bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geographic variation in reproductive success of the parasitoid Asobara tabida in larvae of several Drosophila species
Authors: KRAAIJEVELD ALEX R. , VAN DER WEL NICOLE N. 
Published: March 2008

Abstract.

Asobara tabida is a parasitoid of Drosophila larvae in fermenting substrates. Because it is a widespread species, it may encounter different biotic and abiotic circumstances in various parts of its range.
The species composition of the host population varies over the parasitoid's range: D.obscura‐group species (especially D.subobscura) are the main hosts for northwestern and central European parasitoids; D.melanogaster is the main host for southern European parasitoids.
D.melanogaster larvae can defend themselves against A.tabida by encapsulating the parasitoid egg, and survival in D.melanogaster is always lower than in D.subobscura.
Parasitoids from southern European populations are much better able to survive in D.melanogaster than their northwestern and central European conspecifics; parasitoids from different populations are equally well able to survive in D.subobscura.
The lower survival in D.melanogaster may be partly compensated for by the larger size of parasitoids emerging from this host species compared to parasitoids emerging from D.subobscura.
Within population groups, larger A.tabida females have more eggs in their ovarioles. Additionally, southern European females have more eggs and less fat than northern and western/central European females. The relationship between size and longevity is ambiguous.
It is concluded that parasitoids from different populations are adapted to region‐specific circumstances.
Genotype and environment interact to influence acceptability and suitability of white spruce for a specialist herbivore, Zeiraphera canadensis
Authors: QUIRING D. T. , BUTTERWORTH E. W. 
Published: March 2008

Abstract.

The independent and interacting effects of plant genotype and site (i.e. environment) on the acceptability of white spruce, Picea gluaca (Moench) Voss, to the spruce bud moth, Zeiraphera canadensis Mut. & Free. and on plant suitability for egg development, were studied at four sites in New Brunswick, Canada.
A greater proportion of shoots on trees in two half‐sib families, previously designated as highly susceptible, were partially eaten by spruce bud moths than shoots on trees in two half‐sib families with low susceptibility.
At the site with the highest bud moth population, oviposition was highest on trees in susceptible families and on branches damaged by bud moth larvae. Oviposition was not higher on trees in susceptible families at the other three sites, resulting in a strong tree genotype × site interaction for oviposition.
Although there was a significant tree genotype × site interaction for egg predation, egg survival was higher on trees in susceptible families at all sites, due to lower levels of egg parasitism and predation.
Egg densities were positively but weakly correlated to shoot length and diameter. There were no consistent relationships between shoot length, shoot diameter, needle length or needle density and per cent egg survival, parasitism or predation.
Because egg survival was higher on trees in susceptible families at all sites but egg densities were only higher on trees in susceptible families at one site, host plant acceptability and suitability were positively related at only one site. We speculate that Z.canadensis does not distinguish between hosts of different suitability until trees are heavily damaged.
The superiority of bumblebees to honeybees as pollinators: insect visits to raspberry flowers
Authors: WILLMER P. G. , BATAW A. A. M. , HUGHES J. P. 
Published: March 2008

Abstract.

The behaviour and activity patterns of Apis mellifera and of five species of Bombus were analysed in relation to climatic variables and nectar quality on three varieties of unsprayed cultivated raspberry (Rubus idaeus) in eastern Scotland.
Stages of floral morphology and reward were similar for the three varieties: young flowers offered both nectar and pollen, but medium and old flowers offered nectar only, in diminishing quantities.
A wide range of insects visited raspberry flowers, but bees were dominant, bumblebees being responsible for about 60% of all visits and honeybees making up most of the remaining percentage. All bees had substantial pollen deposited on their bodies during visits, though few specifically collected it.
Bombus spp. were found to favour young (receptive) flowers strongly, especially early in the morning when pollen was most abundant: whilst Apis visited unselectively. Bumblebees also foraged over substantially longer periods of the day, and in poorer weather, some being present at most times of observation; and they foraged more quickly in terms of flower visits per minute.
Bombus carried more pollen on their bodies than Apis, and also deposited more pollen on raspberry stigmas, with B.lapidarius and B.terrestris being particularly effective and also being the most abundant species. All bumblebees also foraged over a longer range, moving between canes and rows more frequently than did honeybees.
Bumblebees are therefore likely to be substantially more important as pollinators of raspberries than are honeybees, especially as raspberries though moderately self‐fertile may exhibit metaxenia. Reasons why Bombus may be the preferred pollinator in most sites of raspberry cultivation are discussed, together with implications for present and future growers.
Persistent size variation in the anthophorine bee Centris pallida (Apidae) despite a large male mating advantage
Authors: ALCOCK JOHN 
Published: March 2008

