bluuebunny/crossref_metadata_2025_split huggingface dataset:
Local population differences in emergence of cabbage root flies from south‐west Lancashire: implications for pest forecasting and population divergence
Authors: FINCH STANLEY , COLLIER ROSEMARY H. , SKINNER GARETH 
Published: March 2008

ABSTRACT.

Emergence of cabbage root fly, Delia radicum (L.), from overwintering populations of puparia collected from twenty‐one sites in south‐west Lancashire, was extremely variable.
The patterns of emergence indicated that there were two extreme biotypes, one with early‐ and the other with late‐emerging flies. There was also evidence of an intermediate biotype, tending more to early than to late emergence.
This gradient of biotypes, or clinal divergence, was maintained by populations breeding at different times and by females mating close to their sites of emergence. Non‐dispersive females then perpetuated their genotype within their own locality.
The time of emergence was not obviously associated with the type of host‐crop on which larvae had developed.
The late‐emerging biotype was most prevalent around Halsall. The minimum distance between populations of the late‐ and the early‐emerging biotypes was 16 km. 20 km south‐east from Halsall only half of the fly population was early‐emerging, possibly a result of a displacement of the Halsall biotype by the prevailing NW wind.
Regional‐based forecasts will need to take into account the emergence characteristics of the populations to predict the peak periods of cabbage root fly activity adequately in south‐west Lancashire and other areas where emergence patterns differ.
The natural diet of the Notonectidae: field trials using electrophoresis
Authors: GILLER P. S. 
Published: March 2008

ABSTRACT.

Field trials were conducted on populations of two sympatic species of the waterbug Notonecta (Hemiptera: Heteroptera), to examine their natural diet using the electrophoretic method of gut contents analysis.
Fingerprint esterase bands were identified from thirty‐three potential aquatic prey types; gut contents of different instars of both species of Notonecta from the field were analysed.
The level of prey identification possible ranged from 73% in fifth instar N.glauca L. to 100% in third instar N.viridis Delcourt.
Type A errors, where no prey remains were detected from a full gut, were found in only 3% of the specimens analysed.
Data on gut states, the number of prey types per gut and details of aquatic prey found in the diet of different instars of field‐collected Notonecta are presented.
These results are compared with previous data on notonectid diets, and the relative merits of different methods of diet analysis are discussed.
Behavioural response of spider mites (Tetranychus urticae) to induced resistance of cotton plants
Authors: HARRISON SUSAN , KARBAN RICHARD 
Published: March 2008

ABSTRACT.

Spider mites (Tetranychus urticae Koch) given a choice between a cotton plant previously damaged by mites and an undamaged control preferentially moved to the control plant.
This host‐choice behaviour was seen in adult female mites but not in immatures.
Adult females were not found to be significantly more fecund on control plants than on previously damaged plants, but the duration of this choice experiment precluded full assessment of effects on fecundity.
Mites responded very quickly, choosing previously undamaged plants without contacting or feeding on the test plants. This suggests that an olfactory response to a chemical substance(s) is involved.
Behavioural and ecological adaptations to the high mountain environment of Polistes biglumis bimaculatus
Authors: LORENZI M. C. , TURILLAZZI S. 
Published: March 2008

ABSTRACT.

Polistes biglumis bimaculatus (G. in Furcroy) (Hymenoptera: Vespidae), a high mountain species, was studied in the Alps. Adaptations of this species to the severe climate and reduced nesting season include nesting characteristics, social organization and division of labour, and caste succession.
Foundress association occurs only in the late pre‐emergence period and is not the same as that seen in low altitude species.
The foundress females continue to forage even in the post‐emergence period and workers and reproductive (males and females) emerge almost contemporaneously.
The use of discriminant analysis for the estimation of sampling biases for female tsetse
Authors: RANDOLPH SARAH E. , ROGERS DAVID J. 
Published: March 2008

ABSTRACT.

