Trabajo presentado al ASAB Summer Meeting, celebrado en Belfast (K) del 23 al 25 de agosto de 2021., Peer reviewed

Floaters constitute the sexually mature but non-breeding part of populations. Despite being ubiquitous in most species, knowledge about floaters is scarce. Ignoring this significant number of individuals may strongly bias our understanding of population dynamics and sexual selection processes. We used the spotless starling (Sturnus unicolor) to examine whether phenotypical and non-phenotypical variables from early and adult life predict reproductive status, focusing on the earliest age at which most individuals start to breed, when the percentage of floaters is the highest. We compiled data from a long-term study involving eight female and seven male cohorts of individuals PIT-tagged at birth. We compared a suite of nestling (condition, hatching date and brood size) and adult variables (condition, size and ornamentation) between floaters and breeders. We found that adult and nestling body condition strongly and positively influenced the likelihood of breeding in males. Path analysis revealed that male reproductive status could only be predicted by considering nestling body condition—the influence of this variable superseded adult body condition. Female reproductive status was only negatively associated with hatching date. Ornamentation was not associated with reproductive status in any of the sexes, although path analyses revealed that body condition was positively associated with throat feather length. We conclude that predictors of reproductive status are sex-specific in the spotless starling, suggesting an important role of body condition in access to breeding resources in males. Our results also highlight the long-term influence of early life on life trajectories and their potential implications on floating status., This work was financed by a grant from the Spanish Ministry of Science and Universities to DG (CGL2017-83843-C2-1-P), and draws on data collected during previous projects of DG (refs.: CGL2008-03501/BOS, CGL2011-26318 and CGL2017-83843-C2-1-P) and LP-R (ref.: PGC2018-099596-B-I00 funded by MCIN/AEI/10.13039/501100011033 and ERDF A way of making Europe)., Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature., Peer reviewed

Datasets used in the analysis of the manuscript entitled: Sexual differences in phenotypical predictors of floating status: body condition influences male but not female reproductive status in a wild passerine. In Oecologia., Peer reviewed

Supporting Information: This file contains supplementary material: - Supplementary Figures - Supplementary Tables., Peer reviewed

Open Access funding provided thanks to the CRUECSIC agreement with Springer Nature. This work was financed by a grant from the Spanish Ministry of Science and Universities to DG (CGL2017-83843-C2-1-P), and draws on data collected during previous projects of DG (refs.: CGL2008-03501/BOS, CGL2011-26318 and CGL2017-83843-C2-1-P) and LP-R (ref.: PGC2018-099596-B-I00 funded by MCIN/AEI/10.13039/501100011033 and ERDF A way of making Europe)., Floaters constitute the sexually mature but non-breeding part of populations. Despite being ubiquitous in most species, knowledge about floaters is scarce. Ignoring this significant number of individuals may strongly bias our understanding of population dynamics and sexual selection processes. We used the spotless starling (Sturnus unicolor) to examine whether phenotypical and non-phenotypical variables from early and adult life predict reproductive status, focusing on the earliest age at which most individuals start to breed, when the percentage of floaters is the highest. We compiled data from a longterm study involving eight female and seven male cohorts of individuals PIT-tagged at birth. We compared a suite of nestling (condition, hatching date and brood size) and adult variables (condition, size and ornamentation) between floaters and breeders. We found that adult and nestling body condition strongly and positively influenced the likelihood of breeding in males. Path analysis revealed that male reproductive status could only be predicted by considering nestling body condition—the influence of this variable superseded adult body condition. Female reproductive status was only negatively associated with hatching date. Ornamentation was not associated with reproductive status in any of the sexes, although path analyses revealed that body condition was positively associated with throat feather length. We conclude that predictors of reproductive status are sex-specific in the spotless starling, suggesting an important role of body condition in access to breeding resources in males. Our results also highlight the long-term influence of early life on life trajectories and their potential implications on floating status., CRUECSIC agreement, Springer Nature, Spanish Government CGL2017-83843-C2-1-P CGL2008-03501/BOS CGL2011-26318, Spanish Ministry of Science and Universities (MCIN/AEI) PGC2018-099596-B-I00, Spanish Ministry of Science and Universities (ERDF A way of making Europe) PGC2018-099596-B-I00