bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlated traits for migration in the Gerridae (Hemiptera, Heteroptera): a field test
Authors: FAIRBAIRN D. J. , BUTLER T. C. 
Published: March 2008

Abstract. 1. The hypothesis that the migratory tendency of macropters is correlated with proportion macropterous in wing‐polymorphic insects is tested by comparing the migration of macropters of three species of waterstriders (Heteroptera, Gerridae) under natural conditions.2. Migration of marked individuals among four permanent and seventeen ephemeral water bodies was recorded between 1 April 1986 and 2 June 1987, within an area of approximately 2 km2.3. The proportion of macropters migrating was significantly lower for G.buenoi Kirkaldy than for L.dissortis Drake and Harris and G.comatus Drake and Hottes. Similar results were obtained in. comparisons of proportions captured on ephemeral sites.4. Distances measured in this study appear to be small relative to the migratory capacity of all of the species, and migration distance did not differ significantly among species. All species migrated primarily in early spring, and differences among species were most apparent at this time.5. The observed differences among species combined with the results of a similar study of macropters from the primarily apterous species, G.remigis Say, support the initial hypothesis. The implications of this for our understanding of the evolution and maintenance of wing polymorphisms are discussed.
Do caterpillars disperse their damage?: larval foraging behaviour of two specialist herbivores, Euphydryas phaeton (Nymphalidae) and Pieris rapae (Pieridae)
Authors: MAURICIO RODNEY , BOWERS M. DEANE 
Published: March 2008

Abstract. 1. To examine ecological and evolutionary aspects of caterpillar foraging behaviour, this study focused on observation of the individual foraging behaviour of two lepidopteran species,Pieris rapae L. andEuphydryas phaeton (Drury), on their respective host plants.2. Periodic observations over the course of a day showed that the larvae move considerable distances, forage on the upper surfaces of leaves, and often immediately leave areas from which they have fed, leaving a pattern of dispersed herbivory.3. Differences in foraging behaviour were not found between the two species, even though one species is aposematic and the other is cryptically coloured, but there were significant differences in the foraging patterns of P.rapae on the two host plants, broccoli and radish.
Cardiac glycosides and oviposition by Danaus plexippus on Asclepias fruticosa in south‐east Queensland (Australia), with notes on the effect of plant nitrogen content
Authors: OYEYELE S. O. , ZALUCKI M. P. 
Published: March 2008

Abstract. 1. Previous studies which attempt to relate oviposition by female monarchs, Danaus plexippus (L.), to the cardiac glycosides of their milkweed host plants are reviewed and found to be defective.2. Here we followed ovipositing females in the field and recorded their oviposition behaviour on individual Asclepias fruticosa (L.) plants. The cardenolide glycoside and per cent nitrogen of each of these plants and also of a control set of plants was recorded.3. Milkweeds accepted by females, on which egg laying took place, had significantly lower mean cardenolide levels compared with rejected plants and a control sets of plants.4. Most oviposition (c. 70%) took place on plants with intermediate cardenolide (CG) levels (=200–300 μg/0.1 g DW).5. The mean CG level in A.fruticosa was 345 μg/0.1 g DW (SD = 138, n=122, range 119–719).6. There was no relationship between monarch oviposition behaviour and plant per cent nitrogen.
Microhabitat use and hindwing phenotype in Hipparchia semele (Lepidoptera, Satyrinae): thermoregulation and background matching
Authors: SHREEVE T. G. 
Published: March 2008