Abstract.

Despite apparent directional sexual selection in favour of large body size, males of the anthophorine bee Centris pallida remain highly variable in body size.
One possible cause of persistent size variation among males is geographic variation in the extent of the large male mating advantage. However, a study of a population in an area not previously investigated revealed that the large male mating advantage was as strong here as it has been elsewhere in other years.
Although the reproductive benefits of being large were consistent in populations separated spatially and temporally, the intensity of bird predation on mate‐searching males varied greatly between locations.
The bee‐killing birds focused exclusively on bees which were digging down to meet emerging females or fighting on the ground, never on flying males. Males which were collected on the ground by hand (to simulate avian predation) were significantly larger on average than flying males collected by sweep netting.
Therefore, in some location in some years, sexual selection in favour of large body size may be opposed by natural selection exerted by predators, perhaps contributing to the maintenance of size variation in this bee.
Direct and indirect effects of plant genetic variation on enemy impact
Authors: FRITZ ROBERT S. 
Published: March 2008

Abstract.

The Tritrophic and Enemy Impact concepts predict that natural enemy impact varies: (a) among plant genotypes and (b) may depend on the abundance of heterospecific herbivores, respectively. I tested these predictions using three herbivore species on potted, cloned genotypes of Salik sericea Marshall in a common garden experiment.
Densities of the leaf miner (Phyllonorycter salicifoliella (Chambers)) and two leaf galling sawflies (Phyllocolpa nigrita (Marlatt) and Phyllocolpa eleanorae Smith and Fritz) varied significantly among willow clones, indicating genetic variation in resistance.
Survival and natural enemy impact caused by egg and larval parasitoids and/or unknown predators differed significantly among willow clones for each of the three herbivore species, indicating genetic variation in survival and enemy impact.
Survival of Phyllonorycter was negatively density‐dependent among clones.
Survival of Phyllonorycter and Phyllocolpa eleanorae were positively correlated with densities of heterospecific herbivores among clones and parasitism of these species were negatively correlated with densities of the same heterospecific herbivores among clones.
At least for Phyllonorycter this positive correlation may suggest either facilitation of survival between herbivore species, which do not share natural enemies, or an apparent interaction caused by host plant genetic variation.
Among clones, egg parasitism of Phyllocolpa eleanorae was weakly positively correlated with density of Phyllocolpa nigrita. Since these species share the same Trichogramma egg parasitoid, this interaction could support the hypothesis of apparent competition.
Squash beetle trenching behaviour: avoidance of cucurbitacin induction or mucilaginous plant sap?
Authors: McCLOUD E. S. , TALLAMY D. W. , HALAWEISH F. T. 
Published: March 2008

Abstract.

Foraging patterns of the squash beetle, Epilachna borealis Fabricius (Coleoptera: Coccinellidae), in field cages are not consistent with the hypothesis that this beetle avoids leaves in which its feeding damage has caused the induction of cucurbitacins.
E.borealis feeding does not induce accumulation of cucurbitacins inside or outside of feeding trenches.
Cucurbitacins do not reduce the survival or growth rate of E. borealis larvae.
High concentrations of cucurbitacins fail to deter E.borealis feeding; rather, cucurbitacins are feeding stimulants for squash beetles.
Trenching behaviour in E.borealis is facultative and correlates with leaf turgor and the degree to which sticky phloem sap oozes from damaged leaves.
Mucilaginous phloem sap in many curcurbit species inhibits feeding by E.borealis when it is applied to beetle mouthparts.
Population suppression for control of the blowfly Lucilia sericata and sheep blowfly strike
Authors: WALL R. , FRENCH N. P. , MORGAN K. L. 
Published: March 2008

Abstract.

