bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of host‐plant quality on the survival of larvae and oviposition by adults of an ant‐tended lycaenid butterfly, Jalmenus evagoras
Authors: BAYLIS M. , PIERCE N. E. 
Published: March 2008

Abstract.

Juveniles of the Australian lycaenid butterfly, Jalmenus evagorus (Donovan), secrete to ants a solution of sugars and amino acids, primarily serine. The attendant ants protect the larvae and pupae from parasites and predators.
The effect of caterpillar nutrition on the defence provided by ants was investigated. Potted food plants of Acacia decurrens were either given water containing nitrogenous fertilizer or were given water alone. Fertilized plants had a higher nitrogen content than unfertilized plants.
Fifth instar larvae of J.evagoras feeding on fertilized plants attracted a larger ant guard than those feeding on unfertilized plants. In the absence of caterpillars, ants were not differentially attracted to fertilized and unfertilized plants.
In the presence of ants, over a 10‐day period, larvae on fertilized plants survived better than larvae on unfertilized plants. In the absence of ants larvae survived equally on fertilized and unfertilized plants. It is concluded that larvae on fertilized plants attracted a larger ant guard, and thereby survived better, than larvae on unfertilized plants.
Adult females of J. evagoras preferred to lay egg batches on fertiized, rather than unfertilized plants, but they did not lay larger egg batches.
Oviposition response of Simulium reptans (Diptera: Simuliidae) to the presence of conspecific eggs
Authors: COUPLAND JAMES B. 
Published: March 2008

Abstract.

The oviposition behaviour of Simulium reptans L. is described from two sites on the River Spey, Scotland. Female aggregations were observed immediately downstream of oviposition sites and were composed mainly of gravid flies (range 60–80%0) together with smaller numbers that were either freshly bloodfed (range 2–17%) or infected with mermithid nematodes (range 0–30%).
The time from landing on the oviposition sites to the onset of oviposition was recorded. The time in the presence of greater than 1‐day‐old eggs did not significantly differ from sites with no eggs present. However, the presence of freshly laid or I‐day‐old eggs significantly shortened the time to onset of oviposition. The cues that elicit oviposition are unknown but it is speculated that they may involve a pheromone.
Host population structure affects field sex ratios of the heteronomous hyperparasitoid, Coccophagus atratus
Authors: DONALDSON J. S. , WALTER G. H. 
Published: March 2008

Abstract.

Second instar Filippia gemina de Lotto scale insects are the preferred hosts of female Coccophugus atrutus Compere larvae. These scale insects were found on their host plants, Chrysanthemoides monilifera Norlindh and Cliffortia strobilifera Mettenius, only at certain times during a 1 year sampling programme.
Late larval instars and prepupae of C.atratus, and a Metaphycus species, are the preferred hosts of male C.atratus larvae. These hosts, although they occurred on the same host plants as hosts for female C.atratus, were most numerous at different times during the sampling period.
The ratio of hosts suitable for C.atratus varied from a predominance of hosts suitable for females through to a predominance of hosts suitable for males. Sex ratios of adult C.atratus followed a similar trend but did not reflect, exactly, the ratio of available hosts. Differences in mortality between sexes and hyperparasitism may account for this anomaly.
Variable population sex ratios observed in C.atratus apparently result from the behaviour of individual females in which brood sex ratios are dependent on the relative availability of hosts for males and hosts for females. This behaviour, in turn, may result from variability in the host population structure but may also result from selection pressures operating at the time that heteronomous hyperparasitism evolved.
Sperm competition in Callosobruchus maculatus (Coleoptera: Bruchidae): a comparison of two methods used to estimate paternity
Authors: EADY P. E. 
Published: March 2008

Abstract.

