Evidence of photosynthate translocation in an algal-acoel symbiotic system: An in vivo, qualitative approach

Convolutriloba retrogemma, like other members of the genus and other symbiotic acoels, does not lend itself well to established methods for the detection and quantification of photosynthate translocation from symbiont to host. We describe a novel method for indirectly detecting evidence of photosynthate movement, in vivo, utilizing differential weight change in animals subjected to light and dark treatments without holozoic feeding. Unfed acoels kept in light lost 28% of their original weight while those kept in the dark lost 41%. Also described is a refined method for the separation of algal symbionts from host tissue in these species, as well as a method for determining accurate wet-weight of this and other soft-bodied, invertebrate species.