In this paper we investigate whether the technique of discriminant analysis can be used to estimate sampling biases for female tsetse.
Discriminant analysis was first applied to laboratory samples of female tsetse, Glossina morshans morsitans Westwood, to test whether flies of known history could be assigned to the correct day of the pregnancy cycle on the basis of their fat, haematin and corrected residual dry weight.
Following the satisfactory results from the laboratory samples, the same technique was applied to field samples of G.m. centralis Machado captured by electric traps and hand nets in Zambia and of G.palpalis palpalis (Robineau‐Desvoidy) captured in biconical traps at five sites in Ivory Coast. The results show that flies on day 1 of the pregnancy cycle were most likely to be caught, with a second peak of day‐6 and day‐7 flies, while very few day‐8 or day‐9 flies were caught.
These major peaks in fly trappability coincide with the known feeding habits of female tsetse, and indicate synchrony of feeding by many members of the population immediately after larviposition and again as the larva in utero moults from the second to third instar. G.palpalis is relatively more available at this later stage of its pregnancy cycle to the capture methods used than is G.morsitans. A third feed may be taken at a more variable point in the pregnancy cycle.
This method of estimating the sampling biases of female tsetse could allow an estimate of total population size, as long as the absolute sampling efficiency of flies on any one day of the pregnancy cycle could be established by, for example, mark‐release‐recapture experiments.
Skeletal economy in certain herbivorous beetles as an adaptation to a poor dietary supply of nitrogen
Authors: REES CHRISTOPHER J. C. 
Published: March 2008

ABSTRACT.

Flying Coleoptera were sampled with light traps from the tree canopy of lowland alluvial rain forest in Brunei, Borneo.
Adult chrysomelid beetles were found to carry significantly less skeleton relative to their overall mass than those of any family other than herbivorous scarabaeids (subfamily: Rutelinae). Xylophagous lucanids and cerambycids and dung‐feeding scarabaeids (subfamilies: Aphodiinae and Scarabaeinae) carried as large a proportion of skeleton by mass as predatory carabids and cicindelids.
Skeletal production requires the commitment of assimilated nitrogen to chitin and proteins. Adequate nitrogen is more readily available to predators, carrion or dung‐feeders, and xylophages (given enough time) than to leaf‐chewing chrysomelids, which are also environmentally exposed to predatory attack. Female chrysomelids were found to carry a larger number of mature eggs/insect than those of any other family. A larger proportion of their mass was represented by eggs than skeleton, as reproductive compensation for reduced skeletal protection.
It was estimated that a chrysomelid beetle required approximately 43% of the nitrogen incorporated by a predatory carabid of the same mass, whereas xylophagous cerambycids and lucanids would need between 84% and 98% of that in the predator.
Egg‐laying by the speckled wood butterfly (Pararge aegeria): the role of female behaviour, host plant abundance and temperature
Authors: SHREEVE T. G. 
Published: March 2008

ABSTRACT.

Egg‐laying by Pararge aegeria (L.) was studied in relation to host plant abundance, temperature and behaviour in one woodland site in central England.
Eggs were laid on the undersides of leaves of fifteen of thirty‐one species of grass located in the study site. Most were deposited singly although on several occasions a number of females laid on a single leaf.
There was no clear relationship between host plant abundance and host plant use, the species used being widespread and abundant.
Most eggs were laid on plants within the temperature range 24–30°C. In spring and later summer these sites were in sunlit open areas but in midsummer they were in the woodland ground layer.
Females distributed their eggs over a large area, usually making a dispersal flight after laying an egg.
The effects of foliage damage on casebearing moth larvae, Coleophora serratella, feeding on birch
Authors: BERGELSON JOY , FOWLER SIMON , HARTLEY SUSAN 
Published: March 2008

ABSTRACT.

Mechanical damage to birch (Betula pendula Roth) leaves leads to an increase in the concentration of phenolic compounds, which spreads throughout the leaf within 8 days.
Coleophora serratella L. (Lepidoptera: Coleophoridae) apparently responds to this chemical change over a similar time scale. Within 24 h of pin‐pricking leaves the casebearer moves from the immediate vicinity of the damage, but is just as likely to move to an undamaged portion of the damaged leaf as to vacate the leaf entirely. After 8 days mines on undamaged portions of damaged leaves were significantly smaller than mines on undamaged leaves.
Furthermore, Coleophora serratella reared on damaged trees took an average of 3 days longer to develop than those reared on undamaged trees.
It has been suggested that increased movement in response to damage‐induced chemical changes causes hyperdispersed damage on plant foliage. Both within and between‐leaf casebearer damage patterns were shown to be aggregated on birch.
Thus although mechanical damage can induce chemical and behavioural changes in the field, these are not reflected in the observed damaged patterns. We speculate on several possible reasons for this.
The osmaterial glands of the swallowtail butterfly Eurytides marcellus as a defence against natural enemies
Authors: DAMMAN HANS 
Published: March 2008

ABSTRACT.

