barclay Hugh J. 
Published: October 2006

SummarySeveral models are presented which examine pest population behaviour with the release of female sex pheromones for the attraction and annihilation of males. These models include male polygamy and female monogamy, various mating frequencies, delayed mating of females, immigration of one or all individual types, and differential survivorship of males and females.In all the models there are two steady states, a stable s.s. at the origin and an unstable s.s. in the positive domain for a given value of pheromone release rate. In all the models, control relies on the reduced ability of males to fertilize virgin females following trapping and male annihilation. As such, control is very sensitive to mating frequency, being very difficult when males mate frequently. Control is also very difficult with the immigration of even a moderate number of fertilized females. Control is much easier when mating is delayed, especially if survivorship is low, or with density dependent population regulation.
Component analysis and modelling of the movement process: The simulation of simple tracks
Authors: Zalucki M. P. , Kitching R. L. 
Published: October 2006

SummaryA model for the simulation of simple snail tracks is presented. The parameters required by the model include: (1) the distribution of turn angles at each step; (2) the mean and (3) the variance of step sizes; (4) the initial bearing angle and (5) the proportion of time spent moving. The model readily generates realistic tracks and predicts adequately values of parameters not specifically built into the model. If observations on the above five parameters are collected at the correct scale, then we suggest the model represents a general, canonical description of movement. The notion of what constitutes correctness is discussed.
Differences in egg wastage by superparasitism, contrasting Venturia (=Nemeritis) canescens searching singly versus searching in groups
Authors: Huffaker C. B. , Matsumoto B. M. 
Published: October 2006

SummaryA statistical and graphic study is presented of the wastage of eggs by Venturia (=Nemeritis) canescens when searching singly and in groups of 10 among hosts at four different host densities in laboratory universes as described byHuffaker andMatsumoto (preceding paper of this journal). The host insect was the fluour moth Anagasta kühniella and the host densities used were 10, 30, 100 and 200 per universe. Intensity of egg wastage due to superparasitim varied significantly according to host density, and between the two parasite densities employed, 1 and 10, using both F‐tests and chi‐square tests. Plots of k‐factor analysis on this egg wastage showed high negative correlations with host density, and the raw data for single parasites was well represented by a parabola while that for the grouped parasites departed from this relationship only at the lowest host density.
Prey capture tactics of spiders: An analysis based on a simulation model for spider's growth
Authors: Nakamura Kazuo 
Published: October 2006

SummaryThe prey capture tactics of spiders was analyzed, considering the energy gained by the capture of prey and that required for it. For the purpose of it, a growth model of spiders was constructed, expressing the flow rate of prey biomass to the spider's body by differential equations. Solving these equations under the differing values of three parameters, growth curves of spiders was obtained. These three parameters are the amount of prey biomass supplied daily to spiders, x0, the rate of prey capture of spiders, α, and a coefficient of the respiration rate required for the capture of prey, k. When the value of k increased, spiders could grow only at high value of x0. These results suggest that habitats with small prey biomass are preferred by spiders adopting a sit‐and‐wait tactics for prey capture, which requires small values of k. Wolf spiders are one of these spiders showing that tactics. On the other hand, web‐builders which require large amount of energy for spinning webs (namely, take large value of k), are able to grow only in the habitats with large prey biomass. Each species of spiders are considered to locate in a certain point between both extremes of these tactics for the capture of prey.
Stabilization of the population of a parasite on fruit by the population of a cleptoparasite
Authors: Yamamura Norio , Iwahashi Osamu 
Published: October 2006

SummaryWhen there exist two species such that one is a parasite on fruit and the other exploits the parasitized fruits, they must compete for a limited resource with each other. The relation between Dacus cucurbitae and Atherigona orientalis is an example of such a situation. We raise a question whether the population of a parasite on fruit can be stabilized by the existence of the cleptoparasite of the parasite on fruit.The changes in their population densities are represented as a differential equation with time delayed parameters, which is deduced from the context of life histories of the two species. An index representing degree of overlapping of generations (g) is defined as an average oviposition period devided by the average preoviposition period, and the value is assumed to be the same in the two species.The stability of the system is classified by three parameters: the reproductive rate of the parasite on fruits (R), the survival probability of it through competition against the cleptoparasite (p), and the generation overlapping index (g).For small values of g, e.g. less than some 0.5, the stability is determined mainly by a product of Rp: the values larger than 1 result in no equilibrium and infinite increase of both species, the values near 0 lead to large amplitude oscillations, and the intermediate values make stable equilibria or regular small oscillations. As g takes the larger values, the stability region in the space (p, R) occupies the larger area.The model presented here is well adjusted to the fluctuating pattern of the population of D. cucurbitae on Okinawa Is., and would also be applied to analysis of both hyperparasitisms and inquilin.