演題詳細
Poster
学習・長期記憶
Learning and Long-term Memory
開催日 | 2014/9/11 |
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時間 | 16:00 - 17:00 |
会場 | Poster / Exhibition(Event Hall B) |
鱗食シクリッドの非対称な捕食行動と顎形態の発達
Development of lateralized predation behavior and morphological asymmetry in a scale-eating cichlid fish
- P1-260
- 竹内 勇一 / Yuichi Takeuchi:1 堀 道雄 / Michio Hori:2 小田 洋一 / Yoichi Oda:3
- 1:富山大医解剖 / Dept Anat, Univ of Toyama, Toyama, Japan 2:京都大院理生物科学 / Dept Zool, Kyoto Univ, Kyoto, Japan 3:名古屋大院理生命理学 / Div Biol Sci, Nagoya Univ, Nagoya, Japan
The developmental process of behavioral laterality which is ubiquitous in vertebrates, has been controversial. The scale-eating cichlid fish Perissodus microlepis in Lake Tanganyika is well known for exhibiting the laterally dimorphic mouth morphology and lateralized behavior in robbing scales from prey fish; righty and lefty individuals are alternative expression of a behavioral laterality as well as handedness in human. We investigated the intensity of behavioral laterality of predation and the mouth asymmetry from juvenile to adult fish which were sampled in the field. The outcome provides a suggestion whether genetic and environmental factors have an effect on these lateralization. The distinct mouth asymmetry in lower jaw bone in even juvenile fish, which had fed on plankton indicates the initiate asymmetry is governed by genetic factors. The bilateral differences of mouth morphology was inclined to increase with body size up to approximately three times, suggesting a phenotypically plastic response to repeated attacks from one particular side. From the stomach content analysis, righty morphs mainly preyed the right flanks of their victim fish while lefty morphs preyed the left flanks at even an early stage. Further, the lateral bias of predation was more pronounced in the adult fish. Because the predation success is higher in preferred side corresponding mouth morph than in non-preferred side, learning and experience of predation would lead to facilitate behavioral preference to attack a particular side of the prey. These findings indicate that genetics determine at least partly the dominant side of behavioral laterality and morphological asymmetry, but environmental input can alter the intensity of these traits.