bluuebunny/crossref_metadata_2025 huggingface dataset:
Cellular and cytokine kinetics after epicutaneous allergen challenge (atopy patch testing) with house dust mites in high‐IgE beagles
Authors: Marsella Rosanna , Olivry Thierry , Maeda Sadatoshi
Published: March 2006

The cellular and cytokine dynamics of reactions triggered by atopy patch testing with house dust mites were studied in six high‐IgE beagles. Sites were scored and biopsied at 6, 24, 48, and 96 h, and samples were processed for histopathology, immunohistochemistry, and polymerase chain reaction (PCR).

All dogs developed positive reactions at some point in time. Mean clinical scores were significantly higher than baseline at 24, 48, and 96 h. Clinically, one of six dogs had a positive reaction at 6 h; two of six reacted at 24 and 48 h, and five of six at 96 h.

Histologically, superficial perivascular mononuclear and granulocytic dermatitis developed (5/6) after 6 h, and progressed in severity at 24 h (6/6). Additionally, at 48 h epidermal spongiosis, hyperplasia and pustules developed (5/6), and were marked at 96 h (6/6). At and beyond 6 h, progressive CD1c‐positive epidermal Langerhans cell hyperplasia with cluster formation and dermal dendritic cell infiltration was noted. Cutaneous infiltration of CD3‐positive T lymphocytes with epidermal clusters developed over time.

mRNA expression for the cytokines gamma‐interferon (γ‐IFN), interleukin‐6 (IL‐6), IL‐12p35, IL‐13, IL‐18, and thymus and activation regulated chemokine (TARC) exhibited significant increases during the challenge compared to baseline, but there was no appreciable alteration in expression for tumour necrosis factor‐alpha (TNF‐α), IL‐12p40, IL‐10, regulated on activation normal T‐cell expressed and secreted (RANTES), IL‐5, IL‐2, IL‐4, and IL‐8. No correlation was detected between clinical scores and cytokines. It is concluded that IL‐6 plays a role in early reactions followed by an increase of TARC and IL‐13, while IL‐18 progressively increases in later reactions.
Factor V Leiden and hepatic artery thrombosis after liver transplantation
Authors: Dunn Ty B , Linden Michael A , Vercellotti Gregory M , Gruessner Rainer WG
Published: March 2006

Abstract:  Factor V Leiden (FVL) and other thrombophilias can be acquired during liver transplantation and can have a significant impact on clinical outcomes as well as cost. Standard practice does not include screening deceased donors for heritable thrombophilias, even if they have a personal history of thrombosis. Here we report a case of hepatic artery thrombosis in a liver recipient whose native and donor livers were heterozygous for FVL. The patient subsequently underwent a successful retransplant. FVL and its variants are expressed phenotypically as activated protein C (APC) resistance. We believe that testing liver donors (deceased or living) for APC resistance – a surrogate marker for the most common liver‐based thrombophilia – will reduce the incidence of thrombotic events by identifying a need for posttransplant prophylactic anticoagulation in patients at risk. The estimated cost of testing all liver donors in the US for APC resistance is less than the cost of two complications secondary to thrombosis. Testing for APC resistance may further improve outcome and reduce cost after liver transplantation.
Quality of life after organ transplantation in type 1 diabetics with end‐stage renal disease
Authors: Sureshkumar Kalathil K , Patel Bhavesh M , Markatos Angelo , Nghiem Dai D , Marcus Richard J
Published: March 2006

Abstract: Quality of life (QOL) should be an important consideration while choosing therapeutic options for patients with type 1 diabetes mellitus (DM) and end‐stage renal disease (ESRD) including dialysis, cadaver (CKT) or living kidney transplant (LKT) or simultaneous pancreas–kidney (SPK) transplant.

Methods: QOL was assessed in four groups of patients with history of type 1 DM and ESRD: recipients of SPK (n = 43), CKT (n = 43), LKT (n = 11) and wait listed (WL) patients (n = 23). Diabetes Quality of Life (DQOL), Short Form‐36 (SF‐36) and Quality of Well‐Being (QWB) questionnaires were utilized. A subset of SPK (n = 19) and CKT (n = 12) recipients underwent longitudinal QOL evaluation.

Results: On DQOL questionnaire, SPK group had better satisfaction subscore compared with CKT (1.8 ± 0.5 vs. 2.2 ± 0.6, p < 0.01) LKT (1.8 ± 0.5 vs. 2.4 ± 0.7, p < 0.05) and WL (1.8 ± 0.5 vs. 2.6 ± 0.6, p < 0.001) groups and better impact subscore compared with CKT (1.7 ± 0.6 vs. 2.1 ± 0.6, p < 0.05) and WL (1.7 ± 0.6 vs. 2.3 ± 0.6, p < 0.01) groups. There were no significant differences on physical/mental composite scores of SF‐36. QWB score was better in SPK group vs. WL group (0.62 ± 0.11 vs. 0.55 ± 0.04, p < 0.05). Longitudinal decline in satisfaction (2.3 ± 0.5 vs. 2.6 ± 0.9, p = 0.058) and impact (2.0 ± 0.5 vs. 2.2 ± 0.5, p = 0.019) subscores of DQOL were noted in CKT group. There were no significant changes in the composite scores of SF‐36 in both groups. QWB scores declined in the CKT group (0.67 ± 0.10 vs. 0.61 ± 0.05, p = 0.01).

