title: Complex heterochrony underlies the evolution of Caenorhabditis elegans hermaphrodite sex allocation.
abstract: Hermaphroditic organisms are key models in sex allocation research, yet the developmental processes by which hermaphrodite sex allocation can evolve remain largely unknown. Here we use experimental evolution of hermaphrodite-male (androdioecious) Caenorhabditis elegans populations to quantify the developmental changes underlying adaptive shifts in hermaphrodite sex allocation. We show that the experimental evolution of increased early-life self-fertility occurred through modification of a suite of developmental traits: increased self-sperm production, accelerated oogenesis and ovulation, and increased embryo retention. The experimental evolution of increased self-sperm production delayed entry into oogenesis-as expected, given the sequentially coupled production of self-spermatogenesis and oogenesis. Surprisingly, however, delayed oogenesis onset did not delay reproductive maturity, nor did it trade-off with gamete or embryo size. Comparing developmental time dynamics of germline and soma indicates that the evolution of increased sperm production did not delay reproductive maturity due to a globally accelerated larval development during the period of self-spermatogenesis. Overall, heterochrony in gametogenesis and soma can explain adaptive shifts in hermaphrodite sex allocation.
authors: Université Nice Sophia Antipolis, CNRS, Inserm, IBV, Parc Valrose, 06100, Nice, France.
authors: Nausicaa
authors: N
authors: Poullet
authors: Université Nice Sophia Antipolis, CNRS, Inserm, IBV, Parc Valrose, 06100, Nice, France.
authors: Anne
authors: A
authors: Vielle
authors: Université Nice Sophia Antipolis, CNRS, Inserm, IBV, Parc Valrose, 06100, Nice, France.
authors: Clotilde
authors: C
authors: Gimond
authors: Instituto Gulbenkian de Ciência, Apartado 14, P-2781-901, Oeiras, Portugal.
authors: Sara
authors: S
authors: Carvalho
authors: Institut de Biologie, École Normale Supérieure, CNRS UMR 8197, INSERM U1024, F-75005, Paris, France. teotonio@biologie.ens.fr.
authors: Henrique
authors: H
authors: Teotónio
authors: Université Nice Sophia Antipolis, CNRS, Inserm, IBV, Parc Valrose, 06100, Nice, France. braendle@unice.fr.
authors: Christian
authors: C
authors: Braendle
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development; D019143:Evolution, Molecular; D057850:Hermaphroditic Organisms / Q000235:genetics* / Q000254:growth & development; D009866:Oogenesis; D057945:Self-Fertilization; D012741:Sexual Maturation / Q000235:genetics*; D013091:Spermatogenesis
keywords: Caenorhabditis elegans; evolution of development; experimental evolution; hermaphrodite; mating system evolution