RT Journal Article T1 Selection on individuals of introduced species starts before introduction. A1 Baños-Villalba, Adrián A1 Carrete, Martina A1 Tella, José Luis A1 Blas, Julio A1 Potti, Jaime A1 Camacho, Carlos A1 Sega Diop, Moussa A1 Marchant, Tracy A. A1 Cabezas, Sonia A1 Edelaar, Pim K1 Biological invasion K1 Brain size K1 Feather corticosterone K1 Invasiveness K1 Pre-introduction selection K1 Selective filters K1 Wildlife trade AB Biological invasion is a global problem with large negative impacts on ecosystems and human societies. When a species is introduced, individuals will first have to pass through the invasion stages of uptake and transport, before actual introduction in a non-native range. Selection is predicted to act during these earliest stages of biological invasion, potentially influencing the invasiveness and/or impact of introduced populations. Despite this potential impact of pre-introduction selection, empirical tests are virtually lacking. To test the hypothesis of pre-introduction selection, we followed the fate of individuals during capture, initial acclimation, and captivity in two bird species with several invasive populations originating from the international trade in wild-caught pets (the weavers Ploceus melanocephalus and Euplectes afer). We confirm that pre-introduction selection acts on a wide range of physiological, morphological, behavioral, and demographic traits (incl. sex, age, size of body/brain/bill, bill shape, body mass, corticosterone levels, and escape behavior); these are all traits which likely affect invasion success. Our study thus comprehensively demonstrates the existence of hitherto ignored selection acting before the actual introduction into non-native ranges. This could ultimately change the composition and functioning of introduced populations, and therefore warrants greater attention. More knowledge on pre-introduction selection also might provide novel targets for the management of invasive species, if pre-introduction filters can be adjusted to change the quality and/or quantity of individuals passing through such that invasion probability and/or impacts are reduced. PB Wiley YR 2020 FD 2020 LK https://hdl.handle.net/10433/19772 UL https://hdl.handle.net/10433/19772 LA en NO EVOLUTIONARY APPLICATIONS 14:781-793 NO Permits for capture and captivity were obtained from the Senegalese Ministry of the Environment and Sustainable Development (Direction des Eaux, Forêts, Chasse et Conservation des Sols—DEFCCS). The research was approved by the bioethical subcommittee of CSIC, Spain. We thank Pepe Ayala, Alberto Jurado and Basti Palacios for field work in Senegal, Graciela Escudero for essential help with organizing and conducting field work in Senegal, and the people of the town of Colonat for their hospitality. This work was supported by the Spanish Ministry of Economy and Competitiveness (grant numbers BES-2013–062905 to A.B-V.; RYC-2009-04860 to M.C.; RYC-2010-07120 to J.B.; SVP − 2013−067686 to C.C.; and RYC-2011-07889, CGL-2012-35232, CGL2013-49460-EXP, CGL2016-79483-P, and PID2019-108971GB-I00 to P.E., with support from the European Regional Development Fund FEDER), by Fundación Repsol, and by grant 38/2010 of the ICTS (Infraestructura Científica y Tecnológica Singular) program to J.L.T. Two anonymous reviewers and the associate editor made insightful comments on earlier versions that substantially improved the quality of this manuscript. NO Biología Molecular e Ingeniería Bioquímica DS RIO RD Apr 23, 2026