Dynamics of nest defense in the Mediterranean labrid fish Symphodus ocellatus (Forsskål, 1775). I. Agonistic behaviour between nesting territorial male and five other labrid species

摘要

This research in the field consists of a study of interspecific agonistic behaviour of territorial male in Symphodus ocellatus. This behaviour is useful for brood and nest defense.Four questions involving Symphodus ocellatus towards S. tinca, S. mediterraneus, S. roissali, Thalassoma pavo et Coris julis were investigated. The questions of interest were: (1) aggressors or intruders motivations (predation of the brood (a) and/or territorial conflicts (b)), (2) the recognition of this or that species (recognition studied with selective attacks by territorial male), (3) the organ(s) of perception used for this recognition and (4) the importance of territorial male investment in nest defense; this role could ensure a successful reproduction of the species.Our observations and experimentations (tested labrid fishes presented to T. males) allow us to affirm that in S. ocellatus, nesting territorial males recognize the various tested labrid fishes; that the organ of perception used for social recognition is the visual channel; that spawn protection insured by territorial male, a task guided by his visual system, is necessary towards menace of his congeners, but also the other fishes living in his habitat.Nevertheless, if it’s becoming clear that the Mediterranean labrid fishes have the ability to recognize and preferentially interact with particular individuals, the answer of the question 1, concerning aggressors motivations, is not yet clearly known.