bluuebunny/crossref_metadata_2025_split huggingface dataset:
The roles of temperature and diapause in the life history of a temperate‐zone dragonfly: Argia vivida (Odonata: Coenagrionidae)
Authors: PRITCHARD GORDON 
Published: March 2008

Abstract. 1. The life cycle of Argia vivida Hagen generally took longer to complete in the field than was predicted on the basis of the thermal sum accumulated in laboratory rearing.2. The prediction of a bivoltine life‐cycle from geothermal sites with either a constant annual temperature of 26°C or thermal range of 11–31°C was not borne out because the intervention of short‐day induced developmental delays in later larval instars extended the life cycle to 1 year.3. This diapause, which synchronizes adult emergence with favourable summer temperatures, was also present in larvae from sites with annual temperature ranges of 0–33°C and 5–20°C.4. At these colder sites completion of the life cycle takes 2 and 3 years respectively and dragonflies must be in cold‐resistant stages during the winter. A long‐day diapause, principally affecting late‐instar larvae below a certain size during the summer, achieves this.5. Large diurnal temperature fluctuations at the 0–33°C site markedly increase the useful thermal energy available to larvae for growth over that predicted by the thermal sum equation.6. The interaction between the effects of temperatures favourable for growth and day‐length‐governed diapause, synchronize the emergence of the low‐temperature sensitive adult stage of this tropical dragonfly with northern‐latitude summers at a variety of habitats.
Oviposition site preference and larval mortality in a leaf‐mining moth
Authors: AUERBACH MICHAEL , SIMBERLOFF DANIEL 
Published: March 2008

Abstract. 1. The univoltine leaf‐mining moth, Lithocolletis quercus Ams., is endemic to Israel, where it spends its 10.5 month larval period feeding only in the leaves of Quercus calliprinos Webb.2. We compared patterns of egg deposition and sources of larval mortality to test whether oviposition patterns and site preferences confer an enhanced likelihood of larval survival.3. Dominant sources of larval mortality were premature leaf abscission and death from unknown causes, whereas predation, parasitism and intraspecific interference accounted for relatively little larval mortality.4. Eggs, and thus mines, were aggregated among leaves of host trees even though premature leaf abscission was positively correlated with density of mines per leaf. Interference competition among larvae was the only other density‐dependent mortality factor.5. Oviposition patterns within leaves mitigated the probability of death from larval interference, and probably also from early leaf abscission.6. Despite these density‐dependent mortality factors, overall probability of larval survival to pupation was independent of initial density of mines on a leaf.7. The long larval period allows synchrony between oviposition flights and times of predictable resource availability.
The influence of host distribution, sex, and size on the level of parasitism by Itoplectis conquisitor (Hymenoptera: Ichneumonidae)
Authors: CRONIN JAMES T. , GILL DOUGLAS E. 
Published: March 2008

Abstract. 1. Parasitism of the bagworm, Thyridopteryx ephemeraeformis Haw. (Lepidoptera: Psychidae), on red cedar was studied at Manassas, Va., U.S.A.2. Fifteen parasitoids, five of which were hyperparasitoids, attacked the pupal stage of the bagworm. The Ichneumonid Itoplectis conquisitor alone accounted for 58% of the parasitized bagworms.3. Parasitism by I conquisitor (Say) was inversely related to host size, but independent of host distribution within a tree. Male bagworms experienced disproportionately higher levels of parasitism than females. We conclude that it is small size that renders bagworms susceptible to parasitism rather than sex per se.4. Ovipositor lengths of I.conquisitor were insufficient to penetrate the larger bagworm hosts (>57 mm); and in fact, as bagworm size increased, the proportion of the I.conquisitor population capable of penetrating the pupa declined abruptly. We suggest that the mechanical difficulties with oviposition, and perhaps the defensive capabilities of larger hosts, are responsible for the relationship between host size and per cent parasitism.5. I.conquisitor could be an important selective agent for bagworm size at pupation, but it is not likely to act as a significant control agent of population density.
Dynamic information and host acceptance by a tephritid fruit fly
Authors: MANGEL MARC , ROITBERG BERNARD D. 
Published: March 2008

