bluuebunny/crossref_metadata_2025 huggingface dataset:
More than motherhood? A feminist exploration of ‘women's health’ in papers indexed by CINAHL 1993–1995
Authors: Raftos Maree , Mannix Judy , Jackson Debra
Published: December 2004

Holism is claimed to be the signifying feature that sets women's health apart from traditional approaches to health care. As such, articles published in the nursing literature about women's health would, one might expect, reflect the centrality of holism to women's health care nursing. The findings of a study which examined the content and the focus of articles published about women's health in journals indexed by CINAHL in the period 1993–1995 challenge this assumption. It was found that women's health is a taken‐for‐granted notion and is used interchangeably and synonymously to refer to reproductive health, maternal health, neonatal health, family health and (hetero)sexual health. Confounding the view that holism is foundational to a women's health perspective, the papers forming the study's sample largely depict issues to do with women's health from a narrow and stereotypical perspective and with a bio‐medical focus. Women were referred to as fragmented bodies, body parts and diseases, and were depicted as being passive and silent. By contrast, the voice (and the activity) of nurses and nursing's imperative to intervene was clearly discernible.
Fitting species–accumulation functions and assessing regional land use impacts on avian diversity
Authors: Flather Curtis
Published: December 2004

As one samples species from a particular assemblage, the initial rapid rate with which new species are encountered declines with increasing effort. Nine candidate models to characterize species–accumulation functions were compared in a search for a model that consistently fit geographically extensive avian survey data from a wide range of environmental conditions. Landscape‐specific species–accumulation curves generated under a bootstrap resampling plan were best described by a generalized Weibull cumulative distribution function. Traditional species–area models of cumulative species richness as a function of accumulated sample had notable functional bias. The Weibull model fitted species–accumulation data equally well among sixty‐six forested landscapes in the eastern U.S. Landscapes with a greater proportion of agricultural and urban land uses accumulated species more slowly than landscapes which retained a greater proportion of natural habitats (r=−0.64, P<0.001). This finding supports predictions of ecosystem behavior under human land use. There was no evidence that intermediate levels of land use intensity maximized accumulation rates. The approach reviewed in this paper makes no assumptions about the form of the species–abundance distribution or how species are distributed in space, thereby offering some advantages over more conventional diversity indices for characterizing how species assemblages respond to anthropogenic disturbance. Investigation of how species accumulation varies over time in a given geographic area is needed to evaluate fully the potential application of this approach to regional land use planning.
Control of Salmincola californiensis (Copepoda: Lernaeapodidae) in rainbow trout, Oncorhynchus mykiss (Walbaum): a clinical and histopathological study
Authors: Roberts R J , Johnson K A , Casten M T
Published: December 2004

A stock of rainbow trout, Oncorhynchus mykiss, held at an experimental facility, was found to be heavily infested with the lernmaeapodid copepod Salmincola californiensis. The efficacy and effects of treatment were compared with ivermectin or manual removal of parasites as a means of control of S. californiensis. One group of fish was orally intubated with 0.2 mg ivermectin active ingredient kg−1 fish. A second treatment was administered after a further 14 days. In a second group of fish, parasites were manually removed from the gills using forceps. These fish were sampled for up to 21 days post‐first removal of parasites. In the ivermectin‐treated fish adult parasites became inactive and changed colour within 18 h of the initial treatment. Copepods began to disappear by day 3 post‐treatment and by day 31 almost all embedded female parasites had disappeared. Gills were clinically normal apart from cavitation deformity resulting from parasite attachment. Post‐ivermectin treatment, there was an increase in the number of eosinophilic granular cells surrounding the bulla of attached S. californiensis, but from day 31 post‐treatment these were replaced by macrophages and epithelioid cells to form a necrotic focus. In manually picked fish there was extensive haemorrhage in the interlamellar spaces as a result of parasite removal. At sites of parasite removal tissue necrosis was minimal and healing was rapid. At the end of the sampling period the structure of the gill was improved. The use of oral dosage with ivermectin is an effective treatment for S. californiensis and could be particularly beneficial for use with endangered salmon broodstocks infested with the parasite.
Presence of anti‐Neoparamoeba sp. antibodies in Tasmanian cultured Atlantic salmon, Salmo salar L.
Authors: Gross K , Carson J , Nowak B
Published: December 2004

