| Budget Amount *help |
¥16,900,000 (Direct Cost: ¥13,000,000、Indirect Cost: ¥3,900,000)
Fiscal Year 2014: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2013: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2012: ¥8,970,000 (Direct Cost: ¥6,900,000、Indirect Cost: ¥2,070,000)
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| Outline of Final Research Achievements |
The skewed-mouthed scale-eating cichlid Perissodus microlepis in Lake Tanganyika is an attractive model of behavioural laterality: each adult robs scales from its prey fishes’ left or right flanks according to the direction in which its mouth is skewed. To investigate the development of behavioural laterality and mouth asymmetry, we analysed stomach contents and lower jaw-bone asymmetry of various-sized P. microlepis sampled in the southern tip of the Lake. The shapes of the pored scales found in each specimen’s stomach indicated its attack side preference. Early-juveniles (SL <45mm) feeding on zooplankton exhibited slight mouth asymmetry. After scale-eating began, the attack side preference was gradually strengthened, as did mouth asymmetry. Our findings show that mouth asymmetry in P. microlepis precedes behavioural laterality, which is established in association with mouth development, and suggest that physical and behavioural lateralities confer a synergistic advantage.
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