Natural enemies account for almost all mortality of zebra swallowtail caterpillars (Eurytides marcellus [Cramer]) feeding on pawpaw (Asimina spp.) in Florida.
The osmaterial glands of the third instar caterpillars reduce predation rates in the spring, but not later in the season.
The seasonal decline in effectiveness of osmateria in deterring natural enemies probably stems from a reduction in the importance of the predators that are repelled by osmateria.
Attachment may be a basis for specialization in oak aphids
Authors: KENNEDY C. E. J. 
Published: March 2008

ABSTRACT.

The potential role of tarsal attachment in host selection was studied in the specialist aphids Tuberculoides annulatus Hartig and Myzocallis schreiberi Hille Ris Lambers and Stroyan.
M.schreiberi could walk freely on its host, Quercus ilex and on Q.robur, whereas T.annulatus could walk freely on its host, Q.robur but had difficulty on Q. ilex.
Attachment to the rough‐textured leaves of Q.robur was achieved by means of the pretarsal claws, and to the smooth upper surface of individual trichomes on the lower surface of Q.ilex using flexible pretarsal empodia.
Both behavioural and allometric differences can account for the inability of T.annulatus to grip onto Q.ilex.
The role of attachment by phytophagous insects in host plant resistance and selection is discussed.
A comparative study of winter survival in two temperate Collembola
Authors: Van Der WOUDE H. A. , VERHOEF H. A. 
Published: March 2008

ABSTRACT.

We studied winter survival of two temperate collembolan species, Orchesella cincta (L.) and Tomocerus minor (Lubbock), that overwinter in adult and juvenile life stages.
A significant seasonal variation in cold hardiness, measured as lethal temperature after 24 h exposure, was found for both species. There was no difference between juveniles and adults in cold hardiness. O.cincta was more cold tolerant than T.minor.
A group of high and a group of low values for lethal temperatures could be distinguished.
Frost periods induced gut evacuation in O.cincta, but not in T.minor.
During frost periods no extra winter mortality was found in T.minor. This species moved down the soil profile as a response to a frost period without snow cover.
The winter mortality of O.cincta was difficult to estimate, since part of the population remained above ground in trees and escaped from sampling. The smallest size classes, which are restricted to the litter, had a lower winter mortality than T.minor.
Primary sex‐ratio and differential progeny survivorship in solitary haplo‐diploid parasitoids
Authors: WELLINGS P. W. , MORTON R. , HART P. J. 
Published: March 2008

ABSTRACT.

A method of partitioning emergence sex‐ratio to give estimates of primary sex‐ratio and male and female offspring survival from oviposition to emergence in solitary haplo‐diploid parasitoids is presented.
This method is applied to sex‐ratio data from a larval parasitoid, Aphidius ervi Haliday, and a pupal parasitoid, Coccygomimus turionella L., parasitizing a range of host types.
There was no evidence of facultative control of primary sex‐ratio in either species. Parasitoid emergence sex‐ratios were similar for all host sizes attacked by C. turionella. In contrast, emergence sex‐ratios of A.ervi showed a significant male bias in smaller hosts. This shift in emergence sex‐ratio was attributable to differential progeny survival.
Pre‐emergence mortality in both species was a function of host size, with few offspring surviving from small hosts. This suggests that host size may be an important component in the dynamics of host‐parasitoid interactions.
The evolution of sex‐ratio regulatory mechanisms in solitary haplo‐diploid parasitoids is discussed in the context of parasitoid life‐history. We suggest that there is a constraint to the evolution of the facultative control of primary sex‐ratio in parasitoids attacking larval stages as a result of the uncertainty of future host resource acquisition rates.
Does alary dimorphism imply dispersal dimorphism in the waterstrider,Gerris remigis?
Authors: FAIRBAIRN D. J. 
Published: March 2008