Previous studies have indicated that when Atlantic salmon, Salmo salar L., are exposed to Neoparamoeba sp. the fish produce anti‐Neoparamoeba sp. antibodies. It appears unlikely that these antibodies elicit any specific protection against amoebic gill disease (AGD) as fish with demonstrable activities have been affected by AGD. Experiments were conducted on Atlantic salmon cultured throughout Tasmania to assess the natural production of antibodies towards Neoparamoeba sp. Fish were sampled from areas where AGD was prevalent and from areas where there had been no reported cases. An enzyme‐linked immunosorbent assay (ELISA) was used to measure anti‐Neoparamoeba sp. antibody activities in serum. All fish from sea water had antibody activities greater than the negative control fish, including fish from areas with no reported cases of AGD. Time trial samples indicated that time after transfer to sea water did not appear to be a significant (P > 0.05) factor in antibody activity, however location was (P < 0.05). There was no agreement (corrected κ value, 0.16) between the ELISA result and the isolation of Neoparamoeba sp. from the gills of the same fish. The results suggest that Atlantic salmon in seawater culture in Tasmania produce anti‐Neoparamoeba sp. antibodies regardless of infection history, suggesting the presence of Neoparamoeba sp. in the environment.
Issues for consideration in dihydropteridine reductase (DHPR) deficiency: a variant form of hyperphenylalaninaemia
Authors: Pogson D.
Published: December 2004

An adult male with intellectual disabilities demonstrated deterioration in many skills over a number of years and an increase in his temper outbursts was also reported. At 18 years of age, he had been diagnosed as having dihydropteridine reductase (DHPR) deficiency, but treatment had proved unsuccessful in the short term and was discontinued. Dihydropteridine reductase deficiency Is a recessively inherited disorder of the amino acid metabolism resulting in a deficiency of tetrahydrobiopterin, an essential cofactor for phenylalanine, tyrosine and tryptophan metabolism. This causes a severe deficiency of neurotransmitters in the brain. Following further neurological examinations, treatment for the subject was recommenced at the age of 30 years. Few reports of late‐diagnosis DHPR have been documented. This paper outlines one case report of DHPR, highlighting the importance of diagnosis, medical treatment and nursing care.
Mortality and avoidable death in people with severe self‐injurious behaviour: results of a Dutch study
Authors: Nissen J. M. J. F. , Haveman M. J.
Published: December 2004

Mortality and avoidable death was studied in a cohort of 1168 people with severe self‐injurious behaviour (SIB) in the Netherlands. Fifty‐seven people died over a 5‐year period (1990–1995). The observed mortality in the cohort studied was higher than the expected mortality. The age‐specific mortality was highest in the 30–39‐year‐old age‐group. Diseases of the respiratory system were found to be the most prevalent cause of death, followed by diseases of the nervous system and sensory organs. In six people (12%), the general practitioner and staff member considered SIB to be related to death. The causes of death were thought to be avoidable in two cases. The results are discussed in terms of data collection and avoidability of death.
Paroxetine in depressed adolescents with intellectual disability: an open label study
Authors: Masi G. , Marcheschi M. , Pfanner P.
Published: December 2004

The aim of this study was to evaluate the efficacy and side‐effects of paroxetine treatment in adolescents with mild intellectual disability and major depressive disorder (MDD). Seven adolescents (14.7–18.4 years of age) were treated with paroxetine (dosage 20–40 mg day−1). Clinical changes were assessed at the beginning of the pharmacological treatment and after 9 weeks utilizing the DSM‐IV diagnostic criteria and the Montgomery‐Asberg Depression Rating Scale (MADRS). Four out of the seven subjects did not fulfil the DSM‐IV diagnostic criteria after the 9‐week treatment. The mean decrease in the total score on the MADRS was significant (41%). Some items of the MADRS showed significant improvement: inner tension (66%); lassitude (55%); apparent sadness (53%); inability to feel (44%); and reported sadness (43%). Three subjects showed sedation, two subjects gastrointestinal complaints and one subject insomnia; all these symptoms were transitory and not severe. No behavioural activation was evident. This preliminary, uncontrolled study of a few cases suggests that adolescents with intellectual disability and MDD may respond to paroxetine, and that adverse side‐effects are mild.
Bilateral scrotal extramammary Paget's disease in a Chinese man
Authors: Kageyama Nobuyoshi , Izumi Allan K.
Published: December 2004

A 67‐year‐old Chinese physician was seen for an eruption on his right scrotum, of several months’ duration. He complained of mild intermittent pruritus, but denied pain or other symptoms. The patient had a past history of extramammary Paget's disease (EMPD) involving the left side of his scrotum 12 years ago. The left scrotal lesion was excised en bloc. The histopathology confirmed that the margins were free of tumor. Periodic acid Schiff (PAS) and carcinoembryonic antigen (CEA) stains were positive, consistent with the diagnosis of EMPD. An evaluation for underlying gastrointestinal and urogenital neoplasia was negative. He continues to have annual examinations, including colonoscopy and prostate‐specific antigen study, which have all been negative.
Two cases of pachydermodactyly
Authors: Kang Byung Duk , Hong Seung Hyun , Kim Ill Hwan , Kim Woo Kyung , Oh Chil Hwan
Published: December 2004

Case 1 A 27–year‐old man had a 15–year history of progressive, asymptomatic, fusiform swelling on fhe medial and lateral aspects of several fingers. There was no history of significant trauma and pain or arthritic symptoms. The family history was noncontributory. His mother said that he had a habit of rubbing his fingers.