The control of ovine myiasis by suppression of populations of the blowfly Lucifia sericata was investigated experimentally on three farms in the south‐west of England in 1992 and 1993.
In blind trials, sheep on one farm (control) were given two doses of placebo, on a second two doses of the larvicide cyromazine (Vetrazin®, CibaGeigy), and on a third cyromazine and a subsequent dose of placebo.
The first treatment was given shortly before the predicted spring emergence of L.sericata and the second shortly before the predicted emergence of the second generation. Previous simulation analysis had identified strategic early‐season treatment as the optimum for blowfly population suppression.
On both treatment farms significantly smaller L.sericata populations were recorded throughout 1992 and the incidence of strike was significantly lower than on the control farm. The results show that appropriate early‐season timing of sheep treatment can suppress populations of L.sericata and could be used by farmers to reduce the incidence of blowfly strike.
The results suggest, however, that the effectiveness of population suppression and strike incidence may have been influenced by immigration into the control areas and by adverse weather, the latter changing the susceptibility of sheep to strike and resulting in rising strike incidence even when L.sericata population densities were low. In practice, therefore, blowfly population suppression should be employed as a component of an integrated strike management programme.
A new inexpensive suction apparatus for sampling arthropods in grassland
Authors: STEWART ALAN J. A. , WRIGHT ANN F. 
Published: March 2008

Abstract.

We describe a new technique for sampling arthropods from grassland and other vegetation, using a modified petrol‐driven suction apparatus called a‘Blow & Vac’.
The new apparatus was tested by comparing its efficiency in extracting arthropods from vegetation with that of a conventional Dietrick, or‘D‐Vac’, suction sampler.
Unimpeded air velocity inside the suction tube was approximately 4 times that of the D‐Vac.
In field trials on semi‐natural grasslands, the Blow & Vac caught more individuals of most spider and certain beetle species compared to the D‐Vac and approximately equal numbers of Auchenorrhyncha.
We conclude that the‘Blow & Vac’has considerable potential for sampling arthropod populations. Its low cost and weight make it a suitable alternative to the conventional D‐Vac apparatus.
The biology of the phonotactic parasitoid, Homotrixa sp. (Diptera: Tachinidae), and its impact on the survival of male Sciarasaga quadrata (Orthoptera: Tettigoniidae) in the field
Authors: ALLEN GEOFF R. 
Published: March 2008

Abstract.

Unlike most parasitoids, tachinid flies of the tribe Ormiini use sound to locate their hosts. Although thought to exert selection pressure on their host's calling behaviour, little is known about the biology of ormiines. Accordingly, this study reports the biology and impact of the ormiine Hornotrixa sp. upon calling males of the univoltine bushcricket Sciarasaga quadrata Rentz in south‐western Australia.
Populations of adult S.quadrata were monitored in the field over two successive calling seasons. Females, which do not call, were not parasitized by Hornotrixa sp., but the risk of parasitism for males increased as the 3‐month calling season progressed. Parasitism did not commence until c. 2 weeks into the calling season, but by the end of the season up to 87% of surviving males were parasitized.
Parasitized males lived for 14 days and were found singing until their penultimate evening before death in the field. Unparasitized males lived on average 69 days and a maximum of 119 days.
Multiparasitism of hosts was common, with up to sixteen fly larvae found within parasitized males. The number of fly larvae within hosts significantly increased at the end of the season. However, successful emergence of fly larvae from hosts, as well as pupal size, significantly decreased as more than one fly larva developed within the host.
Hornotrixa sp. has a long pupal duration of 30–31 days at 20°C. As a consequence, only one complete fly generation, which overwinters in the pupal stage, is likely within each host generation.
No evidence for differential (size‐bias) mortality by Hornotrixa sp. on male S.quadrata was found. The size of parasitized and unparasitized males collected in the field was not significantly different.
It is concluded that Hornotrixa sp. is a significant mortality factor acting on the survival of adult male S.quadrata.
Body size distribution in aphids: relative surface area of specific plant structures
Authors: DIXON A. F. G. , KINDLMANN P. , JAROŠIK V. 
Published: March 2008