Conclusion: QOL was better in type 1 diabetics with ESRD following transplantation when compared with remaining on WL. SPK transplantation had significant positive effect on diabetes‐related QOL which was sustained longitudinally but it was difficult to show an overall improvement in general QOL.
Flowering induced by 5‐azacytidine, a DNA demethylating reagent in a short‐day plant, Perilla frutescens var. crispa
Authors: Kondo Hiroshi , Ozaki Hiroko , Itoh Kimiko , Kato Akira , Takeno Kiyotoshi
Published: March 2006

Treatment with 5‐azacytidine, a DNA demethylating reagent, induced flowering in Perilla frutescens (L.) Britton var. crispa (Thunb. ex Murray) Decne. ex L. H. Bailey, an absolute short‐day plant under long days. The 5‐azacytidine treatment induced slight suppression of vegetative growth but had no obvious effect on any other phenotypes. The Southern hybridization analysis of the genomic DNA isolated from the leaves of 5‐azacytidine‐treated plants and digested with restriction enzyme, methylation‐insensitive Msp I or methylation‐sensitive Hpa II with P. frutescens 25S‐18S rDNA intergenic spacer probe indicated that the 5‐azacytidine treatment caused demethylation of the genomic DNA. The 5‐azacytidine‐induced flowering was delayed as compared with the short day‐induced flowering. Flowers were formed even at the lower nodes which had not been directly treated with 5‐azacytidine. The results suggest that DNA demethylation induced flowering by inducing the production of a transmissible flowering stimulus in P. frutescens.
Protein expression during seed development in Araucaria angustifolia: transient accumulation of class IV chitinases and arabinogalactan proteins
Authors: Dos Santos André Luis Wendt , Wiethölter Nicola , El Gueddari Nour Eddine , Moerschbacher Bruno Maria
Published: March 2006

Protein accumulation and patterns during embryogenesis in the recalcitrant seeds of the gymnosperm species Araucaria angustifolia (Bert.) O. Kuntze were studied. Soluble seed proteins, chitinases, and arabinogalactan proteins (AGPs) were analyzed by means of 2‐D gel electrophoresis, mass spectrometry, isoelectric focusing, Western blot, precipitation and staining with β‐glucosyl Yariv reagent (β‐Glc)3Y, and gas liquid chromatography. Despite the recalcitrant nature of the seeds, the electrophoretic patterns of A. angustifolia seed proteins showed similarities with orthodox seed types. Proteins showing chitinolytic activity were observed in all seed stages analyzed, but the expression of class IV chitinases was restricted to late stages of seed development. AGPs were prominent during stages of seed development characterized by intensive cell division and differentiation, and their decrease during seed maturation might be related to cell wall modifications during the deposition of storage compounds. Gas liquid chromatographic analyzes of AGPs did not show quantitative changes in their carbohydrate moieties during seed development. A low molecular weight protein specifically expressed in mature seeds was precipitated using (β‐Glc)3Y. Amino acid sequences obtained from MS/MS analysis revealed peptides rich in valine and acidic amino acids, but devoid in amino acids normally found in AGPs polypeptides, suggesting that these peptides are not related to classical or non‐classical AGPs. Possible implications of chitinases and AGPs during seed development in A. angustifolia are discussed.
Evidence for a robust sex‐specific trade‐off between cold resistance and starvation resistance in Drosophila melanogaster
Authors: HOFFMANN A. A. , HALLAS R. , ANDERSON A. R. , TELONIS‐SCOTT M.
Published: March 2006

In insects changes in lipid metabolism may underlie a trade‐off between cold resistance and starvation resistance. To test this we examined correlated responses in independent sets of Drosophila melanogaster lines selected for increased cold resistance and increased starvation resistance. The starvation lines showed correlated patterns found in other D. melanogaster populations selected for this trait, including higher lipid levels and increased resistance to desiccation, although the selected lines did not show a longer development time as found in some other studies. Consistent with the trade‐off hypothesis, selected lines with increased starvation resistance showed decreased resistance to a cold stress as measured by mortality, whereas selected lines with increased cold resistance showed a decrease in starvation resistance. To counter the possibility of inadvertent selection accounting for these patterns, selected and control lines from both selection regimes were crossed to form mass bred populations, which were left for four generations prior to establishing isofemale lines. By scoring starvation and cold resistance in these lines derived from both sets of selection regimes, we confirmed the negative association between resistance to these stresses in females but not in males. Potential implications of this trade‐off for surviving cold conditions when food resources are limiting are discussed.
Proximate causes of adaptive growth rates: growth efficiency variation among latitudinal populations of Rana temporaria
Authors: LINDGREN B. , LAURILA A.
Published: March 2006