Physical examination revealed fusiform swellings limited to the medial and lateral sides of the proximal interphalangeal joints of the index, middle, and ring fingers of both hands (Fig. 1). These lesions were firm tumors, and the overlying skin was lichenified. He had a full range of motion of all of his joints with no tenderness. The thumbs, outer aspects of the index and little fingers, and toes were spared.

The roentgenogram of the hands showed soft tissue swellings without bony or articular abnormalities. Routine laboratory findings, including complete blood count, erythrocyte sedimentation rate, urine analysis, liver function test, concentration of nitrogen in the form of urea in the blood (BUN), creatinine, blood sugar, hepatitis B antigen, venereal disease research laboratory (VDRL) test, rheumatoid factor, anti‐nuclear antibody, and chest X‐ray, were either normal or negative.

An excisional biopsy was performed (Fig. 2), which revealed hyperkeratotis, acanthosis, and reticular dermis thickened by deposits of collagen. In the reticular dermis, the collagen was arranged in a haphazard array. A proliferation of thin collagen fibers encircled the adnexal structures and blood vessels. Fibroblasts which were cytologically benign were slightly increased in the lesion. Silver nitrate impregnation staining revealed an increased number of reticulum fibers in the lesion.

An ultrastructural examination of the reticular dermis from the lesional and adjacent normal skin was performed (Fig. 3, Table 1), We tried to measure the diameter and size of the collagen fibers using an image analysis system (AIC Inc., Roswall, GA). Collagen fibers on the lesion were smaller in diameter and area. In the lesion, the mean collagen fiber diameter was 80.43 nm and the mean area was 6.75× 103 nm2. In the control, the mean collagen fiber diameter was 160.04 nm and the mean area was 27.83× 103 nm2. The coefficient of variation in the diameter and area of the collagen fibers revealed a higher value in the lesional site than in the normal control, indicating that the collagen fibers on the lesion were less uniform in diameter and area than those of the normal control.

The patient had subcutaneous and dermal resection over the PIP joint of the right ring finger by way of trial, and has been followed up until now.
Mauricio Goihman‐Yahr, MD, PhD, Editor
Authors: Öge Nurhan , Alli Nuran
Published: December 2004

The Correspondence Section serves as a forum for opinion exchange about subjects of general interest such as dermatoiogic training, reiations between dermatologists and pharmaceutical houses, governmental control of dermatology and medical practice in general, peculiarities of dermatology related to geographic, climatic, or racial factors, the flow of information and publications, as well as other concerns the readership might have. Contributions are welcome and should conform to the usual format for correspondence. Manuscripts will undergo standard editorial procedures. Submit all correspondence to Mauricio Goihman‐Yahr, MD, phD, Editor, Jet International M‐154, PO Box 020010, Miami, FL 33102.
Temperature‐related divergence in experimental populations of Drosophila melanogaster. II. Correlation between fitness and body dimensions
Authors: Cavicchi Sandro , Guerra Daniela , Natali Vanna , Pezzoli Cristina , Giorgi Gianfranco
Published: December 2004

From a laboratory stock of Drosophila melanogaster (Oregon), reared for more than 20 years at 18° C, a new population was derived and maintained at 28° C for 8 years. The chromosomal and cytoplasmic contribution to genetic divergence between the two populations was estimated. Six body traits and reproductive fitness were taken into account. The third chromosome is responsible for the adaptive difference for temperature between the two lines. Temperature‐selected genes which control body size are located on the second and third chromosomes, although the contribution of each chromosome depends on the environment in which the flies develop. The correlation between the chromosomal and cytoplasmic contributions to different traits and fitness, changes with temperature. At 28° C the correlation between fitness and each body trait is proportional to the response to selection exhibited by each of them, but this is not true at 18° C. Body size has, therefore, an adaptive significance in relation to temperature, which is expressed only in the environment where selection occurs. Cytoplasmic genes affect almost all characters to an extent similar to that of chromosomal genes. Inter‐chromosomal and nucleo‐cytoplasmic interactions are present and also change with temperature. In general, genes selected in a given environment produce greater phenotypic changes in that environment than in another. The population that experienced both temperatures is fitter in both environments, suggesting that the capacity to adapt to warm temperatures depends on genes other than those which are involved in the adaptation to cold.
Evolution, speciation, and inbreeding in the parasitic ant genus Epimyrma (Hymenoptera, Formicidae)
Authors: Buschinger Alfred
Published: December 2004

