bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanisms of interference competition in the western tree‐hole mosquito, Aedes sierrensis
Authors: BROADIE KENDAL S. , BRADSHAW WILLIAM E. 
Published: March 2008

Abstract.

Mechanisms of interference competition affecting Aedes sierrensis (Ludlow) were investigated in laboratory microcosms using reconstituted, natural tree‐hole detritus as food and substrate.
Pupation success, larval development time, and pupal weight were all affected by larval density but not by surface area:volume ratio of the microcosm.
Mature fourth instars affected pupation success, pupal weight, and development time of developing cohorts separated from them by a 2 μm pore membrane impermeable to bacteria, indicating that chemical competition is proportional to density of at least older instars.
Cannibalism does not occur, regardless of the presence or absence of food or physical complexity.
Fourth instars inhibited each other's feeding at densities of 64 larvae/ml or greater. Feeding inhibition due to physical contact (encounter competition) was abated but not eliminated by increasing physical complexity of the microcosm by the addition of leaves.
Levels of detritus and larval density both affect weight of day‐1 fourth instars. Resistance to encounter competition is proportional to fourth instar weight and weight‐specific resistance is correlated with rank weight within a developing cohort.
At densities around the population equilibrium in nature, encounter competition should be taking place, especially in tree holes with few leaves or other large litter.
Seasonal variation in generation time, diapause and cold hardiness in a central Ohio population of the flesh fly, Sarcophaga bullata
Authors: CHEN CHENG‐PING , DENLINGER DAVID L. , LEE RICHARD E. 
Published: March 2008

Abstract.

Generation time, diapause phenology and cold tolerance of the flesh fly, Sarcophaga bullata, were examined under confined natural conditions in central Ohio. In this locality, the fly can complete a maximum of four generations annually.
Very few pupae entered diapause in the first and second generations (May to July in 1988). In the third generation (August) 37% of the pupae entered an overwintering diapause, as did all pupae from the fourth generation (September).
The adult eclosion date in the spring and annual generation time can be predicted accurately from degree day data.
Cold tolerance of the field‐overwintering portion of the population was high. After 30 days under field conditions, diapausing pupae readily survived a 7‐day exposure to — 17°C. Glycerol appears to be the major cryoprotectant in S.bullata, and glycerol concentrations in the field population (95–142 mm) remained high throughout the winter.
In contrast, diapausing flies reared under laboratory conditions (20°C, 12:12 LD) were less cold tolerant, and glycerol concentrations were lower (6.9–21.2 mm). Field conditions thus promote the acquisition of high levels of cold tolerance, presumably as a consequence of the accumulation of higher concentrations of glycerol.
In spite of differences in the cold tolerance of laboratory and field flies, the supercooling points of the two groups of flies were nearly the same, thus implying that the supercooling point is not a good indicator of cold tolerance.
Control of gall morphology: tephritid gallformers (Aciurina spp.) on rabbitbrush (Chrysothamnus)
Authors: DODSON GARY N. 
Published: March 2008

Abstract.

Sibling species of tephritid flies occumng on separate subspecies of Chrysofhamizus nauseosus Hall and Clements have distinct gall moiphologies (smooth and cotton).
Cross matings of and subsequent confinement of the flies to particular host plants demonstrated that the insect's and not the plant's genotype dictated the morphology of the gall, although the plant genotype may determine whether or not a gall is produced.
The results implicate a possible single gene control mechanism for external gall morphology.
Intraspecific competition in larvae of the ant‐lion Morter sp. and interspecific interactions with Macroleon quinquemaculatus
Authors: GRIFFITHS DAVID 
Published: March 2008

Abstract.

