bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coexistence of competing species of seaweed flies: the role of temperature
Authors: PHILLIPS DAVID S. , LEGGETT MARGARET , WILCOCKSON RAY , DAY THOMAS H. , ARTHUR WALLACE 
Published: March 2008

Abstract.Competition is shown to be occurring within and between the congenersCoelopa frigidaandC.pilipes;it is noted that the two species frequently coexist despite ongoing competition.Observations on natural wrack‐beds indicate that there is a marked difference in the distributions of the larvae:C.frigidalarvae aggregate in cooler parts of the bed,C.pilipesin warmer parts. This difference in microdistribution reflects a broader‐scale difference in the geographical distributions of the species ‐C.pilipesbeing the more southerly of the two.The larval distributions are shown to be caused primarily by the behaviour of the larvae themselves ‐ not by choices made by ovipositing females, nor (at least to any great extent) by differential survival.The different micro‐distributions within beds constitute a form of niche difference which will cause competitive abilities to be frequency‐dependent and hence have a stabilizing effect. It is possible that this effect may be supplemented by others; and, in particular, effects operating at the level of the‘linear meta‐population’may be worthy of further investigation both inCoelopaand in other coastal species.
Clumped distribution patterns in goldenrod aphids: genetic and ecological mechanisms
Authors: PILSON DIANA , RAUSHER MARK D. 
Published: March 2008

Abstract.

The aphids Uroleucon tissoti and U.nigrotuberculatum both exhibit significantly aggregated distribution patterns across clumps of their common host plant Solidago altissima, the tall goldenrod. However, U.nigrotuberculatum is significantly more aggregated than is U.tissoti. We tested the hypothesis that goldenrod genotype‐by‐U.tissoti genotype interactions for aphid performance characters could partially account for this difference.
Only one of the characters we measured showed a significant genotype‐bygenotype interaction; therefore it is unlikely that such interactions affect the distribution of U.tissoti across goldenrod stems.
In addition, we found that three environmental variables (genetic variation for resistance to herbivory, host plant morphology, and local host density) affect the degree of aggregation found in both U.tissoti and U.nigrotuberculatum populations.
Distribution of male yellow dungflies around ovipasition sites: the effect of body size
Authors: SIGURJÓNSDÓTTIR HREFNA , SNORRASON SIGURðUR S. 
Published: March 2008

Abstract.

Spatial and temporal variation in body size of yellow dungflies, Scatophaga stercoraria, gathering on and around cow droppings was studied in an Icelandic population in order to elucidate the effect of male and female size on male mating tactics.
Males copulating on droppings were on average larger than males copulating in the grass, but of similar size to males guarding ovipositing females. Males searching on droppings were smaller than males copulating or guarding females on droppings but larger than males copulating in the grass. No such differences were found in female size.
Resource‐holding power of males (RHP, i.e. male: female size ratio) differed between the three mating groups and was highest for males on the droppings. Size and RHP clearly affect the tactics of copulating males. Males with low RHP tend to copulate in the grass in spite of the cost of longer copulation duration. We argue that this is caused by risk of takeovers from large searching males.
There was no change in male size with the age of individual droppings. Contrary to what might be expected, large searching males are not predominantly found at fresh droppings when the probability of catching unpaired females is highest. We suggest instead that good prospects in taking females over from other males must make the strategy to search for females on older droppings profitable.
RHP did not change with age of dropping in the three mating groups. The size of ovipositing females increased with age of dropping, probably reflecting longer copulation and egg‐laying times of large females.
We found an overall positive relationship between sizes of male and female partners. This correlation was highly significant for copulating pairs in the grass. This is probably a consequence of males with low RHP copulating in the grass and fights in which larger males take over females from smaller males. A weaker, but significant, correlation was found amongst ovipositing pairs. This must be due to take‐over effects. No size correlation was found for pairs copulating on droppings.
Effect of leaf litter and density on fitness and population performance of the hole mosquito Aedes triseriatus
Authors: LÉONARD PASCALE M. , JULIANO STEVEN A. 
Published: March 2008

Abstract.