This study investigates sperm competition in Cullosobruchus maculatus (F.) (Coleoptera: Bruchidae), and is the first study to make a direct, controlled comparison of the sterile male and genetic marker techniques to estimate sperm precedence.
P2 values (the proportion of offspring fathered by the second male) obtained from the two methods were similar: P2 (sterile male) = 0.82, P2 (genetic marker) = 0.85. Both methods are therefore suitable for studying sperm precedence if the appropriate correction factors are applied.
The importance of general fertilization ability, differential fertilizing capacity and differential zygote mortality are examined and discussed.
Host‐plant mediated geographic variation in the life history of Platycotis vittata (Homoptera: Membracidae)
Authors: KEESE MARK C. , WOOD THOMAS K. 
Published: March 2008

Abstract.

The oak treehopper Platycotis vittata (Fabricius) is bivoltine throughout its range with discrete generations in the early spring and autumn. Females of both generations diapause.
Latitudinal variation in the timing of life history exists among four populations of P. vittata along the eastern coastal plain of the United States.
We disrupted synchronization between P.vittata life history and host‐plant phenology in the springs of 1984 and 1985 by placing southern populations on northern trees with a different phenology. This caused some females to oviposit abnormally in late spring, without entering diapause. The offspring of these females had reduced reproductive success.
Winter diapause can be broken by providing females with a newly flushing tree with high levels of amino nitrogen in the sap. Females terminated winter diapause on trees breaking winter dormancy while females on trees still in winter dormancy did not, under identical photoperiod and temperature regimes.
The role of host‐plant mediated life history variation as a process promoting intraspecific geographic differentiation in the arboreal sap‐feeding guild is discussed.
Mortality risk versus food quality trade‐offs in ants: patch use over time
Authors: NONACS PETER , DILL LAWRENCE M. 
Published: March 2008

Abstract.

Foragers of the ant species Lasius pallitarsis (Provancher) and Myrmica incompleta Provancher were given access to two food patches that differed in nutritive quality. In about half of the trials, the higher quality patch also had a mortality risk for the foragers in the form of a large Formica subnuda Emery ant located along the trail. Colonies were given access to the food for 4 or 24 h, every second day.
Use of the higher quality patch by L.pallitarsis foragers was depressed by the mortality risk. In contrast to the predictions of a food stress hypothesis, foragers used the risky patch more in the longer access trials. This appears due to a decline in the activity level of the F.subnuda, which results in a significantly lower mortality risk per trip.
M.incompfeta also significantly decreased their use of the higher quality patch when a F.subnuda was present. However, the length of time a colony had access to the patches had no effect on the use of the risky patch. M.incompleta foraging behaviour seems relatively insensitive to short‐term food stress or changing levels of mortality risk.
The differences between species in their exploitation of patches and reactions to F.subnuda are discussed in terms of the species’natural history.
Habitat characteristics of grassland Pterostichus species (Coleoptera, Carabidae)
Authors: RUSHTON S. P. , LUFF M. L. , EYRE M. D. 
Published: March 2008

Abstract.

Pterostichus species were sampled on ninety‐two sites distributed throughout north‐east England using pitfall trapping.
The incidence of each species was related to measured site environmental variables using logistic regression.
Four species groups were identified on the basis of size. The extent of overlap in habitat types between species in each group varied. Two large species overlapped considerably whilst the smaller species showed different responses to one or more environmental variable.
Possible causes of the differences in habitat overlap between Pterostichus species are discussed.
Two forms of egg defence in a chrysomelid beetle: egg clumping and excrement cover
Authors: DAMMAN HANS , CAPPUCCINO NAOMI 
Published: March 2008

Abstract.

Field experiments demonstrated that the faecal covering that female Microrhopala vittata (Fabr.) (Coleoptera: Chrysomelidae) place over their egg masses significantly reduces egg mortality.
The bottom egg in the egg mass, which lies against the leaf of the host plant, suffers significantly higher mortality than the other eggs in the egg mass.
The parasite Chrysonotomyia sp. (Hymenoptera: Eulophidae) generally parasitizes only the bottom egg in the egg mass, while predators rarely penetrate the faecal covering.
No significant relationship was found between mortality and the number of egg masses per leaf.
By placing eggs in masses, females may ensure that at least the upper eggs in any egg mass are effectively protected against virtually all natural enemies likely to pose a threat.
Contrasting age structures in cave cricket populations: patterns and significance
Authors: CARCHINI GIANMARIA , RUSSO CLAUDIO DI , SBORDONI VALERIO 
Published: March 2008

Abstract.