In ectothermic organisms, declining season length and lower temperature towards higher latitudes often select for latitudinal variation in growth and development. However, the energetic mechanisms underlying this adaptive variation are largely unknown. We investigated growth, food intake and growth efficiency of Rana temporaria tadpoles from eight populations along a 1500 km latitudinal gradient across Sweden. To gain an insight into the mechanisms of adaptation at organ level, we also examined variation in tadpole gut length. The tadpoles were raised at two temperatures (16 and 20 °C) in a laboratory common garden experiment. We found increased growth rate towards higher latitudes, regardless of temperature treatment. This increase in growth was not because of a higher food intake rate, but populations from higher latitudes had higher growth efficiency, i.e. they were more efficient at converting ingested food into body mass. Low temperature reduced growth efficiency most strongly in southern populations. Relative gut length increased with latitude, and tadpoles at low temperature tended to have longer guts. However, variation in gut length was not the sole adaptive explanation for increased growth efficiency as latitude and body length still explained significant amounts of variation in growth efficiency. Hence, additional energetic adaptations are probably involved in growth efficiency variation along the latitudinal gradient.
Altitudinal variation for stress resistance traits and thermal adaptation in adult Drosophila buzzatii from the New World
Authors: SØRENSEN J. G. , NORRY F. M. , SCANNAPIECO A. C. , LOESCHCKE V.
Published: March 2006

Multiple stress resistance traits were investigated in the cactophilic fly Drosophila buzzatii. Adults from seven populations derived from North‐Western Argentina were compared with respect to traits relevant for thermal stress resistance and for resistance to other forms of environmental stress. The populations were collected along an altitudinal gradient spanning more than 2000 m in height, showing large climatic differences. The results suggest that knock‐down resistance to heat stress, desiccation resistance and Hsp70 expression at a relatively severe stressful temperature best reflect thermal adaptation in this species. Furthermore, cold resistance seemed to be of less importance than heat resistance, at least for the adult life stage, in these populations. Clinal variation in thermal resistance traits over short geographical distances suggests relatively strong adaptive differentiation of the populations. This study provides the first evidence for altitudinal differentiation in stress‐related traits, and suggests that Hsp70 expression level can be related to altitudinal clines of heat‐stress resistance.
ADH enzyme activity and Adh gene expression in Drosophila melanogaster lines differentially selected for increased alcohol tolerance
Authors: MALHERBE Y. , KAMPING A. , VAN DELDEN W. , VAN DE ZANDE L.
Published: March 2006

In Drosophila melanogaster, alcohol dehydrogenase (ADH) activity is essential for ethanol tolerance, but its role may not be restricted to alcohol metabolism alone. Here we describe ADH activity and Adh expression level upon selection for increased alcohol tolerance in different life‐stages of D. melanogaster lines with two distinct Adh genotypes: AdhFF and AdhSS. We demonstrate a positive within genotype response for increased alcohol tolerance. Life‐stage dependent selection was observed in larvae only. A slight constitutive increase in adult ADH activity for all selection regimes and genotypes was observed, that was not paralleled by Adh expression. Larval Adh expression showed a constitutive increase, that was not reflected in ADH activity. Upon exposure to environmental ethanol, sex, selection regime life stage and genotype appear to have differential effects. Increased ADH activity accompanies increased ethanol tolerance in D. melanogaster but this increase is not paralleled by expression of the Adh gene.
The heritability of inducible defenses in tadpoles
Authors: RELYEA R. A.
Published: March 2006

The evolution of plastic traits requires phenotypic trade‐offs and heritable traits, yet the latter requirement has received little attention, especially for predator‐induced traits. Using a half‐sib design, I examined the narrow‐sense heritability of predator‐induced behaviour, morphology, and life history in larval wood frogs (Rana sylvatica). Many of the traits had significant additive genetic variation in predator (caged Anax longipes) and no‐predator environments. Whereas most traits had moderate to high heritability across environments, tail depth exhibited high heritability with predators but low heritability without predators. In addition, several traits had significant heritability for plasticity, suggesting a potential for selection to act on plasticity per se. Genetic correlations confirmed known phenotypic relationships across environments and identified novel relationships within each environment. This appears to be the first investigation of narrow‐sense heritabilities for predator‐induced traits and confirms that inducible traits previously shown to be under selection also have a genetic basis and should be capable of exhibiting evolutionary responses.
A test of quantitative genetic theory using Drosophila– effects of inbreeding and rate of inbreeding on heritabilities and variance components
Authors: KRISTENSEN T. N. , SØRENSEN A. C. , SORENSEN D. , PEDERSEN K. S. , SØRENSEN J. G. , LOESCHCKE V.
Published: March 2006

Inbreeding is expected to decrease the heritability within populations. However, results from empirical studies are inconclusive. In this study, we investigated the effects of three breeding treatments (fast and slow rate of inbreeding – inbred to the same absolute level – and a control) on heritability, phenotypic, genetic and environmental variances of sternopleural bristle number in Drosophila melanogaster. Heritability, and phenotypic, genetic and environmental variances were estimated in 10 replicate lines within each of the three treatments. Standard least squares regression models and Bayesian methods were used to analyse the data. Heritability and additive genetic variance within lines were higher in the control compared with both inbreeding treatments. Heritabilities and additive genetic variances within lines were higher in slow compared with fast inbred lines, indicating that slow inbred lines retain more evolutionary potential despite the same expected absolute level of inbreeding. The between line variance was larger with inbreeding and more than twice as large in the fast than in the slow inbred lines. The different pattern of redistribution of genetic variance within and between lines in the two inbred treatments cannot be explained invoking the standard model based on selective neutrality and additive gene action. Environmental variances were higher with inbreeding, and more so with fast inbreeding, indicating that inbreeding and the rate of inbreeding affect environmental sensitivity. The phenotypic variance decreased with inbreeding, but was not affected by the rate of inbreeding. No inbreeding depression for mean sternopleural bristle number was observed in this study. Considerable variance between lines in additive genetic variance within lines was observed, illustrating between line variation in evolutionary potential.
Stress and adaptation in conservation genetics
Authors: FRANKHAM R.
Published: March 2006

