Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 903-0213, Japan.
Faculty of Fisheries and Marine Science, Halu Oleo University, Kendari 93232, Indonesia.
Zoolog Sci. 2021 Feb;38(1):45-50. doi: 10.2108/zs200114.
In medaka fishes, the family Adrianichthyidae, tropical species are known to be sexually more dimorphic than temperate species. If this reflects that tropical species are exposed to stronger sexual-selection pressures than temperate species, mating behaviors may also differ between tropical and temperate species. Our mating experiments revealed that males of , a tropical species of the family, perform "chasing" another male more frequently than males of , a temperate congener, and that male-male "combats" of tended to be followed by chasing compared with combats of males, indicating that males are more aggressive in male-male interactions than males. Males of also performed "approaching" a female and "mating dance" more frequently than males, indicating that males are also more active in courting females. Males of often omitted "mating dance" in their mating sequences, supporting this view. Moreover, females tended to reject male "wrapping", an attempt for fertilization, more frequently than females, suggesting that females are choosier in mating than females. These findings are concordant with the view that is exposed to stronger sexual-selection pressures than .
在青鳉鱼中，棘鱼科的热带物种比温带物种表现出更强的性二态性。如果这反映了热带物种比温带物种受到更强的性选择压力，那么热带和温带物种的交配行为也可能不同。我们的交配实验表明，热带物种的雄性比温带近缘种的雄性更频繁地进行“追逐”另一只雄性，并且 的雄性之间的“战斗”往往伴随着追逐，而 的雄性之间的战斗则很少追逐，这表明 雄性在雄性间的相互作用中比 雄性更具攻击性。 的雄性也比 的雄性更频繁地进行“接近”雌性和“交配舞蹈”，这表明 雄性在求偶雌性时也更活跃。 的雄性在交配序列中经常省略“交配舞蹈”，这也支持了这一观点。此外， 的雌性比 的雌性更频繁地拒绝雄性的“缠绕”，这是一种受精尝试，这表明 雌性在交配时更具选择性。这些发现与 比 受到更强的性选择压力的观点是一致的。
