bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monogamy in the bark beetle Ips latidens: ecological correlates of an unusual mating system
Authors: Reid MarY. L. 
Published: March 2003

Abstract. 1. The diversity of mating systems in bark beetles (Coleoptera: Scolytidae) is poorly understood. Ips latidens (LeConte) is a small‐bodied species of a harem polygynous genus whose mating system in nature had not been established previously. This study examines the breeding biology of I. latidens breeding in recently dead ponderosa pine (Pinus ponderosa) in California. It was expected that both the heterogeneous habitat quality inherent in dead trees and small body size would favour polygyny.2. Contrary to expectations, I. latidens was found to be monogamous on the basis of excavations of 131 galleries conducted throughout the oviposition period at two wind‐felled trees and at four sites composed of freshly‐cut logs. Males left the galleries much sooner than females (50% gone by 24 and 36 days, respectively).3. Individual females made up to four egg gallery arms extending from the male nuptial chamber, with the number of arms and the length of individual arms increasing with the age of the gallery. The relationship between total gallery length and gallery age was consistent among the trees and log sites, and did not depend on the presence of the male.4. Ips latidens bred in a wide range of tree diameters (10–24 cm), and occurred in both pure aggregations and in aggregations with two other bark beetle species, Dendroctonus brevicomis and I. paraconfusus. The presence of the other species did not appear to influence negatively the density of I. latidens.5. Monogamy in I. latidens may be due to lower male mortality during dispersal associated with a greater range of suitable breeding habitat than occurs for other Ips species, resulting in an even sex ratio at breeding sites.
Diel vertical movements by lotic mayfly nymphs under variable predation risk
Authors: Muotka TimO. , Huhta ArtO. , Tikkanen Pertti 
Published: March 2003

Summary1. The diel foraging periodicities of two grazing mayfly (Ephemeroptera) nymphs, Heptagenia dalecarlica and Baetis rhodani, under variable fish (European minnow) predation risk were examined in a series of laboratory experiments.2. Heptagenia dalecarlica were almost exclusively nocturnal in their use of feeding areas on stone tops. There was a sharp increase in the proportion of nymphs out of refuge at nightfall, both in the control and fish‐odour treatments. In a treatment with freely moving fish, H. dalecarlica decreased their activity during both the day and night. In feeding trials with three freely foraging minnows, nymphs were completely safe when they had access to refuges beneath stones, whereas almost half the nymphs were consumed when no refuges were available.3. Baetis rhodani nymphs reduced their use of stone tops when exposed to four caged minnows or a freely moving fish, but this occurred both day and night. In feeding trials, B. rhodani were captured only while in the water column, and their mortality risk was independent of refuge availability.4. It is suggested that because H. dalecarlica lack efficient post‐encounter defences, they must rely on pre‐encounter mechanisms to reduce the threat of fish predation. It appears that in order to dwell sympatrically with fish, H. dalecarlica have evolved a coexistence by hiding strategy. In contrast, Baetis are vulnerable to fish attacks only if they enter drift in daylight, and are thus able to remain on stone tops both during the day and at night.
Salinity and shade preferences result in ovipositional differences between sympatric tiger beetle species
Authors: Hoback W. Wyatt , Golick Douglas A. , Svatos Tina M. , Spomer Stephen M. , Higley Leon G. 
Published: March 2003

