bluuebunny/crossref_metadata_2025_split huggingface dataset:
Initiation of maternal effects in Lymantria dispar: Genetic and ecological components of egg provisioning
Authors: Rossiter Mary Carol , Cox‐Foster Diana L. , Briggs Michelle A. 
Published: December 2004

AbstractResources supplied by mothers to offspring through the egg are known to significantly influence offspring life history traits in the gypsy moth, Lymantria dispar. The purpose of this research was to determine the relative contribution of genetics (based on familial contribution) and the nutritional environment of the parents to the mean and variance of resources supplied to the eggs. Vitellogin, the dominant egg storage protein in the gypsy moth, was selected as the focus of the study. The amount of vitellogin in individual eggs from 48 mothers reared on one of four host species, quaking aspen, chestnut oak, red oak, or pitch pine was quantified with an immunoassay. Results of a nested analysis of variance show that both genetics and parental nutritional experience make significant contributions to egg vitellogin levels. When parents were reared on quaking aspen, vitellogin levels were highest and the expression of familial variation was greatest. This study shows that polyphagy can amplify phenotypic variance in reproductive traits through the interaction between genotype and nutritional environment. To the extent that egg resources influence offspring vigor, the fitness of offspring can include a time‐lagged component which arises from the interaction between the parental genotype and the parental environment. The time‐lagged expression of such a maternal trait is capable of influencing the rate and direction of character evolution and the stability of local population dynamics.
Multiple origins of self‐fertilization in tristylous Eichhornia paniculata (Pontederiaceae): Inferences from style morph and isozyme variation
Authors: Husband Brian C. , Barrett Spencer C. H. 
Published: December 2004

AbstractPopulations of Eichhornia paniculata (Pontederiaceae) exhibit a wide range of mating systems, from predominant outcrossing to high levels of self‐fertilization. The origin of self‐fertilization in this tristylous species is associated with the loss of style‐length morphs from populations and the spread of self‐pollinating, floral variants. We examined geographic variation in style morph and allozyme frequencies to determine whether the loss of style morphs and transition to selfing could have multiple origins in E. paniculata. Surveys of floral variation in 167 populations from six states in northeastern Brazil revealed that at least one style morph was absent from 29.3%. Non‐trimorphic populations occurred in all states and ranged in frequency from 9% in Ceará to 68% in Alagoas. Selfing variants occurred in 8.5% and 55% of trimorphic and non‐trimorphic populations, respectively, and were distributed among five of six states with primary concentrations in Alagoas and Pernambuco. A comparison of electrophoretic variation at 24 isozyme loci in 28 trimorphic, 13 dimorphic and 3 monomorphic populations indicated that non‐trimorphic populations contained 84% of the allelic variation present in trimorphic populations and were markedly differentiated from one another. Analyses of genetic distance and the distribution of rare alleles indicated that non‐trimorphic populations were often more similar to neighbouring trimorphic populations than to one another. Populations with selfing variants occurred at low frequency in three genetically distinct parts of the range. These results, in combination with genetic and morphological evidence suggest that style morphs are lost repeatedly from populations of E. paniculata and that selfing variants may have originated on at least three separate occasions in northeastern Brazil.
Reproductive energetics of the role reversing bushcricket, Kawanaphila nartee (Orthoptera: Tettigoniidae: Zaprochilinae)
Authors: Simmons L. W. 
Published: December 2004