We tested the effects of food, in the form of leaf litter, and density on population growth and fitness correlates of the tree hole mosquito Aedes triseriatus. Our field experiment used a 2 x 2 randomized block design, with three holes as blocks. In cages within three holes, we manipulated densities of Aedes triseriatus larvae, and presence of leaf litter. Our laboratory experiment used a 2 x 3 factorial design in which we also manipulated densities of larvae and availability of leaf litter within similar cages (inside, outside, or absent). For both experiments we determined effects on survival, days to and mass at eclosion of both sexes, and a composite index of population performance λ′, that estimates finite rate of increase.
In the field experiment, we found significant and large effects of leaf litter and of density on the performance of A. triseriatus. The effect of density did not depend on leaf litter availability. We documented significant variation among tree holes for most correlates of fitness. Often, the effects of treatments varied significantly depending on the tree hole tested.
In the laboratory experiment we found significant effects of density and litter, and that direct browsing on leaf litter is necessary for the effect of litter on performance of A. triseriatus. In the laboratory, the negative effect of increased density was dependent on leaf litter availability.
Our results demonstrate that leaf litter has important effects on population performance of tree hole mosquitoes in natural tree holes. Direct browsing on the surface of leaf litter is the most likely mechanism by which litter enhances population growth. The impact of litter on populations varies among tree holes.
Intraspecific variation in host plant quality: the aphid Cinara cupressi on the Mexican cypress, Cupressus lusitanica
Authors: MEMMOTT J. , DAY R. K. , GODFRAY H. C. J. 
Published: March 2008

Abstract.

In Kenya, the aphid Cinara cupressi (Buckton) has an aggregated distribution across individuals of its host plant, the Mexican cypress, Cupressus lusitanica (Mill).
There are significant differences in host plant quality: C.cupressi nymphs transplanted onto cypress trees with low aphid infestations are significantly less likely to establish than aphids transplanted onto trees with high aphid infestations.
Given that some transplanted nymphs establish, the previous level of infestation does not influence aphid survival.
Evidence for local adaptation to individual plants was not found: nymphs transplanted to the trees from which their parents were collected neither established more readily nor showed lower mortality than those transplanted to other trees with similar levels of infestation. Therefore the variation in host plant quality has not led to the development of local adaptation to particular host plants.
Coastal insect herbivore communities are affected more by local environmental conditions than by plant genotype
Authors: STILING PETER , ROSSI ANTHONY M. 
Published: March 2008

Abstract.

We compared the effects of plant genotype and local environment on population densities of a community of coastal insect herbivores in west‐central Florida. Reciprocal transplants of four genotypes of three species of coastal plants, Borrichia frutescens, Iva frutescens and Limbricata, were made in July 1992 between a series of off‐shore islands.
For each plant species, phytophagous insects with a wide range of feeding modes including gall‐makers, stem borers, leaf miners and sap suckers were affected more by local environment than by plant genotype. Whereas host genotype had a significant effect on the population densities of gall‐makers on B.frutescens in the spring of 1993, no significant effect on the denrities of any other insect species was found and the effect on the gall‐makers on Borrichia disappeared in the summer, 1 year after the transplants had been made. In our study, local environment had by far the greatest effect on insect population densities among islands. This is an unusual result because in other studies over 80% of the insect species examined have been affected by plant genotype (Karban, 1992). This result is consistent with that reported by Stiling (1994), who censused populations of two phytophagous insects on reciprocal transplantr ot Borrichia in north Florida.
Local environment also had an effect on insect population densities within islands. This result contrasts with similar studies performed in north Florida (Stiling, 1994), where population densities did not differ within areas, and underlies how some biotic processes may change with in the same community even over relatively small changes in species range.
Distribution and spacing of Drosophila mycetophaga flies on bracket fungi used as mating arenas
Authors: ASPI JOUNI , HOFFMANN ARY A. 
Published: March 2008

Abstract.

To understand the nature of male aggregations in Drosophila mycetophaga, data were collected on male and female distribution and male spacing on bracket fungi used as mating arenas in cool rainforests of south‐eastern Australia.
Both males and females appeared to be aggregated among bracket fungi that were used as mating arenas. Females were associated with large male aggregations. The probability of a fungus being occupied increased with its area. However, a multiple Poisson regression analysis suggested that fungus area did not affect female distribution when male number was controlled.
The presence of female breeding and feeding resources did not determine where aggregations were formed, because there were aggregations on fungi without resources, and fungi with resources were not used more often than those without them.
D.mycetophaga males did not select and defend territories within bracket fungi, and did not determine female access to areas. However, males were more evenly spaced than expected on the basis of a random distribution, suggesting that males kept apart from each other.
The distribution of the different sexes and male spacing pattern supports the interpretation that D.mycetophaga has a lek mating system.
Sexually transmitted disease in a promiscuous insect,Adalia bipunctata
Authors: HURST GREGORY D. D. , SHARPE ROSIE G. , BROOMFIELD ANGELA H. , WALKER LINDA E. , MAJERUS TAMSIN M. O. , ZAKHAROV ILIA A. , MAJERUS MICHAEL E. N. 
Published: March 2008

