| a framework physical map of drosophila virilis based on p1 clones: applications in genome evolution. | the analysis of patterns of genome evolution may help to evaluate the evolutionary forces that shape the composition and organization of the genome. comparisons between the physical maps of divergent species can be used to identify conserved blocks of closely linked genes whose synteny is possibly under selective constraint. we have used in situ hybridization to determine the genomic position of 732 randomly selected clones from a bacteriophage p1 library of drosophila virilis. the resulting map ... | 1997 | 9215559 |
| characterization of female preference functions for drosophila montana courtship song and a test of the temperature coupling hypothesis. | female mate preferences are a major cause of diversity and elaboration in male sexual traits. here we characterize the shape of female preference functions for pulse length and carrier frequency of the courtship song of drosophila montana by fitting both parametric and nonparametric functions to the incidence of female receptive gestures to synthetic song. preference functions for both traits are strongly directional. that for pulse length is linear and favors short pulses, whereas that for carr ... | 2001 | 11392390 |
| evidence for introgression in differentiated north-american and finnish drosophila montana populations. | the virilis group species drosophila montana is widely distributed around the northern hemisphere. here we show that it consists of at least two well differentiated populations (finnish and north-american populations) that have been diverging for the last 0.55-0.95 my. these populations show significant chromosomal, behavioural and morphological differences, but no apparent postzygotic isolation. evidence for introgression is found for both finnish and north-american populations at two out of th ... | 2005 | 15954499 |
| comparative polytene chromosome maps of d. montana and d. virilis. | chromosomal inversion polymorphism was characterized in finnish drosophila montana populations. a total of 14 polymorphic inversions were observed in finnish d. montana of which nine had not been described before. the number of polymorphic inversions in each chromosome was not significantly different from that expected, assuming equal chance of occurrence in the euchromatic genome. there was, however, no correlation between the number of polymorphic inversions and that of fixed inversions in eac ... | 2007 | 16906413 |
| phylogeographic patterns in drosophila montana. | the drosophila virilis species group offers valuable opportunities for studying the roles of chromosomal re-arrangements and mating signals in speciation. the 13 species are divided into two subgroups, the montana and virilis 'phylads'. there is greater differentiation among species within the montana phylad in both karyotype and acoustic signals than exists among members of the virilis phylad. drosophila montana is a divergent species which is included in the montana phylad. here, we analyse th ... | 2007 | 17305862 |
| male courtship song and female preference variation between phylogeographically distinct populations of drosophila montana. | understanding the variation within and between populations in important male mating traits and female preferences is crucial to theories concerning the origin of sexual isolation by coevolution or other processes. there have been surprisingly few studies on the extent of variation and covariation within and between populations, especially where the evolutionary relationships between populations are understood. here we examine variation in female preferences and a sexually selected male song trai ... | 2007 | 17542854 |
| inducing cold-sensitivity in the frigophilic fly drosophila montana by rnai. | cold acclimation is a critical physiological adaptation for coping with seasonal cold. by increasing their cold tolerance individuals can remain active for longer at the onset of winter and can recover more quickly from a cold shock. in insects, despite many physiological studies, little is known about the genetic basis of cold acclimation. recently, transcriptomic analyses in drosophila virilis and d. montana revealed candidate genes for cold acclimation by identifying genes upregulated during ... | 2016 | 27832122 |
| transcriptional differences between diapausing and non-diapausing d. montana females reared under the same photoperiod and temperature. | a wide range of insects living at higher latitudes enter diapause at the end of the warm season, which increases their chances of survival through harsh winter conditions. in this study we used rna sequencing to identify genes involved in adult reproductive diapause in a northern fly species, drosophila montana. both diapausing and non-diapausing flies were reared under a critical day length and temperature, where about half of the emerging females enter diapause enabling us to eliminate the eff ... | 2016 | 27571415 |
| seasonal gene expression kinetics between diapause phases in drosophila virilis group species and overwintering differences between diapausing and non-diapausing females. | most northern insect species experience a period of developmental arrest, diapause, which enables them to survive over the winter and postpone reproduction until favorable conditions. we studied the timing of reproductive diapause and its long-term effects on the cold tolerance of drosophila montana, d. littoralis and d. ezoana females in seasonally varying environmental conditions. at the same time we traced expression levels of 219 genes in d. montana using a custom-made microarray. we show th ... | 2015 | 26063442 |