AbstractTheory predicts that sexual differences in reproductive strategies arise because of differences in the magnitude of investment made by males and females in reproduction. In some bushcrickets, the typical sex role of competitive male and choosy female is reversed when populations are subject to nutrient stress. Here I present an energetic analysis of reproduction for the role reversing bushcricket, Kawanaphila nartee, that supports the contention that this sex role reversal is a consequence of reversal in the pattern of relative reproductive investment. When fed ad libitum, males spent 16% of their daily energy reserves on the spermatophore compared with 26% spent on calling to attract a mate. Females spent 29% of their daily energy reserves in producing and laying eggs. However, when allowed only limited access to food, female expenditure in eggs was reduced to 23% of daily reserves while male expenditure remained unchanged. After accounting for the incorporation of male nutrients into eggs, female energy expenditure in reproduction exceeded male expenditure when animals were fed ad libitum, but male expenditure exceeded female expenditure when diet was limited. This role reversal in relative energy expenditure that is associated with courtship role reversal supports classical and contemporary theories on the control of sexual selection.
Origin of European rabbit (Oryctolagus cuniculus) in a Mediterranean island: Zooarchaeology and ancient DNA examination
Authors: Hardy Chris , Vigne Jean‐Denis , Casañe Didier , Dennebouy Nicole , Mounolou Jean‐Claude , Monnerot Monique 
Published: December 2004

AbstractMammalian species presently living on Mediterranean islands have been brought in by man. The question of their geographical origin and of the time of their introduction is often a matter of debate. We studied this problem using a population of rabbits (European rabbit: Oryctolagus cuniculus) living in Zembra, an island off Tunisia. Archaeological surveys show that rabbit has been introduced to the island by Bronze Age or Roman people, between the IIIrd Millenium B.C. and the IIIrd century A.D. Part of the 16S‐rRNA gene of mitochondrial DNAs from fossil bones of different ages (dated back to 130–390 A.D.) was characterized and compared to that of present day rabbits of differing geographical origin. The data suggest that animals present on Zembra in late Roman times belonged to the same maternal lineage as present populations from Northern Spain and Southern France.
Molecular biogeography: using the Corsica‐Sardinia microplate disjunction to calibrate mitochondrial rDNA evolutionary rates in mountain newts (Euproctus)
Authors: Caccone Adalgisa , Milinkovitch Michel C. , Sbordoni Valerio , Powell Jeffrey R. 
Published: December 2004

AbstractMitochondrial DNA (mtDNA) sequence variation was examined in the three species belonging to the newt genus Euproctus: E. asper, E. montanus, and E. platycephalus, and in three other species belonging to the same family: Triturus carnifex, T. vulgaris and Pleurodeles waltl. The Euproctus species inhabit mountain streams in the Pyrenean region, Corsica, and Sardinia, respectively. This vicariant distribution is believed to be a result of the disjunction and rotation of the Sardinia‐Corsica microplate from the Pyrenean region and suggested dates for each cladogenetic event are available. A total of 915 bp from 12S and 16S ribosomal rRNA genes were compared for each taxon. These are the first mt‐rDNA sequence data for salamanders. Sequences were used to reconstruct phylogenetic trees, investigate evolutionary rates for these genes, calibrate them with absolute time since divergence, and compare rates with published ones.Using P. waltl as the outgroup, all phylogenetic methods used (parsimony, maximum likelihood, and Neighbor Joining) produced trees with identical topologies and similar bootstrap values associated with each node. These sequence data cannot unambiguously resolve the splitting events leading to the main radiation of the genus Triturus and the origin of the genus Euproctus. These events may well have occurred very close in time, consistent with other sorts of data. Although it is unlikely strict linearity holds for all kinds of substitutions, relative rate tests of the molecular clock hypothesis could not reject clock‐like behavior of sequence changes along Euproctus lineages. Estimates of absolute rates of base changes are 0.35% per Myr since divergence for all substitutions and 0.14% per Myr for transversions; these estimates are similar to other vertebrate estimates. A comparison with distance measures from allozyme studies agrees quite well with regard to relative divergences of the three Euproctus species.
Selecting for floral character associations in wild radish, Raphanus sativus L.
Authors: Stanton Maureen , Young Helen J. 
Published: December 2004

