Male body size and breeding tubercles are both linked to intrasexual dominance and reproductive success in the minnow

• Published in: Animal Behaviour
• Main Authors: Jacob, Alain, Evanno, Guillaume, Renai, Emanuela, Sermier, Roberto, Wedekind, Claus
• Other Authors: Department of Ecology and Evolution, Université de Lausanne = University of Lausanne (UNIL), Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2009
• Subjects: SELECTION SEXUELLE; CARACTERE SEXUEL SECONDAIRE; COMPETITION INTER-MALES; EAU DOUCE; VAIRON; PHOXINUS PHOXINUS; LEK; MALE-MALE COMPETITION; MINNOW; PERL ORGAN; REPRODUCTIVE BEHAVIOUR; SECONDARY SEXUAL CHARACTER; SEXUAL SELECTION; fish; poisson; reproduction animale; comportement animal; [SDV.SA.SPA]Life Sciences [q-bio]/Agricultural sciences/Animal production studies; Minnows; The Minnows
• Online Access: https://hal.science/hal-01453747; https://doi.org/10.1016/j.anbehav.2008.12.006

Male dominance hierarchies are usually linked to relative body size and to weapon size, that is, to determinants of fighting ability. Secondary sexual characters that are not directly used as weapons could still be linked to dominance if they reveal determination or overall health and vigour and hence, indirectly, fighting ability. We studied the mating behaviour of the minnow, Phoxinus phoxinus, a cyprinid fish in which males develop breeding tubercles during the spawning season. The function of these breeding tubercles is still not clear. Using microsatellite markers, we determined male reproductive success under controlled conditions. The minnows were territorial and quickly established a dominance hierarchy at the beginning of the spawning season. Dominance was strongly and positively linked to fertilization success. Although body size and number of breeding tubercles were not significantly correlated in our sample, both large males and males with many breeding tubercles were more dominant and achieved higher fertilization success than small males or males with few tubercles. We found multimale fertilization in most clutches, suggesting that sperm competition is important in this species. Females showed behaviour that may be linked to spawning decision, that is, male dominance might not be the only determinant of male reproductive success in minnows.