spatial sorting drives morphological variation in the invasive bird, acridotheris tristis空间选择驱动器形态变化入侵鸟,acridotheris tristis.pdf

Spatial Sorting Drives Morphological Variation in the Invasive Bird, Acridotheris tristis ´ 1 2,3 1 4 Cecile Berthouly-Salazar *, Berndt J. van Rensburg , Johannes J. Le Roux , Bettine J. van Vuuren , Cang Hui1 1 Centre for Invasion Biology, Department of Botany Zoology, University of Stellenbosch, Stellenbosch, South Africa, 2 School of Biological Science, University of Queensland, Queensland, Australia, 3 Centre for Invasion Biology, Department of Zoology Entomology, University of Pretoria, Pretoria, South Africa, 4 Centre for Invasion Biology, Department of Zoology, University of Johannesburg, Johannesburg, South Africa Abstract The speed of range expansion in many invasive species is often accelerating because individuals with stronger dispersal abilities are more likely to be found at the range front. This ‘spatial sorting’ of strong dispersers will drive the acceleration of range expansion. In this study, we test whether the process of spatial sorting is at work in an invasive bird population (Common myna, Acridotheris tristis) in South Africa. Specifically, we sampled individuals across its invasive range and compared morphometric measurements relevant and non-relevant to the dispersal ability. Besides testing for signals of spatial sorting, we further examined the effect of environmental factors on morphological variations. Our results showed that dispersal-relevant traits are significantly correlated with distance from the range core, with strong sexual dimorphism, indicative of sex-biased dispersal. Morphological variations were significant in wing and head traits of females, suggesting females as the primary