Size, Sex, and Stress: Factors affecting lateralized behaviour and boldness in the convict cichlid (Amatitlania nigrofasciata)

• Author / Creator

  Moscicki, Michele K

• Cerebral lateralization, the partitioning of cognitive functions preferentially into one hemisphere of the brain, is a trait ubiquitous among vertebrates. Although this trait is pervasive, not all individuals show the same degree or direction of lateralized behaviour. Individual differences in the expression of lateralized behaviour have been linked to factors such as growth rate, neuroanatomical asymmetry, and individual personality traits. The research presented in this thesis was conducted to examine the influence of these variables, as well as additional factors, on the expression of lateralized and other behaviours in a species of Central American fish, the convict cichlid (Amatitlania nigrofasciata). Study 1 revealed that differences in growth rate during the juvenile stage affected lateralized behaviour when viewing social stimuli. Study 2 showed that the type of stimuli, social or non-social, as well as the sex of the subject, influenced lateralized behaviour. In Study 3, a stressor altered lateralized behaviour such that the right hemisphere became more heavily involved in processing stimuli. This effect was predominantly found in females. This study also revealed a relationship between lateralized behaviour and neuroanatomical asymmetry that was not apparent when the stressor was absent. Study 4 showed that neuroanatomical asymmetry was unrelated to boldness in convict cichlids. Boldness did, however, influence the response of fish to stressors; this response was modulated by previous experience with stressors in females. These studies reveal that size, sex, stimulus type, stress, and experience interact to affect lateralized and boldness behaviour in the convict cichlid.

• Subjects / Keywords

  • Damage-induced alarm cues
  • Cerebral lateralization
  • Boldness
  • Convict cichlid

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3WM14132

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.