The ant genus Epimyrma exhibits an evolutionary transition from fully developed slave‐making to a completely workerless parasitic condition. Two of the actively dulotic species, like the closely‐related Myrmoxenus gordiagini, engage in mating and dispersal flights as is usual in ants, whereas in the remaining five species intranidal mating of the sexuals and thus continuous inbreeding is observed; the females shed their wings in the nest and disperse on foot. The inbreeding species are very closely interrelated, as was recently demonstrated with hybridization experiments. The reduction of slave‐making and the evolution of intranidal mating in this group can hardly be explained assuming ordinary models of speciation and spreading of species. I therefore suggest the scenario of an original, widespread, polytypic species with partially isolated, host‐specific races and populations in which genetic dispositions for a reduction of worker numbers and slave‐raiding, and for intranidal mating, were adaptive; the latter, however, encountered problems associated with inbreeding. Such a situation then selected for a sex‐determination mechanism resistant to inbreeding which spread throughout the range of the species, completing the life‐pattern. Due to intranidal mating and inbreeding, however, gene flow between populations is interrupted. The inbreeding system has evidently led to the conservation of a status quo in each population it has reached. The original host‐specific races are morphologically and biologically discrete entities, which should be maintained as species, as they were described, even though they consist of reproductively isolated demes which themselves are built up of isolated, clone‐like lineages.
Is there a trade‐off between egg weight and clutch size in wild Lesser Snow Geese (Anser c. caerulescens)?
Authors: Lessells C. M. , Cooke F. , Rockwell R. F.
Published: December 2004

Previous studies of arctic nesting geese suggest that laying is limited by the size of a female's body reserves and that larger eggs contain more nutrients. These observations imply a life‐history trade‐off between egg size and clutch size which may give rise to a negative genetic correlation between the two characters. We estimated the genetic correlation between egg weight and clutch size using measurements from mothers and their daughters in a wild population of Lesser Snow Geese Anser caerulescens caerulescens. Between 65 and 80 % of the variance in egg weight is attributable to differences between individuals, and heritability of egg weight is about 60 %. In contrast, 10–20 % of the variance in clutch size is attributable to differences between individuals, and heritability of clutch size is about 15 %. The genetic correlation coefficient between egg weight and clutch size ranges from 0.09 to 0.32 and does not differ significantly from zero. We discuss the possible reasons for the lack of the expected negative genetic correlation.
Variation in female mate preference across a grasshopper hybrid zone
Authors: Butlin R. K. , Ritchie M. G.
Published: December 2004

A method for studying variation in female preference among populations free from the confounding effects of variation in male characters is described. This method is applied to sixteen populations in a transect across a hybrid zone in the grasshopper, Chorthippus parallelus. Significant variation in preference is revealed among populations. The pattern of this variation is analysed in the context of the reinforcement model of speciation. While the data do indicate an increased homogamic preference on one side of the zone relative to more distant populations, this pattern cannot be distinguished statistically from an abrupt transition in preference over a distance of less than 1 km. We argue that either of these patterns implies that selection operates on female preferences in the hybrid zone.
Molecular analysis of the genomic organization of the Hymenoptera Diadromus pulchellus and Eupelmus vuilleti
Authors: Bigot Yves , Hamelin Marie‐Hélène , Périquet Georges
Published: December 2004

The genomic organization of two parasitic wasps was analyzed by DNA reassociation. Cot curves revealed a pattern with three types of components. A highly repetitive DNA, accounting for 15 to 25% of the genome, was identified as satellite DNA. The moderately repetitive DNA corresponds to 26 to 42% of the genome in both species, and shows large variations in complexity, repetitive frequency and a number of sub‐components between males and females. These variations are seen as resulting from DNA amplification during somatic and sexual differentiation. Dot blot analyses show that such DNA amplifications concern several types of structural and regulatory genes. The presence of repeated mobile elements was studied by the Roninson method to compare the repeated sequence patterns of Diadromus pulchellus and Eupelmus vuilleti with those of Drosophila melanogaster. The occurrence and organization of mobile elements in these Hymenoptera differ from those of the neighboring order of Diptera. The repetitive and unique components define very large genomes (1 to 3 × 109 base pairs). The genomic organization in Parasitica appears to be an extreme drosophilan type. We propose that the germinal genome of these parasitic wasps is primarily composed of satellite DNA blocks and very long stretches of unique sequences, separated by a few repeated and/or variously deleted, interspersed elements of each mobile element family.
SE‐ and SW‐migrating Blackcap (Sylvia atricapilla) populations in Central Europe: Orientation of birds in the contact zone
Authors: Helbig Andreas J.
Published: December 2004

In the Blackcap (Aves: Sylvia atricapilla), a widespread passerine noctural migrant, a “migratory divide” between SE‐ and SW‐migrating populations exists in Central Europe at about 14° E and south of 52° N. The autumn migratory directions are known to have a genetic basis and are expressed in orientation cages in captivity. Migratory directions of birds in the contact zone between the two populations were studied by analysing ringing data and by testing three groups of hand‐raised individuals in orientation cages.