Abstract. 1. Microhabitat use and background matching by adult Hipparchia semele (L.) in a coastal sand dune site in south Wales were studied during the flight period of 1986.2. Microhabitat use by both sexes is related to temperature and activity. When settling substrates are cool, typically during the early morning, most individuals are located on the warmest basking substrate, lichen patches. After a period of warming, males perch to locate mates on exposed areas of sand where there is a large field of view and where they are visually apparent. Egg‐laying females tend to settle on lichen patches throughout the day.3. Overall, females are maximally visually cryptic when settled on lichen patches with unexposed forewings. Male crypsis on lichen is less effective, but greater on most other substrates, than that of females. It is argued that individuals match lichen patches because this substrate is used when they are most liable to detection and capture by vertebrate predators. Male crypsis is probably a compromise between maximizing protection on lichen patches and requirements for resemblance to other substrates.4. The underside hindwing phenotype does not match sand. Background matching to this substrate is probably not important because it tends to be used when individuals are active and can effectively use secondary defence mechanisms.5. It is suggested that the apical eyespot and orange patch on the forewing underside have a dual role in secondary defence, acting as a startling and deflective device, being exposed by disturbed individuals and by those engaged in activities which may disrupt the visual crypsis afforded by the hindwing underside.
Host specificity and seasonal distribution of Alloxysta pleuralis, a cynipoid hyperparasitoid of aphids in India
Authors: SINGH RAJENDRA , SRIVASTAVA PARAS NATH 
Published: March 2008

Abstract. 1. Alloxysta pleuralis (Cameron) is a cynipoid (Hymenoptera) hyperparasitoid of aphids (Homoptera) through their aphidiid (Hymenoptera) parasitoids.2. It was recorded attacking five aphidiids, Lysiphlebus delhiensis (Subba Rao & Sharma), Trioxys indicus Subba Rao & Sharma, Aphidius uzbekistanicus Luzhetzki, Lipolexis scutellaris Mackauer and Lysiphlebia mirzai Shuja‐Uddin (in order of preference) out of eight species of aphidiid parasitoids tested.3. Percentage of hyperparasitism of aphids infesting cucurbits, cereals and pulses is higher than in solanaceous crops. Maximum hyperparasitism was recorded on the T. indicus/Aphis gossypii Glover/cucurbit complex.4. The aphid host as well as the food plants significantly influence its efficiency.5. A.pleuralis is abundant in northeastern Uttar Pradesh in winter (December–March) when large areas of pulses, cereals and cucurbits are infested with aphids serving as hosts for the primary parasitoids.
Oviposition by Danaus plexippus in relation to cardenolide content of three Asclepias species in the southeastern U.S.A.
Authors: ZALUCKI M. P. , BROWER L. P. , MALCOLM S. B. 
Published: March 2008

Abstract. 1. Female monarchs were observed in the field ovipositing on a native North American milkweek host, Asclepias humistrata L. As in a comparable Australian study on an introduced novel host (Asclepias fruticosa L.) we found post‐alighting rejection of plants with low and high cardiac glycoside concentration (CG).2. Most oviposition took place on plants with CG in the range 200–500 μg/0.1 g dry weight. Thin‐layer chromatography showed no obvious qualitative difference in cardenolide types between accepted and rejected plants, excepting an indication that rejected plants may have a higher level of more polar cardenolides.3. In a controlled laboratory experiment comparing oviposition on a low (A.incarnata L.) vs high (A.curassavica L.) CG host plant species we found no relationship between CG and oviposition on the low CG species, but a negative relationship in the high CG species. This corroborates our findings on oviposition on single host species in the field.4. We also record the first indication of a physiological cost of monarch larvae feeding on plants high in CG. There was a significant negative relationship between survival of first instar larvae and CG levels in plants. This study opens the way for further work on the association of monarch butterflies and their toxic milkweed hosts.
Variation in ovariole number and egg size of species of Dacus (Diptera; Tephritidae) and their relation to host specialization
Authors: FITT GARY P. 
Published: March 2008

