References of "Michel, Christian"
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See detailSound production in piranhas and relatives: preliminary results
Melotte, Geoffrey ULg; Michel, Christian ULg; Parmentier, Eric ULg

Poster (2014, December 12)

Acoustic communication plays an important role in the life of many teleost species where it is mainly involved in agonistic and/or courtship behaviour(s). Despite the large number of species in the family ... [more ▼]

Acoustic communication plays an important role in the life of many teleost species where it is mainly involved in agonistic and/or courtship behaviour(s). Despite the large number of species in the family Serrasalmidae (92 species), sound production has been described only in some of them, particularly in the genera Serrasalmus and Pygocentrus. The aim of this study is to investigate the sound producing abilities of different Serrasalmidae species and to understand the corresponding mechanisms. Two herbivorous species of Serrasalmidae, Piaractus brachypomus and Metynnis lippincottianus, produce sounds composed of a single pulse. The mechanism involved in these species is not yet understood. In contrast, the calls emitted by several species of Serrasalmus and Pygocentrus are harmonic sounds composed of several pulses without inter-pulse interval. Their mechanism results from the forced vibration of the swimbladder following the contraction of sonic muscles that are attached to tendons surrounding ventrally the bladder. Another species, Pygopristis denticulata, is able to produce two types of sounds. The first sound consists of several pulses with irregular pulse period and is likely produced by a sonic muscle inserting on the skull and on the rostral part of the swimbladder. The second sound is multi-pulsed and, contrary to all other sounds described here, possesses a high dominant frequency suggesting a mechanism that does not involve the swimbladder and that remains to be determined. According to these results, Serrasalmidae seems to contain many species able to produce sounds by means of different mechanisms. [less ▲]

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See detailCroyances, pratiques et utilisations des tortues marines en médecine traditionnelle sur la côte ouest africaine: Bénin et Sénégal
Dossa, Justine; Diez, Marianne ULg; Hornick, Jean-Luc ULg et al

in Chéloniens : Biologie, écologie, Elevage, Conservation (2009), 14

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See detailDynamique de défense du nid chez Symphodus ocellatus (Forsskål, 1775), poisson labridé méditerranéen. II. Comportements agressifs du mâle territorial nidificateur envers des mollusques gastéropodes
Ylieff, Marc ULg; Michel, Christian ULg; Voss, Jacques

in Cahiers d'Ethologie (1998), 18(1), 39-52

This field research examines aggressive behaviour towards gasteropod molluscs in nesting territorial male of Symphodus ocellatus. This behaviour is useful for brood and nest defense. Four questions ... [more ▼]

This field research examines aggressive behaviour towards gasteropod molluscs in nesting territorial male of Symphodus ocellatus. This behaviour is useful for brood and nest defense. Four questions involving Symphodus ocellatus towards gasteropod molluscs were investigated. Questions of interest were: (1) selective cleaning of the nest according to possible predation danger of molluscs on the eggs, (2) visual recognition of natural mollusc from artificially coloured lure, (3) colours discriminating abilities by the visual system and, more generally (4) the importance of territorial male investment in nest defense; this role could ensure a successful reproduction of the species. Our observations and experimentations (coloured dummies) allow us to conclude that in Symphodus ocellatus, nesting territorial males clean every time their nest, any gasteropod mollusc species whatever; that they have sufficient knowledge of their usual biological environment to be able to discriminate a gasteropod mollusc from a dummy; that the organ of perception used for social recognition is the visual channel constituted by a neural system competent to perceive colours finely , a special quality which support the theory about the use of one preferential colour (red for S.ocellatus) for visual communication; that fry protection insured by territorial male, a task guided by his visual system, is necessary considering dangers from some gasteropod molluscs living in his habitat. [less ▲]

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See detailDynamique de défense du nid chez Symphodus ocellatus (Forsskål, 1775), poisson labridé méditerranéen. I. Comportements agonistiques entre le mâle territorial nidificateur et cinq autres espèces de labridés
Ylieff, Marc ULg; Michel, Christian ULg; Voss, Jacques

in Cahiers d'Ethologie (1997), 17(1), 49-74

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 ... [more ▼]

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. [less ▲]

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