| defensive endosymbionts: a cryptic trophic level in community ecology. | maternally transmitted endosymbionts are widespread among insects, but how they are maintained within host populations is largely unknown. recent discoveries show that some endosymbionts protect their hosts from pathogens or parasites. spiroplasma, an endosymbiont of drosophila neotestacea, protects female hosts from the sterilizing effects of parasitism by the nematode howardula aoronymphium. here, we show that spiroplasma spreads rapidly within experimental populations of d. neotestacea subjec ... | 2010 | 21155960 |
| generality of toxins in defensive symbiosis: ribosome-inactivating proteins and defense against parasitic wasps in drosophila. | while it has become increasingly clear that multicellular organisms often harbor microbial symbionts that protect their hosts against natural enemies, the mechanistic underpinnings underlying most defensive symbioses are largely unknown. spiroplasma bacteria are widespread associates of terrestrial arthropods, and include strains that protect diverse drosophila flies against parasitic wasps and nematodes. recent work implicated a ribosome-inactivating protein (rip) encoded by spiroplasma, and re ... | 2017 | 28683136 |
| a ribosome-inactivating protein in a drosophila defensive symbiont. | vertically transmitted symbionts that protect their hosts against parasites and pathogens are well known from insects, yet the underlying mechanisms of symbiont-mediated defense are largely unclear. a striking example of an ecologically important defensive symbiosis involves the woodland fly drosophila neotestacea, which is protected by the bacterial endosymbiont spiroplasma when parasitized by the nematode howardula aoronymphium. the benefit of this defense strategy has led to the rapid spread ... | 2015 | 26712000 |
| infectious adaptation: potential host range of a defensive endosymbiont in drosophila. | maternally transmitted symbionts persist over macroevolutionary timescales by undergoing occasional lateral transfer to new host species. to invade a new species, a symbiont must survive and reproduce in the new host, undergo maternal transmission, and confer a selective benefit sufficient to overcome losses due to imperfect maternal transmission. drosophila neotestacea is naturally infected with a strain of spiroplasma that restores fertility to nematode-parasitized females, which are otherwise ... | 2012 | 23550746 |
| adaptation via symbiosis: recent spread of a drosophila defensive symbiont. | recent studies have shown that some plants and animals harbor microbial symbionts that protect them against natural enemies. here we demonstrate that a maternally transmitted bacterium, spiroplasma, protects drosophila neotestacea against the sterilizing effects of a parasitic nematode, both in the laboratory and the field. this nematode parasitizes d. neotestacea at high frequencies in natural populations, and, until recently, almost all infections resulted in complete sterility. several lines ... | 2010 | 20616278 |
| association between wolbachia and spiroplasma within drosophila neotestacea: an emerging symbiotic mutualism? | interspecific mutualism can evolve when specific lineages of different species tend to be associated with each other from one generation to the next. different maternally transmitted endosymbionts occurring within the same cytoplasmic lineage fulfil this requirement. drosophila neotestacea is infected with maternally transmitted wolbachia and spiroplasma, which are cotransmitted at high frequency in natural populations. molecular phylogenetic evidence indicates that both endosymbionts have been ... | 2010 | 20002580 |
| lack of behavioral fever in nematode-parasitized drosophila. | the parasitic nematode howardula aoronymphium causes severe fertility reduction and sterility in females of several species of mycophagous drosophila. infected females of drosophila putrida recover their fertility when kept at a postemergence temperature of 29 c but not when kept at 27 c or below. when given a choice of temperatures in a thermal gradient, neither this species, drosophila falleni, nor drosophila neotestacea manifested adaptive behavioral fever in response to parasitism. however, ... | 1995 | 7472853 |
| transcriptional responses in a drosophila defensive symbiosis. | inherited symbionts are ubiquitous in insects and can have important consequences for the fitness of their hosts. many inherited symbionts defend their hosts against parasites or other natural enemies; however, the means by which most symbionts confer protection is virtually unknown. we examine the mechanisms of defence in a recently discovered case of symbiont-mediated protection, where the bacterial symbiont spiroplasma defends the fly drosophila neotestacea from a virulent nematode parasite, ... | 2014 | 24274471 |
| dynamics of the continent-wide spread of a drosophila defensive symbiont. | facultative symbionts can represent important sources of adaptation for their insect hosts and thus have the potential for rapid spread. drosophila neotestacea harbours a heritable symbiont, spiroplasma, that confers protection against parasitic nematodes. we previously found a cline in spiroplasma prevalence across central canada, ending abruptly at the rocky mountains. resampling these populations 9 years later revealed that spiroplasma had increased substantially across the region, resembling ... | 2013 | 23517577 |
| occasional recombination of a selfish x-chromosome may permit its persistence at high frequencies in the wild. | the sex-ratio x-chromosome (sr) is a selfish chromosome that promotes its own transmission to the next generation by destroying y-bearing sperm in the testes of carrier males. in some natural populations of the fly drosophila neotestacea, up to 30% of the x-chromosomes are sr chromosomes. to investigate the molecular evolutionary history and consequences of sr, we sequenced sr and standard (st) males at 11 x-linked loci that span the st x-chromosome and at seven arbitrarily chosen autosomal loci ... | 2016 | 27423061 |
| genomic conflict drives patterns of x-linked population structure in drosophila neotestacea. | intragenomic conflict has the potential to cause widespread changes in patterns of genetic diversity and genome evolution. in this study, we investigate the consequences of sex-ratio (sr) drive on the population genetic patterns of the x-chromosome in drosophila neotestacea. an sr x-chromosome prevents the maturation of y-bearing sperm during male spermatogenesis and thus is transmitted to ~100% of the offspring, nearly all of which are daughters. selection on the rest of the genome to suppress ... | 2013 | 23121224 |
| local selection underlies the geographic distribution of sex-ratio drive in drosophila neotestacea. | "selfish" genetic elements promote their own transmission to the next generation, often at a cost to the host individual. a sex-ratio (sr) driving x chromosome prevents the maturation of y-bearing sperm, and as a result is transmitted to 100% of the offspring, all of which are female. because the spread of a sr chromosome can result in a female-biased population sex ratio, the ecological and evolutionary consequences of harboring this selfish element can be severe. in this study, we show that th ... | 2012 | 22486683 |
| association of polyandry and sex-ratio drive prevalence in natural populations of drosophila neotestacea. | selfish genetic elements bias their own transmission to the next generation, even at the expense of the fitness of their carrier. sex-ratio (sr) meiotic drive occurs when an x-chromosome causes y-bearing sperm to die during male spermatogenesis, so that it is passed on to all of the male's offspring, which are all daughters. how sr is maintained as a stable polymorphism in the absence of genetic suppressors of drive is unknown. here, we investigate the potential for the female remating rate to a ... | 2013 | 24004936 |
| macroevolutionary persistence of heritable endosymbionts: acquisition, retention and expression of adaptive phenotypes in spiroplasma. | the phylogenetic incongruence between insects and their facultative maternally transmitted endosymbionts indicates that these infections are generally short-lived evolutionarily. therefore, long-term persistence of many endosymbionts must depend on their ability to colonize and spread within new host species. at least 17 species of drosophila are infected with endosymbiotic spiroplasma that have various phenotypic effects. we transinfected five strains of spiroplasma from three divergent clades ... | 2015 | 26053523 |