| sequencing, de novo assembly and annotation of the colorado potato beetle, leptinotarsa decemlineata, transcriptome. | the colorado potato beetle (leptinotarsa decemlineata) is a major pest and a serious threat to potato cultivation throughout the northern hemisphere. despite its high importance for invasion biology, phenology and pest management, little is known about l. decemlineata from a genomic perspective. we subjected european l. decemlineata adult and larval transcriptome samples to 454-flx massively-parallel dna sequencing to characterize a basal set of genes from this species. we created a combined ass ... | 2014 | 24465841 |
| circadian clock of drosophila montana is adapted to high variation in summer day lengths and temperatures prevailing at high latitudes. | photoperiodic regulation of the circadian rhythms in insect locomotor activity has been studied in several species, but seasonal entrainment of these rhythms is still poorly understood. we have traced the entrainment of activity rhythm of northern drosophila montana flies in a climate chamber mimicking the photoperiods and day and night temperatures that the flies encounter in northern finland during the summer. the experiment was started by transferring freshly emerged females into the chamber ... | 2016 | 26993661 |
| flies in the north: locomotor behavior and clock neuron organization of drosophila montana. | the circadian clock plays an important role in adaptation in time and space by synchronizing changes in physiological, developmental, and behavioral traits of organisms with daily and seasonal changes in their environment. we have studied some features of the circadian activity and clock organization in a northern drosophila species, drosophila montana, at both the phenotypic and the neuronal levels. in the first part of the study, we monitored the entrained and free-running locomotor activity r ... | 2012 | 23010660 |
| myo-inositol as a main metabolite in overwintering flies: seasonal metabolomic profiles and cold stress tolerance in a northern drosophilid fly. | coping with seasonal changes in temperature is an important factor underlying the ability of insects to survive over the harsh winter conditions in the northern temperate zone, and only a few drosophilids have been able to colonize sub-polar habitats. information on their winter physiology is needed as it may shed light on the adaptive mechanisms of overwintering when compared with abundant data on the thermal physiology of more southern species, such as drosophila melanogaster. here we report t ... | 2012 | 22837463 |
| two distinct genomic regions, harbouring the period and fruitless genes, affect male courtship song in drosophila montana. | acoustic signals often have a significant role in pair formation and in species recognition. determining the genetic basis of signal divergence will help to understand signal evolution by sexual selection and its role in the speciation process. an earlier study investigated quantitative trait locus for male courtship song carrier frequency (fre) in drosophila montana using microsatellite markers. we refined this study by adding to the linkage map markers for 10 candidate genes known to affect so ... | 2012 | 22234247 |
| sequence variation in couch potato and its effects on life-history traits in a northern malt fly, drosophila montana. | couch potato (cpo) has previously been connected to reproductive diapause in several insect species including drosophila melanogaster, where it has been suggested to provide a link between the insulin signalling pathway and the hormonal control of diapause. in the first part of the study we sequenced nearly 3.6 kb of this gene in a northern drosophila species (drosophila montana) with a robust photoperiodically determined diapause and found several types of polymorphisms along the sequenced area ... | 2012 | 22138635 |
| molecular phylogeny and genome evolution in the drosophila virilis species group: duplications of the alcohol dehydrogenase gene. | drosophila virilis is a prominent reference species for comparison with drosophila melanogaster in regard to patterns and mechanisms of molecular and genomic evolution. sequences were determined for 11 adh genes from 8 species of the d. virilis species group, including species from both the virilis phylad and the montana subphylad. the genome of d. virilis contains a 6-kb duplication that includes the entire adh coding region. the pattern of sequence identity within the duplication strongly sugg ... | 1996 | 8583887 |
| cuticular hydrocarbons of drosophila montana: geographic variation, sexual dimorphism and potential roles as pheromones. | sexual selection within populations can play an important role in speciation when divergence in mating signals and their corresponding preferences occur along different coevolutionary trajectories in different populations. in insects, one potential target of sexual selection is the blend of cuticular hydrocarbons (chcs), which often show intra- and interspecific variation, sexual dimorphism and may act as pheromones. in drosophila montana, a cold-adapted, circumboreal member of the drosophila vi ... | 2014 | 24373710 |