AbstractESS models of reproductive allocation have been used extensively to explain patterns of floral diversity in angiosperms. These theoretical explorations assume that proportional allocation to pollen, ovules, and seeds, as well as to secondary features such as showy petals and nectar rewards, can evolve independently within the limits set by total resource availability. In populations of California wild radish, we have shown previously that petal size, a strong determinant of visitation by honey bee pollinators, is positively correlated with both pollen and nectar production, but not with ovule or seed number per flower. These phenotypic associations may reflect selection, environmental correlation, and/or genetic constraint. By exerting selection on the petal size : pollen number ratio over two generations, we eliminated the positive correlation between petal size and pollen production, with both characters showing significant change after a single selection episode. Once these two floral traits became uncoupled, nectar sugar production was significantly correlated only with petal size. Our results suggest that natural selection could readily alter reproductive allocation in these flowers, and that the phenotypic correlations observed in nature may be maintained by selection for effective reproductive phenotypes.
Population structure of Leptothorax ambiguus, a facultatively polygynous and polydomous ant species
Authors: Herbers Joan M. , Grieco Sarah 
Published: December 2004

AbstractWe examined the genetic and spatial structure of Leptothorax ambiguus in a Vermont site. Nests of this tiny ant species have variable queen number and comprise larger polydomous colonies, as do their closest relatives in North America. Nests are patchily distributed in the forest, and sometimes occur in local abundance. We collected 121 nests in four years from plots in which all nests were mapped; furthermore, we subjected nests collected in two separate years to starch gel electrophoresis and estimated relatedness according to the Queller—Goodnight (1989) algorithm. Queens that share a nest site also share 33% of their alleles on average, and relatedness among worker nestmates is about 0.5. The existence of diploid males and nonzero F‐values demonstrate inbreeding in this species, an unusual phenomenon for social insects in general. Mapping data showed that nests with like genotypes tended to cluster in space, forming polydomous colonies. Colonies consisted of 1–6 nest subunits, and about half of all colonies were polygynous. We compare these features of L. ambiguus to its close relative L. longispinosus and a European congener L. acervorum. These comparisons allow us to conclude that an interplay between ecological and genetic factors produces the observed pattern of multiple queening and nest spatial distribution in this species.
Inbreeding depression and mating‐distance dependent offspring fitness in large and small populations of Lychnis flos‐cuculi (Caryophyllaceae)
Authors: Hauser Thure P. , Loeschcke Volker 
Published: December 2004

AbstractThe spatial structure of four Lychnis flos‐cuculi populations, varying in size and degree of isolation, was studied by comparing the fitness of offspring resulting from self‐pollination and pollinations by neighbouring plants, plants within the same population, and plants from other populations. Selfed offspring had the lowest fitness of the four offspring groups. No significant difference was found between the performance of offspring from pollinations by neighbouring plants and offspring pollinated by plants further apart but within the same population. A lower fitness of offspring from pollinations between neighbours would be expected if these matings, on average, yielded inbred offspring which suffered from inbreeding depression. These results imply that either a tight neighbourhood structuring is not present, or that the inbreeding depression for offspring by neighbours is too low to detect, although these are inbred. Crossings between populations produced offspring with a significantly higher fitness than offspring sired within populations. There were no significant differences in response to inbreeding among the populations, and differences in mean fitness among populations had no clear relation to the population size or degree of isolation. A reduced fitness of small populations due to inbreeding depression or a less severe response to experimental inbreeding due to purging of deleterious alleles is therefore not supported by our results.
Thermal evolution of pre‐adult life history traits in Drosophila melanogaster
Authors: Partridge L. , Barrie B. , Fowler K. , French V. 
Published: December 2004

