bluuebunny/crossref_metadata_2025_split huggingface dataset:
Host‐plant effects on Parasyrphus melanderi (Diptera: Syrphidae) feeding on a willow leaf beetle Chrysomela aeneicollis (Coleoptera: Chrysomelidae)
Authors: RANK NATHAN E. , SMILEY JOHN T. 
Published: March 2008

Abstract.

Generalist predators are repelled by chrysomelid (Chrysomela spp., Phratora vitellinue L.) larval defensive secretions that are obtained from salicin in their host plants. But little is known about the effect of these secretions on specialist predators.
In this study, we describe the feeding behaviour of a fly, Parasyrphus melanderi Curran (Diptera: Syrphidae), which feeds on Chrysomela aeneicollis Schaeffer (Coleoptera: Chrysomelidae). Parasyrphus melanderi lays its eggs on C.aeneicollis egg clutches, and its larvae consume C.aeneicollis eggs and larvae.
Chrysomela aeneicollis hatching rates were significantly lower (20%) on clutches with fly eggs than on clutches without them (40%). Half of the clutches with one fly egg had survival rates below 5%, and when two fly eggs were present (four clutches), the entire clutch was consumed.
In nature, P.melanderi eggs were 3 times more abundant on a salicylaterich willow species S.orestera Schneider, than on the medium‐salicylate S.geyeriana Anderss. (1.8 v 0.6 eggs per clutch). On 18% of the S.orestera clones, all the beetle clutches contained fly eggs. In laboratory‐choice tests, P.melanderi larvae fed equally rapidly on C.aeneicollis larvae that were chemically defended (feeding on S.orestera) as on larvae that produced no secretion (feeding on the salicylate‐poor S.lutea Nutt.). This predator does not appear to be deterred by C.aeneicollis's defensive secretion. We discuss the implications of specialist predators on determining host suitability to herbivorous insects.
Oviposition substrate affects adult mortality, independent of reproduction, in the seed beetle Callosobruchus maculatus
Authors: FOX CHARLES W. , TATAR MARC 
Published: March 2008

Abstract.

Seed beetles (Coleoptera: Bruchidae) are commonly used to study the influence of reproduction on life‐span and senescence. To study the physiological trade‐off between reproduction and mortality, many experiments rely on manipulating access to oviposition substrates to manipulate the reproductive rate of females.
The presence of host seeds, independent of reproduction, results in increased mortality of female Cullosobruchus muculutus. This influence on mortality varies between two host seed species, suggesting a role of either allelochemicals or energetic costs associated with behaviour on hosts.
The influence of host seeds on survivorship, independent of reproduction, confounds the interpretation of cost‐of‐reproduction studies with seed beetles. This complication must thus be considered in the design and interpretation of life‐history studies of seed beetles and other insects.
The effects of host plant phenology on the demography and population dynamics of the leaf‐mining moth, Cameraria hamadryadella (Lepidoptera: Gracillariidae)
Authors: CONNOR EDWARD F. , ADAMS‐MANSON ROBERT H. , CARR TIMOTHY G. , BECK MICHAEL W. 
Published: March 2008

Abstract.

We examined the effects of variation in the timing of spring leaf production and autumn leaf fall on the survival, mortality and abundance of Cameraria hamadryadella on Quercus alba and Q.macrocarpa.
We monitored and manipulated the timing of foliation on field and potted Q.alba trees and observed the abundance of C.hamadryadella on those trees. We also monitored and manipulated the timing of leaf fall on Q.alba and Q.macrocarpa trees in the field and observed its effects on survival, mortality and abundance of C.hamadryadella.
Variation in the timing of spring leaf production has no effect on C. hamudryadella abundance. However, a warm winter and spring in 1991 led to accelerated development and the imposition of a facultative third generation in one out of ten years of observation.
In 1989, leaves fell relatively early and leaf fall in the autumn accounted for more than 50% of the mortality of C.hamudryadella. in 1990 and 1991 leaves fell relatively late and leaf fall induced mortality was substantially reduced and overwinter survival was markedly increased.
The abundance of C.hamadryadella remained constant in the spring and summer of 1990 following the previous autumn's relatively early leaf fall, but increased by 10‐fold in the spring of 1991 following the relatively late leaf fall of autumn 1990. The abundance of C.hamadryadella also increased 4‐fold between the summer of 1991 and the spring of 1992 after another autumn of relatively late leaf fall. We attribute these increases in abundance in part to reduced mortality because of later leaf fall.
Variation in the timing of autumn leaf fall may be responsible for initiating outbreaks of C.hamadryadella.
Optimum body size in aphids
Authors: DIXON A.F.G. , KINDLMANN P. 
Published: March 2008