| cold tolerance and cold-induced modulation of gene expression in two drosophila virilis group species with different distributions. | the importance of high and low temperature tolerance in adaptation to changing environmental conditions has evoked new interest in modulations in gene expression and metabolism linked with stress tolerance. we investigated the effects of rapid cold hardening and cold acclimatization on the chill coma recovery times of two drosophila virilis group species, drosophila montana and d. virilis, with different distributions and utilized a candidate gene approach to trace changes in their gene expressi ... | 2012 | 22122733 |
| resolving the phylogenetic relationships and evolutionary history of the drosophila virilis group using multilocus data. | the drosophila virilis group is one of the major lineages of drosophila previously recognised and it has been used as a model for different types of studies. it comprises 13 species whose phylogenetic relationships are not well resolved. in the present study, six nuclear genes (adh, fused, gpdh, nona, cg9631 and cg7219) and the mitochondrial ribosomal rna genes (12s-16s) have been used to estimate the evolutionary tree of the group using different methods of phylogenetic reconstruction. differen ... | 2011 | 21571080 |
| a microsatellite linkage map for drosophila montana shows large variation in recombination rates, and a courtship song trait maps to an area of low recombination. | current advances in genetic analysis are opening up our knowledge of the genetics of species differences, but challenges remain, particularly for out-bred natural populations. we constructed a microsatellite-based linkage map for two out-bred lines of drosophila montana derived from divergent populations by taking advantage of the drosophila virilis genome and available cytological maps of both species. although the placement of markers was quite consistent with cytological predictions, the map ... | 2010 | 20040000 |
| [comparative analysis of hsp70 gene cluster in drosophila virilis species group]. | we cloned and sequenced one of drosophila montana hsp70 genes. 3'-flanking region of this particular copy contains fragment of sgm mobile element. previously this element was found within hsp70 3'-flanking region of other species of the virilis species group namely d. virilis and d. lummei. we have described reorganization of hsp70 gene cluster in one of d. virilis strains involving full-length sgm. our data enable one to suggest evolutionary conservatism of sgm localization within hsp70 gene cl ... | 2009 | 19334525 |
| the extent of variation in male song, wing and genital characters among allopatric drosophila montana populations. | drosophila montana, a species of the drosophila virilis group, has distributed around the northern hemisphere. phylogeographic analyses of two north american and one eurasian population of this species offer a good background for the studies on the extent of variation in phenotypic traits between populations as well as for tracing the selection pressures likely to play a role in character divergence. in the present paper, we studied variation in the male courtship song, wing and genital characte ... | 2007 | 17584251 |
| genetics of esterases in drosophila. iv. slow-migrating s-esterase in drosophila of the virilis group. | a slow-migrating beta-esterase (s-esterase) is described which has been detected in drosophila montana, drosophila imeretensis, and some stocks of drosophila virilis when mixtures of alpha- and beta-naphthyl acetate are used as substrates in histochemical reactions after electrophoresis. sexual dimorphism for s-esterase has been demonstrated. this esterase is contained in male genitalia only, predominantly in the ejaculatory bulb (waxy plug). it appears 3-4 days after emergence of flies. in hybr ... | 1976 | 816350 |
| effect of temperature on the duration of sensitive period and on the number of photoperiodic cycles required for the induction of reproductive diapause in drosophila montana. | correct timing of the induction of photoperiodic reproductive diapause has been found to play an important role in the life cycle of several northern insect species. however, even when the environmental conditions are favourable for diapause, the switch to diapause can only take place when the females are in a proper developmental and physiological stage, referred to as the sensitive period (sp) for diapause. we have previously shown that in a northern fly species, drosophila montana, the develo ... | 2013 | 23428942 |
| variability levels, population size and structure of american and european drosophila montana populations. | the level and patterns of nucleotide diversity have been characterized for two x-linked loci, fused (fu; a region of 2362 bp) and suppressor of sable (su(s); a region of 413 bp), in one european and one american d. montana population. sequence variation at these loci shows that the two populations are divergent, although they may not be completely isolated. data on the level of silent site variability at su(s) (1.1% and 0.5% for the european and american populations, respectively) suggest that t ... | 2001 | 11520351 |