Stress, adaptation and evolution are major concerns in conservation biology. Stresses from pollution, climatic changes, disease etc. may affect population persistence. Further, stress typically occurs when species are placed in captivity. Threatened species are usually managed to conserve their ability to adapt to environmental changes, whilst species in captivity undergo adaptations that are deleterious upon reintroduction into the wild. In model studies usingDrosophila melanogaster, we have found that; (a) inbreeding and loss of genetic variation reduced resistance to the stress of disease, (b) extinction rates under inbreeding are elevated by stress, (c) adaptive evolutionary potential in an increasingly stressful environment is reduced in small population, (d) rates of inbreeding are elevated under stressful conditions, (e) genetic adaptation to captivity reduces fitness when populations are reintroduced into the ‘wild’, and (f) the deleterious effects of adaptation on reintroduction success can be reduced by population fragmentation.
The evolution of polyandry: intrinsic sire effects contribute to embryo viability
Authors: GARCÍA‐GONZÁLEZ F. , SIMMONS L. W.
Published: March 2006

Females typically mate with more than one male despite the costs incurred, thus questioning Bateman's principle. A series of genetic benefits have been proposed to account for the evolution of polyandry, including the acquisition of viability genes for offspring. The ‘intrinsic male quality’ hypothesis suggests that polyandry increases the probability that females produce offspring sired by males that bestow high viability on their offspring. Heritable variation in viability is the basic requirement for the occurrence of this genetic benefit. By using a half‐sib breeding design with a species of cricket in which polyandry is known to increase hatching success, we present clear experimental evidence that intrinsic male quality contributes to embryo viability. Despite recent support for the evolution of polyandry based on compatibility of genotypes between males and females, we show that hatching success is not determined by an interaction between paternal and maternal genotypes but rather that sons inherit paternal genes that influence the viability of eggs laid by their mates. Moreover, our data implicate a potential role for indirect genetic effects of male accessory gland products on embryo viability. Additive genetic contributions to embryo viability may be an important factor underlying the frequently observed benefits of polyandrous behaviour.
Coping with predator stress: interclonal differences in induction of heat‐shock proteins in the water flea Daphnia magna
Authors: PAUWELS K. , STOKS R. , DE MEESTER L.
Published: March 2006

Although predation is a strong selection pressure, little is known about the molecular mechanisms to cope with predator stress. This is crucial to understanding of the mechanisms and constraints involved in the evolution of antipredator traits. We quantified the expression of heat‐shock protein 60 (Hsp60), a potential marker for predator stress, in four clones of the water flea Daphnia magna, when exposed to fish kairomones. Expression of Hsp60 induction increased after 6 h and returned to base levels after 24 h of predator stress. This suggests that it is a costly transient mechanism to temporarily cope with novel predator stress, before other defences are induced. We found genetic variation in the fixed levels and in the fish‐induced levels of Hsp60, which seemed to be linked to each clone's history of fish predation. Our data suggest that Hsp60 can be considered part of a multiple‐trait antipredator defence strategy of Daphnia clones to cope with predator stress.
Altitudinal variation in behavioural thermoregulation: local adaptation vs. plasticity in California grasshoppers
Authors: SAMIETZ J. , SALSER M. A. , DINGLE H.
Published: March 2006

We investigated the adaptive significance of behavioural thermoregulation in univoltine populations of the grasshopper Melanoplus sanguinipes along an altitudinal gradient in California using laboratory tests of animals raised under different temperatures. Trials consisted of continuous body temperature measurements with semi‐implanted microprobes in a test arena, and observation and simultaneous recording of behavioural responses. These responses included mobility, basking and orientation of the body axes (aspect angle) towards a radiation source. Mobility and basking are determined by the altitudinal origin of the parental generation and not by the temperature treatments. With increasing altitude, individuals tend increasingly to raise body temperatures via mobility and increased basking. In contrast, body orientation towards the radiation source is influenced by the temperature treatments but not by the altitude of origin. Individuals experiencing higher temperatures during rearing show a lower tendency to lateral flanking. We conclude that body orientation responses are not adapted locally. In contrast other components of the behavioural syndrome that increase body temperature, such as mobility and basking, are adaptive in response to local selection pressure. The thermoregulatory syndrome of these grasshoppers is an important contribution to life‐history adaptations that appropriately match season lengths.
How a complex life cycle can improve a parasite's sex life
Authors: RAUCH G. , KALBE M. , REUSCH T. B. H.
Published: March 2006

