bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pupation site choice of a North American lycaenid butterfly: the benefits of entering ant nests
Authors: WAGNER DIANE 
Published: March 2008

Abstract.Larvae of the North American lycaenid butterflyHemiargus isolaReakirt tended by the antFormica perpilosaWheeler often enter nests of this ant species, and pupate in tunnels and chambers near the surface. Untended larvae and those tended by the antsDorymyrmexForel sp. (smithicomplex),Forelius foetida(Buckley), andMyrmecocystus mimicusWheeler pupate in crevices in the ground, under bark, and on leaves; but rarely inside ant nests.The location and structure ofF.perpilosanests facilitates discovery byH.isolaprepupae. At the southeast Arizona study site,F.perpilosanests are located at the base ofH.isola'shost plant, whereas other species’nests are in open ground. Also,F.perpilosanest openings are wide, whereas those of other species may be too narrow for prepupae to enter.Prepupae associated withF.perpilosaspent 67% less time on the ground searching for pupation sites than prepupae associated with other ant species. Pupae in artificial chambers connected toF.perpilosanests were 4–5 times less likely to disappear overnight, presumably due to predation, than those not connected to nests.Formica perpilosaants tend pupae inside nests. However, in the laboratory experiments tended pupae did not lose more weight prior to eclosion than untended ones, suggesting that chemicals or sounds produced by pupae as ant attractants are inexpensive, or are produced whether or not ants are present.Newly‐eclosed butterflies exited nests unmolested by ants in the field, but were attacked if confined with ants for several minutes after eclosion in the laboratory.
Effect of mating frequency and brood cell infestation rate on the reproductive success of the honeybee parasite Varroa jacobsoni
Authors: DONZÉ GÉRARD , HERRMANN MIRIAM , BACHOFEN BORIS , GUERIN PAT RICK M. 
Published: March 2008

Abstract.

The reproductve biology of Varroa jacobsoni, whose females infest honeybee brood, was studied in natural and transparent artificial brood cells. These investigations were made under the headings of maturation behaviour and fertilization, and the influence of infestation rate of brood cells on the number of mated females produced per infesting Varroa.
Mating of Varroa daughters, observed in the transparent brood cells with time‐lapse video, occurs just after ecdysis and as soon as they arrive on the faecal accumulation prepared by the mother. Such females are remated for as long as no other freshly moulted daughter arrives on the faecal accumulation.
The number of spermatozoa stocked in the spermatheca increases with remating, a strong indication for sperm mixing in this species when brood cells contain more than one Varroa foundress.
The number of daughters per infesting mother decreases at higher rates of infestation per cell, but the proportion of such daughters with a mate rises sharply due to the higher probability of finding a male within multi‐infested cells. The number of mated daughters per mother is maximal in cells with two foundress Varroa females.
The frequency distributions of infesting mites in drone cells are aggregated, and approximate to negative binomial distributions.
We postulate from the above that the observed non‐random infestation by Varroa in drone brood augments the mite's mean reproductive success through the production of a higher number of mated daughters than the corresponding Poisson distributions would.
Host‐searching and mating in an outbreeding parasitoid wasp
Authors: GUERTIN D.S. , ODE P.J. , STRAND M.R. , ANTOLIN M.F. 
Published: March 2008

Abstract.

Female parasitoid wasps (Hymenoptera) must search for hosts to reproduce, but only require mates if their broods are to contain female progeny. In outbreeding species, females locate mates after dispersal from the emergence site. Unmated females may therefore face a trade‐off between searching for hosts and searching for mates, if hosts and mates are spatially separated.
In the outbreeding parasitoid Bracon hebetor Say (Hymenoptera: Braconidae), males and females are spatially segregated in the field. Females are found primarily below the surface of stored corn where they search for hosts, whereas males are found on or above the surface.
Wasps placed in laboratory observation chambers designed to mimic B.hebetor's stored corn habitat distributed themselves in a manner consistent with field observations. Males remained on the surface of the grain, whereas females moved below the surface to attack hosts.
In the laboratory, female distribution was influenced by their mating status, the presence of males or hosts, and female age. Virgin females were more reluctant to move into the corn than were mated females, younger females foraged deeper than older females, and all females moved deeper into the com when males were present.
10% of all females did not mate even when males were present in the chambers, a percentage consistent with previous observations from the field. If B.hebetor faces a trade‐off between host‐searching and mate‐searching, the trade‐off seems to be part of 'split sex ratio strategies', with some females remaining constrained to producing only male offspring.
Adaptive trade‐offs of leaf folding in Dichomeris caterpillars on goldenrods
Authors: LOEFFLER CAROL C. 
Published: March 2008

