Where is the jury?
Although the general patterns prove robust, I disagree with the comment
that the “jury” lies in the “generality” nor the previous
meta-analysis “challenges” this generality. Both Radersma et
al. (2018) and Uller et al. (2013) revealed an overall
positive (albeit non-significant) effect, and a pattern of generality is
thus anticipated. We may find nothing more than they anticipated, but
the significance of our study, the “jury”, is to obtain the most
detailed picture to show when and for which taxa such an effect is
beneficial. Instead of always being beneficial, this picture shows
transgenerational effects are disadvantageous for some taxa in some
environments, consistent to the high heterogeneity revealed by
Sánchez-Tójar et al.
The comment also suggests focusing on F2 and F3 generations and
excluding the effect of parental condition transfer (Engqvist &
Reinhold 2016). While these concerns are important for experimental
studies, I wonder whether it is feasible to the evidence-demanding
meta-analysis, given the difficulty of conducting multi-generation
experiments and separating parental “cues” and “conditions”
(Engqvist & Reinhold 2016). Furthermore, whether condition transfer
should be considered adaptive is still controversial (Bonduriansky &
Crean 2018; Engqvist & Reinhold 2018). Our study thus represents a
first feasible step, which draws a picture compatible with these
concerns.