Adaptation to life in caves, as a seasonally constant environment, is expected to affect several life history traits. In this paper we investigate the age structure and phenology of twenty‐seven Dolichopodu cave cricket populations from artificial and natural caves subjected to different environmental regimes and to different availability of food resources.
Morphometric data clearly revealed the occurrence of different age structures and phenology, basically indicating two contrasting patterns.
In artificial caves, which have been colonized by Dolichopoda only in historical times and where food resources and climate are chiefly dependent upon surface environment, age structure was seasonal. In contrast, in most natural caves, where cricket colonization appears to be much older and stability of both climatic parameters and trophic resources is higher, age structure was diverse and aseasonal.
However, a seasonal age structure also occurs in natural caves characterized by either recent origin or by a low temperature regime. This suggests that age structure in Dolichopoda is influenced by historical factors, stability of food resources and also by environmental stress.
Ejaculate size varies with socio‐sexual situation in an insect
Authors: GAGE MATTHEW J. G. , BAKER R. ROBIN 
Published: March 2008

Abstract.

Males operate within a finite energy budget and cannot produce limitless supplies of sperm. On the other hand, when a female mates with a second male while still containing fertile sperm from a rival male, selection should favour the male that inseminates more sperm. Optimal strategy should thus be for males to exercise discretion in the allocation of sperm to individual females. Assuming the outcome of sperm competition to be based on either the raffle or kamikaze principles, the sperm competition hypothesis predicts a positive association between the probability that the sperm will find themselves in competition with sperm from rival males and the number of sperm inseminated.
The beetle, Tenebrio molitor L., behaves in accordance with this hypothesis. Males accompanied by a rival male before and during mating inseminate more sperm per ejaculate than unaccompanied males. Accompanied males are also faster to initiate mating and more likely to show post‐copulatory guarding. Adjustment of number of sperm inseminated was shown by males subjected to both long‐term (5 days) and short‐term (5 min) exposure to potential intrasexual competitors. Individual males exposed to both levels also demonstrated the ability to adjust their ejaculate according to socio‐sexual situation.
We conclude that male T.molitor adjust the number of sperm they inseminate according to some perception of the risk of sperm competition.
The size relationship between insects and their hosts
Authors: KIRK WILLIAM D. J. 
Published: March 2008

Abstract.

Regressions of adult insect size on host size were tested. The analysis was restricted to highly host‐specific insects that had thus been exposed to a narrow range of host size.
The phylogenetic regression method was used to analyse the data, so as to allow for the possible phylogenetic effects in cross‐species data.
Significant positive regressions were found in all the groups tested: female flower thrips, Meligethes species of pollen beetle, tephritid flies, and male and female fleas. They were also found by standard regressions within. and between Actornithophilus species of bird louse.
The regression of thrips size on pollen size was not significant, providing evidence against a hypothesis involving food size.
The regression of flea body size on host hair/feather length was significant, which is consistent with a hypothesis involving the size of spaces on the host.
The relationships may have implications for the understanding of evolutionary host shifts.
Host stress influences oviposition preference and performance of a pine sawfly
Authors: TISDALE ROBERT A. , WAGNER MICHAEL R. 
Published: March 2008

Abstract.