Abstract.Sexually transmitted diseases (STDs) have rarely been reported in insects and other invertebrates. The majority of those reported involve organisms where sexual transmission is augmented by either vertical (i.e. inherited) transmission, or horizontal transmission, independent of host sexual activity.We here demonstrate the existence of an STD in the coccinellid beetleAdalia bipunctata. This species bears a parasitic mite of the genusCoccipolipus. We show that, like many other podapolipid mites, this mite is transmitted between host individuals at a high rate during copulation. It also appears to be transmitted at a low rate between non‐copulating individuals.We show that infected femaleA.bipunctataproduced eggs at a reduced rate, and that the eggs produced by infected females have highly decreased viability. However, no effect of infection upon host longevity was observed.The results are discussed in relation to the incidences of sexually transmitted disease in invertebrates in general, the causes of disease symptoms, and the importance of this disease in the evolution ofA.bipunctata.
Do trees in urban or ornamental plantings receive more damage by insects than trees in natural forests?
Authors: NUCKOLS MICHAEL S. , CONNOR EDWARD F. 
Published: March 2008

Abstract.

To determine if trees in urban or ornamental plantings are more susceptible to attack and receive more damage to foliage by herbivores than trees in natural forests, we compared the amount of leaf damage caused by several guilds of insects feeding on seven species of native, broadleaf trees in two geographic locations.
Total leaf damage did not differ significantly between urban or ornamental and natural forests, although trees in natural forests tended to have slightly higher levels of leaf damage.
Damage caused by chewing insects was consistently higher on trees in natural forests than in urban or ornamental plantings. All other feeding guilds showed no consistent pattern in levels of damage between the two habitats.
Total damage levels were highest on canopy trees and lowest on understorey trees.
These results are inconsistent with the view that trees in urban or ornamental settings are more susceptible to insect attack than trees in natural forests.
The lower level of foliar damage caused by chewing insects on trees in urban or ornamental plantings may arise because of low rates of dispersal by insects into urban environments, higher levels of plant resistance to insect attack in urban or ornamental plantings, or lower survival rates of herbivorous insects in urban environments.
Complex competitive interactions in four species of Lucilia blowflies
Authors: PRINKKILÁ MAIJA‐LIISA , HANSKI ILKKA 
Published: March 2008

Abstract.

The effects of intraspecific and interspecific larval competition on larval survival, adult size, adult longevity and fecundity were quantified in four species of coexisting Lucilia blowflies: illustris, silvarum, sericata and caesar.
There was a general negative effect of increasing density on larval and adult survival, size and fecundity. Additionally, complex species‐specific and frequency‐dependent responses were identified, which were not expected in these biologically and morphologically closely similar species.
Lucilia illustris, the numerically dominant species in the natural community, was a superior competitor to L.silvarum at intermediate densities but an inferior competitor at high density. Such nonlinear responses may be related to differences in the life histories and larval behaviour of the species (bigger eggs and more contest‐type outcome of competition in L.silvarum).
We parameterized a model of interspecific competition on a subdivided resource in an attempt to reconcile the conflicting results on larval competitive abilities and the abundances of the species in the field. Using laboratory and field‐estimated parameter values the model predicted coexistence of L.illustris and L.silvarum and the observed numerical dominance of the former species. The average densities of flies in the field are limited to relatively low levels, apparently preventing L.silvarum (the superior competitor at high density) from dominating and excluding L. illustris.
Systematic within‐tree variation in mountain birch leaf quality for a geometrid, Epirrita autumnata
Authors: SUOMELA JANNE , KAITANIEMI PEKKA , NILSON ANNA 
Published: March 2008

Abstract.

We studied within‐tree variation in leaf quality of the mountain birch, Betula pubescens ssp. tortuosa, for larvae of the autumnal moth, Epirrita autumnata.
The purpose of the study was to determine the possible occurrence of systematic differences in larval growth on short shoot leaves (i.e. leaves of the same age): among leaves facing in different compass directions, between leaves of lower and upper branches, among leaves on different positions within a branch and among leaves of different sizes within a short shoot. We also measured larval growth between short shoot and long shoot leaves (i.e. between leaves of different age).
The larvae grew best on leaves on the north side of trees and most poorly on south side leaves, the east and west sides being intermediate. Leaves from the upper branches supported larval growth better than leaves from the lower ones. The larvae grew better on the smallest leaf of each short shoot and were able to utilize it more efficiently than the two larger leaves. Short shoot leaves from the basal and middle parts of the upper branches of the trees were of better quality for the larvae than short shoot leaves from the tip part of the branches. The larval growth rate did not differ between short shoot and long shoot leaves. In general, within‐tree variation in the larval growth rate was lower than variation among different trees.
Damage to leaves can decrease leaf quality for herbivores in the same year (rapidly inducible responses) or the following year(s) (delayed inducible responses). Our results show that systematic within‐tree variation in larval growth can be as great as the effects of rapidly inducible responses and that variation among individual trees can be as great as the mean effects of delayed inducible responses.
The calling behaviour and spatial distribution of male bushcrickets (Sciarasaga quadrata) and their relationship to parasitism by acoustically orienting tachinid flies
Authors: ALLEN GEOFF R. 
Published: March 2008

Abstract.