Available ringing data are insufficient to establish migratory directions in the contact zone north of the Alps. Hand‐raised birds from south‐west Germany and the most eastern part of Austria oriented SW and SE, respectively, confirming directions known from ringing recoveries. A sample of birds from the contact zone near Linz (Austria) oriented SW to NW (mean = 268°) and was significantly different from both adjoining populations. This contrasts with results of a cross‐breeding experiment with mixed pairs of SW‐ and SE‐migrants bred in captivity: The F1‐offspring chose southerly directions, intermediate between both parental populations (Helbig, 1991). It is suggested, therefore, that a distinct subpopulation with a large fraction of birds wintering in the British Isles has established itself in the contact zone. Differences in directional choices between groups of siblings from this area indicate that intrapopulation genetic variability is present. This may have led to a rapid spread of the novel W‐NW migratory direction, because north of the Alps strong selection seems to be acting against mixing of SE‐ with SW‐migrating populations.
Evolutionary implications of the mode of D quadrant specification in coelomates with spiral cleavage
Authors: Freeman Gary , Lundelius Judith W.
Published: December 2004

In annelids, molluscs, echiurans and sipunculids the establishment of the dorsal‐ventral axis of the embryo is associated with D quadrant specification during embryogenesis. This specification occurs in two ways in these phyla. One mechanism specifies the D quadrant via the shunting of a set of cytoplasmic determinants located at the vegetal pole of the egg to one blastomere of the four cell stage embryo. In this case, at the first two cleavages of embryogenesis there is an unequal distribution of cytoplasm, generating one macromere which is larger than the others at the four cell stage. The D quadrant can also be specified by a contact mediated inductive interaction between one of the macromeres at the vegetal pole with micromeres at the animal pole of the embryo. This mechanism operates at a later stage of development than the cytoplasmic localization mechanism and is associated with a pattern of cleavage in which the first two cleavages are equal.

An analysis of the phylogenetic relationships within these phyla indicates that the taxa which determine the D quadrant at an early cleavage stage by cytoplasmic localization tend to be derived and lack a larval stage or have larvae with adult characters. Those taxa where the D quadrant is specified by induction include the ancestral groups although some derived groups also use this mechanism.

The pulmonate mollusc Lymnaea uses an inductive mechanism for specifying the D quadrant. In these embryos each of the four vegetal macromeres has the potential of becoming the D macromere; however under normal circumstances one of the two vegetal crossfurrow macromeres almost invariably becomes the D quadrant. Experiments are described here in which the size of one of the blastomeres of the four cell stage Lymnaea embryo is increased; this macromere invariably becomes the D quadrant. These experiments suggest that developmental change in relative blastomere size during the first two cleavages in spiralian embryos that normally cleave equally may have provided a route that has led to the establishment of the cytoplasmic localization mechanism of D quadrant formation.
Variation in life history and genetic traits of Hawaiian mosquitofish populations
Authors: Scribner K. T. , Wooten M. C. , Smith M. H. , Kennedy P. K. , Rhodes O. E.
Published: December 2004

Mosquitofish (Gambusia affinis) were collected from 17 reservoirs on three islands in Hawaii, USA. Genetic and life history traits for adult females from these populations were used to evaluate hypotheses concerning short‐term evolutionary divergence of populations recently established from a common ancestral source. The effects of founder events and drift on genetic variability and population differentiation were also examined. Significant differences in life history characteristics, allele frequencies, and multi‐locus heterozygosities (H) were found among fish populations collected from different reservoirs and between reservoirs classified as stable or fluctuating on the basis of temporal fluctuation in water level. Females from stable reservoirs exhibited greater standard length (35.1 vs 32.8 mm), lower fecundity (11.9 vs 15.2 embryos), lower reproductive allocation (18.2% vs 22.8%), but larger mean embryo size (1.95 vs 1.67 mg) than females from fluctuating reservoirs. Consistency in means among replicates of each reservoir class and concordance in direction and magnitude of differences reported here and results of sampling conducted from these same locations 10 years previously (Stearns, 1983a) suggest that ecological factors intrinsic to these two environments are important in determing population life history traits.

Females from stable reservoirs exhibited lower heterozygosity than females from fluctuating reservoirs (0.134 vs 0.158, respectively). Levels and direction od differences in heterozygosity, the high proportion of polymorphic loci and lack of fixation of alternative alleles argue against a purely stochastic explanation for genetic and life history variation among reservoir populations. Levels of genetic variability and interpopulation differentiation were similar to those observed in mainland populations of this species. A high proportion of the genetic diversity was apportioned between populations and within populations due to differences between juveniles and adults. Significant genotypic differences between adult and juvenile age classes suggest that the genetic divergence of local populations may occur over short periods of time.
The evolutionary history of Drosophila buzzatii. XX. Positive phenotypic covariance between field adult fitness components and body size
Authors: Santos Mauro , Ruiz Alfredo , Quezada‐Díaz Jorge E. , Barbadilla Antonio , Fontdevila Antonio
Published: December 2004