Intraspecific competition was investigated in the pit‐digging larvae of the ant‐lion Morter sp., which normally occurs at low density in a food‐rich habitat.
Morter larvae interact by displays, challenges, and sand tossing. Challenges/displays affected pit spacing while sand tossing affected pit size. Pit ownership determined the outcome of contests regardless of the relative sizes or feeding condition of the contestants.
Competition had no effect on the pit size of winners but losers showed a density dependent reduction in pit size. Interference competition caused a density dependent reduction in larval growth rates.
Macroleon quinquemaculatus (Hagen) always won contests with Morter, even when smaller. Cannibalism occurred in 60% of these contests.
Little intraspecific competition occurs in Morter in the field. Morter is more willing to incur energy costs than Macroleon.
Response of fire ants (Formicidae: Solenopsis invicta and S.gerninata) to artificial nectars with amino acids
Authors: LANZA JANET 
Published: March 2008

Abstract.

The role that amino acids in extrafloral nectars play in attracting ants to plants was investigated. Workers from laboratory colonies of Solenopsis invicta Buren and S.geminafa (F). (Formicidae) fed from artificial nectaries containing mimics of the extrafloral nectar of Passiflora menispermifoh and P.caerulea; P.menispermifoh nectar contains higher levels of amino acids (1347.3 pdml) than does the nectar of P.currulea (125.2 μm/ml).
When sugar‐only and sugar—amino acid nectar mimics were presented simultaneously, more S.invicta workers were counted at sugar—amino acid nectar mimics than at sugar‐only nectars. S.geminatu did not discriminate between the two nectars.
When the two Pamiflora L. nectar mimics were presented simultaneously, S.invicta and S.geminata workers were more abundant at the nectaries containing high levels of amino acids (P.menispermifolia HBK mimic) than at the nectaries containing low levels of amino acids (P.cuerulea L. mimic).
The behaviour shown by S.invicta and S.gerninata suggests that plants with high levels of amino acids in their extrafloral nectars attract more ant protectors and might suffer less herbivory than plants producing nectars with low levels of amino acids. If so, ants may favour, over evolutionary time, plants that produce nectars with high levels of amino acids.
Day‐to‐day variability in ant behaviour was considerable even among laboratory colonies maintained on the same diet in similar environmental conditions. This variability will reduce the selective impact that ants have on plants and may help to explain why most ant‐plant interactions are facultative.
Is host‐plant quality responsible for the populational pulses of salt‐marsh planthoppers (Homoptera: Delphacidae) in northwestern Florida?
Authors: SILVANIMA JAMES V. C. , STRONG DONALD R. 
Published: March 2008

Abstract.

Rare populational pulses of the sibling species of plant‐hoppers Prokelisia dolus Wilson and P.marginata (Van Duzee) occur along the Gulf Coast of Florida. Densities at least three standard deviations ahove the average number of adult planthoppers per stem host plant are exhibited during these pulses.
This context of rare local irruptions provides a basis for testing a component of T. C. R. White's hypothesis, which states that the trigger for insect outbreaks is an increase in the nutritional quality, in terms of available nitrogen, of host‐plant tissue.
In the field, over approximately five generations of these hoppers (9 months), we elevated foliar nitrogen in host plants substantially by fertilizing, six times, salt‐marsh plots of 10 m2 with ammonium nitrate. No densities approaching a populational pulse occurred in either fertilized or unfertilized plots during the course of this study or in the year following. Fertilization did increase adult densities in the spring but this increase deteriorated over the summer months and was lost in the autumn. Host plants in fertilized plots retained high levels of nitrogen for at least the second year.
Several very dense pulses, of more than thirty adult hoppers per stem, occurred at other sites during the course of this study. Host‐plant nitrogen in a pulse site did not differ from that found in host plants immediately adjacent to the pulse. We conclude that increased foliar nitrogen is not the proximate cause of the populational pulse behaviour exhibited by these planthoppers.
We speculate that these pulses result from behavioural aggregation of adult hoppers.
Sex ratios in field populations of Epidinocarsis lopezi, an exotic parasitoid of the cassava mealybug, in Africa
Authors: DIJKEN MARIANNE J. VAN , NEUENSCHWANDER PETER , ALPHEN JACQUES J. M. VAN , HAMMOND WINFRED N. O. 
Published: March 2008

Abstract.