AbstractReplicated lines of Drosophila melanogaster were allowed to evolve in population cage culture at 16.5° C or 25° C for five years. Their larval and pupal development times, larval growth rates, larval critical weights for pupariation and pre‐adult survival rates were then measured at both temperatures. Pre‐adult survival showed evidence of adaptation of the lines to their thermal selection regimes, with each set of lines showing superior survival when tested at the temperature at which they had been evolving. Pupal periods were similar for all lines when growing at 16.5° C but, at 25° C, the low temperature lines had the longer pupal periods. Irrespective of experimental temperature, low temperature lines grew faster and had shorter larval development periods than the high temperature lines. Larval critical weights for pupariation were higher in the low temperature lines at the low experimental temperature, and higher in the high temperature lines at the higher experimental temperature. The correlations between these traits induced by thermal evolution were in general different from or opposite to the genetic correlations found within a single temperature.
Morphometric variation in a hybrid zone of two subspecies of Gerris costae (Heteroptera: Gerridae) in the Maritime Alps
Authors: Largiadèr Carlo Rodolfo , Klingenberg Christian Peter , Zimmermann Manfred 
Published: December 2004

AbstractTwo morphologically distinct subspecies of Gerris costae form a contact zone extending from the Maritime to the Western Alps. Within this area canonical trend surface analysis revealed a geographic pattern of morphometric variation consistent with topography. From North to South, and from high to low elevation there was a transition from G. c. costae‐like phenotypes to phenotypes resembling pure G. c. fieberi. The same pattern was confirmed with canonical variate analysis not taking geographic location into account; it is therefore not an artifact of trend surface analysis.Comparisons of the pattern of morphometric variation of laboratory‐reared offspring with the pattern of their parents sampled from natural populations show that geographic variation is mostly determined genetically. Intermediate individuals from field populations probably are natural hybrids between the two subspecies, because laboratory‐reared hybrids were intermediate between the offspring of pure strains.We did not find increased morphometric variation within the contact zone. This suggests unimpeded introgression and is in contrast with an increase in size variability that is predicted to be associated with a transition between uni‐ and bivoltine forms.
Life history adaptation along a latitudinal cline in the water strider Aquarius remigis (Heteroptera: Gerridae)
Authors: Blanckenhorn W. U. , Fairbairn D. J. 
Published: December 2004

AbstractWe addressed the general hypothesis that life history differences among eastern populations of the North American water strider, Aquarius remigis (Heteroptera: Gerridae), along a north‐south gradient are manifestations of genetic differentiation due to natural selection. We raised offspring of two field‐caught populations from each of three latitudes in a common laboratory environment at 20° C and two photoperiods. Nearly all Quebec (PQ) individuals (ca. 46° N) entered diapause to reproduce the following spring (univoltine life cycle), while intermediate proportions of New York (NY; ca. 43° N) and New Jersey (NJ; ca. 41° N) individuals reproduced directly, producing a second generation (bivoltine life cycle). PQ females were smaller, developed faster, and laid smaller eggs than NY and NJ individuals; NY and NJ populations differed little in these variables. NY females had longer life spans than either PQ or NJ females, but lower oviposition rates. Total reproductive output did not differ across latitudes. Photoperiod affected body length, development time, and reproductive pathway, resulting in a latitude by environmental interaction. PQ individuals reproduced directly under 15L : 9D (summer) conditions only, while the NY and NJ populations exhibited more direct reproduction under 13L : 11D (spring or fall) conditions. Some life history characters of the NY and NJ populations displayed the higher variability indicative of phenological transition zones. These results indicate local adaptation of populations to long‐term climatic patterns. Water striders appear to adapt to longer seasons by extending development, growing larger, and breeding directly. Larger body size and extended or rapid development are associated with bivoltinism and increase in egg size, but not necessarily with higher fecundity or oviposition rate. The phenological transition zone appears to be unrelated to a transition zone a little further south established by allozyme data and morphology, as all populations studied here could be electrophoretically identified as northern "type".
The genetic basis of female mate preferences
Authors: Bakker Theo C. M. , Pomiankowski Andrew 
Published: December 2004

