Nom du corpus

Corpus Systématique Animale

Titre du document

Size specific predation by herons and its effect on the sex-ratio of natural populations of the mosquito fish Gambusia affinis baird and girard

Lien vers le document
Springer (journals)
Langue(s) du document
Type de document
Nom du fichier dans la ressource
Oiseaux_v2b_02297, Poissons_v2b_004087
  • Robert H. Britton 1
  • Michael E. Moser 1,2
  • 1) Station Biologique de la Tour du Valat, Le Sambuc, F-13200, Arles, France
  • 2) Department of Zoology, University of Durham, South Road, DH1 3LE, Durham, UK

Sex-ratios of Gambusia affinis populations in freshwater marshes in the Camargue (Rhône Delta), are highly biased in favour of males, whereas the sex-ratios in ditches are close to unity. Studies of the diet of free living birds and experimental studies on prey size selection in captivity show that the abnormal sex-ratios in marshes can be attributed to differential heron predation. Ditches are relatively free from predation. Mature female Gambusia are larger, and have an energy content 5–25 times greater than that of mature males. Handling times of Grey Heron (Ardea cinerea) and Little Egret (Egretta garzetta) are only slightly longer for female Gambusia than males. Hence, females represent a much more profitable prey. Analysis of nestling regurgitates show that Gambusia makes up a considerable proportion of the diet of four species of Camargue herons, and that the majority of Gambusia taken are females. Under experimental conditions, captive herons consume almost exclusively female fish, even when offered in ratios where they are heavily outnumbered by males. The relevance of these results to optimal diet theory is discussed.

Catégories Science-Metrix
  • 1 - natural sciences
  • 2 - biology
  • 3 - ecology
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
  • 4 - ecologie animale, vegetale et microbienne
Catégories Scopus
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Ecology, Evolution, Behavior and Systematics
Catégories WoS
  • 1 - science ; 2 - ecology
Identifiant ISTEX


Année de publication
Présence de XML structuré
Version PDF
Score qualité du texte
  • Oiseaux
  • Poissons
Type de publication
Powered by Lodex 9.3.8