Evolution of selfing & lifespan 2.0
The joint evolution of lifespan and self-fertilisation
Flowering plants display a staggering diversity of both mating systems and life histories, ranging from almost exclusively selfers to obligate outcrossers, very short-lived annual herbs to super long lived trees. One pervasive pattern that has attracted considerable attention is the tight correlation that is found between mating systems and lifespan . Until recently, theoretical explanations for these patterns have relied on static models exploring the consequences of several non-mutually exclusive important process: levels of inbreeding depression and ability to successfully were center stage. This make sense: successful colonization after long‐distance dispersal is far more likely to happen for self‐compatible than for self‐incompatible individuals in a sexually reproducing species. Furthermore, inbreeding depression (essentially a genetically driven phenomenon) and reproductive insurance are expected to shape the evolution of both mating system and lifespan.
But modelling jointly several processes and how their interplay to shape the evolution of a trait is challenging enough so models for the evolution of mating system tend invariably – for mathematical convenience and tractability – to fix lifespan .
However, comparative analysis of between species variations that map traits transitions among sister species in phylogenetic trees reveals a pervasive pattern: frequent transitions from a state outcrossing perennial to selfing annuals. This beg the question: is one transition triggering the other and if so, what comes first or are these transitions happening together? In this work, Lesaffre and Billiard use a very sophisticated machinery developed by Kirkpatrick et al.  and consider a general class of so-called modifiers models . They study jointly the evolution of life span and mating system. They do so by using models where different life stages are tracked with life stage having some (fixed for once) amount of inbreeding depression. Their paper is technically demanding, mixing analytics and computer simulations, and along the way generates several important findings that are expected to stimulate further empirical and theoretical studies: (1) pure selfing versus pure outcrossing is the expected stable evolutionary outcomes (despite observation that mixed mating systems can be regularly met in nature), (2) increasing life-span drastically reduces the scope for the evolution of selfing, conversely (3) transition to selfing will also select for shorter life span as a way to mitigate the cumulative effects of inbreeding depression on adult life stages.
As usual there is room for future work, in particular the authors’ model assumes fixed inbreeding depression in the different life stages and this highlights the need for models that explore how inbreeding depression, a pivotal quantity in these models, can itself be molded by both mating system and lifespan. A third-generation of models should be “soon” on the way!
 Grossenbacher D, Briscoe Runquist R, Goldberg EE, and Brandvain Y. (2015) Geographic range size is predicted by plant mating system. Ecology Letters 18, 706–713. doi: 10.1111/ele.12449
 Morgan MT, Schoen DJ, and Bataillon T. (1997) The evolution of self-fertilization in perennials. The American Naturalist 150, 618–638. doi: 10.1086/286085
 Kirkpatrick M, Johnson T, and Barton N. (2002) General models of multilocus evolution. Genetics 161, 1727–1750.
 Lesaffre, T, and Billiard S. (2019) The joint evolution of lifespan and self-fertilisation. bioRxiv, 420877, ver. 3 peer-reviewed and recommended by PCI Evol Biol. doi: 10.1101/420877
Thomas Bataillon (2019) Evolution of selfing & lifespan 2.0 . Peer Community in Evolutionary Biology, 100070. 10.24072/pci.evolbiol.100070
Revision round #22019-02-25
Decision round #2
Dear Thomas & Sylvain First apologies for the very lengthy review process on that round!
Please find enclosed a last set of comments by the two anonymous reviewers.
Basically one of the reviewer is "content" but the second reviewer made a thorough reading of your revised version and flags a number of issues where possibly minor but important clarifications are still needed. He also make some suggestions for minor text reorganisation that are not compulsory per se but well worth considering
I am trusting that these last outstanding issues can be rapidly resolved within a week or two and I will be happy to recommend this paper provided that the revisions and clarifications suggested are implemented (no further review round will be needed).
While you prepare this last needed revisions, I will meanwhile draft my recommendation text.
Thanks again for submitting this interesting piece of theory for recommendation to PCI Evol Biology I look forward to your last and final revised version and to recommend your work within PCI Evol Biology
Additional comments of the managing board:
We'll soon send you a message with specific requirements. So please do not upload the new version of your preprint before we send you this message.
Reviewed by anonymous reviewer, 2018-12-21 16:03
Reviewed by anonymous reviewer, 2018-12-21 16:07
Revision round #12018-10-29
Decision round #1
I am acting as recommender for PCI Evol Biol for your manuscript "The joint evolution of lifespan and self-fertilisation" Authors: Thomas Lesaffre, Sylvain Billiard https://doi.org/10.1101/420877 version 1 - https://www.biorxiv.org/content/early/2018/09/18/420877for recommendation at PCI Evol Biol.
Your manuscript has now been evaluated by two referees. Both have expertise in theoretical population genetics and an interest for mating system evolution. Both reviewers (see detailed reviews) and myself agree that your manuscript has potential to be an interesting contribution that is suitable for being recommended at PCI Evolutionary Biology. But we all feel that before this can happens, fairly extensive revisions should be made.
Here is a synthetic list of the major points that need imperatively to be addressed:
* Reviewer 1 has a number of fairly precise requests (labelled 1 and 2 in the review). These have to do with the presentation of the main results as well as request for clarifying the derivation of the theory results.
* Reviewer 2 has a series of more general comments that are worth considering while revising your manuscript. One important one (labelled comment 2) is how to compare the propensity to evolve selfing while “holding lifetime levels of inbreeding depression constant”. I think that is an important point that together with the points raised by reviewer 1 merits to be addressed in quite a bit of depth.
* Point 4 should be considered at least in the discussion.
* Point 5 is relatively minor but the rev2 has a point regarding what is empirically known on the genetic basis of inbreeding depression.
I very much hope that you can revise your MS to take into account these points.
Best Regards Thomas Bataillon