Abstract.The distribution of the body sizes of British aphids is right‐skewed on a logarithmic axis, as in other taxa. Over the size range 2–5 mm there is a marked decrease in numbers of species with increase in size, which on a log log scale has an exponent of ‐3, The exponent for the right‐hand side of the size distribution of British plants is ‐0.7.The sizes of sixty‐eight species of the genusAphisare weakly correlated with the size of their respective host plants.An aphid's size is strongly correlated with the length of its proboscis, which indicates the depth to which it has to probe plant tissues in order to feed.On average, trees host more species of aphids than either shrubs or herbaceous plants, which appears to be associated with the relative surface area of specific plant structures. The surface area of plants is mainly made of leaves and most species of aphids are leaf feeders. The largest and least numerous species of aphids feed on the branches and trunks of trees, the proportional cover of which is less than that of leaves.Taking into account all the above observations, a functional explanation in terms of the relative surface area of specific plant structures is offered to account for the size diversity curve of aphids.
Philopatry in the alpine grasshopper, Podisma pedestris: a novel experimental and analytical method
Authors: MASON P. L. , NICHOLS R. A. , HEWITT G. M. 
Published: March 2008

Abstract.

Local dispersal and philopatric behaviour of the alpine grasshopper, Podisma pedestris, were studied at two sites in the Alpes Maritimes using a new mark—release—resight technique featuring marking in situ, and multiple resighting without handling. The time‐consuming nature of the design was justified by the quantity and quality of the data yielded.
Philopatry is defined independently of any concept of home range as a phenomenon by which movements over longer periods are less than would be expected by extrapolation of measures over shorter periods.
By this definition, the grasshoppers are shown to exhibit philopatry. Nymphs comprise two heterogenous classes of those which move little and those which move considerable distances.
Daily dispersal estimates were obtained from movements of 1055 nymphs and adults at one site, and of 593 adults at another.
Differences are demonstrated in daily dispersal distances for age, sex and site combinations.
Some differences in microhabitat preference were observed.
The findings are compared with previous measurements of dispersal in this species, and the merits of the new technique are discussed.
Variable chemical defence in the checkerspot butterfly Euphydryas gillettii (Lepidoptera: NymphaIidae)
Authors: BOWERS M. DEANE , WILLIAMS ERNEST H. 
Published: March 2008

Abstract.

Like other checkerspots, Euphydryas gillettii butterflies may contain the defensive chemicals, iridoid glycosides, which are sequestered from their hostplants during larval feeding.
We analysed the iridoid glycoside content of E.gillettii adults from two different populations, Warm Lake, Idaho, and Granite Creek, Wyoming, that have different patterns of hostplant use.
Gas chromatographic analysis of thirty butterflies from the Wyoming population showed that they contained a mean of 1.27 (±0.19 SE) % dry weight iridoid glycosides. Notably, 20% of these butterflies contained no detectable iridoid glycosides.
In contrast, nineteen butterflies from the Idaho population contained a mean of 3.89 (±0.38 SE) % dry weight iridoid glycosides, and all butterflies contained iridoid glycosides.
These results illustrate how the chemical defence of herbivorous insects varies according to differential use of potential hostplants.
Impacts of defoliation by tussock moths (Orgyia vetusta) on the growth and reproduction of bush lupine (Lupinus arboreus)
Authors: HARRISON SUSAN , MARON JOHN L. 
Published: March 2008

Abstract.

