title: Adaptation via symbiosis: recent spread of a Drosophila defensive symbiont.
abstract: 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 of evidence suggest that Spiroplasma is spreading in North American populations of D. neotestacea and that a major adaptive change to a symbiont-based mode of defense is under way. These findings demonstrate the profound and potentially rapid effects of defensive symbionts, which are increasingly recognized as major players in the ecology of species interactions.
authors.affiliation: Department of Biology, University of Rochester, Rochester, NY 14627, USA. john.jaenike@rochester.edu
authors.forename: John
authors.initials: J
authors.lastname: Jaenike
authors.forename: Robert
authors.initials: R
authors.lastname: Unckless
authors.forename: Sarah N
authors.initials: SN
authors.lastname: Cockburn
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Boelio
authors.forename: Steve J
authors.initials: SJ
authors.lastname: Perlman
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D004272:DNA, Mitochondrial / Q000235:genetics; D004330:Drosophila / Q000235:genetics / Q000382:microbiology / Q000469:parasitology / Q000502:physiology*; D005260:Female; D005298:Fertility; D006239:Haplotypes; D006790:Host-Parasite Interactions; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D013149:Spiroplasma / Q000302:isolation & purification / Q000502:physiology*; D013559:Symbiosis; D017187:Tylenchida / Q000033:anatomy & histology / Q000502:physiology*; D020577:Wolbachia / Q000302:isolation & purification / Q000502:physiology
chemical_list: D004272:DNA, Mitochondrial