In the cactophilic species Drosphila buzzatii, it is feasible to infer the action of natural selection by simultaneously sampling different life history stages in the field. During four years of research, samples of mating and non‐mating adults and pupae were taken from a natural population. The main adult fitness components, i.e., mating success, longevity, and fecundity, were recorded in relation to body size, as measured by thorax length. The age of flies was estimated by observing the developmental stage of the reproductive system. Our data showed that larger flies can outlive and outmate small flies, and that mating success is related to age. An estimate of the fitness function showed a linear increase of mating success with increasing thorax length. There was no assortative mating for this trait. We advance the hypothesis that mating success is related to the rate of encounter and courtship time through general activity, which in turn may be related to body size. A positive phenotypic correlation between thorax length and ovariole number, which is related to fecundity, was found in females emerged from wild pupae. Neither the phenotypic nor the genetic (additive) correlations between these two traits were statistically different from zero in laboratory reared females. The genetic consequences of the observed phenotypic selection on body size are discussed.
The influence of local extinctions on the probability of fixation of chromosomal rearrangements
Authors: Michalakis Yannis , Olivieri Isabelle
Published: December 2004

We investigated the influence of local extinctions in a subdivided population on the probability of fixation of an initially rare allele, for different migration rates. The selective regimes considered were strict underdominance, meiotic drive, and underdominance associated with meiotic drive.

We show that local extinctions can increase the probability of fixation of initially rare alleles in underdominant loci for relatively high migration rates, even when both homozygotes have the same fitness. This increase is due to drift during founder events. On the contrary, local extinctions decrease the probability of fixation of alleles favoured by meiotic drive. For a locus where both meiotic drive and underdominance act, the effect of local extinctions depends on the relative strength of the two selective regimes and the initial frequency of the rare allele. For parameter values such that the rare allele is initially selected against, local extinctions decrease the probability of fixation for low migration rates while they cause an increase for moderate migration rates. When the parameter values are such that the rare allele should always be favoured by selection, local extinctions always decrease the probability of fixation. In this latter case, we show the existence of an optimal migration rate which maximizes the probability of fixation.
Developmental stability, sexual selection and speciation
Authors: Møller Anders Pape
Published: December 2004

Fluctuating asymmetry occurs when an individual is unable to undergo identical development of an otherwise bilaterally symmetric trait on both sides of its body. Since both sides of a bilaterally symmetric trait are the result of the actions of a single genome, fluctuating asymmetry represents an epigenetic measure of the sensitivity of development to stress. Different morphological traits may show a direct relationship between their functional importance and their degree of developmental canalization. This may explain why some characters show high degrees of fluctuating asymmetry, and why these characters more often become exaggerated secondary sexual ornaments. The degree of fluctuating asymmetry is generally larger in small marginal populations living in novel environments, and this will particularly lead to relatively large degrees of asymmetry in the least developmentally canalized traits. More stringent selection against heterozygotes in marginal populations may further break down developmental stability and linkage groups which would lead to increased genetic variance. Females may prefer to mate with males having large, but relatively symmetric morphological characters, because it is more difficult to make large traits (a good genes argument), a large trait is more easily perceived (a sensory bias preference), and because symmetry signals ability to cope with stress (a good genes argument). The low degree of developmental stability and the large amount of genetic variance in secondary sexual characters in small, marginal populations could set the scene for rapid development of divergence and speciation in marginal populations.
The ontogenetic complexity of developmental constraints
Authors: Zelditch Miriam Leah , Bookstein Fred L. , Lundrigan Barbara L.
Published: December 2004

Developmental constraint is a theoretically important construct bridging ontogenetic and evolutionary studies. We propose a new operationalization of this notion that exploits the unusually rich measurement structure of landmark data. We represent landmark configurations by their partial warps, a basis for morphospace that represents a set of localized features of form. A finding of developmental constraint arises from the interplay between age‐varying means and age‐specific variances in these subspaces of morphospace. Examination of variances and means in 16 ventral skull landmarks in the cotton rat S. fulviventer at ages 1, 10, 20, and 30 days yielded three types of developmental constraint: canalization (constraint to relatively constant form age by age); chreods (reduction of variance orthogonal to the mean trajectory over ages); and opposition (reduction of age‐specific variance along the mean trajectory over ages). While canalization and chreodic constraints have been noted previously, the oppositional type of constraint appears novel. Only one of our characters, relative length and orientation of the incisive foramen, appears to be canalized. Although skull growth becomes increasingly integrated through ontogeny, our characters display a remarkable spatiotemporal complexity in patterns of variance reduction. The specific assortment of constraints observed may be related to the precociality of Sigmodon. We suggest that Waddington's diagrammatic presentation of the “epigenetic landscape” may be misleading in quantitative studies of developmental regulation.
Rapid changes in pollen production in experimental outcrossing populations of wheat
Authors: David Jacques L. , Pham Jean‐Louis
Published: December 2004

