Acute exposure to 17?-ethinylestradiol alters boldness behavioural syndrome in female Siamese fighting fish

The role of anthropogenic sources in generating, maintaining, and influencing behavioural syndromes has recently been identified as an important area of future research. Endocrine disrupting chemicals are prevalent and persistent in aquatic ecosystems worldwide. These chemicals are known to have marked effects on the morphology and behaviour of exposed individuals and, as such, may serve as a potential influence on behavioural syndromes. However, both the effects of exposure on behaviours beyond courtship and aggression and how exposure might affect behavioural variation at the individual level are understudied. To address this question, the authors examined boldness behaviour in female Siamese fighting fish in three different assays (Novel Environment, Empty Tank, Shoaling) both before and after they were exposed to the oestrogen mimic, 17?-ethinylestradiol (EE2). EE2 influences courtship, aggression, and boldness in males of this species but its effects have not been examined in females, to our knowledge. Females were tested multiple times in each assay before and after exposure so that behavioural consistency could be examined. A behavioural syndrome for boldness and activity level occurred across the three assays. The reductions in boldness and loss of the behavioural syndrome that resulted from EE2 exposure were surprising and suggest that the effects of EE2 exposure on female behaviour and physiology should be examined more frequently. This study is one of the first to examine the effects of EE2 in females as well as on correlated behaviours and emphasises the importance of examining the effects of endocrine disrupting chemicals on individual behavioural variation and consistency.

Authors: Dzieweczynski TL, Campbell BA, Marks JM, Logan B. ;Full Source: Hormones & Behavior. 2014 Aug 23;66(4):577-584. doi: 10.1016/j.yhbeh.2014.08.005. [Epub ahead of print] ;