Abstract.

Leaf folding is a common behaviour among caterpillars that has many potential benefits such as creation of a favourable microclimate and protection from predation or dislodgment.
One cost of leaf folding which has not previously been quantified is the reduction in growth rate that might result from the energetic expenditures of producing silk and applying it to fold leaves.
On caged goldenrods in field and forest habitats, early‐instar Dichomeris leuconotella (Busck) caterpillars that were repeatedly forced to spin new leaf refuges (either folds or webs of silk) actually had higher growth rates than caterpillars left undisturbed.
This surprising result apparently reflected the fact that disturbed caterpillars chose relatively young green leaves for new refuges, whereas undisturbed caterpillars tended to remain in their webs or folds on ageing leaves.
In a glasshouse experiment using plants that underwent little senescence, growth rates were unaffected by the amout of refuge‐making effort, indicating that the costs of such effort were either negligible or easily compensated for by these caterpillars.
On glasshouse plants, caterpillars periodically forced to change refuges had higher disappearance rates than those left undisturbed, despite the absence of predators. Wandering or falling from plants is evidently a major hazard of frequent refuge changes.
Thus, early‐instar Dichomeris caterpillars face a trade‐off in which risks of predation or loss of contact with the host favour the observed low rate of refuge changes, but in which growth rates could actually be improved with more refuge changes.
The usefulness of destructive host feeding parasitoids in classical biological control: theory and observation conflict
Authors: JERVIS MARK A. , HAWKINS BRADFORD A. , KIDD NEIL A.C. 
Published: March 2008

Abstract.

We examine the conventional wisdom among biological control practitioners that destructive host feeding is a desirable attribute in parasitoids employed for classical biological control, using both the predictions of population dynamics theory and historical data on biological control introductions of Hymenoptera against Homoptera.
Population dynamics theory predicts that destructive host feeders, compared with other parasitoids, are (a) either just as likely or more likely to become established, and (b) unable to depress host equilibria as strongly.
Analyses of the B IOC AT database suggest that among parasitoids of Homoptera destructive host feeders are superior to other parasitoids with respect to both establishment rate and success rate.
We present likely explanations for the disparity between the predictions of population dynamics theory and the results of database analysis. A partial explanation for the mismatch between theory and observation with respect to the degree of pest suppression may be that females of destructive host feeding parasitoids rely less upon hosts as a food source when alternative foods such as honeydew and nectar are plentiful.
We conclude that, despite the predictions of population dynamics theory, destructive host feeders are probably better biological control agents than other parasitoids, and certainly no worse, but that it would imprudent to use destructive host feeding as the sole, or even primary, selection criterion when seeking agents for classical biological control.
Consequences of adult size for survival and reproductive performance in a herbivorous ladybird beetle
Authors: OHGUSHI TAKAYUKI 
Published: March 2008

Abstract.

A univoltine herbivorous ladybird beetle Epilachna niponica (Coleoptera: Coccinellidae) shows a large variation in adult size within a population.
Large adults had higher survival from emergence to the reproductive season, and the size‐dependent adult survival was most apparent during hibernation. On the other hand, adult survival during pre‐hibernation contributed little to size‐dependent overall survival.
Neither reproductive lifespan nor lifetime fecundity were a function of adult size, though large females produced larger size of egg batches.
Size of adult beetles was significantly reduced by leaf damage to plants on which they grew up on larval stage. Since leaf herbivory increases through the season, late emerged adults that were subjected to food deterioration during the larval period were smaller than early‐emerged individuals.
Larval development of two parasitic flies (Conopidae) in the common host Bombus pascuorum
Authors: SCHMID‐HEMPEL REGULA , SCHMID‐HEMPEL PAUL 
Published: March 2008

Abstract.