Abstract. 1. An analysis of the number of ovarioles/ovary is presented for fourteen species of Dacus ranging from broad generalists (D.tryoni (Frogg.)) to strict host specialists (D.aglaia Hardy). For eight species data on egg size and the incubation time of eggs is also presented. Interrelationships among these life history variables and their relationships to host specialization were examined.2. There was a broad positive relationship between the breadth of the natural host range (i.e. excluding cultivated fruits) and ovariole number (and hence potential fecundity). Highly polyphagous species had thirty‐five to forty ovarioles/ovary while the specialists ranged from eight to twenty.3. D.musae (Tryon), a specialist on banana, was an exception having an ovariole number similar to that of the most polyphagous species.4. There was no clear relationship between egg size and ovariole number across eight species, though monophages were not fully represented in this analysis. Among these eight species there was no significant relationship between wing length and egg length, nor was there any such relationship among individuals within species.5. There was considerable variation among species in the incubation time (at 25°C) for eggs, ranging from 24 h for D.cucumis French to 53 h for D.cacuminatus (Hering). This variation was only weakly related to egg size, though D.cucumis produced the largest eggs of any species examined.6. Possible explanations for a relationship between potential fecundity and host range are discussed in terms of the balance between the abundance of host resources for generalists and their predictability for specialists. However, the observed relationship between ovariole number and host range must remain tentative, given that only fourteen species from one genus have been examined. Considerably more data is required for other dacines, for species in other tephritid subfamilies, and for other phytophagous insect groups to determine whether the relationship is generally applicable.
Influences of host feeding‐niche and foodplant type on generalist and specialist parasitoids
Authors: HAWKINS BRADFORD A. , ASKEW R. R. , SHAW MARK R. 
Published: March 2008

Abstract. 1. We classified the parasitoids of 185 British herbivorous insect species as being koinobionts (which should tend to be specialists) or idiobionts (potential generalists) to examine the influences of host feeding‐niche and foodplant type on the numbers of parasitoid species attacking individual host species.2. The majority of parasitoid species of exophytic hosts are koinobionts, whereas endophytic hosts support mainly idiobionts.3. Parasitoid assemblage size increases with host foodplant size and complexity; for endophytic hosts this is due to an increase in idiobionts on hosts on large plants, but for exophytic hosts it is the number of koinobionts that increases with foodplant size.4. Comparison of these patterns with those predicted under a competition hypothesis suggests that parasitoid communities associated with endophytic hosts may be commonly limited by interspecific competition, whereas those of exophytic hosts probably are not.
Strategies of mate finding in the European field cricket (Gryllus campestris) at different population densities: a field study
Authors: HISSMANN KAREN 
Published: March 2008

Abstract. 1. Members of a field population of Gryllus campestris L. varied in their walking and calling activity. In both sexes, some individuals occupied burrows whereas others walked around in the observation area. Males at burrows could be either silent or calling.2. In the course of one summer, population density decreased and the initial balanced sex ratio changed to a large surplus of males.3. At high population density, there were equal numbers of non‐calling males at burrows, calling males at burrows and walking males, while walking females predominated over females at burrows. Non‐calling males at burrows achieved more encounters with females than did calling and walking males. Females met males by walking through the population and by waiting at burrows. Thus, calling and phonotaxis were not essential for mate finding and calling was less effective than previously thought.4. At low population density calling males predominated. Calling males at burrows achieved the most encounters with females. Females met males only by walking around in the population area. Calling was thus more important in mate finding than at high population density.5. Changes in sex ratio and population density may cause the flexibility in mate finding behaviour of individual crickets.
Interactions among leaf toughness, chemistry, and harvesting by attine ants
Authors: NICHOLS‐ORIANS COLIN M. , SCHULTZ JACK C. 
Published: March 2008

Abstract. 1. Young and mature leaves of a tropical legume, Inga edulis var. minutula Schery, are strikingly different in secondary chemistry, especially condensed tannins, and leaf toughness.2. Bioassays with the two different leaf types indicate that leaf cutter ants, Atta cephalotes (L.), always find mature leaves relatively more acceptable than young leaves when selection was based on chemical cues.3. Since extracts of young leaves show greziter inhibition of fungal pectinases we suggest that leaf‐cutter ants are capable of distinguishing which leaf types are most suitable for the growth of their symbiotic fungus.4. However, mature leaves are 3 times tougher than young leaves and this prevents leaf‐cutter ants from harvesting the more suitable mature leaves.5. Consequently, bioassays which require cutting before leaf removal indicate that some colonies actually harvest more from the less suitable young leaves.6. We suggest that the quality of a colony's habitat may indicate whether a colony will harvest more of the less suitable young leaves. Colonies which are harvesting from highly suitable host plants avoid the tropical legume I.edulis while those in poorer habitats accept I.edulis but, because of leaf toughness, mostly harvest the less suitable young leaves.
The predators of insects
Authors: SCHOENLY KENNETH 
Published: March 2008

