ABG student Estefania Boada Viteri has had her PhD thesis approved by La Trobe University Academic Board and has been awarded the Nancy Millis Medal in recognition of the exceptional quality of her work. Well done Tefa!
Title: Behavioural partitioning of mainland and island lava lizard assemblages in Ecuador
General Abstract: Species respond in different ways to extrinsic constraints, to avoid competition or adapt to new and changing environments. A common response is to modify their behaviour to meet their needs and to suit the ecological context. Taxonomic groups that are found on islands and mainland habitats have become model organisms to understand the process of evolution of closely related species, which have evolved in different biogeographical conditions. The lava lizards (genus Microlophus) are an ideal system in this regard as their distribution spans mainland South America and the Galápagos Islands, and they possess diverse patterns of behaviour. In this thesis, I examine the influence of extrinsic ecological and environmental constraints on species phenotypes, with a particular focus on the role that behavioural and ecological specialisations play in niche delimitation of Microlophus species from Ecuador. In Chapter 1, I investigated the effect of interspecific competition on the behavioural patterns of two mainland species, Microlophus occipitalis and M. peruvianus in the environmental and ecological context. I found that both species exhibited behavioural, and microhabitat shifts in sympatry, consistent with an increase in interspecific competition and difference in habitat composition. In addition, microhabitat shifts lead to morphological (smaller limbs and slender bodies) and territorial display structure variations (lower amplitudes) for M. occipitalis. I broadened my investigation in Chapter 3 to consider behavioural diversification in the context of phylogenetic relatedness for the mainland species and six species on the Galápagos Islands. I employed a phylogenetic comparative approach to show that lava lizard behaviour varies to varying degrees as a function of the ecological context, the environmental conditions as well as social factors. I inferred that lava lizards’ behavioural divergence does not strongly reflect their evolutionary history. Instead, I proposed that extrinsic ecological, environmental, and social factors played a more important role in their behavioural adaptation. In the final data chapter of my thesis (Chapter 4), I focus on the extent to which anthropogenic factors influence Galápagos lava lizards’ behaviour in the context of varying levels of human population and tourism activities. I also considered habitat modification, by including vegetation assessments and published habitat composition data. I concluded that the accelerated human growth and tourism on the Galápagos islands have negatively impacted the lava lizards’ behaviour leading to possible boldness-awareness behavioural syndromes on species inhabiting urban areas with high visitor rates. Overall, my study demonstrates the important role of ecological and environmental contexts on species phenotypic adaptations. In addition, it is the first research project to take a multifaceted approach to documenting the behavioural ecology of Ecuadorian lizards, laying the groundwork for future research and conservation projects targeting non-emblematic species that are an important component of the natural ecosystem.
