Abstract
Iridescence, when the colour of an object changes with the viewing angle, has been the subject of recent study to see if it acts as protective colouration in animals. Iridescence is a type of colouration produced by the physical structure of the objects; in beetles there are multiple different structures which can produce iridescence, the most common being multilayer reflectors, where the incident light refracts through and reflects off of multiple layers of chitin in the cuticle, resulting in multiple colours being produced. It has been hypothesised that in some metallic green beetles this form of iridescence may be camouflaging.I conducted two survival experiments in Leigh Woods with iridescent Rose Chafer (Cetonia aurata) exoskeletons and various coloured resin models pinned with mealworms. The first experiment tested if survival was correlated with the level of specular gloss of the background, and the second experiment tested if survival was correlated with background complexity. I found iridescence offered no advantage in survival rate compared to the other colour treatments, and background specular gloss did not have an impact on survival. All treatments had a significantly higher survival rate with a more complex background, supporting the previous studies. Overall this contributes to a growing body literature, suggesting that the role of iridescence as protective colouration is more complex than previously thought.
| Date of Award | 9 Dec 2025 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Heather M Whitney (Supervisor) & Sean A Rands (Supervisor) |
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