Scientific Results

Specializations in the compound eye of Talitrus saltator (Crustacea, Amphipoda)

Year: 2020

Authors: Ciofini A., Yamahama Y., Mercatelli L., Hariyama T., Ugolini A.

Autors Affiliation: – Department of Biology, University of Florence, Via Romana 17, 50125 Florence, Italy
– Department of Biology, School of Medicine,
Hamamatsu University, 1-20-1, Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
– National Institute of Optics, CNR, Largo E. Fermi 6, 50125 Florence, Italy
– Institute for NanoSuit Research, Preeminent Medical Photonics Education and Research Center, School
of Medicine, Hamamatsu University, 1-20-1, Handayama, Higashi-ku, Hamamatsu 431-3192, Japan

Abstract: We investigated the eye regionalization in Talitrus saltator by morphological, electrophysiological and behavioural experiments. Each ommatidium possesses fve radially arranged retinular cells producing a square fused rhabdom by R1–R4 cells;
the smaller R5 exists between R1 and R4. The size of R5 rhabdomere is larger in the dorsal part and becomes smaller in the
median and ventral parts of the eye. Spectral-sensitivity by electroretinograms were recorded from dorsal or ventral parts
of the eye. The dorsal part possesses maxima at green and UV-blue region. The main response region in the ventral part is
only from UV (390 nm) to blue (430 nm) decreasing at longer wavelengths. To evaluate the sandhoppers’ celestial orientation, their eyes were painted black either in the dorsal or ventral part, under the natural sky or a blue flter with or without
the vision of the sun. Sandhoppers with the dorsal region of the eyes painted and tested under the screened sun were more
dispersed and their directions varied more than in other groups of individuals. Sandhoppers with this area of the eye obscured
display considerable difculties to head in a specifc direction. This work suggests the existence of regional specializations
in the eye of T. saltator


Volume: 206      Pages from: 711  to: 723

KeyWords: Crustaceans · Sandhoppers · Talitrus saltator · Eye regionalization · Compass orientation
DOI: 10.1007/s00359-020-01432-8

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