Meeting Abstract

92.3  Thursday, Jan. 7  Experimental evidence for the role of fluorescent proteins (GFPs) in prey attraction HADDOCK, SHD*; FIGOSKI, L; WATTS, M; SWEENEY, AM; DUNN, CW; Monterey Bay Aquarium Research Inst.; MBARI; MBARI; Univ. of California, Santa Barbara; Brown University haddock@mbari.org

Autofluorescence is common in the ocean, where a variety of molecules can re-emit absorbed photons as light of a longer wavelength. Common fluorescent molecules include chlorophyll, phycobiliproteins, porphyrins, chitin, and green-fluorescent proteins (GFPs). In many cases, fluorescence seems to be a byproduct of the molecule’s chemistry, and not the primary reason for its presence. In the case of GFP-type fluorescent proteins, however, which are found in cnidarians, crustaceans, chordates, and ctenophores, the proteins are assumed to be present primarily because of their fluorescence. In most cases, the functions of GFP remain unclear: it has been suggested that the functions are related to the expression of bioluminescence, or that they serve to modulate the light environment of algal symbionts, in the case of non-luminous Anthozoa. To test the hypothesis that fluorescent proteins might serve to attract prey, we conducted laboratory experiments using non-luminous fluorescent hydromedusae and juvenile fishes, their natural prey. Under lighting conditions where fluorescent structures on the jellyfish tentacles were visible, fishes were significantly more attracted to the medusa than they were to a jellyfish mimic or to the medusa under non-fluorescent lighting conditions. Additional in situ evidence supported these findings by showing a wide range of fishes attracted to a supernormal visual stimulus. Our results may help explain the presence of fluorescent structures in a diverse range of animals.