Meeting Abstract
Certain insect body and wing surfaces interact with light in unique ways; for example, many scarab beetles have body surfaces that reflect circularly polarized light and many small insects have wing membranes that produce distinct wing interference patterns (WIPs) that are likely to be highly polarized. Our study characterizes not only human-perceived appearances of insect surfaces, but also the polarization signatures and an insect’s perception of these signatures in their natural environment. First, while it has been suggested that some beetles respond behaviorally to circularly polarized light, we still do not know whether any scarab beetles have the necessary optical structures to detect circular polarization. To address this, we are examining beetle species that that do and do not strongly reflect circularly polarized light from their cuticles (measured with a spectropolarimetric reflectometer) and measuring whether there are any quarter wave retarder optical structures in their eye morphologies via electron microscopy and micro-CT. Second, while the visibility of WIPs to the human eye depends strongly on the balance between reflections from the wing vs. the background, we do not know how WIPs may appear to an insect. We are characterizing a broad sampling of insects’ WIPs (e.g. from Odonata, Hymenoptera, and Diptera) using multispectral (UV to near-IR) and polarimetric imaging techniques with a QSI640UV camera. Overall, we expect that our study of these insect surfaces will result in improved reflectance predictions and consideration of additional factors affecting an organism’s ability to perceive the resulting spectral and polarimetric characteristics of light scattered from ultrastructural surface features.