How complex life cycles of parasites are maintained is still a fascinating and unresolved topic. Complex life cycles using three host species, free‐living stages, asexual and sexual reproduction are widespread in parasitic helminths. For such life cycles, we propose here that maintaining a second intermediate host in the life cycle can be advantageous for the individual parasite to increase the intermixture of different clones and therefore decrease the risk of matings between genetically identical individuals in the definitive host. Using microsatellite markers, we show that clone mixing occurs from the first to the second intermediate host in natural populations of the eye‐flukeDiplostomum pseudospathaceum. Most individuals released by the first intermediate host belonged to one clone. In contrast, the second intermediate host was infected with a diverse array of mostly unique parasite genotypes. The proposed advantage of increased parasite clone intermixture may be a novel selection pressure favouring the maintenance of complex life cycles.
Juvenile immune status affects the expression of a sexually selected trait in field crickets
Authors: JACOT A. , SCHEUBER H. , KURTZ J. , BRINKHOF M. W. G.
Published: March 2006

Parasite‐mediated sexual selection theory presumes that variation in sexual traits reliably reflects variation in parasite resistance among available mates. One mechanism that may warrant signal honesty involves costs of immune system activation in the case of a parasitic infection. We investigated this hypothesis in male field cricketsGryllus campestris, whose attractiveness to females depends on characteristics of the sound‐producing harp that are essentially fixed following adult eclosion. During the nymphal stage, males subjected to one of two feeding regimes were challenged with bacterial lipopolysaccharides (LPS) to investigate condition‐dependent effects on harp development as compared to other adult traits. Nymphal nutritional status positively affected adult body size, condition, and harp size. However, nymphal immune status affected harp size only, with LPS‐males having smaller harps than control‐injected males. In addition, the harps of LPS‐males showed a lesser degree of melanization, indicating an enhanced substrate use by the melanin‐producing enzyme cascade of the immune system. Thus, past immune status is specifically mirrored in sexual traits, suggesting a key role for deployment costs of immunity in parasite‐mediated sexual selection.
The evolution of host use and unusual reproductive strategies inAchrysocharoidesparasitoid wasps
Authors: LOPEZ‐VAAMONDE C. , GODFRAY H. C. J. , WEST S. A. , HANSSON C. , COOK J. M.
Published: March 2006

We studied host selection and exploitation, two crucial aspects of parasite ecology, inAchrysocharoidesparasitoid wasps, which show remarkable host specificity and unusual offspring sex allocation. We estimated a molecular phylogeny of 15Achrysocharoidesspecies and compared this with host (plant and insect) phylogenies. This tri‐trophic phylogenetic comparison provides no evidence for cospeciation, but parasitoids do show phylogenetic conservation of the use of plant genera. Patterns of sequence divergence also suggest that the parasitoids radiated more recently (or evolved much faster) than their insect hosts. Three main categories of brood production occur in parasitoids: (1) solitary offspring, (2) mixed sex broods and (3) separate (split) sex broods. Split sex broods are very rare and virtually restricted toAchrysocharoides, while the other types occur very widely. Our phylogeny suggests that split sex broods have evolved twice and provides evidence for a transition from solitary to mixed sex broods, via split sex broods, as predicted by theory.
A role for habitat area in the geographic mosaic of coevolution between red crossbills and lodgepole pine
Authors: SIEPIELSKI A. M. , BENKMAN C. W.
Published: March 2006

Understanding how resource abundance limits adaptive evolution and influences species interactions is an important step towards developing insight into the role of microevolutionary processes in establishing macroevolutionary patterns. We examined how variation in resource abundance (forest area of lodgepole pinePinus contortassp.latifolia) influenced patterns of co‐adaptation and coevolution between red crossbill (Loxia curvirostracomplex) and lodgepole pine populations. First, we found that crossbill abundance increased logarithmically as forest area increased in mountain ranges lacking a preemptive competitor (pine squirrelsTamiasciurus hudsonicus). Second, seed defences against predation by crossbills increased with increases in crossbill density, suggesting that seed defences have likely evolved in proportion to the intensity of selection that crossbills exert. Third, the average bill size of crossbill populations increased with increasing seed defences, which implies that crossbill offenses increased with increases in seed defences. The large bill size on the largest range is the result of coevolution with lodgepole pine with this crossbill population perhaps speciating. Local adaptation of crossbill populations on smaller ranges, however, is more likely the result of resident crossbills representing a subset of the potential colonists (phenotypic sorting) than of local evolution. In the smallest range, migration and possibly more frequent extinction likely impede local adaptation and may result in maladaptation.
Costly carotenoids: a trade‐off between predation and infection risk?
Authors: VAN DER VEEN I. T.
Published: March 2006

Carotenoid reserves in copepods seem costly in terms of predation risk because they make individuals conspicuous. However, carotenoids also seem to play an important role in immune defence as free radical scavengers. To test whether predation risk influences carotenoid levels and whether changes in carotenoid levels are related to changes in immune defence, I examined individual changes in large carotenoid and other lipid droplets upon exposure to predation risk and subsequent exposure to parasites in the copepod Macrocyclops albidus. Copepods reduced carotenoid reserves upon exposure to predators, through which they potentially avoided the costs of being conspicuous under predation risk. Thus, the size of carotenoid reserves is a plastic trait. Such a decrease in carotenoid reserves may also have a negative impact on the copepods’ immune system as individuals that decreased their reserves suffered higher parasite prevalence upon exposure to the cestode Schistocephalus solidus. These results suggest that carotenoid reserves may be individually optimized to trade‐off each individual's unique costs (predation risk) and benefits (immune defence) of having these reserves.
Growth form evolution and shifting habitat specialization in annual plants
Authors: BONSER S. P. , GEBER M. A.
Published: March 2006

