| dc.description.abstract | Eyespots, generally defined as circular markings composed of contrasting colours to the surrounding body, are a widespread anti-predator defence mechanism in lepidoptera (butterflies and moths). This colour strategy has caught the attention of evolutionary biologists for centuries, yet how key factors influence eyespot effectiveness remains unclear. This thesis investigates how the effectiveness of eyespots is shaped by factors within the markings themselves, by other protective strategies, and by external seasonal influences, providing a more comprehensive understanding of their evolution and maintenance. In the second chapter, I explore the role of three-dimensional (3D) illusions within eyespots. While the intimidating effect of eyespots is well documented, the underlying mechanism of deterrence is debated. This includes two main theories: eye-mimicry and conspicuousness. By testing whether the apparent 3D form on eyespots affects survival against wild avian predators, we can understand the significance of the resemblance to vertebrate eyes. My results found no influence of either real 3D or the illusion of 3D form on survival, suggesting 3D illusions do not play a role in the effectiveness of eyespots, and that mimicry likely plays a minimal role in their evolution. Following this, in the third chapter, I explore the interaction between eyespots and crypsis, as well as how seasonal shifts in predator experience influences this relationship. Eyespots are often studied in isolation, without considering the effects of other colour strategies or seasonal changes. Fluctuations in predator experience across a season may vary selection pressure on eyespots and crypsis, enabling these strategies with seemingly opposite functions to coexist. By testing the survival of models with eyespots placed on either a cryptic or conspicuous wing background over a five-month period, we gain a more holistic understanding of how eyespots and crypsis have evolved together. I found that there was no negative interaction between eyespots and crypsis, and that this interaction did not vary according to the season, suggesting seasonal variations do not impact the relationship between the strategies. However, further research is needed to validate this conclusion. By highlighting the lack of seasonal modulation in eyespot effectiveness and finding no support for the role of 3D illusions, this thesis offers valuable insights into the evolutionary factors that have shaped the evolution of eyespots. | en_GB |