Abstract. 1. Insect–insectivore trophic relations were reviewed using presence–absence data from sixty‐one invertebrate‐dominated food webs and fifteen food webs from Briand's (1983) original forty web collection. From counts of prey links in higher taxa (orders, classes, phyla), six phyla and thirteen classes of non‐insect insectivores and fourteen orders of insect predators and prey were found.2. Detritus‐based habitats (phytotelmata, felled logs, carcasses, dungpads) harboured fewer orders of insects, that interact with other insects, than webs from grazer‐based (host plants, some galls) and mixed‐based systems (aquatic webs). Consumer–resource networks of higher insect taxa in these webs shared several features found in some species‐level biological networks: the trend was towards few pairs of strong asymmetrical links, several weak links and many null interactions.3. From counts of insect predator–insect prey links, hymenopterans as terrestrial predators and parasitoids interacted with the most number of higher insect taxa. Hymenopterans were also linked as prey more often than other terrestrial insects. In freshwater habitats, plecopterans were linked as predators more often than other aquatic taxa, whereas dipterans were listed as prey more often than other insects.4. Dipterans were linked in the diets of non‐insect insectivores from seven of eight common taxonomic classes. Arachnids were identified as insect predators by food web researchers in the largest number of webs, followed by passerine birds and cyprinodont fishes. From analysis of prey links at the ordinal level, predaceous insects were less polyphagous than other predators (other ectotherms and endotherms).5. Analysis of chain lengths, as expected, showed that insect prey occupied mostly lowermost trophic levels, non‐insect insectivores were found mostly at uppermost trophic levels, and predaceous insects were found mostly at intermediate trophic levels across most habitats.6. This analysis offers evidence that insects are not just occupying intermediate trophic levels in some communities. Indeed, some taxa feed at the upper ends of long food chains, for example eupelmids in galls, staphylinids in carcasses, and perlid plecopterans in streams.
Pre‐oviposition mate‐guarding and mating behaviour of Argia vivida (Odonata: Coenagrionidae)
Authors: CONRAD K. F. , PRITCHARD G. 
Published: March 2008

Abstract. 1. At Halcyon Hotsprings, British Columbia, Canada, male and female Argia vivida Hagen encountered to mate in two different ways.2. In the morning (before 12.30 hours solar time), males basked at sunspots in the forest and darted out at passing females, attempting to take them in tandem (the first method of encounter).3. If a male was successful, the pair engaged in a 31.3±4.8 min copulation followed by an hour of tandem flight before beginning oviposition.4. As the day progressed, unmated males moved slowly toward the water and arrived at the water at about the same time as the earliest ovipositing pairs (1131±27.5 min solar time).5. Males retained their grasp on their mates during oviposition (contact‐guarding) but since some tandems separated during oviposition, non‐tandem males at the water could capture recently released, gravid females (the second method of encounter).6. The new pairs performed a brief copulation (10.2±3.38 min) and began ovipositing immediately thereafter.7. Some females that avoided recapture attempted to oviposit unguarded.8. We believe the long duration of morning copulations and period of tandem constitute a male strategy, which we call ‘pre‐oviposition guarding’, to guard females until it is warm enough at the oviposition site for the females to begin ovipositing.9. Separation of tandems during oviposition may be initiated by either member of the pair and we suggest that one benefit to a female of leaving a guarding mate is increased efficiency of oviposition when the intensity of male harassment is low.10. The mating system of A. vivida thus comprises a series of complementary male and female mating behaviours.
The influence of host size on sex ratios in the parasitoid Diglyphus begini (Hymenoptera: Eulophidae)
Authors: HEINZ KEVIN M. , PARRELLA MICHAEL P. 
Published: March 2008