Whenever parasitism by more than one female occurs, larvae of parasitoids not only have to resist host defence but also face competition with other (unrelated) larvae. Competition is particularly important in solitary parasitoids where only one larva is able to complete its development. Such a situation is found in Conopidae (Diptera) parasitizing adult bumble bees where larvae of two species of conopid flies, Sicus ferrugineus L. and Physocephala rufipes F. often compete within the common host Bombus pascuorum Scopoli. This study analysed the larval development of the two species and asks how competition among larvae may be regulated.
Parasitized workers of B.pascuorum were caught in the field and kept according to different experimental schedules in the laboratory. This provided stage‐structured data for the temporal course of development of the parasitic larvae. For the analysis, a simulation model was constructed that estimated the duration of all parasitic stages (Manly, 1990, first method). In both species the egg stage was found to be approximately 2 days, first instar 3 days, second instar 4 days, and third instar 3 days. The total development time is an estimated 10.8 days from oviposition in S.ferrugineus and 11.4 days in P.rufipes. S.ferrugineus develops faster in the beginning, probably because of its larger egg size, whereas P.rufipes pupates at larger size. First‐instar larvae of both species possess strong, pointed mandibles.
The success of conopid larvae seems only marginally affected by host defence, for a single larva per host almost always completes development. Under competition, however, mortality rate increases substantially, and most larvae die in their first instar. Moreover, they show signs of melanization. The estimates for developmental times and the patterns found in this study suggest that conopid larvae seem capable of physical attacks, particularly during the first instar, when elimination of competitors is most common, and that S.ferrugineus has a time advantage because of its faster early development. Because most studies have previously been carried out with hymenopteran parasitoids, this study provides new information about the other large group of parasitoid insects, the Diptera, and demonstrates convergent patterns.
Alien herbivores and native parasitoids: rapid developments and structure of the parasitoid and inquiline complex in an invading gall waspAndricus quercuscalicis(Hymenoptera: Cynipidae)
Authors: SCHÖNROGGE K. , STONE G.N. , CRAWLEY M.J. 
Published: March 2008

Abstract.Rapid and substantial changes have occurred in the parasitoid and inquiline community associated with the agamic gallsof Andricus quercuscalicissince it invaded Britain in the late 1950s. The number of parasitoid and inquiline species has risen from one to thirteen over a 15‐year period. Although the number of species has been relatively consistent over the last 8 years, the species composition has changed considerably and in a highly characteristic way during this period.The parasitoid complex can be divided into two broadly distinct sets of parasitoid species; one set attacks only the gall former whereas the other set concentrates on the inquilines living in the wall of the gall.The most dramatic change, however, is in the abundance of inquilines which were reported to be virtually absent in earlier studies on this community in Britain. Over a period of only 5 years, between 1988 and 1993, inquiline attack rose from less than 0.01 to an average of 0.26 inquilines per gall. The intensity of inquiline attack is geographically heterogenous, with high inquiline numbers restricted to south‐east England. Because of the relatively high specificity of the parasitoids, high inquiline abundance is positively correlated with parasitoid species richness in knopper galls.Parasitism rates, particularly on the gall former, were generally low (<10%). Over the last 5 years, however, seven parasitoid species have been consistently recorded and the mortality caused by these species has increased continuously. The species composition of the community associated with this alien gall wasp in Britain has quickly converged to the community known from its native range in continental Europe. Parasitoid species known to attack the galls ofA.quercuscalisison the continent have been recorded from it in Britain for the first time mainly in areas where inquilines have recently become abundant.Since rates of parasitism of the gall former are still low, parasitoids are unlikely to play a major role in the population dynamics of this invading gall wasp at present, but the rapidly increasing inquiline and parasitoid attack could be a source of increased mortality for native cynipid species which are the alternative hosts of those parasitoid species.
Duration and benefits of biparental brood care in the dung beetle Onthophagus vacca (Coleoptera: Scarabaeidae)
Authors: SOWIG PETER 
Published: March 2008

Abstract.

