bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predation pressure on the arboreal epiphytic herbivores of larch trees in southern England
Authors: TURNER B. D. 
Published: March 2008

Abstract. 1. Quantitative collections were made of arthropod predators from larch trees at Ranmore Common, Surrey, from August 1977 to September 1978.2. Spiders were numerically the most important predators accounting for 64% of the total.3. Antisera of the main larch dwelling, epiphyte herbivore orders, Collembola and Psocoptera, and the other common arboreal herbivore group at Ranmore, the Honioptera (principally Psyllidae) were prepared in rabbits.4. Serological determinations of predator diets indicated that, with a few exceptions, the predators were taking approximately equal proportions of the three prey groups.5. This apparent non‐specificity of the predators is analysed in relation to both the numerical abundance and biomass of the three prey types during the study period.6. These arboreal arthropod predators are selecting for large but rare prey items in preference to small and common ones.7. These findings are discussed in relation to the population dynamics of arboreal epiphytic herbivores.
Density dependence and the augmentative release of egg parasitoids against graminaceous stalk borers
Authors: HAMBURG H. VAN , HASSELL M. P. 
Published: March 2008

Abstract. 1. The augmentative release of Trichogranznza species for the biological control of graminaceous stalkborers is reviewed.2. Previous experiments indicate strong density dependence acting on the early larval stages of the sorghum stalkborer (Chilo partellus). These data are described by a simple model for density dependence, whose properties are briefly described.3. The effects upon the total mortality of different levels of egg parasitism are discussed when combined with density dependent larval losses that vary from under‐ to over‐compensating.
Latitudinal effects on treehopper species richness (Hornoptera: Membracidae)
Authors: WOOD THOMAS K. , OLMSTEAD KAREN L. 
Published: March 2008

Abstract. 1. Membracid species richness declines with increasing latitude in the Western hemisphere but begins to increase again in temperate regions. In northern latitudes this transition occurs in the highlands of Mexico and is the result of the emergence of a new tribe and greater host specialization.2. The relationship between number of species per genus and latitude is parabolic.3. We suggest the low number of species per genus in tropical regions may be due to the lack of host specialization and reduced coordination of life history with host phenology.
The fecundity, development and host relationships ofCeratobaeusspp. (Hymenoptera: Scelionidae), parasites of spider eggs
Authors: AUSTIN A. D. 
Published: March 2008

Abstract.1.Ceratobaeusspp. enter the nest of their host spider and oviposit into eggs through the thin silk eggsac.2. Temperatures below 15° C limit oviposition by slowing parasites down.3. Males emerge prior to females and mate with their sibs. Sex ratios of 6.6–6.0:1 in favour of females were observed in the field and laboratory for two species.4. Even though females can oviposit almost immediately after emergence their full complement of eggs (x̄= 65) is not reached until several days later.5. Superparasitism is low and appears to occur from subsequent accidental ovipositions. No marking of the external surface of hosts was observed.6. Parasites overwinter as adults under bark. They do not feed as adults nor do they reabsorb their eggs, but rather oviposit as soon as host eggs become available in spring.7. Successful oviposition occurs in later stages of host eggs reared at 15° C and 20° C than it does at 25°C. Different rates of development between host and parasite is proposed as an explanation for this phenomenon.8. The species studied show varying degrees of specificity but each has a dominant host. Location of hosts involves cues from the habitat (bark), silk nests of spiders, and some factor associated with host eggs.
Bud burst and success of the beech weevil, Rhynchaenus fagi: feeding and oviposition
Authors: BALE J. S. 
Published: March 2008

Abstract. 1. Overwintered and starved weevils fed on beech within 5 min of contacting the plant in spring, and oviposition occurred in less than 48 h after feeding.2. Size of unlaid eggs was significantly reduced when feeding weevils were subsequently starved from beech for 3 days.3. Date of bud burst did not affect the amounts of feeding or oviposition by weevils.4. Weevils fed and oviposited preferentially among trees, and the same trees were preferred in two successive years. This preference was independent of bud burst date.
Predator gut state and prey detectability using electrophoretic analysis of gut contents
Authors: GILLER P. S. 
Published: March 2008

