title: Travelling at a slug's pace: possible invertebrate vectors of Caenorhabditis nematodes.
abstract: How do very small animals with limited long-distance dispersal abilities move between locations, especially if they prefer ephemeral micro-habitats that are only available for short periods of time? The free-living model nematode Caenorhabditis elegans and several congeneric taxa appear to be common in such short-lived environments, for example decomposing fruits or other rotting plant material. Dispersal is usually assumed to depend on animal vectors, yet all current data is based on only a limited number of studies. In our project we performed three comprehensive field surveys on possible invertebrate vectors in North German locations containing populations of C. elegans and two related species, especially C. remanei, and combined these screens with an experimental analysis of persistence in one of the vector taxa.
  
  
  
  Our field survey revealed that Caenorhabditis nematodes are commonly found in slugs, isopods, and chilopods, but are not present in the remaining taxonomic groups examined. Surprisingly, the nematodes were frequently isolated from the intestines of slugs, even if slugs were not collected in close association with suitable substrates for Caenorhabditis proliferation. This suggests that the nematodes are able to enter the slug intestines and persist for certain periods of time. Our experimental analysis confirmed the ability of C. elegans to invade slug intestines and subsequently be excreted alive with the slug feces, although only for short time periods under laboratory conditions.
  
  
  
  We conclude that three invertebrate taxonomic groups represent potential vectors of Caenorhabditis nematodes. The nematodes appear to have evolved specific adaptations to enter and persist in the harsh environment of slug intestines, possibly indicating first steps towards a parasitic life-style.
authors.affiliation: Department of Evolutionary Ecology and Genetics, Zoological Institute Christian-Albrechts University, Am Botanischen Garten 1-9, 24118, Kiel, Germany. cpetersen@zoologie.uni-kiel.de.
authors.forename: Carola
authors.initials: C
authors.lastname: Petersen
authors.affiliation: Department of Evolutionary Ecology and Genetics, Zoological Institute Christian-Albrechts University, Am Botanischen Garten 1-9, 24118, Kiel, Germany. ruben.hrmnn@hotmail.com.
authors.forename: Ruben Joseph
authors.initials: RJ
authors.lastname: Hermann
authors.affiliation: Department of Evolutionary Ecology and Genetics, Zoological Institute Christian-Albrechts University, Am Botanischen Garten 1-9, 24118, Kiel, Germany. m.barg85@gmx.de.
authors.forename: Mike-Christoph
authors.initials: MC
authors.lastname: Barg
authors.affiliation: Department of Evolutionary Ecology and Genetics, Zoological Institute Christian-Albrechts University, Am Botanischen Garten 1-9, 24118, Kiel, Germany. rebecca.schalkowski@googlemail.com.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Schalkowski
authors.affiliation: Department of Evolutionary Ecology and Genetics, Zoological Institute Christian-Albrechts University, Am Botanischen Garten 1-9, 24118, Kiel, Germany. pdirksen@zoologie.uni-kiel.de.
authors.forename: Philipp
authors.initials: P
authors.lastname: Dirksen
authors.affiliation: Department of Evolutionary Ecology and Genetics, Zoological Institute Christian-Albrechts University, Am Botanischen Garten 1-9, 24118, Kiel, Germany. cbarbosa@zoologie.uni-kiel.de.
authors.forename: Camilo
authors.initials: C
authors.lastname: Barbosa
authors.affiliation: Department of Evolutionary Ecology and Genetics, Zoological Institute Christian-Albrechts University, Am Botanischen Garten 1-9, 24118, Kiel, Germany. hschulenburg@zoologie.uni-kiel.de.
authors.forename: Hinrich
authors.initials: H
authors.lastname: Schulenburg
mesh_terms: D063147:Animal Distribution; D000818:Animals; D002107:Caenorhabditis / Q000145:classification / Q000502:physiology*; D058893:DNA Barcoding, Taxonomic; D017753:Ecosystem; D049851:Gastropoda / Q000145:classification / Q000469:parasitology*; D005858:Germany; D007422:Intestines / Q000469:parasitology; D033321:Isopoda; D008969:Molecular Sequence Data