bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduced realised fecundity in the pine looper Bupalus piniarius caused by host plant defoliation
Authors: Šmits Agnis , Larsson Stig , Hopkins Richard 
Published: March 2003

Summary1. Whether the potential fecundity of herbivorous insects is realised or not may depend on female behaviour, which in turn may be influenced by host plant acceptability. Female Bupalus piniarius were observed to discriminate against needles growing out the year following defoliation (current‐year needles) of its host plant Pinus sylvestris.2. It was hypothesised that the discriminatory behaviour was due to current‐year needles being less secure as a substrate. Field and laboratory experiments were designed to test this hypothesis and to estimate the discrepancy between potential and realised fecundity when females were offered defoliated branches.3. In a laboratory oviposition experiment, B. piniarius females were exposed to branches bearing either current‐year needles only or both mature and current‐year needles. Daily oviposition rate, egg batch size, longevity, and mature eggs and fat retained at death were recorded for each female. In field experiments, the rate at which eggs dropped from expanding needles and the capacity of neonate larvae hatching from the dropped eggs to colonise a tree were assessed.4. Significantly fewer eggs were laid when females were exposed to defoliated branches.5. Twenty‐six and 16% of the eggs laid on current‐year needles dropped from the needles in 1998 and 1999 respectively, whereas no eggs dropped from mature needles in 1998 and only one egg (< 1%) dropped in 1999.6. A very small proportion of larvae hatching on the forest floor (simulated egg drop) was able to recolonise host trees.7. These results emphasise the importance of oviposition behaviour on realised fecundity when analysing insect population dynamics. In the case of B. piniarius, egg placement, although a minor detail during the normal course of events, became of key importance when defoliation deprived females of their preferred egg attachment site.
Determinants of sperm precedence in a noctuid mothHeliothis virescens: a role for male age
Authors: Lamunyon Craig W. 
Published: March 2003

Summary1. Females of the noctuid mothHeliothis virescensF. mate more than once. Thus, sperm from two or more males normally compete for fertilisations within the female reproductive tract. The eggs are typically fertilised by sperm from only one male, either the female's last mate or an earlier mate. Twice‐mated females store only one ejaculate's worth of fertilising sperm (eupyrene) but nearly two ejaculates' worth of a nonfertilising sperm morph (apyrene), which is thought to play a role in sperm competition.2. The mechanism of sperm use inH. virescenswas investigated by examining factors that vary with paternity, which was assigned based on allozyme variation. The factors included male and female body masses and ages, male genital characters, the size of the sperm package, and the number of sperm stored by the female.3. One male typically gained sperm precedence; this was nearly twice as likely to be the second male as it was to be the first. Two factors were found to vary significantly with paternity: female mass and male age. The second male to mate was more likely to gain sperm precedence if the female was larger and if the male was older than the female's first mate.4. The significance of male age and female mass to several hypothetical models of the mechanism of sperm use is discussed.
Oviposition preferences of the Hessian fly and their consequences for the survival and reproductive potential of offspring
Authors: Harris M. O. , Sandanayaka M. , Griffin W. 
Published: March 2003

Summary1. The relationship between oviposition preference and offspring performance was investigated experimentally for the Hessian flyMayetiola destructor(Say) using 10 grass genotypes that represented five different genera and six different species. Oviposition preferences were quantified in a choice test using arrays of 200–400 plants. Offspring performance was estimated by recording survival during three phases of the insect–plant association and by measuring wing length, a correlate of adult reproductive potential. Density effects were examined for all offspring variables, and were taken into account when offspring performance was compared across the 10 grasses.2. Egg counts from the oviposition choice test revealed a consistent ranking of plants: 18ITSN triticale > Otane bread wheat = Caldwell bread wheat = Stacy bread wheat > 3424 bread wheat = PND durum wheat = Fleet barley = Valetta barley = Matua brome grass > Awapuni oat.3. Survival and adult wing length varied significantly on the 10 plant types. Survival was ranked: Otane bread wheat > 3424 bread wheat = Fleet barley = Matua brome grass > Caldwell bread wheat = Valetta barley > 18ITSN triticale = PND durum wheat = Stacy bread wheat > Awapuni oat. Adult male and female wing lengths were greatest on Otane, the bread wheat that also provided the best survival.4. For Hessian flies on each of the 10 plant types, data on survival, wing length, and wing length–fecundity relationships were combined into a single fitness measure. When these fitness measures were compared with egg counts, no overall pattern emerged. On seven of the 10 plant types, there was a positive linear relationship between egg counts and offspring fitness. On the other three plant types, egg counts were high while fitness was low. Possible reasons why Hessian fly females lay eggs on plants that are poor hosts for their offspring are discussed.
Parental care in the whitefly Aleyrodes singularis
Authors: Guershon Moshe , Gerling Dan 
Published: March 2003