ABSTRACT.The hypothesis that wing dimorphism reflects dimorphism for dispersal ability is tested in two populations of stream‐dwelling waterstriders,Gerris remigisSay, in southern Quebec, Canada.Movements were assessed directly by recaptures of marked adults, and indirectly by comparisons of residence times and patterns of disappearance of macropterous and apterous morphs. Sampling was done weekly, over a period of 26 months, and 4828 adultG.remigiswere individually marked during this time.Movements of >100 m were very rare for both morphs. The movement patterns of the two morphs were very similar, and differed only over the winter, when no macropters moved upstream. This latter observation suggests that macropters may be less successful than apterous individuals at moving overland, or rowing against a current at this time of year.Residence times and patterns of disappearance of the two morphs were very similar during all seasons.These results suggest that macropterousG.remigisdo not, in general, disperse using any means unavailable to the apterous morph, and that macropters in this species should not be simply categorized as long‐distance dispersers.
Temporal constancy in grasshopper assemblies (Orthoptera: Acrididae)
Authors: JOERN ANTHONY , PRUESS† KENNETH P. 
Published: March 2008

ABSTRACT.

Temporal constancy in the structure of grasshopper assemblies (about forty‐five species each) from two types of North American grasslands was assessed; one site was followed 25 years and the other 7 years.
Densities and relative abundances varied but composition of assemblies based on ranks suggested significant structure when three or more species were included in the analysis.
Results compared favourably with other insect herbivore assemblies which have been examined; variability in population change was intermediate along the spectrum of organisms which have been studied.
The harmonic radar: a new method of tracing insects in the field
Authors: MASCANZONI DANIEL , WALLIN HENRIK 
Published: March 2008

ABSTRACT.

A novel technique for tracing the movements of insects in the field is described.
The detection system is based on radar technology originally developed for locating avalanche victims. The key of the system is a tiny electronic diode that, glued to the insect, can reflect microwave beams emitted by portable detection equipment.
The technique has been successfully tested in a field‐tracing experiment with carabid beetles. The results show that these insects are capable of dispersing surprisingly long distances in a relatively short period of time.
Effects of root nodules and taproots on survival and abundance of Sitona hispidulus (Coleoptera: Curculionidae) on Medicago sativa
Authors: QUINN MARK A. , HOWER ARTHUR A. 
Published: March 2008

ABSTRACT.

The effects of food resources on populations of larvae of Sitona hispidulus (F.), a root and nodule herbivore of Medicago sativa L., were investigated in 1983 and 1984.
Density‐dependent mortality among first‐instar larvae indicated that a lack of available root nodules, the primary resource for first instars, contributed to the 66.2±5.2% and 80.7±4.1% mortalities of first‐instar larvae in 1983 and 1984, respectively. Initial densities of larvae entering the soil were 31.7±2.4 and 15.6±1.3 per soil sample (10.5 cm diam. ×15 cm deep) in 1983 and 1984, respectively (±SEM).
Survivorship and number of first‐instar larvae per soil core sample were significantly related to number and biomass of nodules per soil sample. Percentage soil moisture was not consistently correlated with survivorship and number of larvae per soil sample.
Numbers of second‐ and third‐instar larvae were not consistently correlated with either nodule or taproot biomass.
Numbers of fourth‐instar larvae were associated with taproot biomass, suggesting that taproot surface area may also limit population levels of S.hispidulus. No correlations were found between taproot and nodule biomass on any sampling date indicating that high numbers of fourth‐instar larvae associated with larger taproots were not merely due to a greater survival of first instars associated with larger taproots.
The study suggests that population levels of nodule‐herbivores are controlled by the availability of root nodules. A sparse distribution of nodules results in high levels of mortality among nodule‐herbivores of Medicago sativa.
Aggregation of parasitoids and density‐independence of parasitism in field populations of the wasp Aphytis melinus and its host, the red scale Aonidiella aurantii
Authors: SMITH A. D. M. , MAELZER D. A. 
Published: March 2008

ABSTRACT.