Abstract. 1. Female apple maggot (Rhagoletis pomonella Walsh) flies held in field cages usually oviposited in an unparasitized (non‐pheromone marked) fruit when it was encountered.2. Oviposition in a previously parasitized (pheromone marked) fruit depended upon the time since the last oviposition (TSLO) and the percentage of infested fruit encountered during search for oviposition sites.3. Previous theories of host acceptance suggest that the acceptance or rejection of a host should depend dichotomously on time since last oviposition and the fraction of marked hosts in the last five encounters. The experiments, however, show considerable variability and are thus not consistent with the theory.4. A new theory for the experiments is introduced. This model involves physiological (egg complement) and informational state variables and leads to intuitive understanding of the experimental results. In particular, the model shows how the plasticity in oviposition site selection may arise from fitness maximizing behaviour. Alternative models are also discussed. All of the models stress the importance of physiological and informational states.
Soil softness, nest initiation and nest sharing in the wasp, Cerceris antipodes (Hymenoptera: Sphecidae)
Authors: McCORQUODALE D. B. 
Published: March 2008

Abstract. 1. The relationship between soil softness and nest initiation was studied at two aggregations of a ground nesting sphecid wasp, Cerceris antipodes Smith, in New South Wales, Australia.2. Nests of C.antipodes were initiated throughout the active season. Nests were started more frequently during moist conditions and when more wasps were active.3. Nest initiation was clumped on days after periods of rain. Nest initiation was only observed when the soil was soft.4. Two experimental plots that were watered had significantly softer soil and more nests initiated on them than two control plots. Searching female wasps spent considerably more time on the watered plots than the controls.5. Nest initiation through hard surface soils presents a problem to C.antipodes. Soil softness must be considered in any analysis of nest sharing in this species.
Effects of changing photoperiods in the life cycle regulation of the comma butterfly, Polygonia c‐album (Nymphalidae)
Authors: NYLIN SÖREN 
Published: March 2008

Abstract. 1. Regulation of adult reproductive diapause and seasonal polyphenism was studied in two populations of the comma butterfly, Polygonia c‐album (L.) (Nymphalidae), from Stockholm, Sweden, and Oxford, England.2. In the univoltine Stockholm population short and long constant day‐lengths (in the range 12–22 h) at 20°C were ineffective in averting the production of the dark, generally diapausing, morph, but the non‐diapausing light morph could be produced if daylengths were increased during larval development. The procedure was especially effective with increases from 12 to 22 h, but the tendency was the same with a more realistic increase, from 18 to 20 h.3. In the partially bivoltine English population a critical constant day‐length for morph and diapause induction was found between 12 and 18 h. Decreasing daylengths above the critical daylength early or late in larval development resulted in production of the diapausing morph.4. These results suggest a system for environmental control where day‐lengths which increase throughout the larval period indicate an early date before summer solstice, meaning that there is sufficient time for a second generation of offspring to reach the hibernating adult stage before winter. The ecological significance of the results is discussed.
An analysis of the deterrent effect of aphids on cabbage root fly (Delia radicum) egg‐laying
Authors: FINCH S. , JONES T. H. 
Published: March 2008

Abstract. 1. The cabbage root fly, Delia radicum (L.), was deterred from laying eggs on brassica plants with >250 cabbage aphid, Brevicoryne brassicae (L.), or peach‐potato aphid, Myzuspersicae (Sulz.).2. Flies did not lay on plants infested with >250 aphids.3. Preparations of (E)‐β‐farnesene, the aphid alarm pheromone, deterred the flies from laying only at the extremely high dose of 32 mg/plant.4. Although M. persicae secreted large (1 ng/insect) amounts of alarm pheromone and B. brassicae extremely small (<0.01 ng/insect) amounts, both aphids equally deterred D. radicum from laying.5. The deterrent effect appeared to result from the aphids physically disturbing the flies during host‐plant selection.
Secretion‐grooming in the water bug Plea minutissima: a chemical defence against microorganisms interfering with the hydrofuge properties of the respiratory region
Authors: KOVAC D. , MASCHWITZ U. 
Published: March 2008

