Compound Eye Miniaturization in Lepidoptera: a comparative morphological analysis |
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Authors: | Stefan Fischer Victor Benno Meyer‐Rochow Carsten H. G. Müller |
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Affiliation: | 1. Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, , Nova Scotia, Canada, B3H 4R2;2. Faculty of Engineering and Science, Jacobs University Bremen, , 28759 Bremen, Germany;3. Department of Biology, Oulu University, , SF 90014 Oulu, Finland;4. Department Cytology and Evolutionary Biology, Zoological Institute and Museum, Ernst‐Moritz‐Arndt‐University Greifswald, , 17487 Greifswald, Germany |
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Abstract: | Superposition and apposition compound eyes are commonly associated with moths and butterflies, respectively. However, recently intermediate eye designs, combining features of both apposition and superposition eyes were found in tiny insects. Here, we examine the eyes of 12 species of moth, ranging from 1.88 to 6.03 mm body size, by scanning and transmission electron microscopy. Correlations between body and eye sizes are discussed with regard to the eyes' functionality. Although all of the species shared an ommatidial organization characteristic of pterygote insects, three optical designs were found: (a) an apposition eye, (b) an eye resembling apposition eyes, but with a unique crystalline cone, and (c) an eye intermediate in structure between apposition and superposition eyes. Our comparisons also revealed a new type of basal matrix for the Lepidoptera. The results show that in most of the examined compound eyes (with the exception of the apposition eye of Micropterix aruncella), a clear distinction between apposition and superposition eyes is not feasible. Due to functional morphological constraints as a consequence of miniaturization, evolutionary transformations from superposition into apposition optics may have occurred several times independently in various ‘microlepidopteran’ taxa. The Phyllonorycter medicaginella eye appears to illustrate this evolutionary scenario best. |
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Keywords: | apposition basal matrix insect superposition vision |
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