Abstract. I. An investigation of the effects of position of food in the gut (gut state), time since feeding, meal size and environmental temperature on the detection of prey using the electrophoretic separation of proteins with esterase activity was undertaken. The waterbug Notonecta glauca Linn (Hemiptera/Heteroptera) was used as the model predator.2. Seven easily recognizable gut states can be identified at different times since commencement of a meal.3. Specific prey esterase ‘fingerprint’ bands can be detected whilst food remains in the foregut.4. Meal size and environmental temperature (affecting digestion and assimilation rates) both affect the rate of filling and emptying of the foregut, and hence the time period over which prey proteins can be detected by electrophoresis following a meal. Small meals and high temperatures lead to quite rapid changes in gut state with time and thus reduce the time period over which prey can be identified from gut contents (20 h). Large meals and low temperatures extend this period (48 h).5. Predator gut state is the most important parameter in prey detectability from gut contents, and from a visual examination of the gut state it is immediately evident whether or not prey detection by electrophoresis will be possible.6. There is further evidence in support of a twocompartment food processing model for Nofoonecru, and the significance of this type of processing in relation to gut content analysis of sucking predators is discussed.
Host‐specific variation in Ieaf miner population dynamics: effects on density, natural enemies and behaviour of Stilbosis quadricustatella (Lepidoptera: Cosmopterigidae)
Authors: MOPPER SUSAN , FAETH STANLEY H. , BOECKLEN WILLIAM J. , SIMBERLOFF DANIEL S. 
Published: March 2008

Abstract. 1. We compared high and low density populations of a leaf miner (Stilbosis quadricustatella (Cham.)) on two host oaks to ascertain mechanisms influencing abundance. High density miner populations occurred on sand live oak, Quercus geminata (Fagaceae), found in homogeneous stands at inland and coastal sites. Quercus nigra, water oak, a patchily distributed inland species, supported a low density leaf miner population.2. Average foliar nitrogen of Q.geminata was significantly lower than that of Q.nigra, and lad mining period on Q.geminata was correspondingly longer than on Q.nigra.3. The average leaf area of Q.nigra was significantly greater than that of Q.geminata.4. Parasitism was significantly greater in Q.geminata miner populations and predation was significantly higher in Q.nigra populations. However, parasitism and predation rates were roughly reciprocal so that overall larval mortality did not differ significantly between hosts.5. In a laboratory experiment, pupal overwintering survivorship did not differ significantly between moist and dry treatments of the sand and loam soil types that typify Qgeminata and Q.nipra habitats, respectively.6. Within‐leaf miner density on Q.geminata significantly affected larval survivorship, parasitism and predation. Leaf area and within‐leaf miner density were positively correlated.7. We detected no host‐patch area or isolation effect on miner densities on coastal Qgeminata and there was no significant gradient of local coastal conditions affecting larval survivorship or natural enemies.8. Coastal leaf miner densities were significantly higher on oak patch edges than in interiors.
The chironomid larvae of a small chalk stream in Berkshire, England
Authors: WRIGHT J. F. 
Published: March 2008

Abstract. 1. The longitudinal distributions of larval Chironomidae (Diptera) were examined for 1 year in the intermittent and perennial sections of the Winterbourne, a small chalk stream in Berkshire, England.2. Forty‐nine chironomid taxa were recorded at ten major sites which were sampled on six occasions and four additional taxa were recorded at sites sampled only once.3. Cluster analyses using data from the major sampling sites identified three groups of sites. A pond in the stream channel which had a distinct chironomid fauna was distinguished from all other sites before the remaining intermittent sites were separated from all perennial sites on the basis of the chironomid fauna.4. In the perennial stream, a site heavily shaded by trees had low species richness compared with partially and unshaded sites further downstream. The lowest site, which was near to the confluence with a larger chalk stream, the River Lambourn, had the highest number of taxa (thirty‐five), including several which were frequent in the Lambourn.5. By recording the occurrence of prepupae, an indication of emergence periods was obtained and many taxa were shown to have extended periods of emergence.
Facultative defences and specialist herbivores? Cinnabar moth (Tyria jacobaeae) on the re growth foliage of ragwort (Senecio jacobaea)
Authors: CRAWLEY M. J. , NACHAF'ONG M. 
Published: March 2008