Abstract. 1. Sex ratio in the ectoparasitoid, Diglyphus begini (Ashmead), attacking larvae of the dipterous leafminer Liriomyza trifolii (Burgess) in glasshouse marigolds, is best depicted by a model where sex ratio varies as a function of host size.2. Male D. begini progeny are produced in hosts significantly smaller in size than those producing female progeny.3. Female wasps attack and oviposit on the largest leafminer larvae available and whether a host is large or small depends upon the size of the other hosts attacked.4. Diglyphus begini females adjust the thre:shold size for the change‐over in sex allocation relative to the size of hosts attacked; however, the sex ratio is maintained at between 60% and 70% males.5. The patterns observed in these glasshouse studies are not due to sex‐specific differential mortality or superparasitism.
Differential susceptibility to variable plant phenology and its role in competition between two insect herbivores on oak
Authors: HUNTER MARK D. 
Published: March 2008

Abstract. 1. The population dynamics of Tortix viridana L. (Lepidoptera: Tortricidae) and Operophtera brumata L. (Lepidoptera: Geometridae) on the pedunculate oak Quercus robur L. are driven by the degree to which larval hatch coincides with oak budburst in spring.2. Experiments with first instar larvae demonstrate that T. viridana has a much narrower dietary breadth, is less inclined to disperse from closed oak buds, and can resist starvation for longer periods than the polyphagous O.brumata.3. As a result of its specialist foraging strategy, T. viridana may be less susceptible to mortality associated with colonization of oak in spring than O.brumata. This may explain why T. viridana populations are, on average, higher.4. These results are discussed in the light of previous work which described the competitive advantage of O. brumata in field cage experiments. Stochastic mortality factors, which drive population change in both species independently of competition, favour T.viridana larvae, and over‐ride the competitive superiority of O.brumata.
Insect responses to plant water deficits. I. Effect of water deficits in soybean plants on the feeding preference of Mexican bean beetle larvae
Authors: McQUATE GRANT T. , CONNOR EDWARD F. 
Published: March 2008

Abstract. 1. We examined the preference of larvae of the Mexican bean beetle, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), for foliage of soybean (Glycine max [L.] Merr.) grown under several levels of water deficit. Third instar larvae were exposed simultaneously to excised foliage from plants that were either well‐watered (control) or had experienced water deficits (treatment).2. Water‐deficient plants were re‐watered 12 h prior to initiating feeding trials to eliminate physical differences between control and treatment foliage such as leaf water potential, diffusive resistance, relative water content, and foliage toughness.3. Examination of the free amino acid contents of re‐watered and excised foliage indicated that amino acid concentrations increased markedly in foliage grown under water deficits, and that this increase persisted during the preference tests.4. Larvae preferred control foliage, but shifted preference to treatment foliage under mild water deficits. When the leaf water potential of water‐deficient treatment foliage was lower than – 1.13 MPa or when it was more than 0.5 MPa lower than that of control foliage, larvae preferred to feed on foliage from well‐watered control plants.5. The expression of preference for well‐watered control foliage was coincident with increases in the concentrations of total free amino acids and individual free amino acids in the water‐deficient treatment foliage.6. These results are inconsistent with White's (1974) hypothesis because Mexican bean beetle larvae avoid plants grown under water deficits that have increased concentrations of free amino acids.
Phenology of nutritional differences between new and mature leaves and its effect on caterpillar growth
Authors: STAMP NANCY E. , BOWERS M. DEANE 
Published: March 2008

Abstract. 1. We determined the phenology of the shrub Spiraea latifolia Ait. Bork. (Rosaceae), which has indeterminate shoot growth, and the effects of phenological changes in leaf quality on growth rate of the early‐spring feeding buckmoth caterpillars, Hemileuca lucina Hy. Edw. (Saturniidae).2. Leaves, regardless of whether they were newly expanded or several weeks old, were tougher later in the growth season (mid‐June) than similarly aged leaves collected earlier; correspondingly, water and nitrogen content for leaves of all ages declined through the larval period. By July, newly expanded leaves had no more nitrogen than mature leaves.3. Relative growth rate of third instar larvae fed new leaves or a mixture of new and mature leaves in early June was higher than that of those fed mature leaves, and efficiency of conversion of digested food to biomass was higher for larvae fed new leaves than for those fed mature leaves or a mixture.4. In another experiment, larvae were reared on new leaves through the fourth instar and then fed a diet of new, mature or a combination of new and mature leaves, a regimen that was similar to the phenologies of both plants and caterpillars in the field. There was no difference in time to pupation or pupal weights among these treatments.