In cassava fields in Africa, population sex ratios of Epidinocarsis fopezi vaned from 0.44 (males to total parasitoids) at low host densities to highly male‐biased ratios of 0.70 at high host densities.
This variability is caused by the difference in allocation of sons and daughters to hosts of different sizes, through the following mechanisms: (a) small, i.e. second instar, hosts are mainly used for the production of male offspring, whereas in large, i.e. third instar, hosts a variable, female‐biased sex ratio is produced; (b) E.fopezi does not selectively oviposit into large hosts but always accepts both small and large hosts for oviposition upon encountering; (c) in the field, this parasitoid is time‐limited, and not egg‐limited. On the basis of an optimal diet model, such general host acceptance is shown to be the best strategy.
Thus, sex ratio increases with host density for three reasons: the proportion of small hosts encountered in the field increases with increasing host density, small hosts are used for male production, and hosts are always accepted when encountered.
Ecology of baculovirus‐infected and healthy adults of Oryctes rhinoceros (Coleoptera: Scarabaeidae) on coconut palms in the Philippines
Authors: ZELAZNY B. , ALFILER A. R. 
Published: March 2008

Abstract.

Males and females of Oryctes rhinoceros (L.), a serious pest of coconut palms, congregate in decaying coconut trunks to mate, oviposit and prepare the wood for the young larvae. A baculovirus disease is often transmitted from beetle to beetle in this environment and transmission to and from larvae probably also occurs.
Young beetles are mainly found feeding on palms, where they also frequently contract the virus disease, presumably through mating with diseased partners.
Monitoring beetle populations in the Philippines with attractant traps and by collections from palms showed seasonal fluctuations which were often inversely correlated with the incidence of the virus disease. Disease prevalence matched closely the proportion of females in the population. Possible explanations for this correlation and for the seasonality of the disease prevalence are outlined.
The seasonality of arboreal arthropods foraging within an Australian rainforest tree
Authors: BASSET YVES 
Published: March 2008

Abstract.

The seasonality of arboreal arthropods foraging within the crown of the canopy tree Argyrodendron actinophyllum. Edlin (Sterculiaceae) was studied in a subtropical rain forest near Brisbane, Australia, during 2 years with interception traps and restricted canopy fogging.
Minimal air temperatures explained most of the seasonal variance in arthropod‘density activity'. However, the host phenology was important for several phytophagous groups. Rainfall, relative humidity and lunar phase influenced arthropod activity slightly.
Seasonal ranges were significantly different among arboreal guilds and were related to food resource availability in time, associated with both the host and the rainforest environment. Seasonal peaks of herbivores were more marked than in tropical rain forests, but less sharp than in temperate woodlands.'
Quantitative changes in arthropod density activity and abundance were important for most groups, with a marked trough during cool and dry months. The numerical contribution of most arthropod guilds to the arboreal community was not constant throughout the year.
Seasonal changes in the species composition of the arboreal community appeared not as a succession of well‐defined subcommunities throughout the year, but as a continuum of species of extended seasonal ranges.
This subtropical insect‐plant system presented several phenological features which were classified under tropical and temperate characteristics. This partition is open to discussion.
The influence of the ability to disperse on generation length and population size in the flour beetle, Tribolium castaneum
Authors: BEN‐SHLOMO RACHEL , MOTRO UZI , RITTE UZI 
Published: March 2008

Abstract.

In Tribolium castaneum Herbst, in which dispersal is genetically determined, it is possible to select for strains that are characterized by high and low dispersal, High dispersal (HD) beetles are better adapted than low dispersal (LD) beetles for colonization, as can be seen from differences that exist between the two groups with regard to several life‐history parameters.
Comparisons were made between the dynamics of seventy‐two HD and seventy‐two LD populations. Generation length in HD populations was significantly shorter than in LD populations. After 91/2 weeks, in open treatments (from which dispersal away from the set was allowed), HD populations had more beetles than LD populations, whereas in closed treatments (from which dispersal away from the set was not allowed) the opposite was true.
These findings may explain the maintenance of the genetic variability of dispersal behaviour in natural populations of T.castmeurn.
Pine sawfly defence and variation in host plant resin acids: a trade‐off with growth
Authors: BJÖRKMAN CHRISTER , LARSSON STIG 
Published: March 2008

Abstract.

