Timing of maternal exposure to toxic cyanobacteria and offspring fitness in Daphnia magna: Implications for the evolution of anticipatory maternal effects. Issue 24 (20th November 2018)

• Record Type: Journal Article
• Authors: Radersma, Reinder; Hegg, Alexander; Noble, Daniel W. A.; Uller, Tobias
• Is Part Of: Ecology and evolution. Volume 8:Issue 24(2018)
• Page Start: 12727
• Page End: 12736
• Publication Date: 2018-11-20
• Subjects: egg size -- fitness -- microcystin -- parental effects -- stress -- tolerance -- transgenerational effects; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.4700
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Organisms that regularly encounter stressful environments are expected to use cues to develop an appropriate phenotype. Water fleas ( Daphnia spp.) are exposed to toxic cyanobacteria during seasonal algal blooms, which reduce growth and reproductive investment. Because generation time is typically shorter than the exposure to cyanobacteria, maternal effects provide information about the local conditions subsequent generations will experience. Here, we evaluate if maternal effects in response to microcystin, a toxin produced by cyanobacteria, represent an inheritance system evolved to transmit information in Daphnia magna . We exposed mothers as juveniles and/or as adults, and tested the offspring's fitness in toxic and non‐toxic environments. Maternal exposure until reproduction reduced offspring fitness, both in the presence and in the absence of toxic cyanobacteria. However, this effect was accompanied by a small positive fitness effect, relative to offspring from unexposed mothers, in the presence of toxic cyanobacteria. This effect was mainly elicited in response to maternal exposure to toxic cyanobacteria early in life and less so during reproduction. None of these effects were explained by changes in egg size. A meta‐analysis using our and others' experiments suggests that the adaptive value of maternal effects to cyanobacteria exposure is weak at best. We suggest that the beneficial maternal effect in our study is an example of phenotypic accommodation spanning generations, rather than a mechanism evolved to transmit information about cyanobacteria presence between generations. Abstract : Waterfleas are negatively affected by toxic cyanobacteria, and therefore, mothers are expected to mitigate the negative effects to their offspring. We use a series of experiments to test whether these beneficial maternal effects represent an inheritance system evolved to transmit information about the toxicity of the environment. Our results and meta‐analysis of previous work suggest that although there can be fitness benefits of having a mother exposed to cyanobacteria, these effects are unlikely to be a result of selection for a mechanism that enables transmission of information across generations.