For evolutionary reasons, pollen production is expected to be modified when changes occur in plant mating systems. In this study, outcrossing was enforced through male‐sterility in usually autogamous populations of winter wheat. The correlated changes in pollen production were studied after a 6‐year period of natural evolution. Both the disappearance of individuals with the lowest pollen production and the increase in the production of fertile pollen per spike were observed in male‐fertile plants. The results are interpreted as a selection on male function. Some morphological differences also appeared in evolved populations between male‐fertile and male‐sterile plants. These differentiations are discussed in light of resource allocation theory.
Estimating the minimum rate of genetic transformation in bacteria
Authors: Smith J. Maynard
Published: December 2004

Extensive data from multilocus electrophoresis are available for many bacterial populations. In some cases, for example Neisseria gonorrhoeae, these data are consistent with the population being in linkage equilibrium. This raises the following question. What frequency of transformation, or other means of genetic recombination, is needed, relative to mutation, to produce apparent panmixis? Simulation of a finite‐population model suggests that, if transformation is at least twenty times as frequent as mutation, the population structure will be indistinguishable from a panmictic one, using the best available data sets. That is, relatively infrequent transformation is sufficient to produce approximate linkage equilibrium.
Opposing fitness consequences of colour pattern in male and female snakes
Authors: Forsman Anders
Published: December 2004

Local populations of the adder, Vipera berus, are polymorphic for dorsal colour pattern, containing both melanistic (black) and zig‐zag patterned individuals. Colour patterns in snakes influence crypsis and thermoregulatory capacity and therefore may be subjected to natural selection. To find an explanation for the maintenance of this polymorphism I examined temporal and spatial variation in morph frequency, and tested for differential selection among morphs using data from a six year capture‐mark‐recapture study. The data derive from six groups of islands in the Baltic Sea off the Swedish east coast, two mainland localities near the coast, and one inland locality.

Morph frequency did not change over time within a population but varied among populations: melanistic individuals were not found at the inland locality, but comprised from 17 to 62% of the coastal and island populations. Adders frequently moved between islands within a group, but the tendency to disperse was independent of morph. These results suggest that the polymorphism is stable and maintained by a deterministic process. Scar frequency was twice as high among melanistic as among zig‐zag snakes, and melanistic individuals were easier to capture, indicating that predation may be higher on the melanistic morph. Colour morphs did not differ in body size, but analysis of recapture data shows evidence for differential survival among morphs. Zig‐zag males survived better than melanistic males, but the relative survival rates of morphs were reversed in females. This difference was consistent through time and may be due to sexual differences in behaviour, with melanism increasing predation intensity when associated with male but not with female behaviour. Opposing fitness consequences of colour pattern in the two sexes may help maintain colour polymorphism within populations of Vipera berus.
Origin of clonal diversity in triploid parthenogenetic Trichoniscus pusillus pusillus (Isopoda, Crustacea) based upon allozyme and nucleotide sequence data
Authors: Friis Theisen Bent , Christensen Bent , Arctander Peter
Published: December 2004

Variation in PGM (phosphoglucomutase) and MDH (malate dehydrogenase) allozymes and in mitochondrial and nuclear (ribosomal) DNA gives evidence of at least three independent origins of triploid Trichoniscus pusillus pusillus. Much of the genetic variation found may reflect variation within the parental diploid population(s), but it is argued that some of the variation in PGM allozymes have accumulated within the parthenogenetic lines. Based upon the variation at this locus, 15 genetically distinct clones are distinguished.
Thermal evolution of rate of larval development in Drosophila melanogaster in laboratory and field populations
Authors: James Avis C. , Partridge Linda
Published: December 2004

The duration of Drosophila melanogaster larval and pupal periods was measured in laboratory thermal lines and in populations collected along a latitudinal transect in eastern Australia. In replicated laboratory lines kept for 9 years at 16.5° C or 25° C the duration of larval development had continued to diverge compared with 4 and 5 years previously, with more rapid larval development, and hence reduced total duration of pre‐adult development, in the low temperature lines at both experimental temperatures. After 4 years of separate evolution, lines derived from the 25° C lines and subsequently cultured at 29° C showed no evidence of significant divergence in the duration of any part of the pre‐adult period. The geographic populations showed a decrease in the duration of larval development, and hence of the total pre‐adult period, with increasing latitude. In both laboratory and field populations, evolution at lower temperature was associated with more rapid larval development to a larger adult body size, the opposite genetic correlation between these traits to that found within a single temperature. The indications are that lower temperatures may be permissive of more efficient growth in D. melanogaster. It will be important to discover if evolution in response to temperature induces similar correlations in other ectotherms.
Differentiation trees, a junk DNA molecular clock, and the evolution of neoteny in salamanders
Authors: Martin C. Cristofre , Gordon Richard
Published: December 2004