Single males, single females or pairs of dung beetles, Onthophagus vacca, were released on artificial small (100 g) or large (1000 g) dung pats in the laboratory. Emigrating beetles were trapped at 12 h intervals, and the number and size of the brood chambers were recorded after each replicate.
Emigration of males was delayed if females were present in the same dung pats, whereas emigration times of females were independent of the presence or absence of males.
A residency of 60 h proved to be a threshold value. Females emigrating before this time did not breed, whereas those emigrating later had built at least two brood chambers.
Females paired with males built more brood chambers than single females.
The reproductive success of pairs was not influenced by the size of the dung pats.
The effects of crop microclimate and associated physiological constraints on the seasonal and diurnal distribution patterns of raspberry beetle (Byturus tomentosus) on the host plant Rubus idaeus
Authors: WILLMER P.G. , HUGHES J.P. , WOODFORD J.A.T. , GORDON S.C. 
Published: March 2008

Abstract.

The occurrence of raspberry beetles (Byturus tomentosus) on the host plant Rubus idaeus is extremely variable between seasons, between days and within days, with occupancy of the available raspberry flowers (the feeding and oviposition sites) varying from 0 to 60%.
This variation could not be explained by plant chemistry or food quality (leaf nitrogen, carbon or water levels, or floral nectar reward); however, beetle distributions were in part attributable to microclimatic constraints acting via the insects’physiological constraints.
Initial ascent into raspberry canes from soil emergence sites was limited by the three‐fold higher water loss rates from recently eclosed young adult beetles as compared with mature beetles. Young adults reduced their hygric stress by remaining in the humid microclimate of tightly furled primocane leaftips.
Mature beetles spread upwards over the plant, but showed a preference for insolated sites (tops of canes, east or west facing according to time of day). In such sites their body temperatures could rise above the threshold for flight (requiring a Tb of 15°C in laboratory studies). Flight activity was therefore common only in the early afternoon of warm days. Later in the day, beetles moved down and sometimes off the plants, starting to return at around dawn.
Thus physiological constraints, even on adult beetles (relatively well‐protected insect stadia), can be important components in predicting insect movements and locations on a host plant; they are likely to be even more crucial to less highly sclerotized plant‐feeding adult insects and many larval herbivorous pests.
Prey selection and baculovirus dissemination by carabid predators of Lepidoptera
Authors: VASCONCELOS SIMÃO D. , WILLIAMS TREVOR , HAILS ROSEMARY S. , CORY JENNIFER S. 
Published: March 2008

Abstract.

The interaction between coleopteran predators and baculovirus‐infected larvae was studied in the laboratory and the field in order to assess the potential role of predators in the dissemination of a nucleopolyhedrovirus (NPV).
Preference tests using three carabid species, Harpalus rufipes De Geer, Pterostichus melanarius Illiger and Agonum dorsale Pont, showed no evidence of discrimination between healthy and diseased larvae of the cabbage moth Mamestra brassicae L. (Lepidoptera: Noctuidae) as prey items.
Virus infectivity was maintained after passage through the predator's gut. NPV mortality ranged from 97% to 20% when test larvae were exposed to faeces collected immediately after and 15 days post‐infected meal respectively.
The potential for transfer of inoculum in the environment was estimated in the laboratory by soil bioassay. Carabids continuously passed infective virus to the soil for at least 15 days after feeding on infected larvae.
Field experiments showed that carabids which had previously fed on diseased larvae transferred sufficient virus to the soil to cause low levels of mortality in larval populations of the cabbage moth at different instars.
Competition and resistance to starvation in larvae of container‐inhabiting Aedes mosquitoes
Authors: BARRERA ROBERTO 
Published: March 2008