Summary1. Patches of Aleyrodes singularis nymphs are characterised by a distinctive phenotype composed of the nymphs' exuviae, which are piled on the nymph, and by a covering layer of wax secreted by the adults; these characteristics have been found to confer defensive properties against natural enemies.2. In contrast to the behaviour typical for ovipositing females of other aleyrodids, A. singularis females tend to remain near the patch of their progeny throughout their development. These mothers were therefore tested to show whether they exhibited active defensive behaviour towards natural enemies, beyond their contribution to passive defence achieved through the secretion of wax on the immatures.3. The behaviour of whitefly adults differed significantly when performed in the presence of conspecific adults from their behaviour in the presence of natural enemies (either a parasitoid or a predator). The differences were expressed in the mean time devoted to some behavioural events, the frequency at which events were performed, and the number of transitions between pairs of events.4. Most of the recorded behavioural differences were associated with departure of the natural enemies, facilitating immature survival.5. This is the first report of active behavioural changes that convey defence of immature offspring for the family Aleyrodidae. Conditions characterising these findings and their relationship with those in which parental care is expected are discussed.
Avoidance of occupied hosts by the Hessian fly: oviposition behaviour and consequences for larval survival
Authors: Kanno H. , Harris M. O. 
Published: March 2003

Abstract1. Unoccupied wheat plants and wheat plants occupied by conspecific eggs or larvae were presented to ovipositing female Hessian flies in choice tests.2. The presence of conspecific eggs on the leaf surfaces of wheat plants did not appear to have any effect on the responses of ovipositing Hessian fly females.3. The presence of conspecific larvae at the base and nodes of wheat plants for 1, 6, or 11 days had significant effects on Hessian fly oviposition. Eggs oviposited on plants were inversely proportional to larval densities and days of larval occupation.4. Feeding by Hessian fly larvae is associated with several changes in wheat plants. One of these changes, the growth arrestment of the plant, was measured by recording the heights of plants used in oviposition tests. Plant heights were inversely proportional to both larval densities and days of occupation. Plant heights were directly proportional to eggs oviposited on plants.5. The consequences of adult female avoidance of plants occupied by conspecific larvae were investigated by allowing females to oviposit on unoccupied plants and 1‐day, 6‐day, and 11‐day larval occupied plants, then scoring at the end of the first larval instar the survival of the offspring that resulted from this oviposition.6. Survival during the first larval instar was 88% for the offspring of females that oviposited on unoccupied plants, decreasing to 82, 31, and 4% on the 1‐day, 6‐day, and 11‐day occupied plant treatments. On these four plant treatments, a positive correlation was found between larval performance (i.e. survival) and the preferences of ovipositing females.7. On the four plant treatments, relationships between first‐instar larval density and first‐instar larval survival varied significantly. On unoccupied plants, survival was inversely proportional to density. On plants oviposited on at 6 days of larval occupation, survival was directly proportional to density.
Chemical defence ofBattus philenorlarvae against attack by the parasitoidTrogus pennator
Authors: Sime Karen 
Published: March 2003