Obligate neotenic salamanders die if forced to metamorphose. We suggest that this can be explained by assuming: 1) their “excess” DNA is “junk” DNA; 2) the “adult” specifying portion of the DNA becomes junk DNA and is available for repeated duplication. This suggests a “new” junk DNA molecular clock. We obtain remarkable agreement in “predicting” the amount of DNA per nucleus in present day non‐obligate neotene salamanders from this molecular clock. These observatons are consistent with the idea that the development of these animals is describable in terms of differentiation trees whose branches (gene cascades) corresponding to adult somatic tissues accumulate deleterious mutations over evolutionary time. We show that the amount of DNA per nucleus increases linearly with the phylogenetic age of salamander families. The lack of constraints by natural selection, on unused adult branches, may account for the large amount of so‐called “junk DNA” in obligate neotenic salamanders. The effects of this excess DNA, via increased cell size, suggest a positive feedback, ecophysiological explanation for such junk DNA: adaptation to cool water environments is enhanced by the lower metabolism associated with more DNA, larger cells and slower developmental time.
Rapid evolution of courtship song pattern in Drosophila willistoni sibling species
Authors: Ritchie M. G. , Gleason J. M.
Published: December 2004

Courtship behaviours may provide a more reliable means of identifying reproductively isolated taxa than traits such as morphology or many genetic markers. Here we describe the courtship songs of the Drosophila willistoni sibling species group, which consists of several species and subspecies. We find that song pattern is species‐specific, despite significant differences among strains within species. D. paulistorum has the most variable song pattern, which reflects this species' traditional subdivision into semispecies. All the other species could be unambiguously identified by song. The major differences among these species was in the interpulse interval, as has been found in other studies of fly song. However, the interpulse intervals of the species studied here were often multimodal. This was partly due to the presence of multiple song types within the courtship repertoire, but it also reflected changes in interpulse interval within a song type by some males. Unusually, some species had distinctively patterned variation in interpulse interval. Song must have evolved rapidly within the species complex, probably due to sexual selection.
Sexual selection in the barn swallow Hirundo rustica. VI. Aerodynamic adaptations
Authors: Møller A. P. , De Lope F. , Saino N.
Published: December 2004

Secondary sexual characters are assumed to be costly to produce and maintain, and this will select for morphological modifications that reduce the magnitude of such costs. Here we test whether a feather ornament, the sexually exaggerated outermost tail feathers of male barn swallows Hirundo rustica, a trait currently subject to a directional female mate preference, and other aspects of the morphology used for flight have been modified to increase aerodynamic performance. This was done by making comparisons among sexes within populations, among individuals varying in tail length within populations, and among populations from different parts of Europe. Male barn swallows experienced reduced drag from their elongated tail feathers by morphological modifications of the ornamental feathers as compared to females. Morphological features of the outermost tail feathers were unrelated to tail length in both males and females within populations. Wing and tail morphology (length of central tail feathers and wings, wing span, wing area, wing loading, and aspect ratio) was modified in males compared to females. Barn swallows with long tails had morphological tail and wing modifications that reduced the cost of a large ornament, and similar modifications were seen among populations. The costs of the exaggerated secondary sexual character were therefore reduced by the presence of cost‐reducing morphological modifications. The assumptions of reliable signalling theory, that signals should be costly, but more so to low than to high quality individuals, were not violated because long‐tailed male barn swallows had the largest cost‐reducing morphological characters.
Malformed offspring, sibling matings, and selection against inbreeding in the sand lizard (Lacerta agilis)
Authors: Olsson M. , Gullberg A. , Tegelström H.
Published: December 2004

We demonstrated that sand lizards (Lacerta agilis) are more likely to have malformed offspring when they mate with siblings. Offspring with malformations, such as deformed limbs and heads, have zero survival in a natural population. Normal‐looking siblings of malformed hatchlings also had a reduced survival in the wild, compared to offspring from clutches in which all siblings appeared normal. The proportion of malformed hatchlings in the natural population was ca. 10%, in spite of differences in juvenile dispersal between males and females. Male juveniles disperse significantly further from their natal sites than do female juveniles.
Resource allocation: a conflict in the fig/fig wasp mutualism?
Authors: Anstett M.‐C. , Bronstein J. L. , Hossaert‐McKey M.
Published: December 2004

Conflicts of interest are omnipresent between mutualist species. In the monoecious fig/pollinator wasp mutualism, each female flower produces either a seed or a pollinator offspring (which has fed on a single seed). Pollen from a syconium (i.e. fig, a closed urn‐shaped inflorescence) is only dispersed by female pollinator offspring born in this syconium. Thus the fig tree is selected to produce both seed and pollinator offspring whereas for the pollinator there is no short term advantage in seed production. Using controlled pollination experiments (pollen injection, and foundress introduction), we show that 1) The relative proportion of seeds and pollinator offspring produced (i.e., the effective allocation between female and male function) depends mainly on the number of foundresses that entered the syconium. 2) Many female flowers within every syconium mature neither a seed nor a wasp (from 25% to 33%). 3) All the female flowers within a syconium that are not vacant at maturity have the potential to produce a seed, and at least 80% of them can produce a pollinator. Several hypotheses concerning mechanisms that govern the partitioning between seed and wasp production are discussed, and their evolutionary consequences are considered.