Abstract. 1. The water bug Plea minutissima Leach (Hemiptera: Pleidae) from time to time crawls out of the water and distributes secretion from its metathoracic glands over the ventral part of its body. By this ‘secretion‐grooming’ antiseptic gland substances, mostly hydrogen peroxide, are applied to the hydrofuge hairs which hold the respiratory air bubble.2. When the bugs are prevented from leaving the water, their mortality increases significantly, and individuals lacking the air bubble are observed. Examination of such bugs with Scanning Electron Microscopy techniques reveals bacteria growing on their hydrofuge hairs, whereas in bugs allowed to secretion‐groom the hairs are not contaminated by microorganisms.3. Artificial application of diluted metathoracic gland secretion on the body surface of P. minutissima kills bacteria, while specific ciliates, which never colonize the respiratory region, are not harmed by the secretion.4. It can be concluded that secretion‐grooming prevents the contamination of the hydrofuge respiratory region that leads to the wetting of the hydrofuge respiratory regions, resulting in the loss of the air bubble, and, finally, the drowning of the animals.5. Other possible functions of the secretion, such as chemical defence against predators or wetting of the body surface, could not be demonstrated or seem unlikely.
Leaf shape and the host‐finding behaviour of two ovipositing monophagous butterfly species
Authors: MACKAY D. A. , JONES R. E. 
Published: March 2008

Abstract. 1. Ovipositing Eurema brigitta (Wallace) and Eurema herla (W. S. Macleay) butterflies were followed in the field to determine the nature and extent of the pre‐alighting discrimination shown by these insects towards their only host plant, Cassia mimosoides (L).2. Both species tended to search in areas where plants with long, thin leaves (primarily grasses) were less common, on average, than in randomly placed quadrats. Both species were also more likely to alight on non‐host plants with leaves of a similar size and shape to those of the host plant than on non‐hosts with leaf shapes dissimilar to that of the host.3. The search behaviour of these monophagous insects was not so specialized that the butterflies never alighted on non‐hosts; in fact the majority of alightings were on non‐host plants and the pre‐alighting discrimination shown by these insects is clearly not the prime behavioural determinant of their monophagy.
Seasonal emergence, host‐seeking activity, age composition and reproductive biology of the mosquito Aedes punctor
Authors: PACKER M. J. , CORBET PHILIP S. 
Published: March 2008

Abstract. 1. Seasonal patterns of adult emergence, host‐seeking and reproductive ageing in a population of the woodland mosquito Aedes punctor (Kirby) are described from field studies in northern Britain in 1984 and 1985.2. The pattern of emergence showed little variation between years but duration did vary. Males started emerging before females. Sex ratios at emergence showed a marked female bias. A late, second period of emergence apparently represented a second generation in this normally univoltine species.3. Host‐seeking females were first caught at human bait within a few days of the start of emergence and peak numbers at bait occurred 3–4 weeks later. High numbers lasted for c. 2 weeks. The duration of host‐seeking activity was related to weather. The second emergence in 1985 resulted in a second peak of activity in early September and probably extended the flight season.4. As the season progressed the proportion of females that were parous increased. However, this proportion never reached 1.0, indicating variation in individual reproductive success, which differed between years.5. The reproductive biology of individuals within the population was investigated. No autogeny was detected, suggesting that the population was entirely anautogenous.
The timing of oviposition and larval growth by two tephritid fly species in relation to host‐plant development
Authors: STRAW N. A. 
Published: March 2008

