magistrsko delo
Eva Debevc (Author), Marko Kreft (Reviewer), Gregor Belušič (Mentor), Marko Ilić (Co-mentor)

Abstract

Pri metuljih pisančkih (Nymphalidae) je predniški trikromatski vid razširjen do tetrakromatizma z rdeče občutljivimi bazalnimi fotoreceptorji R9 v rdeče sijočih omatidijih. Rdeč filtrski pigment (rfp) premakne vrh absorpcije dolgovalovnega opsina (LW) proti rdečemu delu spektra. V omatidijih, kjer se LW opsin izraža v celicah R1 in R2, te tvorijo oponentni par z R9 (G+R-). Pri celicah G+R- vrste Heliconius melpomene so bile opažene razlike v razmerju občutljivosti med zelenim in modrim delom spektra (G/B). Zanimalo nas je, ali spektralna občutljivost sistematično variira s položajem celic vzdolž dorzoventralne (D-V) osi in ali lahko variacijo razložimo s prostorsko zgradbo svetlobnega okolja. Preučevali smo štiri vrste: H. melpomene, H. cydno, Brenthis hecate in Morpho peleides. Spektralne odzive celic smo merili elektrofiziološko in beležili njihovo lego na D-V osi. Posneli smo očesni sij in histološko preverili lokacijo rfp. Za H. melpomene smo izračunali ulov fotonov G+R- celic na D-V osi glede na iradiančne spektre, izmerjene v naravnem okolju. Gradient G/B občutljivosti smo opazili pri vseh vrstah razen pri M. peleides. Dorzalno prevladujejo zeleno, ventralno pa modro občutljive celice, inhibirane v rdečem. To sovpada z usmerjenostjo dorzalnega očesa v nebo, bogato z ultravijolično in modro svetlobo, ter ventralnega v tla in vegetacijo, kjer prevladujeta zelena in rdeča. Neenoten očesni sij in pogostejši rdeče sijoči omatidiji ventralno potrjujejo vlogo filtrskega pigmenta pri uglasitvi vida. Primerjava med vrstami metuljev kaže, da je gradient spektralne občutljivosti med zeleno- in modroobčutljivimi celicami vrstno specifičen, najbrž v skladu s svetlobnimi razmerami habitatov.

Keywords

pisančki;barvni vid;fotoreceptor;spektralna občutljivost;oponenca;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [E. Debevc]
UDC: 638.124.2:591.5(043.2)
COBISS: 248868355 Link will open in a new window
Views: 107
Downloads: 20
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Other data

Secondary language: English
Secondary title: Spectral sensitivity variation of green-red opponent receptors in the retina of fritillaries (Lepidoptera: Nymphalidae)
Secondary abstract: In brush-footed butterflies (Nymphalidae), ancestral trichromatic vision is expanded to tetrachromacy with red-sensitive basal photoreceptors R9 in red-shining ommatidia. A red filtering pigment (rfp) shifts the absorption peak of the long-wavelength opsin (LW) toward the red part of the spectrum. In ommatidia where LW opsin is expressed in cells R1 and R2, these form an opponent pair with R9 (G+R–). In G+R– cells of Heliconius melpomene, differences were observed in the sensitivity ratio between green and blue parts of the spectrum (G/B). We asked whether spectral sensitivity systematically varies with cell position along the dorsoventral (D–V) axis, and whether this variation can be explained by the spatial structure of the light environment. We studied four species: H. melpomene, H. cydno, Brenthis hecate and Morpho peleides. Spectral responses of cells were measured electrophysiologically and their positions along the D–V axis recorded. We captured eyeshine and verified rfp histologically. For H. melpomene, we calculated photon catch of G+R– cells along the D–V axis relative to irradiance spectra measured in the natural environment. A gradient of G/B sensitivity appeared in all species except M. peleides. Green-sensitive cells dominated dorsally, blue-sensitive ones ventrally, both inhibited in the red. This corresponds to the dorsal eye facing the sky, rich in ultraviolet and blue light, and the ventral eye ground and vegetation, where green and red predominate. Uneven eyeshine and more frequent red-shining ommatidia ventrally confirm the role of filtering pigment in tuning vision. Comparison between species shows the gradient of spectral sensitivity between green- and blue-sensitive cells is species-specific, likely reflecting habitat light conditions.
Secondary keywords: brush-footed butterflies;colour vision;photoreceptor;spectral sensitivity;spectral opponency;
Type (COBISS): Master's thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za biologijo, Magistrsko delo magistrskega študijskega programa 2. stopnje Molekulska in funkcionalna biologija
Pages: 1 spletni vir (1 datoteka PDF (X, 42 str.)
ID: 27639301