Abstract.

Smallness in British plant‐sucking bugs is associated with feeding on the contents of individual plant cells, especially phloem.
The sizes of species of aphids living in similar habitats and the rates of water loss from those that have and lack a filter chamber do not support the contention that small size in aphids is a means of maximizing the loss of water by cuticular transpiration.
An optimum energy partitioning model, previously developed for aphids, was used to predict the interspecifie relation between adult weight and birth weight that would maximize the population growth rate, rm. Using the observed rm/IRGR ratio (0.8–0.9) and that the gonads are smaller than the soma at birth the predicted relation between the logarithm of the adult weight and the logarithm of the birth weight is linear and has a slope of 1.
The relation between the logarithm of the adult weight and the logarithm of the birth weight for eighteen species of aphids is linear and has a slope of 1.
Birth size differs between species of aphids and in each species is assumed to be the minimum size necessary for feeding. Accepting this constraint then the optimum adult size for maximizing rm is approximately 15 times the birth size.
Host range expansion by British moths onto introduced conifers
Authors: FRASER SIMON M. , LAWTON JOHN H. 
Published: March 2008

Abstract.Over 2% of British angiosperm‐feeding moths (Lepidoptera) have been recorded feeding on conifers introduced to Britain, and may be undergoing host range expansion.We compared some of the life‐history traits and ecological characteristics of fifty such species, originally exploiting angiosperms and now recorded feeding on conifers, with those of 400 non‐shifting angiosperm‐feeding moths, to identify those factors linked with host shifting.Shifting species attack a wider range of angiosperms than non‐shifting species, their original hosts tend to be woody tress and shrubs, and they hatch from the egg earlier in the year.Comparisons with the random control samples suggest that larval feeding habit and overwintering stage are also important (species with less intimate relations with the host plant, and those overwintering as eggs are more likely to shift); these trends persisted when the taxonomic distribution of the shift species was controlled for, though were no longer significant.Moth species in habitats and on host plant families which are associated with conifer afforestation in upland Britain are more likely to shift, suggesting that ecological opportunity is an important factor in host range expansion.
Herbivorous insect species in the tree canopy of a relict South African forest
Authors: MORAN V.C. , HOFFMANN J. H. , IMPSON F. A. C. , JENKINS J.F.G. 
Published: March 2008

Abstract.

The herbivorous insects on twelve species of evergreen broadleafed trees were repeatedly sampled over a period of 11 months in a small relict forest on the east coast of South Africa. This extraordinarily speciose forest patch has an unusually high proportion of endemic tree species, some of which are extremely rare.
The insect herbivore fauna (number of species) seems to be markedly depauperate compared to that reported on native, broadleafed trees from other parts of the world. Some possible reasons for this are discussed.
The total number of herbivorous insect species on each tree species was strongly correlated with the local relative abundance of the host plant species.
There was no relationship between the total number of insect herbivore species on each tree species and the relative taxonomic isolation of the trees. The proportion of seemingly unique (= specialist) herbivorous insect species (i.e. those that occurred on one tree species only) was greatest on taxonomically isolated trees.
A fundamental deficiency in the interpretation of the data in this study, and of many other similar studies that report on the number of insect species on plants, is discussed, namely the lack of clarity on the closeness of the association between individual insect herbivore species and their respective host plants.
Relation between temporal persistence of host plants and wing length in leafhoppers (Hemiptera: Auchenorrhyncha)
Authors: NOVOTNý VOJTĚCH 
Published: March 2008

Abstract.