| postmating-prezygotic isolation between two allopatric populations of drosophila montana: fertilisation success differs under sperm competition. | postmating but prezygotic (pmpz) interactions are increasingly recognized as a potentially important early-stage barrier in the evolution of reproductive isolation. a recent study described a potential example between populations of the same species: single matings between drosophila montana populations resulted in differential fertilisation success because of the inability of sperm from one population (vancouver) to penetrate the eggs of the other population (colorado). as the natural mating sy ... | 2016 | 27087932 |
| preparing for winter: the transcriptomic response associated with different day lengths in drosophila montana. | at northern latitudes, the most robust cue for assessing the onset of winter is the shortening of day lengths. many species use day length as a cue to increase their cold tolerance and/or enter into diapause, but little is known about changes in gene expression that occur under different day lengths. we investigate the gene expression changes associated with differences in light/dark cycles in drosophila montana, a northerly distributed species with a strong adult photoperiodic reproductive diap ... | 2016 | 26976440 |
| the genetic architecture of sexually selected traits in two natural populations of drosophila montana. | we investigated the genetic architecture of courtship song and cuticular hydrocarbon traits in two phygenetically distinct populations of drosophila montana. to study natural variation in these two important traits, we analysed within-population crosses among individuals sampled from the wild. hence, the genetic variation analysed should represent that available for natural and sexual selection to act upon. in contrast to previous between-population crosses in this species, no major quantitative ... | 2015 | 26198076 |
| localization of quantitative trait loci for diapause and other photoperiodically regulated life history traits important in adaptation to seasonally varying environments. | seasonally changing environments at high latitudes present great challenges for the reproduction and survival of insects, and photoperiodic cues play an important role in helping them to synchronize their life cycle with prevalent and forthcoming conditions. we have mapped quantitative trait loci (qtl) responsible for the photoperiodic regulation of four life history traits, female reproductive diapause, cold tolerance, egg-to-eclosion development time and juvenile body weight in drosophila mont ... | 2015 | 25877951 |
| temperate drosophila preserve cardiac function at low temperature. | most insects are chill susceptible and will enter a coma if exposed to sufficiently low temperature. this chill coma has been associated with a failure of the neuromuscular system. insect heart rate (hr) is determined by intrinsic regulation (muscle pacemaker) with extrinsic (nervous and humoral) input. by examining the continually active heart of five drosophila species with markedly different cold tolerance, we investigated whether cardiac performance is related to the whole animal critical th ... | 2015 | 25871726 |
| reproductive isolation among allopatric drosophila montana populations. | an outstanding goal in speciation research is to trace the mode and tempo of the evolution of barriers to gene flow. such research benefits from studying incipient speciation, in which speciation between populations has not yet occurred, but where multiple potential mechanisms of reproductive isolation (ri: i.e., premating, postmating-prezygotic (pmpz), and postzygotic barriers) may act. we used such a system to investigate these barriers among allopatric populations of drosophila montana. in al ... | 2014 | 25302639 |
| northern drosophila montana flies show variation both within and between cline populations in the critical day length evoking reproductive diapause. | reproductive diapause, and its correct timing, plays an important role in the life cycle of many insect species living in a seasonally varying environment at high latitudes. in the present paper we have documented variation in the critical day length (cdl) for adult reproductive diapause and the steepness of photoperiodic response curves (pprcs) in seven clinal populations of drosophila montana in finland between the latitudes 61 and 67°n, paying special attention to variation in these traits wi ... | 2013 | 23702203 |
| involvement of circadian oscillation(s) in the photoperiodic time measurement and the induction of reproductive diapause in a northern drosophila species. | an ability to predict forthcoming changes in environmental conditions and get prepared for them in advance is crucial for the survival and reproduction of organisms living in a seasonally changing environment. we have studied the possible involvement of circadian oscillator(s) in the photoperiodic timer controlling seasonal responses by tracing drosophila montana females' diapause induction in constant darkness and in a classical nanda-hamner experiment. nearly all females developed ovaries in c ... | 2013 | 23665332 |
| photoperiodic regulation of life-history traits before and after eclosion: egg-to-adult development time, juvenile body mass and reproductive diapause in drosophila montana. | photoperiod is the main environmental cue used by northern insects to predict the forthcoming seasonal changes and to adjust their life-history traits to fit these changes. we studied the effects of photoperiod on egg-to-adult development time, juvenile body mass and female reproductive diapause in two northern drosophila montana populations with different patterns of voltinism. the most interesting findings were consistent between the populations: (1) when maintained before eclosion in short da ... | 2012 | 23026647 |