Abstract. 1. Hypotheses about declining populations of container‐inhabiting Aedes mosquitoes following the invasion by additional species were tested.2. The larval competition hypothesis was studied experimentally in pure and mixed cultures of Aedes aegypti (L.), A.albopictus (Skuse) and A.triseriatus (Say). The experiments used decomposing leaf litter in the laboratory, as opposed to most previous research which used non‐natural food.3. Resistance to starvation is introduced as a new measure of larval performance and competitiveness. The hypothesis is that more successful larvae store larger energy reserves and resist the lack of food longer.4. Contrary to previous research showing better performance of A.aegypti in mixed cultures, A.albopictus developed faster and had greater survival when natural food was used.5. Resistance to starvation was greater in the better performing species (i.e. A.aegypti with non‐natural food and A.albopictus with leaf litter). Oxygen consumption by starved larvae was similar in the three container species, and in the ground‐water mosquito, A.taeniorhynchus (Wied.), whose resistance to starvation was comparatively very low.
Insect invasion sequences: systematic or stochastic?
Authors: HODGE SIMON , ARTHUR WALLACE 
Published: March 2008

Abstract. 1. This study examined the invasion sequence of Drosophila species arriving at decomposing strawberries.2. It was found that the age of fruit affected the likelihood of Drosophila arrival, flies preferring relatively fresh fruit. However, there were no repeatable trends in invasion sequence of Drosophila species, different species responding in a similar manner to changes in fruit age.3. Although no systematic trends in invasion sequence were observed, species tended to be temporally separated due to stochastic differences in their arrival at the fruit.4. It is suggested that stochastic, as well as repeatable, temporal separation of species can have an important influence on subsequent community development.
Searching behaviour and mate recognition by males of the two‐spot ladybird beetle, Adalia bipunctata
Authors: HEMPTINNE J‐L. , DIXON A. F. G. , LOGNAY G. 
Published: March 2008

Abstract. 1. Adult males of the two‐spot ladybird beetle, Adalia bipunctata, did not show a functional response to increase in aphid abundance and consumed markedly fewer aphids than do the females.2. At high densities of prey, females spent more time in area‐restricted search than when prey was scarce. Males were always less active than females and they did not respond to an increase in prey abundance by a change in searching behaviour.3. After a brief encounter with a female, a male showed area‐restricted searching behaviour. This behaviour occurred in response to encountering a female's elytra and in particular to a chloroform‐soluble component (sex pheromone) present on or in the elytra.4. Males needed to encounter a female in order to respond to her presence, which indicated the pheromone is a contact pheromone.5. The searching behaviour of males appeared to be mainly directed towards locating females; that of females towards locating aphids. This difference between the sexes should be taken into account when quantifying the predatory response of ladybirds to aphid abundance in the field.
Components of male fitness in relation to body size in Epirrita autumnata (Lepidoptera, Geometridae)
Authors: TAMMARU TOOMAS , RUOHOMÄKI KAI , SAIKKONEN KARI 
Published: March 2008

Abstract. 1. The effect of body size on different components of male fitness was studied for Epirrita autumnata, a geometrid known for its eruptive population dynamics. Body size is the main determinant of female fecundity in this species.2. Longevity of males was found to have a weak negative correlation with body size at low temperatures. No significant correlation was found at higher temperatures.3. We found no correlation between male size and female fecundity or egg size which is consistent with the small size of spermatophores in this species.4. Small and large males were equally successful when allowed to compete for females in laboratory conditions.5. In one or two field collections, males found mating were larger than males found singly. Large males also had an advantage in finding of virgin females, offered experimentally. No size‐assortative mating was recorded.6. We conclude that size‐dependent mate location ability is the factor accounting for most of the variance in male fitness in E.autumnata. The dependence of fitness on body size may well be equally strong in males and females.