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Vol. 54, 2015
Differentiation of
visual spectra and nuptial colorations of two Paratanakia himantegus subspecies (Cyprinoidea:
Acheilognathidae) in response to the distinct photic conditions of
their habitats
Chia-Hao
Chang1,2, Yi Ta Shao3,4, Wen-Chung Fu3,
Kazuhiko Anraku5, Yeong-Shin Lin1,6 and Hong
Young Yan3,7*
1Department
of Biological Science and Technology, National Chiao Tung University,
Hsinchu, Taiwan
2Department of Biology, St. Louis University, St.
Louis, MO, USA
3Sensory Physiology Laboratory, Marine Research
Station, Academia Sinica, I-Lan, Taiwan
4Present Address: Institute of Marine Biology,
National Taiwan Ocean University, Keelung, Taiwan
5Faculty of Fisheries, Kagoshima University,
Kagoshima, Japan
6Institute of Bioinformatics and Systems Biology,
National Chiao Tung University, Hsinchu, Taiwan
7Hanse-Wissenschaftskolleg Institute of Advanced
Study, Delmenhorst, Germany
Abstract
Background: Vision, an important sensory
modality of many animals, exhibits plasticity in that it adapts to
environmental conditions to maintain its sensory efficiency. Nuptial
coloration is used to attract mates and hence should be tightly coupled
to vision. In Taiwan, two closely related bitterlings (Paratanakia himantegus himantegus and Paratanakia himantegus chii) with
different male nuptial colorations reside in different habitats. We
compared the visual spectral sensitivities of these subspecies with the
ambient light spectra of their habitats to determine whether their
visual abilities correspond with photic parameters and correlate with
nuptial colorations.
Results: The electroretinogram (ERG) results
revealed that the relative spectral sensitivity of P. h. himantegus was higher at 670
nm, but lower at 370 nm, than the sensitivity of P. h. chii. Both bitterlings could
perceive and reflect UV light, but the UV reflection patterns differed
between genders. Furthermore, the relative irradiance intensity of the
light spectra in the habitat of P.
h. himantegus was higher at long wavelengths (480–700 nm), but
lower at short wavelengths (350–450 nm), than the light spectra in the
habitats of P. h. chii.
Conclusions: Two phylogenetically
closely related bitterlings, P. h.
himantegus and P. h. chii,
dwell in different waters and exhibit different nuptial colorations and
spectral sensitivities, which may be the results of speciation by
sensory drive. Sensory ability and signal diversity accommodating
photic environment may promote diversity of bitterling fishes. UV light
was demonstrated to be a possible component of bitterling visual
communication. The UV cue may assist bitterlings in gender
identification.
Key words: Bitterling; Electroretinogram;
Sensory drive; UV reflection pattern.
*Correspondence: E-mail: hyyan@gate.sinica.edu.tw
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