The defence capability of pine sawfly larvae reared on Scots pines with low or high concentrations of resin acids was determined in a field experiment, where larvae were exposed to predatory ants, and in a laboratory experiment in which the rate of defence droplet replenishment was measured.
Larvae on low resin‐acid shoots disappeared faster than larvae on high resin‐acid shoots when exposed to predatory ants.
Larvae fed high resin‐acid needles produced 50% larger defence droplets than larvae fed low resin‐acid needles.
In an additional experiment high predation pressure was simulated by repeatedly removing defence droplets. Larvae responded by feeding more on tissue rich in resin acids, but at the cost of a reduction in growth rate.
Based on these data and earlier findings that survival and development of sawfly larvae are negatively affected by high resin‐acid concentrations, we conclude that pine sawflies face a dilemma of conflicting demands, i.e. although high needle resin‐acid concentrations enhance defence capability, they also reduce growth and survival. Our data also suggest that it is not necessarily the ovipositing female that has to balance this trade‐off: plasticity in larval feeding behaviour provides larvae with a means to at least partly solve the dilemma.
Phenotypic plasticity, seasonal climate and the population biology of Bicyclus butterflies (Satyridae) in Malawi
Authors: BRAKEFIELD PAUL M. , REITSMA NICO 
Published: March 2008

Abstract.

Seasonal polyphenism is studied in a community of five African butterflies of the genus Bicyclus at the transition between a wet and a dry season from May to July.
Butterflies characterized by large eyespots and, especially in B.sufitza (Hewitson), a pale band (the wet season form) are replaced over this period by butterflies lacking conspicuous wing markings (the dry season form, dsf). The latter butterflies also tend to be larger, but more variable in size. Butterflies of an intermediate phenotype are recruited over a comparatively short interim period.
This turnover coincides with a period of declining temperature and drying of the habitat, including the grasses on which larvae feed. Butterflies are progressively more likely to rest on brown leaf litter rather than on green herbage.
A relationship with temperature is supported by laboratory experiments with B.saJitza and B.anynana (Butler) showing that increasingly extreme dsf butterflies develop with decreasing rearing temperature in the final larval instar.
Some differences in behaviour and activity were observed between the seasonal forms. Butterflies of the dsf develop ovarian dormancy and fat bodies. They can survive to reproduce at the beginning of the rains in November.
Capture‐recapture experiments showed that the adult butterflies have a comparatively long life expectancy and are quite sedentary.
The results are discussed in relation to a hypothesis linking the polyphenism to seasonal changes in resting background and selection for crypsis.
Colonization, survival, and causes of mortality of Camerariu hamadryadella (Lepidoptera: Gracillariidae) on four species of host plants
Authors: CONNOR EDWARD F. 
Published: March 2008

Abstract.