Wing form frequencies in 255 populations of 101 species of leafhoppers (Auchenorrhyncha) in temporary and permanent habitats were documented.
The proportion of brachypterous specimens in the leafhopper assemblages on ruderal host plants in temporary habitats (median 2%, range 0–8%) was significantly lower than that on permanent host plants in undisturbed habitats (median 22%, range 0–94%).
Leafhopper species typical of temporary habitats were either monomorphic, macropterous, or wing‐dimorphic with macropterous forms prevailing in both sexes.
Among the eighty‐nine species recorded in permanent habitats, forty‐five species were wing dimorphic. In forty‐one dimorphic species, a brachypterous form prevailed. This prevalence was found for both sexes in thirty‐one species, for only females in nine species and for only males in one species.
The prevalence of brachypters in males, but not in females, found in Anoscopus flavostriatus, is probably the first such documented case in Auchenorrhyncha.
The hypothesis is proposed that in temporary habitats, density‐dependent production of macropters in wing dimorphic species is an adaptation to frequent habitat deterioration caused by factors independent of the density of the species.
The predominance of brachypters in permanent habitats indicates that a density‐dependent decrease in fitness usually does not offset the potential decrease in fitness connected with macroptery and dispersal. Because of this inability of leafhopper populations to decrease significantly the quality of their resources, a high population density cannot be used as a predictor of future quality of these resources, which is information essential for efficient dispersal behaviour.
Parasitism and predation as agents of mortality of winter moth populations in neglected apple orchards in Nova Scotia
Authors: PEARSALL I.A. , WALDE S.J. 
Published: March 2008

Abstract.

This study compared the roles of pupal mortality and parasitism in winter moth (Operophtera brumata) population dynamics in Nova Scotian apple orchards and assessed the importance of beetles as pupal predators.
The component of pupal mortality termed predation accounted for greater stage‐specific mortality of winter moth than parasitism by Cyzenis albicans in four neglected orchards.
Parasitism by Cyzenis albicans was not spatially density‐dependent in any orchard, whereas the predation component of pupal mortality was spatially density‐dependent in the two orchards most densely populated by winter moth.
Field experiments indicated that over 60% of pupal predation may be attributed to beetles, and that about 46% of pupal predation occurred within 4 weeks after pupal drop.
Mortality of introduced populations of winter moth in Nova Scotia resembles that of native populations in England where density‐dependent predation regulates the winter moth population and reduces the parasitoid population to minimal levels. The situation in Nova Scotia appears to have changed appreciably since the establishment of parasitoids into the system in the 1950s.
Effects of scale on detecting interactions between Coleophora and Eriocrania leaf‐miners
Authors: VALLADARES G. R. , HARTLEY S. E. 
Published: March 2008

Abstract.

The possibility of interactions between leaf‐miners in the genus Eriocrania and Coleophora serratella L. on birch (Betula pendula Ehrh. and B.pubescens Roth.) was studied via: (i) co‐occurrence patterns on random samples of leaves; (ii) palatability of Eriocraniidae‐mined leaves to C.serratella, in laboratory and field preference tests.
In the field, C.serratella and Eriocrania spp. fed on common leaves less frequently than expected by chance. This result is consistent with, and could be explained by, the avoidance of mined leaves shown by C.serratella in most of the feeding trials.
Avoidance was not observed at the between‐tree level, i.e. the number of leaves mined by each type of insect was unrelated. However, when tree species was taken into account, an inverse distribution was observed: mine abundance was higher for Eriocrania spp. on B.pubescens, whereas for C.serratella it was higher on B.pendula.
B.pubescens leaves mined by Eriocrania spp. had consistently higher phenolic contents and were better at precipitating proteins than unmined leaves. These induced chemical changes could explain the reduced preference shown by C.serrate1la for Eriocrania mined leaves.
We speculate about the evolution of adult host‐plant selection shown by these insects in response to potential larval interactions.
On the relationship between food, reproduction and survival of two carabid beetles: Calathus melanocephalus and Pterostichus versicolor
Authors: VAN DIJK TH. S. 
Published: March 2008

Abstract.