Abstract. 1. The relationships between the timing of oviposition, larval establishment and host development were studied in the tephritids Tephritis bardanae (Schrank) and Cerajocera tussilaginis (Fab.) which attack flowerheads of Arctium minus (Hill) Bernh. (Compositae).2. T. bardanae laid eggs in small sized flowerheads that were at an early stage of development, and appeared to use the external dimensions of the head as an oviposition cue. In contrast, C. tussilaginis females laid eggs into heads that were near to flowering and the timing of their attack was most closely related to particular lengths of florets and achenes inside the head. Both tephritids apparently recognized suitable heads by comparing aspects of their own body size with the size of particular flowerhead structures.3. Individual heads were suitable for oviposition for a period of 10–11 days for both species, but the periods of susceptibility to each species did not overlap.4. Attack by T. bardanae was timed to exploit the flowering phase of flowerhead development. Larval establishment and early development were synchronized with increasing nutrient availability occurring during the rapid growth of the florets and achenes before and during anthesis.5. In contrast, the later attack by C. tussilaginis was timed to exploit the seed maturation phase of head development. Individual C. tussilaginis larvae operated as highly specialized ‘achene parasites’, utilizing the influx of nutrients into single achenes after fertilization.6. Larvae of both tephritids induced abnormal host‐tissue growth, but oviposition in both species was timed primarily to synchronize larval development with natural periods of high nutrient availability inside flowerheads, rather than with the presence of tissues suitable for gall induction.
Interspecific differences among swallowtail larvae (Lepidoptera: Papilionidae) in susceptibility to aristolochic acids and berberine
Authors: MILLER JAMES S. , FEENY PAUL P. 
Published: March 2008

Abstract. 1. The larvae of four swallowtail butterfly species, Papilio polyxenes Fabr. in the Papilionini, Parides bunichus (Hübner) and Battus polydamas (L.) in the Troidini, and Eurytides marcellus (Cramer) in the Graphiini, were grown on host leaves to which test compounds had been added.2. The test chemicals are biosynthetically related. Berberine, a 1‐benzyl‐tetrahydroisoquinoline‐related (1‐BTIQ) alkaloid, is found in many rutaceous hosts of the Papilionini; laudanosine, a simpler 1‐BTIQ alkaloid, is found in the Papaveraceae, plants on which no papilionids feed; aristolochic acids are found only in the Aristolochiaceae, hosts of the Troidini.3. Swallowtail larvae can tolerate the compounds characteristic of their host plants, but not chemicals found in the hosts of other papilionid groups. Diets with laudanosine did not affect the test species.4. Our results support the contention that plant secondary chemicals, such as berberine and aristolochic acids, are important feeding barriers, and are partially responsible for host specificity in swallowtails.
Dispersal of the thistle gallfly Urophora cardui and its endoparasitoid Eurytoma serraiulae (Hymenoptera: Eurytomidae)
Authors: SCHLUMPRECHT HELMUT 
Published: March 2008

Abstract. 1. The dispersal of the gall‐forming tephritid Urophora cardui L. (Diptera: Tephritidae) and its endoparasitoid Eurytoma serratulae Latr. (Hymenoptera: Eurytomidae) from an experimental colony were investigated over a period of 4 years.2. The dispersal rate for both fly and endoparasitoid was one to two magnitudes higher than in previous studies, which found 100 m per generation maximally. The dispersal rate of the endoparasitoid was not less than that of its host. Most newly founded colonies were small and had high extinction rates.3. The viability of colonies of U. cardui did not correlate with the distance from the dispersal centre.4. The dispersal rates observed are high enough to allow a multiple spread and extinction in mid‐Europe in the post‐pleistocene period.
Reduced pesticide inputs on cereal field margins: the effects on butterfly abundance
Authors: DOVER JOHN , SOTHERTON NICOLAS , GOBBETT KAY 
Published: March 2008

Abstract. 1. On a study farm in Hampshire where large blocks of cereal fields had the pesticide inputs on their headlands experimentally and selectively reduced (the practice known as ‘conservation headlands’), numbers of butterflies were monitored over 4 years by using transect counts.2. Consistently more butterflies were seen flying over field edges sprayed under the conservation headland regime compared to those that were fully sprayed.3. A comparison of changes in butterfly abundance on the study farm containing conservation headlands with data from the National Butterfly Monitoring Scheme indicated that population increases in some species may result from the use of conservation headlands.4. The implications of resource provisioning and the potential reduction of spray drift into field‐margin habitats are discussed in relation to farmland butterflies.
Host plant variation in mortality of the leaf‐folding sawfly on the arroyo willow
Authors: FRITZ ROBERT S. , NOBEL JENNIFER 
Published: March 2008