Optimal plant growth form should vary across environments. We examined the potential for mutations causing large changes in growth form to produce new optimal phenotypes across light environments. We predicted that the upright growth form would be favoured in a light limiting environment as leaves were in a position to maximize light interception, while a rosette (leaves in a basal position) growth form would be favoured in a high light environment. Growth form genotypes ofBrassica rapa(upright wild‐type and rosette mutants) andArabidopsis thaliana(large rosette wild‐type and increasingly upright growth form mutants) were grown in a greenhouse in control (ambient) and filtered (low) light treatments. Compared to upright genotypes, rosette genotypes had relatively high fitness in control light but had a relatively large fitness reduction in filtered light. Our results demonstrate the potential importance of rapid growth form evolution in plant adaptation to new or changing environments.
The Isthmus of Panama: a major physical barrier to gene flow in a highly mobile pantropical seabird
Authors: STEEVES T. E. , ANDERSON D. J. , FRIESEN V. L.
Published: March 2006

To further test the hypothesis that the Isthmus of Panama is a major barrier to gene flow in pantropical seabirds, we applied phylogeographic methods to mitochondrial control sequence variation in masked booby (Sula dactylatra) populations on either side of the Isthmus of Panama and the southern tip of Africa. In accord with Steeves et al. (2003), we found that all Caribbean masked boobies with the ‘secondary contact’ cytochrome b haplotype (m‐B) shared a control region haplotype (Sd_100), which grouped with Indian–Pacific haplotypes and not Caribbean–Atlantic haplotypes. In addition, Sd_100 was more closely related to control region haplotypes in the Indian Ocean than in the Pacific. We also found that the ‘secondary contact’ birds diverged more recently from extant populations in the Indian Ocean than in the Pacific. Thus, it appears that these masked boobies did not breach the Isthmus of Panama. Rather, birds likely dispersed around the southern tip of Africa during favourable oceanographic conditions in the Pleistocene.
Variable assortative mating in replicate mating trials usingDrosophila melanogasterpopulations derived from contrasting opposing slopes of ‘Evolution Canyon’, Israel
Authors: DRAKE A. , RASHKOVETSKY E. , D. WONG  , RUNDLE H. D. , MOOERS A. Ø.
Published: March 2006

Significant assortative mating in laboratory studies has been previously shown between two populations ofDrosophila melanogastercollected from micro‐climactically contrasting and opposing slopes of ‘Evolution Canyon’ (Lower Nahal Oren, Israel;Korolet al., 2000). Coupled with evidence that the two populations are adapted to their respective environments, this has been suggested as a rare example of ongoing behaviourally mediated speciation occurring in the face of gene flow. Reproductive isolation between these populations, however, has never been confirmed by replicate experiments in an independent laboratory. For this reason, we tested recent collections of these populations for premating isolation in both the original (Haifa) and a new (Burnaby) laboratory under a variety of experimental protocols. Although non‐random mating was found in the majority of trials conducted in Haifa, we were unable to replicate these strong results in Burnaby. Most notably, we failed to detect assortative mating in four separate double choice experiments. Significant non‐random mating was detected, however, in three of six single choice experiments in Burnaby, suggesting that the populations are behaviourally differentiated in some manner. Why nonrandom mating was weaker in Burnaby than Haifa is not understood, but suggests that assortative mating may be sensitive to unknown environmental factors.
Patterns of speciation in endemic Mexican Goodeid fish: sexual conflict or early radiation?
Authors: RITCHIE M. G. , WEBB S. A. , GRAVES J. A. , MAGURRAN A. E. , MACIAS GARCIA C.
Published: March 2006

Currently there is much interest in the potential for sexual selection or conflict to drive speciation. Theory proposes that speciation will be accelerated where sexual conflict is strong, particularly if females are ahead because mate choice will accentuate divergence by limiting gene flow. The Goodeinae are a monophyletic group of endemic Mexican fishes with an origin at least as old as the Miocene. Sexual selection is important in the Goodeinae and there is substantial interspecific variability in body morphology, which influences mate choice, allowing inference of the importance of female mate choice. We therefore used this group to test the relationship between sexual dimorphism and speciation rate. We quantified interspecific variation in sexual dimorphism amongst 25 species using a multivariate measure of total morphological differentiation between the sexes that accurately reflects sexual dimorphism driven by female mate choice and also used a mtDNA‐based phylogeny to examine speciation rates. Comparative analyses failed to support a significant association between sexual dimorphism and speciation rate. In addition, variation in the time course of speciation throughout the whole clade was also examined using a similar tree containing 34 extant species. A constant rates model for the growth of this clade was rejected, but analyses instead indicated a decline in the rate of speciation over time. These results support the hypothesis of an early expansion of the group, perhaps due to an early radiation influenced by the key innovation of live bearing, or the prevalence of Miocene volcanism. In general, support for the role of sexual selection in generating patterns of speciation is proving equivocal and we argue that vicariance biogeography and adaptive radiations remain the most likely determinants of major patterns of diversification of continental organisms.
Comparing artificial and natural selection in rate of adaptation to genetic stress in Aspergillus nidulans
Authors: SCHOUSTRA S. E. , SLAKHORST M. , DEBETS A. J. M. , HOEKSTRA R. F.
Published: March 2006