The relative influences of temperature and availability of food on reproduction, survival and growth of all developmental stages of two carabid beetle species are discussed with special reference to the suggested relationship between availability of food, size of egg production and survival of adults from one breeding season to the next.
Temperature as well as food supply influence the length of larval growth and adult body size. Beetles grown at low temperatures and low amounts of food are smaller than those grown at higher temperature and with more food.
The number of eggs laid per female was correlated with the amount of food gathered. There was no inverse relationship (trade‐off) between reproductive output and survival in the field until the next breeding season.
In 1980 no significant relationship was found between winter mortality and the amounts of food gathered by beetles in the period after reproduction and before winter diapause. However, in 1981 in C. melanocephalus a lower number of starved beetles survived the winter than the fed ones and‘field’beetles.
Only in the first part of the feeding activity period in autumn can enough food be gathered by C.melunocephalus for successful hibernation. In the second part of this period there is not enough food to build up the fat reserves needed to survive the winter.
Difference in population fluctuations of both species are discussed in relation to their life histories.
Reproductive seasonality in tropical satyrine butterflies: strategies for the dry season
Authors: BRABY M. F. 
Published: March 2008

Abstract.

In tropical savanna environments rainfall is often very seasonal, so that much of the year is characterized by a long and unpredictable dry season. Because the timing and availability of rain exerts a major influence on plant growth and production, many species during the dry period exhibit dramatic reduction in leaf quality. Accordingly, and kind of behaviour shown by phytophagous insects that synchronizes larval feeding with food availability will be adaptive.
The reproductive status of three Mycalesis butterflies was monitored over a 2‐year period (1989–90) in north‐eastern Queensland, Australia, at a lowland site (Cardwell, 18°16's, 146°02′E) which experiences a pronounced dry season. Females of these species and of five other satyrines (Ypthima, Hypocysta spp.) were also examined less intensively during the dry season in areas throughout northern and central Queensland, north of the tropic of Capricorn.
These relatively sedentary butterflies exhibit three different strategies for dealing with the unpredictable dry period and associated deterioration of larval food plants (grass). First, five species appear to breed continuously, though for most reproductive activity (mature egg number) declines markedly in the late dry season. Two of these (Hypocysta irius, H.metirius) are restricted to less seasonal and more favourable (wetter) areas but the three others (Ypthima arctous, H.adiante, H.pseudirius) occur widely in the relatively dry savanna, where they may specialize on grass in moister microenvironments. Second, two species (M.terminus, M.sirius) live in predictably moist habitats which are buffered from climatic extremes; they breed for much of the season but reproductive activity declines as the dry season progresses and may cease late in the season. Third, one species (M.perseus) is more opportunistic, breeding for only a limited interval during the favourable (wet) periods; during the long dry season adults contract to moist refugia and remain in reproductive diapause.
Spending the late dry season as an adult, either in diapause or with mature eggs, may improve the capacity to utilize new growth of grasses at the start of the favourable season, thereby enhancing population growth during good times. It may also provide additional flexibility to counter the temporal uncertainty of the dry season.
The strategy of residing in more equitable habitats or specializing on predictable foods may be the most restrictive in terms of distribution.
The effect of season and group size on survivorship and larval growth in Plagiodera versicolora
Authors: CROWE MARY L. 
Published: March 2008

Abstract.