Abstract. 1. Ovipositing females of cinnabar moth lay just as many eggs on regrowth foliage as on normal rosette leaves of ragwort.2. Larvae reared on regrowth tissues achieve the same weight at pupation as insects fed on primary leaves and capitula. Diet affected neither survival rate nor development time.3. Larvae from eggs laid on normal foliage achieve lower pupal weights when fed regrowth tissues, and larvae from eggs laid on regrowth leaves perform less well on a diet of normal foliage.4. The complex of changes associated with re growth following defoliation does not appear to reduce the fitness of this specialist herbivore, nor does it reduce the likelihood that the plant will be attacked by ovipositing adult moths.5. A facultative response which consisted of an increase in ‘qualitative defences’ is unlikely to be effective against adapted herbivores.
Sex ratios of Spalangia endius (Hymenoptera: Pteromalidae), in relation to current theory
Authors: DONALDSON J. S. , WALTER G. H. 
Published: March 2008

Abstract. 1. Spulungiu endius Walker is a solitary parasitoid of house fly puparia.2. The sex and size of S.endius was not related to host size.3. In the laboratory the mean sex ratio of all offspring of nine groups, each comprising twenty females, was consistently female‐biased (x = 83.5%, range 79–87%). The sex ratio in the field was less female‐biased and showed greater fluctuation (61–75%). This may be a consequence of females laying male eggs before mating, some females remaining unmated, possible shorter adult life expectancy in the field than in the laboratory, and, perhaps, the presence of conspecific females.4. The sex ratio of offspring of individual females varied from 66% to 100% females, and males were deposited early in the oviposition sequence.5. Although a large number of fly puparia died before adult flies or parasitoids emerged (64.5%; n= 5874), there was no differential mortality of either sex.6. Our results fit no general sex ratio hypothesis and we conclude that (i) the genetic nature of sex ratios in these insects needs careful examination, and (ii) the prevalence of female‐biased sex ratios in solitary parasitoids needs investigation.
The complex hatching response of Aedes eggs to larval density
Authors: LIVDAHL TODD P. , KOENEKOOP ROBERT K. , FUTTERWEIT STEPHEN G. 
Published: March 2008

Abstract. 1. We investigated the effects of hatching medium, larval density and larval instar on egg hatching in Aedes triseriutus (Say) (Diptera: Cuficidae).2. In a nutrient broth medium, hatching rates, responded positively to low densities of large larvae, but were suppressed by high densities.3. The magnitude of suppression was moderated through the use of a yeast hatching medium, which provides a food source for the large larvae. Small instars generally exerted positive effects on hatching, with the exception of first in star larvae in the yeast medium, which inhibited hatching at low and moderate densities.4. The results demonstrate an ability of eggs to assess indirectly the potential risks of hatching through their responses to changes in dissolved oxygen concentration.
Manipulation of host plant development by the gall‐midge Rhabdophaga strobiloides
Authors: WEIS ARTHUR E. , KAPELINSKI AUDREY 
Published: March 2008

Abstract. 1. The gall‐midge Rhabdophaga strobiloides (O.S.) forms a gall in the apical bud of actively growing willow twigs.2. Galls were not randomly distributed among twigs. Twigs that arose towards the distal end of the branch were much more likely to be galled. Distally located twigs also grew to greater girth than more proximally located twigs.3. Comparisons of galled twigs with normal twigs in similar locations along their branch showed that the gall causes even greater growth in twig girth than when no gall is present.4. The hypothesis that galled twigs draw photosynthate produced elsewhere in the plant was tested in an experiment that measured the growth of galled and normal twigs. with their leaves intact, to galled and normal twigs that were manually defoliated. Defoliation caused reduced growth in normal twigs, but galled twigs grew equally well with or without their leaves. Leaf removal had no effect on gall growth.5. Twig diameter was positively correlated with gall diameter. Call diameter was positively correlated with larval biomass.6. Patterns of twig and gall growth suggest that the gall‐midge manipulates host plant growth and development to provide resources for growth and survival. Manipulation of the host may be an important phenomenon in the evolution of parasitic organisms.
The responses of polyphagous predators to prey spatial heterogeneity: aggregation by carabid and staphylinid beetles to their cereal aphid prey
Authors: BRYAN KEVIN M. , WRATTEN STEPHEN D. 
Published: March 2008