Repeated counts were made of the number of adult Aphytis melinus (DeBach) wasps per fruit on Valencia oranges in an orchard over two successive periods. Resulting rates of parasitism per fruit were measured at the end of each period.
For both periods, corresponding to high and low mean numbers of adult parasites, there was a significant positive regresssion of adult wasps per fruit on the number of available hosts per fruit. However, there was a high level of variability about the regression, and the overall aggregative response appears to be weak.
For both periods, rates of parasitism per fruit were independent of host density per fruit and they showed a high level of variability at all densities. Similar patterns were found in another, commercial, orchard over a wide range of mean host densities.
There was no evidence for aggregation of parasites or density dependence of parasitism at a patch size corresponding to the whole tree.
Suggestions based on some host‐parasitoid models, that aggregations of parasite attack in areas of high host density are necessary for effective biological control, are rejected. However, the model of Hassell (1982), incorporating aggregation of parasites and limitations on the effectiveness of the parasite, seems to fit the data quite well.
Wing and flight muscle polymorphism in a lygaeid bug, Horvathiolus gibbicollis: determinants and life history consequences
Authors: SOLBRECK CHRISTER 
Published: March 2008

ABSTRACT.

Horvathiolus gibbicollis (Costa), a ground‐living seed‐feeding bug of the mediterranean region, has two wing morphs. In macrop‐terous bugs both pairs of wings are fully developed. In brachypterous ones forewings are reduced to about two‐thirds and hindwings to less than a third of their length in macropters.
Each morph bred true with regard to wing length when reared under variable density, food and temperature conditions for several generations.
All F1 offspring between crosses of the two morphs were brachypterous. In F2 approximately 25% were macropters and 75% brachypters implying monogenic control of wingform.
Flight muscles in macropters vary from fully developed to totally reduced. This variation is determined by environmental conditions during adult life. Most young adult bugs have flight muscles, and totally starved or unmated bugs retain their flight muscles. Fed and mated females histolyse flight muscles as they start laying eggs, while most males of the same group retain their muscles.
Brachypterous bugs have a smaller thorax and larger abdomen than macropterous ones.
Brachypterous bugs reach adulthood slightly before macropterous ones, and they have a distinctly shorter adult preoviposition period.
Lifetime egg production does not differ significantly between the two wing morphs. However, the temporal pattern of egg laying is different in the two morphs. The mx‐curve of macropters starts later, then attains a higher peak and finally decreases faster than that of brachypters.
Initially, macropters lay smaller eggs than brachypters, but egg volume increases with age in macropters and eventually approaches that of brachypters.
The initial increase in reproductive effort (egg volumexegg number) of macropters is concomitant with wing muscle histolysis and the mobilization of thorax space for reproduction.
Adult survival rate does not differ between the morphs.
Habitat choice of some field‐inhabiting carabid beetles (Coleoptera: Carabidae) studied by recapture of marked individuals
Authors: WALLIN HENRIK 
Published: March 2008

ABSTRACT.

Habitat choice of some field‐inhabiting carabid beetles was studied in the field, and included the adult‐overwintering Bembidion lampros Herbst, Pterostichus cupreus L. and Agonum dorsale Pontoppidan, and the larval‐overwintering Trechus secalis Paykull, Pterostichus melanarius Illiger, P.niger Schaller and Harpalus rufipes De Geer. These were compared to the forest‐inhabiting and adult‐overwintering species, Carabus nemoralis Müller.
Marked beetles were released in the centre of a circular enclosure which was placed on the edge between a cereal field and a wood. The direction of movement in this circle was compared with that in a control circle placed entirely in the cereal field.
In the field/wood circle, adult‐overwinterers and the larval‐overwin‐terer H.rufipes choose to move into the cereal field. The majority of T.secalis. P.melanarius and C.nemoralis, however, moved into the wood, while P.niger exhibited no preference.
In the field circle, adult‐overwinterers moved towards the more sun‐exposed parts of the circle, whereas the movements of larval‐overwin‐terers were random.
Some species‐specific characteristics considered important for habitat choice by these carabid beetles, and the relevance of these characteristics for their dispersal behaviour are discussed.