engleski

Predation of the Mediterranean ascoglossans on the introduced tropical species Caulerpa taxifolia

Two species of the endemically Mediterranean sacoglossans Oxynoea olivacea and Lobiger serradifalci are consumers of the indigenous algae Caulerpa taxifolia. From the Summer of 1997, these two species have been observed on the introduced tropical alga C. taxifolia in the Sarigrad Bay (43°10’54’’N-16°35’00’’E)(Hvar Island, Adriatic Sea, Croatia). Although traces of predation can be found in the whole algae affected area, only a small number of specimen were found: O. olivacea and aprox. 30 specimens of L. serradifalci. They have a species-specific pattern of feeding on the fronds and stolons of the C. taxifolia. The species O. olivacea consume the alga thalli more systematically; sucking mostly on the pinnules and stolons. On the contrary, L. serradifalci sucks mostly on the frond axis and stolon. After predation, the wounded parts of the thalli are easily breakable due the hydrodinamism. The area with L. serradifalci especially had plenty of algae fragments. These fragments, mostly pieces of the fronds, can easily regenerate into new plants. In that way, the low density population of the sacoglossans improve the vegetative reproduction and spreading of C. taxifolia.

Oxynoea olivacea; Lobiger serradifalci; Gastropoda; predation; Caulerpa taxifolia; Hvar Island; Adriatic Sea; Croatia

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