Meeting Abstract
The ‘superpower’ of invisibility is a reality and a necessity for many animals that live in featureless environments like the open ocean, where there is nowhere to hide. How do animals achieve invisibility? Many animals match their color patterns to their background, but this strategy is limited when the background scene is dynamic. Transparency, however, allows organisms to match any background all the time. It is unclear how clear crustaceans with complex bodies (i.e. with hard cuticles, thick muscles, and internal organs) maintain transparency across their entire body volume. Transparent crustacean species that have relatively large (> 25 mm long and > 2 mm thick) bodies and that occupy physically different (pelagic vs. benthic reef) habitats serve as useful model organisms. Making comparisons between these transparent crustaceans and closely related opaque crustaceans provides some of the first insights into the physical basis of transparency, from nano-scale to organismal-scale. I will discuss how light scattering can be minimized both at an animal’s surface and internally, as well as whether transparency can be disrupted and what the underlying mechanisms of this disruption are. A variety of microscopy techniques were used to investigate the ultrastructure of transparent animals. We found multiple unique adaptations, such as anti-reflective nanostructures on the exterior cuticle surfaces of certain crustaceans. In addition, we found adaptations for minimizing interior light scattering, such as differences in myofibrillar diameters (i.e. differences in number of scattering interfaces) as well as differences in blood perfusion between transparent and opaque species, suggesting there may be tradeoffs to transparency.