| sexual selection on song and cuticular hydrocarbons in two distinct populations of drosophila montana. | sexual selection has the potential to contribute to population divergence and speciation. most studies of sexual selection in drosophila have concentrated on a single signaling modality, usually either courtship song or cuticular hydrocarbons (chcs), which can act as contact pheromones. we have examined the relationship between both signal types and reproductive success using f(1-3) offspring of wild-collected flies, raised in the lab. we used two populations of the holarctic species drosophila ... | 2012 | 22408728 |
| adaptation to a seasonally varying environment: a strong latitudinal cline in reproductive diapause combined with high gene flow in drosophila montana. | adaptation to seasonal changes in the northern hemisphere includes an ability to predict the forthcoming cold season from gradual changes in environmental cues early enough to prepare for the harsh winter conditions. the magnitude and speed of changes in these cues vary between the latitudes, which induces strong selection pressures for local adaptation.we studied adaptation to seasonal changes in drosophila montana, a northern maltfly, by defining the photoperiodic conditions leading to adult r ... | 2011 | 22393492 |
| photoperiodic regulation of cold tolerance and expression levels of regucalcin gene in drosophila montana. | temperature-induced plasticity of cold tolerance has been reported in many insect species, but cold tolerance can also be affected by changes in day (or night) length. in the present study we elucidate the direct and indirect effects of photoperiod on the cold tolerance of females of two drosophila montana strains--one which possesses a robust photoperiodic diapause and another which does not. in the diapause-strain the time needed for recovery from chill coma showed a positive correlation with ... | 2012 | 22360999 |
| multiple quantitative trait loci influence intra-specific variation in genital morphology between phylogenetically distinct lines of drosophila montana. | the evolution of animal genitalia has gained renewed interest because of their potential roles during sexual selection and early stages of species formation. although central to understanding the evolutionary process, knowledge of the genetic basis of natural variation in genital morphology is limited to a very few species. using an outbred cross between phylogenetically distinct lines of drosophila montana, we characterized quantitative trait loci (qtls) affecting the size and shape of the dist ... | 2011 | 21635604 |
| sexual and postmating reproductive isolation between allopatric drosophila montana populations suggest speciation potential. | widely distributed species with populations adapted to different environmental conditions can provide valuable opportunities for tracing the onset of reproductive incompatibilities and their role in the speciation process. drosophila montana, a d. virilis group species found in high latitude boreal forests in nearctic and palearctic regions around the globe, could be an excellent model system for studying the early stages of speciation, as a wealth of information concerning this species' ecology ... | 2011 | 21396136 |
| effects of photoperiodically induced reproductive diapause and cold hardening on the cold tolerance of drosophila montana. | coping with seasonal and daily variation in environmental conditions requires that organisms are able to adjust their reproduction and stress tolerance according to environmental conditions. females of drosophila montana populations have adapted to survive over the dark and cold winters at high latitudes and altitudes by spending this season in photoperiodically controlled reproductive diapause and reproducing only in spring/summer. the present study showed that flies of a northern population of ... | 2011 | 20932841 |
| changes in gene expression linked with adult reproductive diapause in a northern malt fly species: a candidate gene microarray study. | insect diapause is an important biological process which involves many life-history parameters important for survival and reproductive fitness at both individual and population level. drosophila montana, a species of d. virilis group, has a profound photoperiodic reproductive diapause that enables the adult flies to survive through the harsh winter conditions of high latitudes and altitudes. we created a custom-made microarray for d. montana with 101 genes known to affect traits important in dia ... | 2010 | 20122138 |
| sexual conflict over the duration of copulation in drosophila montana: why is longer better? | conflicts of interest between the sexes are increasingly recognized as an engine driving the (co-)evolution of reproductive traits. the reproductive behaviour of drosophila montana suggests the occurrence of sexual conflict over the duration of copulation. during the last stages of copulation, females vigorously attempt to dislodge the mounting male, while males struggle to maintain genital contact and often successfully extend copulations far beyond the females' preferred duration. | 2009 | 19523190 |