In an experimental study of adaptation to negative pleiotropic effects of a major fungicide resistance mutation in the filamentous fungus Aspergillus nidulans we have investigated the relative effectiveness of artificial selection vs. natural selection on the rate of compensatory evolution. Using mycelial growth rate as a fitness measure, artificial selection involved the weekly transfer of the fastest growing sector onto a fresh plate. Natural selection was approximated by transferring random samples of all the spores produced by the mycelium. Fungicide resistant and fungicide sensitive haploid and diploid strains were used in an evolution experiment over 10 weekly transfers, which is equivalent to 1200 cell cycles. Two different environmental conditions were applied: a constant fungicide‐free environment and a weekly alternation between presence and absence of fungicide. Results show that for all strains and conditions used the transfer of a random sample of all spores leads to more rapid adaptation than the transfer of the visually ‘fittest’ sector. The rates of compensatory evolution in the constant and the alternating environment did not differ. Moreover, haploid strains tend to have a higher rate of adaptation than isogenic diploid strains.
Heat stress and age induced maternal effects on wing size and shape in parthenogenetic Drosophila mercatorum
Authors: ANDERSEN D. H. , PERTOLDI C. , SCALI V. , LOESCHCKE V.
Published: March 2006

Maternal effects on progeny wing size and shape in a homozygous parthenogenetic strain of Drosophila mercatorum were investigated. The impact of external maternal factors (heat stress) and the impact of internal maternal factors (different maternal and grand maternal age) were studied. The offspring developed under identical environmental conditions, and due to lack of genetic variation any phenotypic difference among offspring could be ascribed to maternal effects. Wing size was estimated by centroid size, shape was analysed with the Procrustes geometric morphometric method and variation in landmark displacement was visualized by principal component analysis. Both kinds of maternal effects had a significant impact on progeny wing size and shape. Maternal heat stress led to the same pattern of response in size and shape among the progeny, with increased difference between the control group and progeny from heat stressed flies in both size and shape with increased maternal heat stress temperature. The effects of maternal age, however, led to different responses in size and shape between the different progeny groups. The observed variation in landmark displacements was similar, and in both cases mainly associated with shape differences of the posterior part of the wing. Finally, our results suggest that maternal effect has some evolutionary implications by altering the genetic correlations among traits, which can affect the response to selective pressures.
How stress selects for reversible phenotypic plasticity
Authors: GABRIEL W.
Published: March 2006

Stress occurring in periods shorter than life span strongly selects for reversible phenotypic plasticity, for maximum reliability of stress indicating cues and for minimal response delays. The selective advantage of genotypes that are able to produce adaptive reversible plastic phenotypes is calculated by using the concept of environmental tolerance. Analytic expressions are given for optimal values of mode and breadth of tolerance functions for stress induced and non‐induced phenotypes depending on (1) length of stress periods, (2) response delay for switching into the induced phenotype, (3) response delay for rebuilding the non‐induced phenotype, (4) intensity of stress, i.e. mean value of the stress inducing environment, (5) coefficient of variation of the stress environment and (6) completeness of information available to the stressed organism. Adaptively reversible phenotypic plastic traits will most probably affect fitness in a way that can be described by simultaneous reversible plasticity in mode and breadth of tolerance functions.
Nitrogen availability and weed invasion in a remnant native woodland in urban Melbourne
Authors: BIDWELL S. , ATTIWILL P. M. , ADAMS M. A.
Published: March 2006

Abstract  The woodlands of Studley Park, and the greater Yarra Bend Park, are within 4 km of the centre of the city of Melbourne and total more than 200 ha. Weeds are major contributors to the loss of diversity of native species. We examined the hypothesis that an increase in the availability of nitrogen (N) may be responsible for the increase in weed abundance. In a small field trial, nitrogen availability was greater in areas invaded by weeds and weeds had greater nitrate reductase activity than native species. Both invaded and uninvaded areas were well‐supplied with weed seed, although the composition of the seed bank varied greatly between sites. Diaspores of the weed Romulea rosea were abundant in uninvaded sites while those of Ehrharta erecta and Ehrharta longiflora were abundant in invaded sites. The abundance of weed diaspores suggested that increased N availability may be a precondition for invasion. Formation of a dense litter layer by senescent weeds is likely to promote the capture and retention of N added from anthropogenic sources including air pollution and overland flow from nearby roads and drainage channels.
Rapid genetic delineation of local provenance seed‐collection zones for effective rehabilitation of an urban bushland remnant
Authors: BUSSELL JOHN D. , HOOD PETER , ALACS ERIKA A. , DIXON KINGSLEY W. , HOBBS RICHARD J. , KRAUSS SIEGFRIED L.
Published: March 2006

