RESEARCH ARTICLE Someone like me: Size-assortative pairing and mating in an Amazonian fish, sailfin tetra Crenuchus spilurus 1,2 1 1 Elio de Almeida BorghezanID *, Kalebe da Silva Pinto , Jansen Zuanon , Tiago Henrique da Silva Pires1 1 LaboratoÂrio de Ecologia Comportamental e EvolucËão, Instituto Nacional de Pesquisas da AmazoÃnia, Av. Andre ArauÂjo, Manaus, AM, Brazil, 2 Wildlife Research Center of Kyoto University, Sakyo-ku, Kyoto, Japan a1111111111 a1111111111 *
[email protected] a1111111111 a1111111111 a1111111111 Abstract In the absence of constraints, preference for larger mates is expected to evolve, as larger individuals are typical of higher potential fitness. Large females are often more fecund and OPEN ACCESS carry larger eggs (which result in higher number and better quality of offspring), whereas Citation: Borghezan EdA, Pinto KdS, Zuanon J, large males usually have more conspicuous ornaments and are better at defending Pires THdS (2019) Someone like me: Size- resources. However, intrasexual competition can constrain the access to larger partners, assortative pairing and mating in an Amazonian especially when opportunities for mate takeover abound. Here we investigate the relation- fish, sailfin tetra Crenuchus spilurus. PLoS ONE 14 ship between individual's size and mate choice in relation to one's own size and their (9): e0222880. https://doi.org/10.1371/journal. pone.0222880 respective mate's size using the sailfin tetra, a sexually dimorphic Amazonian fish species. We show that ornaments of larger males are exponentially more conspicuous, and larger Editor: John A. B. Claydon, Institute of Marine Research, NORWAY females are more fecund and carry larger eggs. Contrary to expectation, neither males nor females associated for longer with the larger of two offered potential mates.