The effect of ponderosa pine (Pinus ponderosa Doug]. ex Laws) water stress, measured by xylem water potential, on oviposition preference and egg development of Neodiprion fulviceps was determined by two laboratory experiments in 1987 and 1988.
In the first experiment, adult females were allowed to choose between foliage from water‐stressed, watered, and untreated control trees.
Significant differences were found between treatments in xylem water potential in 1987 but not in 1988.
Females chose water‐stressed trees and a positive correlation was found between female preference and xylem water potential in 1987 but not in 1988.
In the second experiment, females were placed in globe cages with a single branch from each treatment and allowed to oviposit.
Significant differences were found among treatments in egg survival in 1987 but not in 1988.
These results indicate that sawflies can distinguish between stressed and non‐stressed trees and that this behaviour is adaptive in that egg survival was greatest on the preferred treatment.
Patterns of host selection by four species of aphidiid (Hymenoptera) parasitoids: influence of host switching
Authors: CHOW A. , MACKAUER M. 
Published: March 2008

Abstract.

We tested switching behaviour in four species of aphidiid parasitoids, using a two‐aphid experimental system consisting of second‐instar nymphs of pea aphid (Acyrthosiphon pisum (Harris)) and alfalfa aphid (Macrosiphum creelii Davis) feeding on broad beans in the laboratory.
Aphidius ervi Haliday, A.pisivorus Smith, A.smithi Sharma & Subba Rao, and Pram pequodorum Viereck showed an innate preference for pea aphid when both host species were provided in equal numbers.
Wasps encountered both aphid species equally but differed in their acceptance of alfalfa aphid. Females of A.pisivorus and P.pequodorum accepted alfalfa aphids when few pea aphids were available, but A. smithi always concentrated attacks on pea aphid. Aphidius ervi super‐parasitized an increasing proportion of pea aphids as their availability declined.
Switching to the alfalfa aphid occurred in A.ervi and P.pequodorum (but not in A.pisivorus and A.smithi) under the condition of a 1:3 ratio of pea aphids:alfalfa aphids. Wasps did not switch when more pea aphids than alfalfa aphids were provided (3:1 ratio).
Alfalfa aphids were more likely than pea aphids to escape from parasitoid attack.
Switching to the most abundant host may not be adaptive in these four species of aphid parasitoids. A foraging wasp incurs a potentially higher cost in lost opportunity time when attacking (and failing to oviposit in) alfalfa aphids. In addition, alfalfa aphids may have lower host quality than pea aphids, a difference that could influence offspring fitness.
Nectar sugar and amino acid preferences of Battus philenor (Lepidoptera, Papilionidae)
Authors: ERHARDT ANDREAS 
Published: March 2008

Abstract.

Butterflies of Battus philenor were tested for their preferences for nectar sugars and amino acids in an outdoor cage experiment.
The butterflies clearly preferred both sucrose and fructose over glucose. They also preferred sucrose over fructose.
No other preferences were found to be statistically significant, although male butterflies tended to prefer a plain sugar solution over a sugar solution containing a mixture of amino acids: females consumed both of these solutions in almost equal proportions.
The results are discussed with respect to nectar composition of butterfly pollinated flowers, flower preferences, physiological and reproductive aspects of butterflies.
The long‐distance migration of Nilaparvata lugens (Stål) (Delphacidae) in China: radar observations of mass return flight in the autumn
Authors: RILEY J. R. , XIA‐NIAN CHENG , XIAO‐XI ZHANG , REYNOLDS D. R. , GUO‐MIN XU , SMITH A. D. , JI‐YI CHENG , AI‐DONG BAO , BAO‐PING ZHAI 
Published: March 2008

Abstract.