Abstract  The rehabilitation of native plant communities in urban bushland remnants is an increasingly important activity requiring the collection of large amounts of seed. Best practice generally identifies that local seed are best, but how far does the local provenance extend? Using the DNA fingerprinting technique amplified fragment length polymorphism, we assessed genetic differentiation between potential seed source populations and the target population, Bold Park, a large and significant bushland remnant in Perth, Western Australia. For each of 15 species, analysis of molecular variance was used to partition genetic variation within and among populations. Genetic differentiation between Bold Park and potential seed source populations was assessed by non‐metric multidimensional scaling ordination, and statistically by Fisher’s exact tests. The partitioning of variation among populations (ΦST) varied from 0.66 for Santalum acuminatum to 0.04 for Mesomelaena pseudostygia. For eight of 15 species, Bold Park plants were completely or largely non‐overlapping with other populations in ordinations, suggesting genetic differentiation and a narrow provenance. Five species showed overlap between Bold Park and some other, but not all, populations sampled, with geographically closest populations generally undifferentiated. Only two species, Acanthocarpus preissii and Mesomeleana pseudostygia, showed little genetic differentiation between Bold Park and all other populations, suggesting a regional genetic provenance. These species can be classified into three broad provenance classes – narrow, local and regional – to help guide decisions about appropriate seed‐collection zones for the rehabilitation of urban bushland remnants.
Butterfly communities in South Australian urban reserves: Estimating abundance and diversity using the Pollard walk
Authors: COLLIER N. , MACKAY D. A. , BENKENDORFF K. , AUSTIN A. D. , CARTHEW S. M.
Published: March 2006

Abstract  Remnant habitats within and surrounding urbanized areas are becoming increasingly important for maintaining butterfly diversity. The ‘Pollard walk’ protocol has been used widely overseas to estimate and monitor species diversity and abundance of butterflies. However, there has been limited use of this technique in Australia. Here, we used the Pollard walk method to estimate the diversity of butterflies at three urban sites around Adelaide, South Australia: Belair National Park (BNP), Shepherds Hill Recreation Park (SHRP) and Brownhill Creek Recreation Park (BCRP). In total, 21 species of butterfly were detected across the three sites. Pollard walks detected butterfly species from five families, including rare and highly localized lycaenid and hesperiid species. The highest diversity of species was found at BCRP (16) followed by BNP (14) and SHRP (14). Multivariate analysis on the data revealed a distinct and temporally variable butterfly community at BNP when compared with the SHRP and BCRP. The results of this study show that the Pollard walk can be effectively used to distinguish communities and detect a wide variety of butterflies, including cryptic and rare species, within urban habitats of Adelaide.
Review of the ecology of Australian urban fauna: A focus on spatially explicit processes
Authors: GARDEN JENNI , MCALPINE CLIVE , PETERSON ANN , JONES DARRYL , POSSINGHAM HUGH
Published: March 2006

Abstract  Cities have a major impact on Australian landscapes, especially in coastal regions, to the detriment of native biodiversity. Areas suitable for urban development often coincide with those areas that support high levels of species diversity and endemism. However, there is a paucity of reliable information available to guide urban conservation planning and management, especially regarding the trade‐off between investing in protecting and restoring habitat at the landscape level, and investing in programmes to maintain the condition of remnant vegetation at the local (site) level. We review the literature on Australian urban ecology, focusing on urban terrestrial and aquatic vertebrate and invertebrate fauna. We identify four main factors limiting our knowledge of urban fauna: (i) a lack of studies focusing at multiple ecological levels; (ii) a lack of multispecies studies; (iii) an almost total absence of long‐term (temporal) studies; and (iv) a need for stronger integration of research outcomes into urban conservation planning and management. We present a set of key principles for the development of a spatially explicit, long‐term approach to urban fauna research. This requires an understanding of the importance of local‐level habitat quality and condition relative to the composition, configuration and connectivity of habitats within the larger urban landscape. These principles will ultimately strengthen urban fauna management and conservation planning by enabling us to prioritize and allocate limited financial resources to maximize the conservation return.
Impact of urbanization on coastal wetland structure and function
Authors: LEE S. Y. , DUNN R. J. K. , YOUNG R. A. , CONNOLLY R. M. , DALE P. E. R. , DEHAYR R. , LEMCKERT C. J. , MCKINNON S. , POWELL B. , TEASDALE P. R. , WELSH D. T.
Published: March 2006

Abstract  Urbanization is a major cause of loss of coastal wetlands. Urbanization also exerts significant influences on the structure and function of coastal wetlands, mainly through modifying the hydrological and sedimentation regimes, and the dynamics of nutrients and chemical pollutants. Natural coastal wetlands are characterized by a hydrological regime comprising concentrated flow to estuarine and coastal areas during flood events, and diffused discharge into groundwater and waterways during the non‐flood periods. Urbanization, through increasing the amount of impervious areas in the catchment, results in a replacement of this regime by concentrating rain run‐off. Quality of run‐off is also modified in urban areas, as loadings of sediment, nutrients and pollutants are increased in urban areas. While the effects of such modifications on the biota and the physical environment have been relatively well studied, there is to date little information on their impact at the ecosystem level. Methodological issues, such as a lack of sufficient replication at the whole‐habitat level, the lack of suitable indices of urbanization and tools for assessing hydrological connectivity, have to be overcome to allow the effects of urbanization to be assessed at the ecosystem level. A functional model is presented to demonstrate the impact of urbanization on coastal wetland structure and function.