Abstract1. Parasitoids in the genusTrogus(Hymenoptera: Ichneumonidae) attack the larvae of swallowtail butterflies (Lepidoptera: Papilionidae). Only two of the three major tribes of the subfamily Papilioninae are attacked although species of all three tribes commonly occur together. The tribe Troidini is relatively free of parasitoids of any kind, and it has been proposed that the aristolochic acids sequestered by troidines protect them from parasitism.2. The responses ofT. pennator(Fabricius) to the sympatric troidineBattus philenor(Linnaeus) were examined. Three hypotheses that could explain why this wasp does not parasitiseB. philenorwere considered. (1)Battus philenordoes not produce compounds used by the wasp to locate hosts. (2) The larval integument contains compounds that deter attack. (3) The parasitoid offspring cannot survive inB. philenor.3. The first hypothesis was not supported as the frass ofB. philenorlarvae was found to act as a searching arrestant comparable to the frass of a host species.4. The second hypothesis was supported. TheB. philenorlarvae were rejected when the wasps examined them using their antennae, and ethanolic washes ofB. philenorcuticle deterred attack byT. pennatorwhen applied to otherwise acceptable host larvae. Bioassays of fractions of the ethanolic wash and of pure aristolochic acids established that aristolochic acids were at least partly responsible for the deterrent effect.5. The third hypothesis was also supported. Larvae ofB. philenorattacked by the parasitoids developed into butterflies.6. These results indicate that both behavioural and physiological barriers, the former attributable at least in part to sequestered compounds and the latter of unknown mechanism, preventT. pennatorfrom parasitisingB. philenor.
Uptake of Bt‐toxin by herbivores feeding on transgenic maize and consequences for the predator Chrysoperla carnea
Authors: Dutton A. , Klein H. , Romeis J. , Bigler F. 
Published: March 2003

Abstract  1. Chrysoperla carnea is an important predatory insect in maize. To assess the ecological effects of Bt‐maize, expressing the Cry1Ab protein, on larvae of this predator, the following factors were examined: (1) the performance of three prey herbivores (Rhopalosiphum padi, Tetranychus urticae, and Spodoptera littoralis) on transgenic Bt and non‐transgenic maize plants; (2) the intake of the Cry1Ab toxin by the three herbivores; and (3) the effects on C. carnea when fed each of the prey species.2. The intrinsic rate of natural increase (rm) was used as a measure of performance for R. padi and T. urticae. No difference in this parameter was observed between herbivores reared on Bt or non‐transgenic plants. In contrast, a higher mortality rate and a delay in development were observed in S. littoralis larvae when fed Bt‐maize compared with those fed the control maize plants.3. The ingestion of Cry1Ab toxin by the different herbivores was measured using an immunological assay (ELISA). Highest amounts of Cry1Ab toxin were detected in T. urticae, followed by S. littoralis, and only trace amounts detected in R. padi.4. Feeding C. carnea with T. urticae, which were shown to contain the Cry1Ab toxin, or with R. padi, which do not ingest the toxin, did not affect survival, development, or weight of C. carnea. In contrast, a significant increase in mortality and a delay in development were observed when predators were fed S. littoralis larvae reared on Bt‐maize.5. A combined interaction of poor prey quality and Cry1Ab toxin may account for the negative effects observed on C. carnea when fed S. littoralis. The relevance of these findings to the ecological risks of Bt‐maize on C. carnea is discussed.
Using age grading by wing injuries to estimate size‐dependent adult survivorship in the field: a case study of the yellow dung fly Scathophaga stercoraria
Authors: Burkhard Dieter U. , Ward Paul I. , Blanckenhorn Wolf U. 
Published: March 2003

Abstract 1. Studies of natural selection depend on estimates of longevity and mortality in the wild. In small and mobile species such as insects, direct, mark–recapture (resight), studies are difficult to perform because individuals cannot be tracked easily.2. It was investigated whether age grading based on wing injuries alone can be used to estimate size‐specific survivorship in the field in the yellow dung fly Scathophaga stercoraria (L.) (Diptera: Scathophagidae).3. The accumulation of different types of wing injury throughout the spring and autumn flight seasons for both sexes was recorded: tears, notches (both reflecting regular wear), and large missing areas (probably due to intra‐ and inter‐specific interactions).4. Female longevity increased with body size in both spring and autumn, whereas male longevity increased slightly with size in spring but decreased in autumn.5. The two sexes and males of different size classes accumulated the various types of wing injury differentially, presumably due to differential patterns of intraspecific interactions. Additionally, body size exhibited a seasonal pattern, complicating interpretation of the relationship between body size and wing injuries.6. It is therefore concluded that estimating adult viability selection on body size using wing injuries is problematic in dung flies, and potentially also in other species. It is suggested that before this method is applied in any particular species, pilot studies should be conducted to verify whether wing injuries accumulate equally in all classes of individuals of interest. In addition, it is necessary to investigate the causes of different types of wing injury.
Between‐forest variation in vertical stratification of drosophilid populations
Authors: Tanabe Shin‐Ichi 
Published: March 2003