Abstract. 1. Discrete patches of aphids were artificially created in winter wheat fields in 1982 and in 1983 using field cages.2. Aggregation by polyphagous predators at these patches following cage removal was measured using pitfall traps in patch and control areas.3. Several species of polyphagous beetle (Carabidae and Staphylinidae) aggregated in these patches while other species did not.4. The consequences of aggregation by polyphagous predators to a single prey species are discussed.
Aide memoire mimicry*
Authors: ROTHSCHILD MIRIAM 
Published: March 2008

Abstract. 1. Animals and plants may gain protection by reminding would‐be aggressors of failure, or an unpleasant experience following an attempt at capture and ingestion. Thus they need not be mistaken for noxious or dangerous prey; defence is adequate if the aggressor is forced to recall the attributes of such species, or the disagreeable sequela to a previous assault upon them.2. Batesian mimics and mildly toxic Mullerian mimics can also add to their repertoire by such defensive strategies.3. Several examples of this phenomenon, designated aide mémoire mimicry, are described.
The distribution of aphids in response to variation among individual host plants: Uroleucon rudbeckiae (Homoptera: Aphididae) andRudbeckia laciniata (Asteraceae)
Authors: SERVICE PHILIP 
Published: March 2008

Abstract. 1. An investigation was conducted to determine the effects of variation among individual plants of Rudbeckia laciniata L. on the distribution and abundance of the aphid Uroleucon rudbeckiae (Fitch).2. Wild plants were examined repeatedly for up to 21/2 years to obtain information about plant growth and flowering, and about aphid densities on individual plants.3. Aphid densities on individual plants were positively associated with several measures of plant vigour, including height, growth since previous year, and occurrence of flowers.4. The colonization of plants by alate aphids was more highly correlated with plant height than with plant exposure. Aphid densities on individual plants were more strongly associated with plant height than with number of colonists.5. In all years there were many hosts which were never colonized by aphids. Some of these plants produced shoots but did not flower. Experimental infestation of these plants showed that they were unsuitable for aphid growth and reproduction. Some plants which did flower and which escaped aphid infestation were nevertheless suitable hosts. Previously unsuitable host individuals were able to support aphids when grown under glass‐house conditions.
Discrimination and release of unpalatable butterflies by Nephila clavipes, a neotropical orb‐weaving spider
Authors: VASCONCELLOS‐NETO JOÃO , LEWINSOHN THOMAS MICHAEL 
Published: March 2008

Abstract. 1. Nephila clavipes (L.), a common spider in neotropical forests, discriminates some unpalatable prey and releases them unharmed from its web. Release is not accidental but results from a specific behavioural sequence.2. Field trials with twenty‐seven butterfly species showed that spiders respond consistently to butterfly species and higher taxa. Ithomiinae and some Danainae are almost always released while Heliconiinae, Nymphalinae, Acraeinae, Pieridae and Papilionidae are usually eaten.3. Paired tests showed that an immediately preceding experience with a different butterfly did not reveal any change in the spider's usual response to a particular butterfly.4. Warning coloration is not involved in spider response. Spiders rejected the models but ate the mimics of two different butterfly species pairs. Distastefulness is probably signalled by chemical cues.5. Some unpalatable butterflies stay motionless when entangled and while the spiders release them. Motionlessness in webs seems to be a requisite to allow recognition of their distastefulness without being bitten by the spider.6. Spiders differ from vertebrates in the prey accepted and in rejection mechanics. Although there is no indication of learning, spiders may select butterflies for distastefulness, chemical signals and motionlessness, at the individual level.
The influence of food plant dispersion on caterpillar searching success
Authors: CAIN M. L. , ECCLESTON J. , KAREIVA P. M. 
Published: March 2008