Summary1. Adult tiger beetles of the genus Cicindela often co‐occur within a habitat but larvae do not. Larvae are sedentary and form usually permanent burrows at the site of oviposition where they require 1–3 years for development.2. To test niche partitioning based on ovipositional preference, the behaviour of two sympatric salt marsh tiger beetles, Cicindela circumpicta and C. togata (Coleoptera: Cicindelidae), were examined.3. In laboratory studies, female C. circumpicta and C. togata distinguished between experimental salinities, with the former preferring 4 parts per thousand (ppt) and the latter preferring 12 ppt. In the field, C. circumpicta larvae were associated with lower salinities (1–3 ppt) and vegetation along the edges of salt flats while C. togata larvae were found on open salt flats often near halophytes (average salinity = 7.8 ppt).4. In the field, females chose sites for oviposition in response to shade but not vertical landmarks. In a direct test, 53 of 56 new larval burrows occurred in shaded treatments, three in nonshaded controls.5. Compared with nonshaded controls, shade increased survival of eggs that were collected in the laboratory and placed in the field. For C. circumpicta eggs, 78% placed in shaded treatments hatched, while significantly fewer (22%) hatched in exposed treatments. For C. togata, 43% of eggs placed in the shade hatched, while no eggs placed in exposed treatments hatched.6. These results support the hypothesis of niche partitioning between C. circumpicta and C. togata based on ovipositional choice and resulting larval habitat.
Insect–plant interactions among gall size determinants of adelgids
Authors: Ozaki Kenichi 
Published: March 2003

Summary1. The adelgid Adelges japonicus induces shoot galls in ezo‐spruce Picea jezoensis. The relative importance of shoot characteristics and the number of adelgids that induce a gall in determining resource availability on a shoot was examined. Gall volume, which is highly correlated with the number of larvae that mature in a gall, was used as a measure of resources available for adelgids on a shoot. Gall volume was partitioned into two components: the number of chambers and the chamber volume.2. Path analysis revealed that the number of chambers in a gall was not affected by the number of leaves (which is an indirect measure of shoot length), the whorl where the gall was attached, or the number of surrounding shoots arising from the 1‐year‐old parent shoot. Each of these shoot characteristics, however, affected chamber volume: chamber volume increased with increasing numbers of leaves and surrounding shoots and with increasing heights of the whorls.3. Two generations of adelgids contributed to gall enlargement in different ways: the number of gall founders affected the number of chambers, and the number of gall inhabitants affected chamber volume.4. In a path diagram that incorporated the effects of both shoot characteristics and the numbers of adelgids, the numbers of adelgids in the two generations together accounted for 30% of the variance in gall volume, whereas the three shoot characteristics explained only 3.7% of the variance. This suggests that the amount of resources available in a gall is affected mainly by the numbers of adelgids but only slightly by shoot characteristics.
Response of Cydia pomonella to selection on mobility: laboratory evaluation and field verification
Authors: Keil Sabine , Gu Hainan , Dorn Silvia 
Published: March 2003

Summary1. The codling moth Cydia pomonella (L.), largely regarded as a sedentary species, shows great variation in flight capacity among individuals in the laboratory, as has been reported for tethered flight. The occurrence of individuals with the ability to fly over long distances is considered ecologically significant for the colonisation of new habitats in response to deteriorating environmental conditions. The work reported here was designed to investigate the importance of the genetic component in regulating dispersal in C. pomonella.2. Bi‐directional selection on mobility measured by actograph was carried out in the laboratory. Both male and female codling moths responded significantly to the upward and downward selections. Divergence between the two selected strains occurred after one generation of selection and increased as further selections continued. The realised heritabilities for mobility were estimated as 0.43 in males and 0.29 in females when averaged from the two selection directions.3. The dispersal capacity of the selected mobile and sedentary strains was verified by mark–release–recapture experiments in the field, though only the released male moths were captured effectively. Flight distances by males differed significantly between the two strains, with the mobile strain showing a greater dispersal capacity than the sedentary strain.4. This study demonstrated a positive correlation between mobility measured by actograph and field dispersal capacity in the codling moth. Furthermore, it provides the first experimental data to show field performances of different genotypes in insect dispersal.
Host plant specificity in several species of generalist mite predators
Authors: Beard J. J. , Walter G. H. 
Published: March 2003