Abstract1. The spatial distribution pattern of forest‐dwelling drosophilid flies was compared among species and among four forests with markedly different vertical foliage structures, including secondary and primary forests, with special reference to vertical stratification.2. All 20 drosophilid species analysed showed vertically stratified distribution patterns, which were detected statistically in at least one forest site during the 2‐year study period. As a whole, the vertical distribution patterns were stable, with or without stratification, over the 2 years.3. The ratio of species with stratified distribution to the total number of species changed in a similar trend with the vertical foliage complexity of forests, both showing a large gap between secondary and primary forests, even for species common to all four forests.4. Many species, most of which were tree‐sap feeders, showed highly predictable patterns of vertical stratification across forests and years. This was associated strongly with regular preference for microhabitat, mostly for the canopy, suggesting that the unvarying nature of canopy environments in any forest is very important in producing, maintaining, and promoting the vertical stratification in organism abundance, and contributes to the ubiquity of the pattern.5. Some species with a wider range of food resources than other species, most of which showed no clear preference for the canopy, were characterised by large between‐forest differences in vertical distribution patterns and tended to show non‐stratified patterns in secondary forests, contributing to the lower ratio of species with stratified distribution in the two secondary forests than in the primary forests.6. The role of forest structure in organising the environment is discussed; it is suggested that vertical complexity of foliage structure affects the prevalence of vertical stratification in animal communities indirectly through the vertical heterogeneity of environmental conditions.
Life‐history responses of a mayfly to seasonal constraints and predation risk
Authors: Tseng Michelle 
Published: March 2003

Abstract. 1. An experiment was conducted in the laboratory to examine the effects of photoperiod and predation risk on life‐history variation in the mayfly Ephemerella subvaria.2. Both photoperiod and predation risk affected age at maturity significantly but neither factor affected size at maturity. Mayflies perceiving themselves to be late in the growing season matured in fewer days than those perceiving themselves to be early in the growing season. The presence of predators delayed mayfly maturity significantly.3. These results suggest that the large variation in life‐history traits observed in aquatic insects may be attributed partially to seasonality but that other biotic and abiotic factors may also underlie variation in these traits.
A functional defect in hereditary haemochromatosis monocytes and monocyte‐derived macrophages
Authors: Moura  , Verheul  , Marx  
Published: March 2003

BackgroundHereditary haemochromatosis (HH) is a disease of the metabolism of iron characterized by increased iron absorption and heavy parenchymal iron deposition, but with the presence of little iron in the mononuclear phagocytic system (MPS).MethodsTo investigate the role of the MPS, the phagocytic ability of HH monocytes (MNs) and in vitro monocyte‐derived macrophages (MDMs) was studied. HH patients with different degrees of iron accumulation were chosen.ResultsWe observed that HH patients' MNs and MDMs have a significantly decreased ability to phagocytose rabbit red blood cells (RRBCs) and that HH MNs possess a significantly decreased capacity to phagocytose Staphylococcus aureus (S. aureus). The decrease in the ability to phagocytose S. aureus, however, was kinetic in nature, explaining the absence of increased prevalence of bacterial infections among HH patients. Both RRBCs and S. aureus were preopsonized with heat‐inactivated serum. No alteration in the complement‐dependent phagocytosis of Cryptococcus neoformans was demonstrated when normal human serum was used. The phagocytosis defect was observed in 100% of HH patients and was independent of the magnitude of iron overload, age or liver damage, and affected the antibody‐mediated uptake of bacteria and (R)RBCs.
Effect of thyroid hormone on plasma apolipoproteins and ApoA‐ and ApoB‐containing lipoprotein particles
Authors: Liu  , Rahman  , Bagdade  , Alaupovic  , Kannan  
Published: March 2003