Outbreaks of tussock moths (Orygia verusta Bdv.) on bush lupines (Lupinus arboreus Sims) may be very intense, although spatially localized, and may last >10 years. To understand better how such outbreaks may persist, we defoliated lupine bushes using variable realistic numbers of tussock moth larvae, and measured the immediate and delayed impacts of defoliation on the growth and seed production of lupine bushes.
Immediate effects of defoliation included the production of new leaves that were significantly smaller in diameter and biomass, and lower in water content, than the new leaves of undamaged bushes. Also, seed output was reduced by up to 80% on heavily damaged bushes.
In the longer term, surviving bushes recovered remarkably well, despite having received the full range of possible (survivable) insect densities. After 1 or 2 years’rapid growth, surviving bushes were not affected in terms of height, basal stem diameter or volume by their previous defoliation. However, there was a significant tendency for juvenile bushes to produce more seeds the more heavily they had been attacked the previous year.
The ability of the host plant to recover, in terms of its biomass, helps to explain the sustained nature of the insect outbreak.
Effects of temperature on phenological synchrony and altitudinal distribution of jumping plant lice (Hemiptera: Psylloidea) on dwarf willow (Salix lapponum) in Norway
Authors: HILL JANE K. , HODKINSON IAN D. 
Published: March 2008

Summary.

The geographical distributions of three species of jumping plant lice (psyllids) along an altitudinal transect (988–1300 m a.s.l.) in southern Norway were restricted within the range of their host plant Salix lapponum. One species, Cacopsylla propinqua, occurred at all sampling locations between 988 and 1222 m, whereas C.palmeni was confined to higher altitudes (1153–1222 m) and C.brunneipennis was more abundant at lower altitudes (988–1101 m).
C.brunneipennis and C.palmeni developed only on female catkins. Development times of catkins and psyllids were similar (approximately 50 days) and successful psyllid development depended on close phenological synchrony with catkins.
Thermal requirements for development of female catkins were greater at low altitude (988 m) compared with higher altitude (1222 m), showing local adaptation of S.lapponum to altitude. In general, thermal requirements of psyllids were less than those of catkins at the same location. C.brunneipennis had higher thermal requirements than C.palmeni.
Field experiments, using polythene enclosures to elevate temperatures at two sites at different altitudes (by 0.6–1.4 deg. C), showed that insects had an enhanced relative rate of development under elevated temperatures compared with their host plants.
Indices of phenological synchrony were calculated from thermal requirements of psyllids and catkins. Under elevated temperatures, phenological synchrony decreased at both sites. This resulted in the subsequent development of smaller adult insects at low altitude, although at higher altitude, insects developing under elevated temperatures were larger and had a higher survival rate compared with controls.
Effects of temperature on phenological synchrony may explain the limits to the geographical range of psyllids. The consequences of climate change on psyllid populations will depend on the effects of decreased phenological synchrony on insect development and this may differ within the insect's geographical range.
Colony founding in the primitively eusocial wasp,Ropalidia marginata(Hymenoptera: Vespidae)
Authors: SHAKARAD MALLIKARJUN , GADAGKAR RAGHAVENDRA 
Published: March 2008

Abstract.In a 16‐month study in Bangalore, India, about 35% of the newly founded colonies ofRopalidia marginatawere single foundress colonies and the remainder were multiple foundress colonies with two to twenty‐two individuals.Larger colonies did not have a significantly higher per capita productivity, did not produce significantly heavier progeny and did not produce them significantly faster than smaller colonies did.Predation by the hornetVespa tropicaappeared to be independent of group size.Single foundress colonies failed more often but not often enough to make them have a lower average per capita productivity, compared to multiple foundress colonies.Some of the advantages of multiple foundress associations came from the greater predictability of their attaining the mean per capita productivity, the relatively lower rates of usurpation experienced by them compared to single foundress colonies, and the opportunities provided by queen turnovers for workers to become replacement queens and gain direct individual fitness.