The effect of size and hormonal state on the establishment of dominance in young males of Tilapia mariae (Pisces: Cichlidae)

Schwanck, Erkki

doi:10.1016/0376-6357(80)90048-0

Cited by 14 publications

(3 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pseudofemales also seemed to be more aggressive towards males than the females were. The results are reinforced by the weight disadvantage of pseudofemales with respect to females, which would suggest a different fight outcome (Schwanck, 1980). This difference of aggressiveness between females and pseudofemales tended to increase with stocking density.…”

Section: Discussionmentioning

confidence: 86%

Influence of sexual genotype on the behaviour of females (genotype WZ) and pseudofemales (genotype ZZ) in the tilapia Oreochromis aureus

Ovidio

Desprez

Mélard

et al. 2002

Aquatic Living Resources

View full text Add to dashboard Cite

Abstract17α-ethynylestradiol sex-reversed males of Oreochromis aureus (pseudofemales, ∆F, genotype ZZ) are used in aquaculture to produce a male monosex population by crossing with ZZ homogametic normal males. When placed with males (M) and females (F) in the same spawning tank, the spawning rate of F is higher than for ∆F. In order to understand this phenomenon, comparisons were made between the behaviour of 18 F (446 ± 96 mm) and 18 ∆F (401 ± 59 mm). ∆F showed a more aggressive behaviour and were significantly more dominant than normal F in fighting pair experiments (F × ∆F) or in fighting group experiments in four different stocking densities (8, 12, 16 and 83 fish 10 -3 l with F/∆F ratio = 1). ∆F were also more aggressive towards males than F were. The results support the idea that behavioural differences exist between F and ∆F. These differences are probably due to the effect of the sexual genotype on behaviour. © 2002 Ifremer/CNRS/Inra/IRD/Cemagref/Éditions scientifiques et médicales Elsevier SAS. All rights reserved. RésuméInfluence du génotype sexuel sur le comportement de femelles (génotype WZ) et de pseudofemelles (génotype ZZ) chez le tilapia Oreochromis aureus. En aquaculture, l'inversion du sexe de mâles Oreochromis aureus au moyen d'un traitement hormonal à la 17α-ethynylestradiol est utilisée pour produire des pseudofemelles (∆F, génotype ZZ) qui croisées avec un mâle homogamétique (ZZ) donneront une progéniture constituée de 100% de mâles. Cependant, lorsque des femelles (F) et des pseudofemelles (∆F) sont placées dans un même bassin avec des mâles (M), la fréquence de ponte de femelles est supérieure à celle des pseudofemelles. Dans le but de comprendre ce phénomène, nous avons étudié le comportement de 18 F (446 ± 96 mm) et 18 ∆F (401 ± 59 mm). Dans les expériences de combat par paire (F × ∆F) et en groupes (8, 12, 16 et 83 poissons 10 -3 l avec une proportion F/∆F de 1) les ∆F se sont montrées plus agressives que les F. D'autres expériences ont montré que les ∆F se montrent plus agressives que les F vis-à-vis de mâles. Ces expériences montrent qu'il existe des différences comportementales entre F et ∆F qui sont le résultat de l'effet du génotype sexuel sur le comportement. © 2002 Ifremer/CNRS/Inra/Cemagref/Éditions scientifiques et médicales Elsevier SAS. Tous droits réservés.

show abstract

Section: Discussionmentioning

confidence: 86%

Influence of sexual genotype on the behaviour of females (genotype WZ) and pseudofemales (genotype ZZ) in the tilapia Oreochromis aureus

Ovidio

Desprez

Mélard

et al. 2002

Aquatic Living Resources

View full text Add to dashboard Cite

show abstract

“…Differences in the bump on the head may reflect changes in hormone production (Liley, 1969;Meunier & François, 1992). Hierarchical social status has been related to differences in androgenic hormone level in Tilapia mariae (Boulenger) (Schwanck, 1980). So morphological differences between individual fishes in the present study may reflect both territorial behaviour and hormone levels.…”

Section: Differences Between Malesmentioning

confidence: 62%

Ecomorphological individual variation in a population of Haplochromis nyererei from the Tanzanian part of Lake Victoria

Fermon¹,

Cibert

1998

Journal of Fish Biology

View full text Add to dashboard Cite

Intraspecific morphological variation among a population of Haplochromis nyererei (Teleostei, Cichlidae) from Lake Victoria was investigated. Three main groups of variables were used: general shape, outline of the head, and trophic group (intestinal length, stomach contents, teeth and jaw shape, lower jaw length and width). Fishes were arranged into four groups: G1, large males with a prominent bump on the head, a thickset body and anatomical structures related to a strictly insectivorous diet; G2, large males lacking a bump on the head but more or less thickset and showing anatomical structures related to omnivorous feeding habits, though favouring insects; G3, males and a few females with a slight bump on the head, a slender body shape and showing anatomical structures related primarily to a herbivorous tendency; and G4, females and a few small males without a bump on the head, a slender body and showing anatomical structures related to an omnivore with herbivorous tendencies. Several hypotheses related to behaviour are presented partly to explain the intraspecific variation observed. Differences between individuals could arise as a result about the establishment of dominance and territory in males. 1998 The Fisheries Society of the British Isles

show abstract

“…Among teleosts, the causal relation between androgen levels and agonistic behavior is variable (reviewed in VILLARS 1983). In some cichlids, dominance (SCHWANCK 1980) and aggression levels (HOLDER et al 1991;POLDER 1971) vary with reproductive state, and presumably androgen levels. But these correlations are insufficient to establish cause and effect because androgens can affect agonistic behavior and, in turn, agonistic behavior can affect androgen levels (BEACH 1965;BERNSTEIN et a].…”

Section: Discussionmentioning

confidence: 99%

Castration Lowers Aggression but not Social Dominance in Male Haplochromis burtoni (Cichlidae)

et al. 1992

View full text Add to dashboard Cite

Adult males of the African cichlid fish Haplochromis burtoni are either territorial or nonterritorial. In nature and aquaria, only territorial males breed and they have markedly more developed testes than do nonterritorial males. Territorial males are clearly dominant over nonterritorial males of the same age and size, and also exhibit higher levels of aggression. In this study, territorial males were gonadectomized in order to assess the effects of lowered androgen levels on their aggression and dominance status. Completely castrated males showed a pronounced reduction in both testosterone and 11‐ketotestosterone, as well as significantly lower aggression scores than sham‐operated males. Partially castrated males (> 0.005 g gonadal tissue remaining at autopsy) exhibited intermediate levels of both androgen levels and aggression. Surprisingly, in dyadic encounters with normal nonterritorial males of the same size, castrated territorial males retained their dominance despite decreased androgen levels and aggression.

show abstract

The effect of size and hormonal state on the establishment of dominance in young males of Tilapia mariae (Pisces: Cichlidae)

Cited by 14 publications

References 24 publications

Influence of sexual genotype on the behaviour of females (genotype WZ) and pseudofemales (genotype ZZ) in the tilapia Oreochromis aureus

Influence of sexual genotype on the behaviour of females (genotype WZ) and pseudofemales (genotype ZZ) in the tilapia Oreochromis aureus

Ecomorphological individual variation in a population of Haplochromis nyererei from the Tanzanian part of Lake Victoria

Castration Lowers Aggression but not Social Dominance in Male Haplochromis burtoni (Cichlidae)

Contact Info

Product

Resources

About