Bohlen, J.

Behaviour and microhabitat of early life stages of Cobitis taenia

Folia Zoologica 49 Suppl. 1: 173-178

Folia Zoologica 49 Suppl. 1: 173-178 (2000)

Behaviour and microhabitat of early life stages of Cobitis taenia

BOHLEN J.

Abstract

The present study investigates the mobility and phototactic behaviour of early life stages of spined loach in order to define the microhabitat of the different ontogenetic phases. The eggs were placed by the spawning adults into dense vegetation. Since the embryos did not show any mobility until eye pigmentation, they face the same microhabitat as the eggs. After eye pigmentation, they became negatively phototactic. In the field, the light gradient would lead them beneath the centre of the vegetation. With the beginning of exogenous feeding, phototaxis changed into a positive reaction. This would lead the larvae towards the lighter marginal areas under the vegetation. Afterwards, the spontaneous mobility of the larvae increased and the phototactic behaviour lost its importance. When early life stages of Cobitis were exposed to 13 invertebrate and vertebrate predators, they showed a high vulnerability to predation. Therefore, the dense vegetation acts as a shelter for predation.