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| Kadry,Vivian Oliveira; Barreto,Rodrigo Egydio. |
| Among fishes, when residents and intruders fight, residents usually win, most likely because they value the residence more than intruders. We hypothesized that enriched environments increase the value of an area in dispute, causing a resident to more fiercely defend a resource-rich environment than a poor one. However, in the present study, intruder-resident tests with the pearl cichlid, Geophagus brasiliensis, showed environmental enrichment actually reduces aggression and can even lead to co-habitation without fighting. Additionally, in our experiments, the prior residence effect occurred irrespective of enrichment condition. Decreased visibility from increased habitat complexity reduces interactions between fish and consequently might explain the lower... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fighting; Territoriality; Intruder-resident paradigm; Resource holding power; Cichlidae. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252010000200011 |
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| Barreto,R.E.; Volpato,G.L.. |
| Plasma cortisol and glucose levels were measured in 36 adult Nile tilapia males, Oreochromis niloticus (standard length, mean ± SD, 14.38 ± 1.31 cm), subjected to electroshock and social stressors. Pre-stressor levels were determined 5 days after the adjustment of the fish to the experimental aquaria (1 fish/aquarium). Five days later, the effects of stressors on both cortisol and glucose levels were assessed. The following stressors were imposed for 60 min: pairing with a larger resident animal (social stressor), or a gentle electroshock (AC, 20 V, 15 mA, 100 Hz for 1 min every 4 min). Each stressor was tested in two independent groups, one in which stress was quantified immediately after the end of the 60-min stressor imposition (T60) and the other in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Stress; Aggression; Agonistic behavior; Fighting; Social stress; Electroshock. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006001200012 |
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