| factors affecting male song evolution in drosophila montana. | d. montana (a species of the d. virilis group) has spread over the northern hemisphere, populations from different areas showing both genetic and phenotypic divergence. the males of this species produce an elaborate courtship song, which plays a major role both in species recognition and in intraspecific mate choice. the genetic architecture and physical constraints, as well as the importance of the signal for species recognition, set boundaries within which this signal can vary. within these li ... | 2005 | 15949536 |
| the role of male courtship song in species recognition in drosophila montana. | in many drosophila species the male courtship song is an essential part of a successful courtship, playing a role in species-recognition and/or in sexual selection exercised by the females on conspecific males. in drosophila montana, specific traits of the courtship song (the length and the carrier frequency of sound pulses) have earlier been shown to play an important role in intraspecific mate choice. here we show that the male song (especially the interpulse interval) also plays a role in spe ... | 2005 | 15864441 |
| inbreeding and outbreeding depression in male courtship song characters in drosophila montana. | in drosophila montana, male courtship song frequency is closely associated with male courtship success and offspring survival. other pulse characters (pulse length and cycle number) may also affect female mate choice, whereas pulse train characters (interpulse interval, pulse number and pulse train length) are not associated with these male fitness components. inbreeding depression in these song characters was investigated by comparing the songs of inbred and outbred fly strains. the average cha ... | 2000 | 10762398 |
| variability and evolvability of male song characters in drosophila montana populations. | in drosophila montana, the male courtship song (especially the pulse characters of the song) plays an important role in sexual selection. the heritabilities and the amount of additive and residual variation in different characters of the male song were measured in two populations using father-son regression and sib analysis. the songs of the males from the oulanka population were recorded for a second time after the males had been kept in 4 degrees c for 6 months. heritabilities measured for dif ... | 1999 | 10364824 |
| male courtship song frequency as an indicator of male genetic quality in an insect species, drosophila montana. | most theoretical models on evolution of male secondary sexual characters and female preferences for these characters suggest that the male characters evolve in response to female preferences that may themselves evolve in response to direct or indirect benefits of choice. in drosophila montana (a species of the d. virilis group), females use male song in their mate choice, preferring males that produce songs with short sound pulses and a high carrier frequency. we demonstrate here that the female ... | 1998 | 9569668 |
| laboratory and natural heritabilities of male courtship song characters in drosophila montana and d. littoralis. | we estimated heritabilities for several male courtship song characters in two drosophila species using father-son regression under conditions where both fathers and sons had been raised in the laboratory. in d. montana the heritabilities of song characters were rather high (-0.23 to 0.80) and in most cases significant. in d. littoralis the heritabilities of song characters were generally lower (-0.33 to 0.18), and none of them was significantly larger than zero. we also estimated heritabilities ... | 1993 | 8496069 |
| frequency of multiple insemination in a natural population of drosophila montana. | the frequency of multiple insemination was studied in a boreal drosophila montana population using mother-offspring data for a sex-linked allozyme locus. mating with respect to the marker studied was random. in crowded laboratory cultures the heterozygous offspring had higher viability than homozygotes, but no deviations from hardy-weinberg proportions were found in natural populations. in multiply sired progenies the males did not contribute equally to the progeny, but the proportion sired by t ... | 1992 | 1459857 |
| an esterase of bacterial origin in drosophila montana. | | 1981 | 7247932 |
| evolution of the alpha-esterase duplication within the montana subphylad of the virilis species group of drosophila. | previous studies on linkage disequilibrium involving four tightly linked genes that code for the alpha-esterases of drosophila montana suggest that these loci arose from a primitive esterase gene by gene duplication, followed by tandem duplication (roberts and baker 1973). we have examined the esterase variants in the closely related species, lacicola, flavomontana and borealis. these studies reveal that borealis has only a single esterase locus, and flavomontana may have only two loci. cytologi ... | 1980 | 17249016 |
| linkage disequilibrium over space and time in natural populations of drosophila montana. | the previously described allelic frequencies and linkage disequilibrium among the active and null alleles of four tightly linked loci coding for the alpha-esterases were found to be maintained by one population for 5 years, and were found to be present in two other populations which were shown to be genetically distinct from the first. it appears that enzyme variants coded by these highly polymorphic loci are being maintained in the populations by selective forces. | 1975 | 1060092 |
| nuclear elongation and cytokinesis in drosophila montana. | | 1971 | 5167431 |