A case study is presented of the autumn migration of the brown planthopper, Nilaparvata lugens (Stål), in the area of Nanjing in the People's Republic of China. The study was made using a high frequency (8 mm wavelength) radar and a net suspended from a kytoon.
The observations confirmed that long‐distance return migrations occur in China in mid and late September, with N.lugens being carried on the prevailing north‐easterly wind towards the autumn infestation and overwintering areas of the species.
After mass take‐off in the late afternoon or at dusk, the migrants flew for several hours during the evening, often in a dense layer which formed at heights between about 400 and 1000m above ground. These layers often had well‐defined ceilings corresponding to an air temperature of about 16°C. The migration height was above the top of the surface temperature inversion, i.e. the migrants did not fly at the height of the warmest air.
The dense layer concentrations overflying the radar were backtracked to source areas up to 240 km away in the north‐east of Jiangsu Province. Planthoppers observed emigrating from the Nanjing area would reach areas in south Anhui Province or north Jiangxi Province if they flew for 12 h.
There was a second period of mass take‐off at dawn. Insect layers sometimes formed but did not last longer than 1–2h.
The present results were strikingly different from those previously observed in the dry season in the Philippines, where migratory flight durations were largely confined to periods of about 30min at dusk and dawn.
Our observations are discussed in relation to the equator‐wards return migrations undertaken in autumn by other insect species, and the importance of these migrations for the maintenance of long‐flying genotypes in the overwintering populations is considered.
How many species are there in apple insect communities?: testing the resource diversity and intermediate disturbance hypotheses
Authors: SZENTKIRÁLYI F. , KOZÁR F. 
Published: March 2008

Abstract.

In European and American apple orchards the insect species richness, calculated from our own, and published data, varied widely (30–940 species). The dominance of insect orders was similar to that found in natural communities.
To test the predictions of the‘resource diversity hypothesis’(RDH) and the‘intermediate disturbance hypothesis’(IDH) of insect diversity, we analysed the simultaneous impact of vegetational diversity and intensity of orchard management practice on the species richness of characteristic insect categories in six types of apple stands, over 5 years, in Hungary.
The more diverse was the vegetation adjacent to the orchard and the less intensively was the orchard managed, the greater was the total insect species richness, supporting both hypotheses.
The number of agricultural pest species found in the apple orchards depended above all on the diversity of adjacent agricultural vegetation, supporting only the RDH.
The species richness of specialized apple pests was limited only by the intensity of pest control, supporting only the IDH.
Within the category of generalist natural enemies species richness mainly varied with the diversity of adjacent vegetation, supporting the RDH.
The aeroentomofauna constituted a surprisingly high percentage (>50%) for both total species and agricultural pests, but was poorly represented within the natural enemies category, and absent from the specific apple pest category.
A general conclusion is that the number of insect species in perennial orchard‐systems within agricultural areas is determined primarily by the regional extra‐orchard vegetational diversity and secondly by the degree of local intra‐orchard disturbances and plant diversity. Consequently, at the community level the predictions of both hypotheses can be simultaneously valid at different spatial scales and are not mutually exclusive. However, within the community, at the level of the different insect categories studied here, only one of the hypotheses proved to be valid.
Influence of leaf traits on the spatial distribution of arboreal arthropods within an overstorey rainforest tree
Authors: BASSET YVES 
Published: March 2008

Abstract.

Several attributes of foliage were measured from the Australian rainforest tree Argyrodendron actinophyllum Edlin (Sterculiaceae). These were related to estimates of abundance per leaf area of the most common arthropod guilds and families sampled with restricted canopy fogging.
When all these arthropod groups were considered, much of the overall variance in arthropod spatial distribution could be attributed to leaf age characteristics, arthropod aggregation patterns, arthropod activity and distance to tree trunk.
The fraction of variance which could be specifically explained by foliage attributes such as nitrogen‐, water‐ and fibre‐content, specific leaf weight, and epiphyll load was small for most arthropod groups (usually <30%). However, an index of food quality explained a higher proportion of variance (50%) in the abundance of phloem‐feeders. Leaf size and foliage compactness did not influence significantly the abundance of any arthropod group.
Most herbivores were more abundant on young foliage than on mature leaves. With the exception of Corylophidae and Chrysomelidae, which were more abundant in the lower and upper canopy respectively, arthropod stratification was not conspicuous within the inner core of tree crowns.
The results firstly emphasize the distribution of young foliage as a key factor affecting the abundance of many herbivores and, secondly, the importance of the local illumination regime for host leaf production and its indirect effects on the spatial distribution of arboreal arthropods.