The abundance, survival, and causes of mortality of Cameraria hamadryadella (Clemens) (Lepidoptera: Gracillariidae) were examined on four host plant species in Virginia, U.S.A. Quercus alba L. and Q.rubra L. are native within the geographic range of C.hamadryadella, and Q.robur L. and Q.benderi Baenitz are exotic. Q.robur is native to Europe, North Africa, and Asia and was probably introduced prior to 1850, and Q.benderi is of hybrid origin and introduced to cultivation before 1900. Q.alba and Q.robur are in the subgenus Lepidobalanus (white oaks), and Q.rubra and Q.benderi are in the subgenus Erythrobalanus (red oaks).
Larval mines of C. hamadryadella were abundant on both white oak species, including the exotic Q.robur, but were rare on host plants in the red oak subgenus. Un‐hatched eggs of C.hamadryadella were not observed on red oaks. Other observations on host distribution indicate that C.hamadryadella is rarely found on red oaks. These observations are interpreted as circumstantial evidence that C. hamadryadella generally avoids ovipositing on red oaks.
Survival of C.hamadryadella to the adult stage was similar among all host species, but larvae tended to survive longer on hosts in the red oak subgenus. The observation of higher survival rates of early instar larvae on red oaks suggests that no nutritional or secondary chemical barrier reinforces the observed pattern of oviposition.
Significant differences in the distribution of the causes of mortality were detected between native and exotic host plant species. Larvae and pupae on native hosts were more likely to die because of predation, while those on exotic host plants were more likely to die because of parasitism and host feeding by adult female parasitoids. This pattern could arise because parasitoids prefer to forage on exotic host plants or because predators avoid foraging on exotic plants.
This study shows for C. hamadryadella that the only barriers to colonization and use of exotic hosts, in the white and red oak subgenera, are the presence of cues sufficient to stimulate oviposition and/or the absence of cues to deter oviposition. It also suggests that the presence of closely related native host plants in the region of introduction will increase the probability that exotic plants will be colonized by phytophagous insects.
Changes in feeding habit as caterpillars grow
Authors: GASTON KEVIN J. , REAVEY DUNCAN , VALLADARES GRACIELA R. 
Published: March 2008

Abstract.

200 of 1137 species of British microlepidoptera make a single marked change in feeding habit as they grow.
Most numerous are species that change from leaf mining to one of case bearing, spinning, tying and rolling or concealed feeding, and species that change from concealed feeding to case bearing or spinning, tying and rolling.
Although in some instances numbers of closely related species make similar changes in behaviour, most changes observed are scattered among subfamilies.
Leaf miners have considerably smaller adults than concealed feeders, which themselves are smaller than external feeders and spinners, tiers and rollers. When case bearers are excluded from the analyses, species that remain as leaf miners or concealed feeders throughout larval development are on average smaller as adults than those that start out with these feeding habits but later change.
We suggest a number of reasons why larvae might make such fundamental switches.
Egg size increases with maternal age in the cotton stainer bugs Dysdercus fasciatus and D.cardinalis (Hemiptera: Pyrrhocoridae)
Authors: KASULE F. K. 
Published: March 2008

Abstract.

Egg‐size variation over the reproductive span of laboratory‐reared females is described in two species of cotton stainers: Dysdercus fasciatus Sign. from woody Malvales and D.cardinalis Gerst. from herbaceous Malvales.
Egg size increases with maternal age due to a decrease in clutch size as maternal age advances in both species.
The two species are similar in size, but egg size is about 28% larger and clutch size about 19% smaller in D.fasciatus than in D.cardinalis. These contrasts may be related to the host‐plant biology which differs between the two species.
The influence of habitat use and foraging on the replacement of one introduced wasp species by another in New Zealand
Authors: HARRIS R. J. , THOMAS C. D. , MOLLER H. 
Published: March 2008

Abstract.

New Zealand was colonized by the German wasp, Vespula germanica (F.), in the 1940s and it subsequently became established throughout the country. The common wasp, V.vulgaris (L), colonized in the late 1970s and is still spreading.
The common wasp has replaced the German wasp in some habitats in New Zealand. Samples from a nationwide postal survey indicate that the common wasp is now the more abundant species in honeydew beech forests (Nothofagus spp.), and to a lesser extent in other native forests. The German wasp is still the more abundant wasp in rural areas (excluding forest). The two species are at present co‐dominant in urban areas, although this may be a transient phase.
In honeydew beech forest the two species show different foraging patterns that provide the potential for local coexistence. Although both species are generalist feeders, the German wasp is more commonly found foraging for protein amongst the forest litter, whereas the common wasp forages more on shrubs and tree saplings. Despite this difference, the common wasp can still replace the German wasp in honeydew beech forest within a few years of invasion.
In honeydew beech forests in which the German wasp is the more abundant species it dominates honeydew trunks (sugar resource), whereas the common wasp dominates honeydew trunks in areas where it is the more abundant species. The change from German to common wasp domination of honeydew trunks is more rapid than the change in dominance in other microhabitats. Aggressive interactions may be taking place on this high quality, potentially defensible sugar resource.