Titre :	Size heterogeneity prevails over kinship in shaping cannibalism among larvae of sharptooth catfish clarias gariepinus
Type de document :	texte imprimé
Auteurs :	Baras, Etienne, Auteur
Importance :	pp. 251-256
Langues :	Français (fre)
Index. décimale :	578 Histoire naturelle des organismes vivants
Résumé :	Because preying on close relatives may cause a loss of inclusive fitness, cannibalistic animals are generally deemed to cannibalise non-related conspecifics preferentially to kins. Whether this basic principle also applies to fish exerting intracohort cannibalism at an early developmental stage is uncertain, and more intense cannibalism among mixed progenies might just be a consequence of greater size heterogeneity. To investigate this, progenies of sharptooth catfish of equivalent initial body weights but with contrasting size heterogeneity were reared separately or in mixed groups containing equal proportions of each progeny (27 ± 1°C, 12 h light: 12 h night, 2.5 L aquaria, 100 or 200 fish-L-1). Cannibalism was monitored on a daily basis until the end of the larval stage (3-15 days after hatching). Cannibalism in mixed groups was intermediate between those in pure progenies, and was positively correlated (R2 = 0.803. P<0.01) with initial size heterogeneity, irrespectively of fish origin. This finding does not exclude that catfish larvae were able to discriminate between siblings and non-related fish, but this obviously had very little influence on cannibalism. The implications of this finding are discussed, as they apply to prey selection in fast growing larvae, and aquaeulture of catfish.

Size heterogeneity prevails over kinship in shaping cannibalism among larvae of sharptooth catfish clarias gariepinus [texte imprimé] / Baras, Etienne, Auteur . - [s.d.] . - pp. 251-256.
Langues : Français (fre)

Index. décimale :

578 Histoire naturelle des organismes vivants

Résumé :

Because preying on close relatives may cause a loss of inclusive fitness, cannibalistic animals are generally deemed to cannibalise non-related conspecifics preferentially to kins. Whether this basic principle also applies to fish exerting intracohort cannibalism at an early developmental stage is uncertain, and more intense cannibalism among mixed progenies might just be a consequence of greater size heterogeneity. To investigate this, progenies of sharptooth catfish of equivalent initial body weights but with contrasting size heterogeneity were reared separately or in mixed groups containing equal proportions of each progeny (27 ± 1°C, 12 h light: 12 h night, 2.5 L aquaria, 100 or 200 fish-L-1). Cannibalism was monitored on a daily basis until the end of the larval stage (3-15 days after hatching). Cannibalism in mixed groups was intermediate between those in pure progenies, and was positively correlated (R2 = 0.803. P<0.01) with initial size heterogeneity, irrespectively of fish origin. This finding does not exclude that catfish larvae were able to discriminate between siblings and non-related fish, but this obviously had very little influence on cannibalism. The implications of this finding are discussed, as they apply to prey selection in fast growing larvae, and aquaeulture of catfish.