MethodsApolipoprotein and apoB‐ and apoA‐containing lipoprotein particle concentrations were determined in 10 athyreotic patients 4 weeks after withdrawal of Synthroid replacement therapy [T4, 0.96 ± 0.66 μg mL−1; thyroid‐stimulating hormone (TSH), 62.7 ± 22.8 μIU mL−1] and again 4 weeks after reinstitution of treatment.ResultsThyroid hormone replacement was associated with significant decreases in plasma cholesterol (TC), triglyceride (TG), apolipoprotein B and apolipoprotein C‐III (P < 0.01). Both the cholesterol ester‐rich LP‐B particles and triglyceride‐rich LP‐Bc particles declined significantly in response to thyroid hormone (LP‐B withdrawal 81.6 ± 24.0 vs. replacement 65.1 ± 22.0; LP‐Bc withdrawal 14.3 ± 6.0 vs. replacement 10.9 ± 4.8 mg%, P < 0.01). ApoC‐III also decreased in high‐density lipoprotein (HDL) (apoC‐III‐HS) and in very low‐density lipoprotein (VLDL) + low‐density lipoprotein (LDL) (apoC‐III‐HP), but this reduction was proportionate so that the apo‐C‐III‐HS/apoC‐III‐HP ratio, an indirect estimate of the efficiency of lipoprotein lipase (LPL), was unchanged. Apolipoprotein A‐I concentrations also decreased significantly (withdrawal 140.7 ± 27.0 vs. replacement 127.1 ± 30.0 mg%, P < 0.01) in parallel with the changes in LP‐A‐I and LP‐A‐I:A‐II particles (LP‐A‐I withdrawal 35.8 ± 7.7 vs. replacement 31.5 ± 6.3; LP‐A‐I:AII withdrawal 104.9 ± 20.0 vs. replacement 95.5 ± 26.0; P < 0.05).ConclusionThese findings indicate that thyroid hormone influences the transport not only of both TG‐rich and cholesterol‐rich apoB‐containing lipoprotein particles but also of those that contain apoAI.
Inflammatory bowel disease: no association between allele combinations of the interleukin (IL) 1β and IL‐1 receptor antagonist gene polymorphisms
Authors: Hacker  , Bidlingmaier  , Gomolka  , Keller  , Eigler  , Hartmann  , Folwaczny Chr. , Fricke  , Albert  , Loeschke  , Endres  
Published: March 2003

BackgroundInterleukin 1 (IL‐1) and its physiological antagonist interleukin‐1 receptor antagonist (IL‐1ra) play a crucial role in the pathogenesis of inflammatory bowel disease. Polymorphisms in the genes coding for these cytokines, the restriction enzyme TaqI polymorphism for IL‐1β and the variable number of tandem repeats (VNTR) polymorphism for IL‐1ra, have been shown to influence cytokine synthesis in vitro. Recently, an association has been described for distinct allele combinations of these two polymorphisms in patients with ulcerative colitis and with Crohn's disease but not in healthy control subjects.MethodsWe studied 56 patients with ulcerative colitis, 64 patients with Crohn's disease and 196 healthy control subjects. All were unrelated Caucasians of European ancestry. After polymerase chain reaction (PCR) the amplification products were analysed on agarose gels. For the IL‐1β polymorphism the PCR product was additionally digested using the restriction enzyme TaqI.ResultsThe allele and genotype frequencies as well as the carriage rates of the IL‐1βTaqI polymorphism in healthy control subjects were in agreement with previous findings in other populations. Allele and genotype frequencies of the IL‐1β polymorphism were not different in inflammatory bowel disease patients compared with healthy control subjects. Comparing allele combinations of both polymorphisms no association could be idengified either within healthy control subjects or in the groups of patients with ulcerative colitis or Crohn's disease.ConclusionThus, we could not confirm the results of a previous study reporting an association between the IL‐1ra and IL‐1β gene polymorphisms in patients with inflammatory bowel disease.