This paper examines the calling behaviour and spatial distribution of male Sciarasaga quadrata Rentz (Orthoptera: Tettigoniidae), a bushcricket that is subject to attack by an acoustically orienting parasitoid fly, Homotrixa sp. (Diptera: Tachinidae: Ormiini).
Checks on calling activity in populations of S.quadrata confirmed that calling began 2–3 h before sunset and continued well beyond midnight. Calling activity was not restricted by temperature with males calling over air temperatures of 10.6–24.2°C.
Nearest‐neighbour analyses, within the sampled areas, revealed that the spacing between calling males was random and the minimum distance between calling males was 3.74 m. Mean distances between calling males varied between 9.2 m and 23.0 m and significantly changed as male density, which peaked at 0.36 calling males per 100 m2, declined over the calling season.
Males showed no preference for any one plant species, with their distribution across bushes not significantly different to the frequency of the plants within the habitat. The perch height of calling males was on average half way up the height of a bush and was significantly influenced by the height of the bush. Perch height was not significantly influenced by proximity to calling males or by whether or not males were parasitized.
Site fidelity of males was low with only 0–10% of bushes occupied by calling males over successive nights. Males, though flightless, moved on average 6.70 m and up to 26.56 m per night.
No evidence was found for the use of aggregation in S.quadrata as a primary defence against ormiine attack. Commencing calling prior to sunset, frequent movement, and a lack of association with any particular plant species, although possibly relevant to ormiine attack, could also be explained in terms of other activities such as male‐male interactions and mating behaviour.
A test of the validity of insect food‐plant and life‐history records: Lepidoptera on heather (Calluna vulgaris)
Authors: FIELDING C. A. , COULSON J. C. 
Published: March 2008

Abstract.

A comparison was made between data collected from a literature search and a field study on the species richness and larval phenology of the Lepidoptera that feed as larvae on Calluna vulgaris.
Of the macrolepidopteran species that the literature predicted should be found as larvae on C.vulgaris during the field study, 55% were never recorded. The literature was used to classify these unrecorded species into species that are uncommon or confined to unsampled habitats (60%) which were less likely to be recorded, and common species (40%) that were more likely to be recorded. Various reasons are suggested for the absence of these latter species, including the possibility of inaccurate host plant records in the literature.
Of the macrolepidopteran species that were discovered during the field study, 27% were not reported by the literature as feeding on the plant. The omission by the literature of C.vulgaris from the food plant lists of these species occurred both because of the inability of the literature to list all the hosts of widely polyphagous species (40%) and because of possible inaccurate recording (60%).
The literature was found to contain inaccuracies in its descriptions of the larval phenology for 61% of the macrolepidopteran species. This resulted in marked differences between the two data sources in their estimations of seasonal changes in species richness of larval macrolepidoptera feeding on C.vulgaris.
Reproductive and subsocial behaviour in the ovoviviparous leaf beetle Gonioctena sibirica (Coleoptera: Chrysomelidae)
Authors: KUDO SHIN‐ICHI , ISHIBASHI EIJI , MAKINO SHUN'ICHI 
Published: March 2008

Abstract.

In the spring, females of the leaf beetle Gonioctena sibirica deposited larvae on the ventral surface of growing young leaves situated on the apical position of shoots of the willow Salix bakko.
The parent females remained with the larvae usually on the underside of the basal part of leaves, facing toward the base of shoots. When other arthropods approached, the females temporarily moved towards these intruders, showing aggressive behaviour such as swinging the body or stamping the legs. Many females remained with their larvae until the larvae grew into the final (fourth) instar. No female produced an additional brood in the field.
Broods from which parent females were experimentally removed suffered higher mortality than those in which females were left intact. Arthropods such as spiders and ants were observed preying on the larvae. In contrast, the survivorship of broods from which females were removed and intruders were excluded with a sticky substance applied to the base of twigs was not different from that of control broods. These results demonstrate that the main mortality factor of offspring is pedestrian arthropod predators and females physically repel the predators.
Potentially alternative reproductive strategies, such as producing a large number of offspring by iteroparity and/or larger brood(s) with less or no care, seem to be inhibited in G.sibirica by larval dependence on growing young leaves which are temporally limited and by ovoviviparity which may have limited brood size.