Abstract. 1. We tested the hypothesis that survival and sources of mortality of the leaf‐folding sawfly (Phyllocolpa sp.) varied significantly among host plants of the arroyo willow (Salix lasiolepis Bent ham).2. Survival of the leaf folder differed among field and potted willows in a common environment in two of three cases, and sources of mortality differed among plants in four of five cases.3. Egg mortality differed among field plants but not among the potted willow plants.4. Larval mortality and parasitism differed among field and potted willows in 2 years, and appeared to be compensatory mortality sources.5. Leaf folder density among plants was not generally correlated with percentage of leaf folds with no egg (galls formed but no subsequent oviposition), percentage survival, or percentage mortality, indicating a general lack of density dependence.6. The proportion of folds with no egg oviposited differed significantly among field and potted plants, and was only correlated with survival or sources of mortality in one of three years.7. The data support the hypothesis that host plant genotype affects the interaction of the leaf folder with its natural enemies, and thus represents a three trophic level interaction.
Asymmetric intraspecific competition among larvae of the damselfly Ischnura elegans (Zygoptera: Coenagrionidae)
Authors: GRIBBIN SIMON D. , THOMPSON DAVID J. 
Published: March 2008

Abstract. 1. A laboratory competition experiment is described in which the growth and development rates of larvae of the damselfly Ischnura elegans (Lind.) were measured over an entire instar.2. Two larval instars which commonly occur together in the field were used in the experiment; they were maintained with a superabundance of prey and either larvae from the same or the larger/smaller instar.3. Small larvae suffered increased development times and decreased size increases at the moult in the presence of large larvae but similar interference effects were not evident when these smaller larvae were in the presence of other small larvae.4. Development time and size increases of large larvae were not significantly affected by the presence of small larvae.5. Irrespective of the instar combinations investigated, interference effects were reduced when there were more perches available, although in only a few cases was this reduction significant.6. The consequences of the asymmetric competition reported in the experiment for the study of lifetime reproductive success in damselflies are discussed. Late emerging adults may incur reduced reproductive success.
The effects of group size and host species on development and survivorship of a gregarious caterpillar Halisidota caryae (Lepidoptera: Arctiidae)
Authors: LAWRENCE W. S. 
Published: March 2008

Abstract. 1. The effect on growth and survivorship of the number of Halisidota caryae (Harris) caterpillars in groups feeding on three taxonomically distinct hosts was examined experimentally in the field.2. Caterpillars grew more rapidly and survived better in larger sized groups than in smaller sized groups.3. Caterpilliars grew more rapidly and survived better on Carya ovata (Koch) than on Hamamelis virginiana (L) or Quercus velutina (Lam.).4. There were equal numbers of invertebrate predators on groups of different sizes and thus larger groups had significantly fewer predators per caterpillar than did smaller groups.5. Invertebrate predators accounted for at least a 10% daily decrease in survivorship.6. Local movement reduced predation because moving groups had fewer predators than did stationary groups.
Seasonal dynamics, movements and the effects of experimentally increased female densities on a population of imaginal Calopteryx aequabilis (Odonata: Calopterygidae)
Authors: CONRAD K. F. , HERMAN T. B. 
Published: March 2008

Abstract. 1. A population of Calopteryx aequabilis Say was sampled daily on a tributary of Canard River, Kings County, Nova Scotia, for the entire flight season in 1983 (29 May to 13 August), using capture–mark–recapture techniques.2. 2701 sightings of 678 individuals were obtained along a 635 m segment of the stream. A maximum daily count of 174 imagines was reached on 11 June, after which the population gradually declined.3. More females than males were marked but sexually mature males outnumbered females at the water on all but four days.4. Immigration rather than local emergence accounted for a large proportion of the population after 20 June.5. Females were consistently vagile; males were site–specific but occasionally moved long distances between captures.6. Males and females first marked as tenerals became reproductively mature after about 5 days.7. We experimentally increased female density on a partially isolated section of the study stream to see how increased female numbers affected the demographics and movement patterns of the population.8. Residence times for introduced and resident females were similar. In contrast, during a similar introduction of males a year earlier, most introduced males disappeared quickly.9. Males decreased the distance they travelled daily between captures, their total distance travelled and their range following the introduction, and females showed a tendency (not statistically significant) toward increased movements and dispersal, as predicted.