Adaptation via Symbiosis: Recent Spread of a Drosophila Defensive Symbiont

  title={Adaptation via Symbiosis: Recent Spread of a Drosophila Defensive Symbiont},
  author={John Jaenike and Robert L. Unckless and Sarah N. Cockburn and Lisa M. Boelio and Steve J. Perlman},
  pages={212 - 215}
Offsetting the Cost of Parasitism Fruit flies, like most animals, are vulnerable to infection by a range of organisms, which, in co-infections, can interact with sometimes surprising effects. Jaenike et al. (p. 212) discovered that a species of Spiroplasma bacterium that is sometimes found in flies, and that is transmitted from mother to offspring, protects its host from the effects of a nematode worm parasite, Howardula aoronymphium. The worm sterilizes the female flies and shortens their… 

Ecology of a novel defensive symbiont of Drosophila: Spiroplasma-mediated protection against parasitic nematodes

This thesis found that D. neotestacea harbours a strain of the bacterial symbiont Spiroplasma that restores fertility to nematode-parasitized female flies, and Sequencing a number of Spiro Plasma genes, as well as fly mitochondrial DNA, strongly suggests that the defensive symbionts is spreading westward.

Host Defense via Symbiosis in Drosophila

What is known of Drosophila as an intriguing and emerging model of defensive symbiosis is summarized to shift the perception of many facultative inherited symbionts from that of manipulative parasites toward helpful mutualists.

Endosymbiont-based immunity in Drosophila melanogaster against parasitic nematode infection

An interaction between Wolbachia endosymbionts with the immune response of D. melanogaster against infection with the entomopathogenic nematodes is suggested and indicates a complex interplay between insect hosts, endosYmbiotic microbes and pathogenic organisms.

A ribosome-inactivating protein in a Drosophila defensive symbiont

This study identifies a novel RIP in an insect defensive symbiont and suggests an underlying RIP-dependent mechanism in Spiroplasma-mediated defense.

Male killing Spiroplasma protects Drosophila melanogaster against two parasitoid wasps

The results indicate that Spiroplasma MSRO prevents successful development of both wasps, and confers a small, albeit significant, increase in larva-to-adult survival of flies subjected to wasp attacks, and the conditions under which defense can contribute to Spiro Plasma persistence are modeled.

Rapid spread of the defensive endosymbiont Spiroplasma in Drosophila hydei under high parasitoid wasp pressure.

The defensive mechanism may contribute to the high prevalence of Spiroplasma in host populations despite imperfect vertical transmission, and any possible fitness costs to harboring Spiraplasma are addressed.

No evidence for behavioural adaptations to nematode parasitism by the fly Drosophila putrida

There are no direct effects of eating α‐amanitin on this host–parasite interaction, and it is suggested that toxin tolerance is more likely maintained by selection due to competition for resources than as a mechanism to avoid parasite infection or to reduce the virulence of infection.

Defensive endosymbionts: a cryptic trophic level in community ecology.

It is shown that Spiroplasma spreads rapidly within experimental populations of D. neotestacea subject to Howardula parasitism, but is neither strongly favored nor selected against in the absence of Howardula, exhibiting effectively consumer-resource trophic dynamics.

Toxin and Genome Evolution in a Drosophila Defensive Symbiosis

The results suggest that distantly related Spiroplasma RIP toxins may perform specialized functions with regard to parasite specificity and suggest an important role for horizontal gene transfer in the emergence of novel defensive phenotypes.

Functional analysis of RIP toxins from the Drosophila endosymbiont Spiroplasma poulsonii

The results indicate that RIPs released by S. poulsonii contribute to the reduction of host lifespan and embryo mortality, which suggests that SpRIPs may impact the insect-symbiont homeostasis beyond their protective function against parasites.



The Bacterial Symbiont Wolbachia Induces Resistance to RNA Viral Infections in Drosophila melanogaster

It is reported that a bacterial infection renders D. melanogaster more resistant to Drosophila C virus, reducing the load of viruses in infected flies and identifying these resistance-inducing bacteria as Wolbachia.


Virulence is evolutionarily labile in associations between Drosophila testacea group species and their Howardula parasites, and changes in the sterility component of virulence are due primarily to host evolution, whereasChanges in the host mortality component are due in large part to parasite evolution.


  • J. Jaenike
  • Biology
    Evolution; international journal of organic evolution
  • 1996
Field and laboratory evidence shows that the nematode parasite Howardula aoronymphium is relatively avirulent to one of its principal host species, Drosophila falleni, whereas it is much more virulent to D. putrida and D. neotestacea, suggesting that there may be substantial vertical transmission in D. falleni.

Evolutionarily stable infection by a male-killing endosymbiont in Drosophila innubila: molecular evidence from the host and parasite genomes.

Molecular data suggest that this male-killing strain of Wolbachia discovered in natural populations of D. innubila is evolutionarily old, a conclusion supported with a simple model of parasite and mtDNA transmission dynamics.

Associations between mycophagous Drosophila and their Howardula nematode parasites: a worldwide phylogenetic shuffle

Overall, these host associations are highly dynamic, and appear to be driven by a combination of repeated opportunities for host colonization due to shared breeding sites and large potential host ranges of the nematodes.

Facultative bacterial symbionts in aphids confer resistance to parasitic wasps

Investigation of aphids for vulnerability of the aphid host to a hymenopteran parasitoid, Aphidius ervi, shows that infection confers resistance to parasitoids attack by causing high mortality of developing Parasitoid larvae.

Ecology and Evolution of Host‐Parasite Associations: Mycophagous Drosophila and Their Parasitic Nematodes

A biogeographic analysis of the relative abundance of different Drosophila species has shown that H. aoronymphium may facilitate the coexistence of different species of Drosophile that compete for larval food resources.

Multiple introductions of the Spiroplasma bacterial endosymbiont into Drosophila

A multilocus sequence analysis is used to reconstruct a robust Spiroplasma endosymbiont phylogeny, assess genetic diversity, and look for evidence of recombination in Drosophila populations.

Heritable Endosymbionts of Drosophila

Findings indicate that in contrast to some other insect groups, other heritable symbionts are uncommon in Drosophila species, possibly reflecting a robust innate immune response that eliminates many bacteria.

Bacteriophages Encode Factors Required for Protection in a Symbiotic Mutualism

The results show that these mobile genetic elements can endow a bacterial symbiont with benefits that extend to the animal host, and that phages vector ecologically important traits, such as defense against parasitoids, within and among Symbiont and animal host lineages.