Summary1. Species in the genus Neoseiulus are considered to be generalist predators, with some species used in biological control programmes against phytophagous mites and insects.2. A general survey of Neoseiulus species in inland Australia indicated that different species are associated with particular tree species. This pattern of host plant use was investigated for four Neoseiulus species (N. buxeus, N. cappari, N. brigarinus, N. eremitus) by means of a sampling programme through time and across space.3. Each species of Neoseiulus was collected entirely or mostly from one species of tree; little or no overlap was detected despite the tree species growing in well‐mixed stands. Host plant specificity thus appears to be strong in this genus.4. Species in two other genera (Pholaseius and Australiseiulus), also considered to be predatory, showed a similar association with particular tree species.5. The implications for the use of these predators in biological control are considerable. In particular, phytoseiid species with specific needs in terms of host plants may not be suitable for use as general purpose predators. Meeting the needs of phytoseiids through the modification of host plant attributes may be a step towards enhancing their efficacy as biological control agents.
Probing behaviour of Aphis craccivora Koch on host plants of different nutritional quality
Authors: Traicevski Violeta , Ward Seamus A. 
Published: March 2003

Abstract 1. Reciprocal transfer experiments were undertaken using four different hosts to examine the effects of a change in host at adult moult on the probing behaviour of the cowpea aphid Aphis craccivora Koch.2. The highest intrinsic rate of increase rm was achieved by aphids born and reared on cowpea, followed by those born and reared on broad bean, then Larissa, and finally Huia.3. Mean probing time, time to first probe, number of probes per time allocation, and non‐probing time were all examined. Host quality rm did not affect the instantaneous probability of probing, and aphids that did not find a probing site within 200 s did not settle and did not probe further on that leaf/stem.
Sexual size dimorphism in the two spot ladybird beetle Adalia bipunctata: developmental mechanism and its consequences for mating
Authors: Yasuda Hironori , Dixon Anthony F. G. 
Published: March 2003

Abstract  1. The literature on ladybirds indicates that males are consistently smaller than females but take the same length of time to complete their development. Rearing Adalia bipunctata at 20 and 25 °C confirmed that protandry cannot account for sexual size dimorphism in this species, nor can a difference in egg size.2. Female larvae consumed more food and had a higher relative growth rate in the fourth instar than did male larvae.3. When food is limited, small males appear to be more successful at mating than are large males.4. To account for these results, it is hypothesised that the gonads of male larvae compete more strongly with the soma for resources and that this reduces the growth potential of the soma of male larvae relative to that of female larvae. The greater mating success of small males when food is limited supports the eat or mate hypothesis, which predicts that when food is limited small males will spend less time feeding and more time mating than will large males.
Intraspecific competition between healthy and parasitised hosts in a host–parasitoid system: consequences for life‐history traits
Authors: Bernstein Carlos , Heizmann Annie , Desouhant Emmanuel 
Published: March 2003

Abstract  1. In two different treatments, groups of healthy hosts (Ephestia kuehniella) or hosts parasitised by Venturia canescens competed for a limited amount of food. The larva to adult survival in each group, as a function of the initial number of hosts and treatment, was fitted to the generalised Beverton and Holt and generalised Ricker survival functions, and a number of life‐history traits of the parasitoids was measured.2. Intraspecific competition was scramble‐like, and the parasitised hosts were less susceptible to competition than were their healthy counterparts.3. For both the healthy and the parasitised hosts, the number of larvae surviving to adulthood gave a good fit to both the generalised Beverton and Holt and generalised Ricker models, but the values of all the parameters differed between the two treatments.4. Parasitoid size, egg load, and adult survival time decreased significantly with the initial host number.5. Previous theoretical work suggests that both lower susceptibility to competition by parasitised hosts and scramble competition contribute to the dynamical instability of host–parasitoid systems. Changes registered in life‐history traits may also affect host–parasitoid dynamics. These changes have not yet been incorporated into host–parasitoid models.
Increases in egg production in multiply mated female bushcrickets Leptophyes punctatissima are not due to substances in the nuptial gift
Authors: Vahed Karim 
Published: March 2003