AbstractWe review the evidence for genetic variation in female and male mate preferences. Genetic differences between species and partially isolated races show that preferences can evolve and were genetically variable in the past. Within populations there is good evidence of genetic variation, both of discrete genetic effects (8 cases) and quantitative genetic effects (17 cases), from a diverse range of taxa. We also review evidence for the presence of genetic covariance between mate preferences and sexual traits in the other sex. The 11 studies go a long way to validating the theoretical prediction of positive genetic covariance. The few negative results are best explained by a lack of appropriate experimental design. One unresolved question is whether genetic covariance is due to linkage disequilibrium between unlinked genes or physical linkage. Some evidence points to linkage disequilibrium but this is not yet conclusive.
Introduced Swedish Canada geese (Branta canadensis) have low levels of genetic variation as revealed by DNA fingerprinting
Authors: Tegelström H»kan , Sjöberg Göran 
Published: December 2004

AbstractThe Swedish, Finnish and Norwegian population of Canada geese (Branta canadensis), now amounting to some 30–50 000 birds, was founded by only five individuals. We used DNA fingerprinting to assess the level of genetic variability in minisatellite loci of Swedish Canada geese from two northern areas. For comparison, we estimated the minisatellite variability in lesser white‐fronted geese (Anser erythropus), barnacle geese (Branta leucopsis) and a reintroduced stock of Canadian giant Canada geese (Branta canadensis maxima).The mean similarity between Swedish Canada geese was 0.76 ± 0.15, which is higher than recorded for any other natural bird population. The high similarity implies that a fourfold increase of homozygosity has taken place in this population. The probable cause for the loss of variation is the low number of birds originally introduced and a history of repeated translocations, leading to a sequence of founder events. As a consequence of the high similarity, it has not been possible to use DNA fingerprinting for determination of parenthood in the population studied.
Temporal stability in hybridization between Bufo microscaphus and Bufo woodhousii (Anura: Bufonidae): Behavior and morphology
Authors: Sullivan Brian K. 
Published: December 2004

AbstractI analyzed temporal variation in hybridization between the southwestern toad (Bufo microscaphus) and Woodhouse's toad (Bufo woodhousii) along the Virgin River in southwestern Utah and northwestern Arizona. Bufo woodhousii is largely restricted to the floodplain of the Virgin River from southern Nevada to the vicinity of St. George, Utah. By contrast, B. microscaphus is confined primarily to the tributaries of the Virgin River, only occupying the Virgin River proper exclusive of B. woodhousii along its upper reaches east of La Verkin Creek. As in all other zones of sympatry for these bufonids, behavior and morphology provide clear evidence of hybridization at a number of sites along the Virgin River. Analysis of morphology and behavior indicates that the distribution of these taxa and their hybrids is largely unchanged relative to that documented forty years ago by Blair (1955). Comparisons of morphological hybrid index scores reveal slight shifts in relative numbers of parental taxa at only one site. Hybridization between these anurans has been relatively stable geographically, and may be related to the nature of the riparian habitat available for breeding.
Sex‐ratio distortion in Drosophila simulans: co‐occurence of a meiotic drive and a suppressor of drive
Authors: Merçot Hervé , Atlan Anne , Jacques Micheline , Montchamp‐Moreau Catherine 
Published: December 2004

AbstractA sex‐ratio distortion factor was found at high frequency in D. simulans strains from Seychelles and New Caledonia. This factor is poorly or not expressed within those strains which are resistant to it. Its presence was detected by crossing females from New Caledonia or the Seychelles with males from a different geographic origin. Most of the F1 males obtained produced an excess of females (up to 99%) in their progeny. The two strains are infected with Wolbachia, but these micro‐organisms are not involved in the sex‐ratio distortion. The sex‐ratio factor is shown to be an X‐linked meiotic driver; nuclear resistance factor(s) act by suppressing the drive. It is likely that the same X‐located driver invaded the two populations, which subsequently developed resistance factor(s) against it.