The larvae of the multivoltine imported willow leaf beetle, Plagiodera versicolora (Laicharting), are found in larval aggregations during the first half of the larval stage. An experimental study was conducted to test for seasonal (brood) and group size effects on larval fitness. For each of the three broods, egg group sizes of1, 4, 8, 16, 24 and 32 were established in the field and monitored for the first 6 days post‐hatching.
There was no effect of group size on larval weight, but there was a significant effect of group size on survival. Individuals from group size 16 had the highest survival, which coincides with the mean natural cluster size of 15.3 eggs.
There were no significant interactions between brood and group size.
The effect of larval weight on adult fitness was determined in the laboratory and the field. Larval weight was correlated with egg production in the laboratory but not in the field.
Genetic differentiation as a result of adaptation to the phenologies of individual host trees in the galling aphid Kaltenbachiella japonica
Authors: KOMATSU TADASHI , AKIMOTO S. 
Published: March 2008

Abstract.

The adaptation of the non‐migratory galling aphid Kaltenbachiella japonica (Matsumura) to the budburst phenologies of individual host trees (Ulmus davidiana var. japonica Nakai) was investigated. There was a large variation in budburst time between individual host trees. We tested a hypothesis that aphid populations on respective host trees are genetically differentiated through adaptation to the budburst phenologies of host trees.
There was significant correlation between the budburst time of eight host trees in two successive years.
Tree‐associated populations differed significantly in egg‐hatching time, and the mean hatching time was significantly correlated with the mean budburst time of respective host trees.
Mating was made between male and female sexuales of the same clone (i.e. self‐mating) to obtain selfed eggs. Hatching patterns of selfed eggs showed that there was a substantial amount of genetic variance in hatching time between clones (galls). Nested ANOVA demonstrated that the between‐tree component contributed more to the phenotypic variance than the within‐tree or within‐gall components.
Reciprocal crosses between males and females of different clones furthermore demonstrated significant differences in hatching time between cross combinations, but no significant differences between the two reciprocals within combinations. This result suggests that there are no maternal effects for the timing of egg hatch and that the differences between selfed lines are attributable to genetic variance.
The fine‐scale adaptation hypothesis was supported by egg‐hatching experiments, which further suggest that budburst phenology varying between individual trees is acting as intense selective pressure on the egg‐hatching time of associated insects.
Population biology of swift (Apus apus) ectoparasites in relation to host reproductive success
Authors: LEE PATRICIA L. M. , CLAYTON DALE H. 
Published: March 2008

Abstract.We censused ectoparasite populations of adult and nestling swifts over the course of the host's breeding season. Nearly all of the birds were infested with chewing lice and two‐thirds of the nests were infested with louse flies. Feather mites were observed but not quantified.Lice and louse flies both showed aggregated distributions among hosts. Louse eggs, hatched lice and adult louse flies had negative binomial distributions, whereas the aggregated distribution of louse fly pupae was not adequately described by negative binomial or Poisson models.Transmission of lice from parents to offspring was documented. A comparison of the age structure of lice on parents and offspring indicated that most transmission was by nymphal lice.Host reproductive success and survival appeared to be independent of the number of lice or louse flies. Neither parasite correlated with the number, body mass, or date of fledging of young birds, nor with the overwinter survival of adults. We caution, however, that experimental manipulations of parasite load are required for a definitive test of the impact of ectoparasites on evolutionary fitness components.
Larval age differences and competition between Drosophila aldrichi and D.buzzatii
Authors: KREBS ROBERT A. , BARKER J. S. F. 
Published: March 2008

Abstract.

Competitive interactions among larvae of Drosophila species using the same habitat will usually involve individuals varying in age and size. Older, larger larvae might be expected to outcompete younger, smaller larvae.
Newly hatched laryae of Drosophila aldrichi and D.buzzatii were placed on induced cactus necroses (simulating the natural habitat), either simultaneously, or with a 1 or 2 day difference in the time at which individuals of the other species were added.
Evidence for competitive differences with larval age were found. In both species, body weight was significantly higher for those larvae added first than for later addition larvae, and a longer time to complete development was required for those larvae added 2 days later. However, pre‐adult viability of D.aldrichi was significantly higher for larvae started 1 or 2 days after larvae of D.buzzatii. For D.buzzatii, viability was lowest for larvae started simultaneously with D.aldrichi, but not different between those started either before or after D.aldrichi.
Considering all three traits, no clear advantage for the early addition larvae was observed.