MRC Data Sets

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  • Dataset
    Dynamic masquerade with morphing 3D skin in cuttlefish
    ( 2017-02-03) Panetta, Deanna ; Buresch, Kendra C. ; Hanlon, Roger T.
    Masquerade is a defence tactic in which a prey resembles an inedible or inanimate object thus causing predators to misclassify it. Most masquerade colour patterns are static although some species adopt postures or behaviours to enhance the effect. Dynamic masquerade in which the colour pattern can be changed is rare. Here we report a 2-step sensory process that enables an additional novel capability known only in cuttlefish and octopus: morphing 3D physical skin texture changes that further enhance the optical illusions created by the coloured skin patterns. Our experimental design incorporated sequential sensory processes: addition of a 3-dimensional rock to the testing arena, which attracted the cuttlefish to settle next to it; then visual processing by the cuttlefish of physical textures on the rock to guide expression of the skin papillae, which can range from fully relaxed (smooth skin) to fully expressed (bumpy skin). When uniformly white smooth rocks were presented, cuttlefish moved to the rock and deployed a uniform body pattern with mostly smooth skin. When a rock with small-scale fragments of contrasting shells was presented, the cuttlefish deployed mottled body patterns with strong expression of papillae. These robust and reversible responses indicate a sophisticated visual sensorimotor system for dynamic masquerade.
  • Dataset
    An unexpected diversity of photoreceptor classes in the Longfin squid, Doryteuthis pealeii
    ( 2015-07-10) Kingston, Alexandra C. N. ; Wardill, Trevor J. ; Hanlon, Roger T. ; Cronin, Thomas W.
    Cephalopods are famous for their ability to change color and pattern rapidly for signaling and camouflage. They have keen eyes and remarkable vision, made possible by photoreceptors in their retinas. External to the eyes, photoreceptors also exist in parolfactory vesicles and some light organs, where they function using a rhodopsin protein that is identical to that expr essed in the retina. Furthermore, dermal chromatophore organs contain rhodopsin and other components of phototransduction (including retinochrome, a photoisomerase first found in the retina), suggesting that they are photoreceptive. In this study, we used a modified whole - mount immunohistochemical technique to explore rhodopsin and retinochrome expression in a number of tissues and organs in the longfin squid, Doryteuthis pealeii. We found that fin central muscles, hair cells (epithelial primary sensory neu rons), arm axial ganglia, and sucker peduncle nerves all express rhodopsin and retinochrome proteins. Our findings indicate that these animals possess an unexpected diversity of extraocular photoreceptors and suggest that extraocular photoreception using v isual opsins and visual phototransduction machinery is far more widespread throughout cephalopod tissues than previously recognized.
  • Dataset
    Neural control of tuneable skin iridescence in squid
    ( 2012-07-25) Wardill, Trevor J. ; Gonzalez-Bellido, Paloma T. ; Crook, Robyn J. ; Hanlon, Roger T.
    Fast dynamic control of skin coloration is rare in the animal kingdom, whether it be pigmentary or structural. Iridescent structural coloration results when nanoscale structures disrupt incident light and selectively reflect specific colours. Unlike animals with fixed iridescent coloration (e.g. butterflies), squid iridophores (i.e. aggregations of iridescent cells in the skin), produce dynamically tuneable structural coloration, as exogenous application of acetylcholine (ACh) changes the colour and brightness output. Previous efforts to stimulate iridophores neurally or to identify the source of endogenous ACh were unsuccessful, leaving researchers to question the activation mechanism. We developed a novel neurophysiological preparation in the squid Doryteuthis pealeii and demonstrated that electrical stimulation of neurons in the skin shifts the spectral peak of the reflected light to shorter wavelengths (>145 nm) and increases the peak reflectance (>245 %) of innervated iridophores. We show ACh is released within the iridophore layer and that extensive nerve branching is seen within the iridophore. The dynamic colour shift is significantly faster (17 s) than the peak reflectance increase (32 s) revealing two distinct mechanisms. Responses from a structurally altered preparation indicate that the reflectin protein condensation mechanism explains peak reflectance change, while an undiscovered mechanism causes the fast colour shift.