McGaughran, AngelaNunn, Daniel2025-03-142025-03-142024https://hdl.handle.net/10289/17257Biological invasion is a complex puzzle, and its significance is at an all-time high. Current research highlights that the success of invasive species is partly due to their superior performance in key behavioural traits, such as aggression and boldness, especially when compared to ecologically similar native species. However, less attention has been given to differences in these traits among invasive species themselves. Not all invaders are created equal; they vary in their degree of invasiveness, often characterised by the extent of their global spread. If behavioural traits are crucial for invasiveness, it stands to reason that more invasive species - those with greater success - should outperform less invasive ones. I tested this hypothesis using larval competition between differentially invasive blowfly species. Calliphora stygia has a limited distribution, found only in Australia and New Zealand, whereas Lucilia sericata and Lucilia cuprina (Lucilia spp.) are invaders with almost global distributions. Under direct laboratory competition, the highly invasive Lucilia spp. exhibited fewer body size reductions than C. stygia, regardless of intra- or interspecific competition levels. These findings suggest that competitive traits may exist along a continuum from native to invasive species, increasing predictably with invasiveness. This insight highlights invasiveness as a potentially reliable metric for predicting competition outcomes between ecologically similar sympatric invaders.enAll items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.Thesis