Meeting Abstract
In nature, many animals routinely suffer physical injury and some species can subsequently regenerate damaged or lost tissue. In sexually reproducing species, one of the most commonly observed effects of injury and regeneration is a reduction in reproductive investment. However, in asexual species, how injury and regeneration affect reproduction remains poorly studied. We investigated how the frequency of injury and regeneration affects reproductive investment under both high and low food conditions in the asexual annelid Pristina leidyi. This species regenerates readily after injury and reproduces by fission by releasing offspring (zooids) from the posterior end. In our experiment, we amputated the anterior end of the body zero, one, two, or three times and assessed reproductive output. Unexpectedly, injury frequency had no effect on total fecundity or offspring quality. Food availability had a large effect on reproduction and survival, with high food availability significantly increasing reproductive rate, total reproductive output, and offspring quality while reducing injury-related mortality. Although offspring size varied substantially across our treatments, regeneration rate of offspring showed low variation and was independent of parent feeding treatment. Findings indicate that in P. leidyi reproductive investment is largely a function of resource availability but is not constrained by injury and regeneration. Reproduction proceeds in injured “parent” worms even if it results in their death, indicating that allocation towards offspring is strongly favored over self-preservation. This study demonstrates that asexually reproducing animals can evolve distinct mechanisms of resource management between reproduction and regeneration.