Abstract. 1. A positive effect of the degree of polyandry on egg production is widespread in insects, particularly in species in which the male provides a nuptial gift.2. This study aimed to determine whether or not this effect is due to females using nutrients from the nuptial gift (spermatophore and spermatophylax) to manufacture more eggs in the bushcricket Leptophyes punctatissima.3. Females were permitted either a single or a double mating (with two different males) and, in both mating categories, were either prevented from consuming any part of the spermatophore or were permitted to consume the entire spermatophore.4. Doubly mated females were found to lay over twice as many eggs over a 4‐week period compared with singly mated females. This difference did not appear to be caused by the consumption of extra nuptial gift material: mating was found to have a significant positive effect on the number of eggs laid, while nuptial gift feeding had no effect.
Glutathione homeostasis is disturbed in CD4‐positive lymphocytes of HIV‐seropositive individuals
Authors: Van Der Ven  , Blom  , Peters  , Jacobs  , Verver  , Koopmans  , Demacker  , Van Der Meer  
Published: March 2003

BackgroundNumerous in vitro tests have suggested that a disturbed cellular glutathione homeostasis plays an important role in the pathogenesis of human immunodeficiency virus (HIV) infection.MethodsUsing validated high‐performance liquid chromatography (HPLC) methods, glutathione concentrations were determined in plasma and in cytosol of CD4+ lymphocytes and CD14+ cells of HIV‐seropositive individuals and healthy control subjects. We measured concentrations of total glutathione, which is the sum of reduced (GSH) and oxidised (GSSG) glutathione and mixed disulphides of which there are two fractions: soluble mixed disulphides (GSSR) and protein bound glutathione (ProSSG). Also, non‐protein‐bound glutathione was measured, which is the sum of GSH, GSSG and GSSR. Thirty‐five healthy control subjects and 35 HIV‐infected individuals participated in the study.ResultsWe found that in CD4+ lymphocytes from HIV‐seropositive individuals, total glutathione levels were significantly higher than in healthy control subjects, whereas the fraction of non‐protein‐bound glutathione was not different. This can only be explained by an increase in the protein‐bound fraction of glutathione indicating the presence of oxidative stress in CD4+ lymphocytes of HIV‐seropositive individuals. Glutathione measurements of cytosol of CD14+ cells and plasma were, however, not compatible with significant increased oxidation. Glutathione precursors (cysteine, cysteinylglycine, glutamylcysteine and homocysteine) and products of lipid peroxidation (thiobarbituric acid‐reactive substances) were also measured in plasma and did not differ between healthy control subjects and HIV‐seropositive individuals.ConclusionWe conclude that the glutathione homeostasis is disturbed in CD4+ lymphocytes of HIV‐seropositive individuals. The glutathione redox dysbalance in CD4+ lymphocytes could be important in the pathogenesis of HIV infection and have implications for therapy.
Monitoring of extracellular matrix metabolism and cross‐linking in tissue, serum and urine of patients with chromoblastomycosis, a chronic skin fibrosis
Authors: Ricard‐Blum  , Hartmann  , Esterre  
Published: March 2003

BackgroundChromoblastomycosis is a fungal disease leading to a granulomatous reaction associated with dermal fibrosis.MethodsIn an attempt to elucidate the mechanisms leading to improvement in the cutaneous lesions after treatment with terbinafine, a new antifungal drug, we analysed collagen content and cross‐linking before and at the end of the treatment. The turnover of extracellular matrix was monitored for 1 year by following up serum and urinary metabolites.ResultsThe serum levels of type III collagen and its N‐terminal propeptide were correlated with the lesion size (P < 0.035) after 4 and 12 months of treatment respectively. After 4 months of treatment, urinary pyridinoline was higher (P = 0.04) in patients whose lesion size was reduced by more than 50% and serum hyaluronan was lower in patients who had lesions active for less than 5 years (P < 0.05). The treatment increased pyridinoline and pentosidine cross‐links in the lesions but significantly reduced the collagen content (P = 0.05).ConclusionThis is the first demonstration that, in addition to its fungicidal activity, terbinafine acts in vivo as an antifibrotic drug.
Carotid intima–media thickness and plaque in patients with familial hypercholesterolaemia mutations and control subjects
Authors: Tonstad  , Joakimsen  , Stensland‐Bugge  , Ose  , Bønaa  , Leren  
Published: March 2003

