Caenorhabditis elegansnematodes are not attracted to the terrestrial isopodPorcellio scaber

Abstract

Phoresy is a behavior in which an organism, the phoront, travels from one location to another by 'hitching a ride' on the body of a host as it disperses. Some phoronts are generalists, taking advantage of any available host. Others are specialists and travel only when specific hosts are located using chemical cues to identify and move (chemotax) toward the preferred host. Free-living nematodes, like Caenorhabditis elegans, are often found in natural environments that contain terrestrial isopods and other invertebrates. Additionally, the C. elegans wild strain PB306 was isolated associated with the isopod Porcellio scaber. However, it is currently unclear if C. elegans is a phoront of terrestrial isopods, and if so, whether it is a specialist, generalist, or developmental stage-specific combination of both strategies. Because the relevant chemical stimuli might be secreted compounds or volatile odorants, we used different types of chemotaxis assays across diverse extractions of compounds or odorants to test whether C. elegans is attracted to P. scaber. We show that two different strains -the wild isolate PB306 and the laboratory-adapted strain N2 -are not attracted to P. scaber during either the dauer or adult life stages. Our results indicate that C. elegans was not attracted to chemical compounds or volatile odorants from P. scaber, providing valuable empirical evidence to suggest that any associations between these two species are likely opportunistic rather than specific phoresy.

Opposing directions of stage-specific body length change in a close relative of C. elegans

“…Caenorhabditis dauer larvae have been frequently observed on such vectors, and they presumably carry dauers to new rotting plant resources where they disembark and mature. C. elegans has been observed on snails (Helix, Oxychilus, and Pomatias species [31,32]), slugs (Deroceras, Arion, and Ambigolimax species [31,33,34]), isopods (Porcellio, Oniscus, and Armadillidium species [33,35,36]), millipedes (Glomeris species [32]), and centipedes [33,37]. C. briggsae and C. remanei have also been observed on similar vectors (gastropods, isopods, and myriapods [13,34,[37][38][39].…”

“…Silhouettes of invertebrates are to scale. C. elegans has been observed traveling on Arion slugs [33] (~65 mm long [41]), Helix snails [31] (~60 mm long [56]), Porcellio isopods [33,35,36] (~10 mm long [40]), and Glomeris millipedes [32] (~10 mm long [57]). C. inopinata disperses on Ceratoslen bisculatus fig wasps [15,18], which are much smaller in size (~1.7 mm long [42]).…”