Abstract. 1. Collards (Brassica oleracea L.) grown in clumps were more difficult for unstarved, early instar cabbage white caterpillars (Pieris rapae L.) to find than collards spaced at regular intervals, although total plant densities were identical.2. Early instar, unstarved larvae are less mobile than later instar larvae (our data) or starved larvae (Jones' 1977 data).3. Starved larvae and late instar larvae tend to find plants more readily than do unstarved or younger larvae.4. We contend that larval mobility governs the success of searching caterpillars and their sensitivity to variations in plant dispersion.5. Our results show that the dispersion of targets can influence searching success even though target density is constant. This means that the degree of clumping in host plants is capable of influencing their availability to herbivores.
Survival of honeybees in cold climates: the critical timing of colony growth and reproduction
Authors: SEELEY THOMAS D. , VISSCHER P. KIRK 
Published: March 2008

Abstract. 1. The adaptive significance of the timing of growth and reproduction by honeybee, Apis mellifera L., colonies in cold climates was studied by describing the seasonal patterns of food storage, brood rearing, and swarming, and then observing the consequences of experimentally perturbing the seasonal cycles of brood rearing and swarming.2. Colonies consume large amounts of food over winter (20+ kg of honey), but have only a brief period (about 14 weeks) for food collection each year.3. The honeybee's striking habits of starting brood rearing in midwinter and swarming in late spring evidently help colonies achieve maximum use of the short summer season. Colonies whose onset of‐brood rearing was experimentally postponed until early spring showed greatly retarded colony growth and swarming. Other experiments demonstrated that late swarms starve more often during winter than do early swarms.4. We conclude that the timings of colony growth and reproduction are essential elements in the honeybee's suite of adaptations for winter survival.
Insect chemosensory responses: a chemical legacy hypothesis
Authors: CORBET SARAH A. 
Published: March 2008

Abstract. 1. Changes in the chemosensory responses and physiological host tolerance of phytophagous insects and parasitoids may result in new host associations. This paper considers the origin of those changes in ecological and evolutionary time.2. The chemical legacy hypothesis postulates that effects of larval chemosensory environment on adult chemosensory responsiveness depend not (or not only) on persistent neural changes (‘memory’), but on traces of chemical cues, inside or outside the insect's body, which influence adult behaviour, perhaps particularly during a ‘sensitive period’ associated with adult emergence or hatching of the egg.3. Chemical cues bequeathed by earlier stages may affect adults or larvae by reducing peripheral sensitivity. Depending on the form of the dose–response curve, this change could decrease aversion or increase a positive response to a previously deterrent stimulus.4. Attention is drawn to a possible link between this behavioural induction and the induction of detoxification enzymes. This link might be of practical importance if exposure to host allelochemicals were to influence insects' responses to insecticides, and vice versa.5. An influence on the chemosensory responsiveness of an individual by chemical cues derived from its parents would be hard to distinguish from a genetic effect.6. Some testable postulates of the chemical legacy hypothesis are identified.
Wound‐induced changes in the acceptability of tomato to larvae of Spodoptera littoralis: a laboratory bioassay
Authors: EDWARDS P. J. , WRATTEN S. D. , COX H. 
Published: March 2008

Abstract. 1. Leaves of tomato (cv. Moneymaker) were artificially damaged and offered to Spodoptera larvae at a range of intervals following damage. Grazing levels on these leaves were compared with those on undamaged leaves on the same or different plants.2. In separate experiments, three leaves in a middle position on the main stem were clipped and after 48 h grazing levels on undamaged leaves above and below those damaged were compared with similar leaves from control plants.3. Within 8 h, grazing levels on damaged leaves were significantly lower than those on control leaves, and within 24 h, leaves adjacent to damaged ones were similarly affected. These effects persisted for at least 7 days and leaves above and below those damaged were affected. There was up to nine‐fold reduction in area consumed.4. The possible ecological consequences of reduced palatability at these levels are discussed.