BackgroundIn individuals with familial hypercholesterolaemia (FH), ultrasonographic measurement of carotid intima–media thickness (IMT) and plaque may provide a non‐invasive assessment of cardiovascular risk.MethodsWe examined carotid artery IMT and its determinants in 79 non‐smoking, normotensive, treated men and women with FH aged 26–46 years, and in 79 non‐smoking, normotensive sex‐, age‐ and body mass index‐matched control subjects. FH was verified by molecular genetic analyses. The underlying mutation in the low‐destiny lipoprotein receptor gene included a splice‐site mutation, mutations predicted or shown to lead to class 2B mutations or other mutations that probably represent class I mutations (null alleles).ResultsThe carotid bifurcation and common carotid artery IMT was increased in men with FH compared with control subjects (0.81  ±  0.15 mm vs. 0.74  ±  0.19 mm and 0.61  ±  0.13 mm vs. 0.55  ±  0.14 mm respectively; P  <  0.05). The carotid bifurcation IMT was increased in women with FH compared with control subjects (0.74  ±  0.17 vs. 0.66  ±  0.15; P = 0.005). More subjects with FH had carotid plaque (54% vs. 14%; P  =  0.0001). In multivariate analysis, male gender, level of low‐density lipoprotein‐cholesterol, cholesterol–years score and xanthoma were associated with IMT and plaque in subjects with FH. FH subjects with class 2B mutations had lower cholesterol levels than subjects with mutations belonging to the other classes. They also had a tendency towards a decreased common carotid artery IMT.ConclusionThese findings confirm the importance of gender, xanthoma and lifetime cholesterol levels in relation to carotid atherosclerosis in FH. Whether the type of mutation causing FH modulates carotid artery IMT and plaque requires further study.
Moderate red wine consumption in healthy volunteers reduced plasma clearance of apolipoprotein AII
Authors: Gottrand  , Beghin  , Duhal  , Lacroix  , Bonte  , Fruchart  , Luc  
Published: March 2003

BackgroundThe mechanisms of the positive relationship between alcohol intake and plasma concentration of high‐density lipoprotein (HDL) are still unclear. The present study shows the metabolism modifications of apolipoprotein (apo) AI and apoAII in normolipidaemic healthy volunteers after a period of moderate red wine consumption.DesignFive non‐smoking male subjects were studied at the end of two consecutive 4‐week periods, one without alcohol and the other with an intake of 50 g per day of alcohol, in random order. The metabolic parameters of apoAI and apoAII in HDL were determined after endogenous labelling using amino acid labelled with stable isotope. Cholesterol, triacylglycerols, HDL‐cholesterol, apoAI, apoAII, LpAI, LpAI:AII were determined in plasma at the end of the two study periods.ResultsCholesterol and triacylglycerols did not vary significantly during the two periods, whereas HDL‐cholesterol increased from 43.8 to 50.0 mg dL−1 (P < 0.05). ApoAI and apoAII increased significantly (20% and 60% respectively) after the diet was supplemented with alcohol. LpAI:AII increased from 73.8 to 101.6 mg dL−1 (+32%) (P < 0.05), whereas alcohol had no effect on the concentration of LpAI. The alcohol treatment did not significantly alter the metabolism of apoAI. Conversely, the fractional catabolic rate of apoAII decreased significantly by 21% (P < 0.05) with alcohol, whereas the production rate of apoAII tended to increase by 18% (P = 0.08).ConclusionThe decrease in the fractional catabolic rate of apoAII could lead to an accumulation of apoAII‐containing lipoproteins in plasma and account for the dramatic increase in LpAI:AII observed in the plasma of subjects consuming alcohol.