Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Germany.
PLoS One. 2012;7(9):e44670. doi: 10.1371/journal.pone.0044670. Epub 2012 Sep 6.
Scale-eating cichlid fish, Perissodus microlepis, from Lake Tanganyika display handed (lateralized) foraging behavior, where an asymmetric 'left' mouth morph preferentially feeds on the scales of the right side of its victim fish and a 'right' morph bites the scales of the left side. This species has therefore become a textbook example of the astonishing degree of ecological specialization and negative frequency-dependent selection. We investigated the strength of handedness of foraging behavior as well as its interaction with morphological mouth laterality in P. microlepis. In wild-caught adult fish we found that mouth laterality is, as expected, a strong predictor of their preferred attack orientation. Also laboratory-reared juvenile fish exhibited a strong laterality in behavioral preference to feed on scales, even at an early age, although the initial level of mouth asymmetry appeared to be small. This suggests that pronounced mouth asymmetry is not a prerequisite for handed foraging behavior in juvenile scale-eating cichlid fish and might suggest that behavioral preference to attack a particular side of the prey plays a role in facilitating morphological asymmetry of this species.
坦噶尼喀湖慈鲷鱼，小口无须鱊，具有明显的（单侧）取食行为，其中不对称的“左”嘴型偏好取食其猎物鱼右侧的鳞片，而“右”嘴型则偏好取食左侧的鳞片。这种鱼类已成为生态特化和负频率依赖性选择程度惊人的典型例子。我们研究了小口无须鱊取食行为的手性强度及其与嘴部形态侧化的相互作用。在野外捕获的成年鱼中，我们发现嘴部侧化与它们的偏好攻击方向有很强的相关性。此外，即使在幼年时期，实验室饲养的幼鱼也表现出强烈的侧化取食行为偏好，尽管最初的嘴部不对称程度似乎很小。这表明，明显的嘴部不对称并不是幼年食鳞慈鲷鱼手性取食行为的先决条件，这可能表明对猎物特定一侧进行攻击的行为偏好在促进该物种的形态不对称性方面发挥了作用。
