@article{oai:nagasaki-u.repo.nii.ac.jp:00001179,
 author = {Takeuchi, Seiji and Suzuki, Kota and Nakagawa, Taishi and Tamaki, Akio},
 journal = {Journal of Sea Research},
 month = {Aug},
 note = {The infaunal clam Ruditapes philippinarum exhibits highly polymorphic shell coloration, but the function of the coloration remains uncertain. Here, a hypothesis that such shell coloration functions to enhance visual crypsis (i.e., background color matching) in juveniles (<15 mm in shell length) was tested with a combination of a field survey and laboratory experiments. Shell and background colorations were expressed as mean brightness values. Firstly, the association between shell and background brightness was investigated. For this, a field survey for two sympatric subpopulations with distinct substrates was conducted on an intertidal sandflat in western Kyushu, Japan. Secondly, the visual-crypsis hypothesis was tested experimentally using half-valve clam shells filled with paste of raw clam meat as prey and the pufferfish Takifugu niphobles as a visually hunting predator, in a tank with one to two dark-colored substrates and one light-colored substrate. The field survey showed that shell brightness significantly differed between the two sympatric subpopulations of juvenile clams and was positively associated with background brightness. The laboratory experiments indicated that prey items with comparatively light (dark) coloration on dark- (light-) colored substrate were consumed by predators more immediately and at a higher rate than in the color-matched combinations. Consequently, shell?background color matching could help juvenile clams avoid attack from visually hunting predators. The results provide a new insight into effective management planning for this clam species, creating sand habitats with a more matched coloration., Journal of Sea Research, 138, pp.8-18; 2018},
 pages = {8--18},
 title = {Visual crypsis as a possible function of polymorphic shell coloration in the infaunal clam Ruditapes philippinarum},
 volume = {138},
 year = {2018}
}