What do Sunburst Diving beetle larvae see? The role of polarization sensitivity

Abstract

Event Abstract Back to Event What do Sunburst Diving beetle larvae see? The role of polarization sensitivity Annette Stowasser1* and Elke K. Buschbeck1 1 University of Cincinnati, Department of Biological Sciences, United States Although polarization sensitivity has been studied fairly well in adult insects, little is known about it in larvae. Nevertheless it is likely that at least some larvae, such as Thermonectus marmoratus, could substantially benefit from it. In previous work, the possibility of polarization sensitivity in one of their retinas had been raised based on the ultrastructure. However, because light travels through more distal photoreceptors (that potentially could influence polarization) before reaching this region, the polarization sensitivity remained unclear. We used electrophysiological methods and single-cell staining to confirm polarization sensitivity in the proximal retina of eyes E1 and E2. Larvae of the aquatic beetle T. marmoratus are highly successful visually guided predators. Their principal eyes E1 and E2 each have a single lens, are tubular in shape, and have at least two distinct retinas: the distal and proximal retinas. The former is sensitive to green light, whereas, the latter is sensitive to UV light. Based on transmission electron microscopy the proximal retina of E1 and E2 is composed of three distinct cell types: T1, T2, and T3. These cells are arranged in an alternating pattern. Cells of type T1 and T2 are somewhat larger, and have vertically and horizontally aligned microvilli, respectively. T3 is organized similar to T1, but it’s rhabdomeric portion is much smaller. As expected from the ultrastructure, cells of the type T1 are most sensitive to vertically polarized light, while cells of the type T2 are most sensitive to horizontally polarized light. While we could not directly confirm the polarization sensitivity of T3 cells, there is evidence that we recorded from all three morphologically distinct cell types. Two cell populations were most sensitive to vertically polarized light, with polarization sensitivity (PS) values of 13.9 (± 7.5 s.d., n = 16) and 3.1 (± 0.4 s.d., n = 4) respectively. Cells most sensitive to horizontally polarized light showed a PS value of 9.3 (± 3.2 s.d., n = 14). Compared to other insects these values are relatively high, suggesting that polarization sensitivity likely plays an important role in the visual system of these larvae. Based on their natural history and behavior, possible functions are: (1) finding water after hatching, (2) finding the shore before pupation, and (3) making prey more visible, by filtering out horizontally polarized haze, and/or by using polarization features for prey detection. Behavioral experiments will be necessary to determine for which of these behaviors polarization sensitivity might be important. Acknowledgements We thank John E. Layne for lending us his rotating arm. We thank Shannon Werner for helping with beetle care and Randy Morgan and the Cincinnati Zoo & Botanical Garden for providing Sunburst Diving Beetles. This work was supported by the NSF (IOS0545978 and IOS1050754). Keywords: coleoptera, Dytiscidae, stemmata Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster Presentation (see alternatives below as well) Topic: Sensory: Vision Citation: Stowasser A and Buschbeck EK (2012). What do Sunburst Diving beetle larvae see? The role of polarization sensitivity . Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00172 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Ms. Annette Stowasser, University of Cincinnati, Department of Biological Sciences, Cincinnati, United States, annette.stowasser@uc.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Annette Stowasser Elke K Buschbeck Google Annette Stowasser Elke K Buschbeck Google Scholar Annette Stowasser Elke K Buschbeck PubMed Annette Stowasser Elke K Buschbeck Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.