Submission to Graduation: PhD Completion!



The day has finally arrived, and I have officially graduated from Macquarie University as Dr. Julia Riley!

The process from submitting your PhD thesis until walking across the stage at graduation can sometimes feel like a long journey - especially for someone who is a little impatient like me! In Australia you first submit a copy of your thesis to be reviewed externally. Once reviewer's comments are addressed, and it has been approved you submit the hardbound version of your thesis and then your PhD is conferred at graduation. Below are some photos of my journey during this time, and, for inquiring minds, my thesis summary.

It has taken so many wonderful people to be successful in this achievement. I would like to thank everyone for their help with my research, and for celebrating this wonderful time in my life with me!

Thesis Summary

For group-living animals social experience during ontogeny is known to influence multiple facets of animal behaviour. Rearing social animals isolated from any conspecific contact can hinder development of behavioural traits, cognitive ability, and social competence. This thesis is an overview of how social environment effects behavioural development in a family-living lizard, Egernia striolata. I experimentally manipulated E. striolata early social environment, and raised skinks either in isolation or in pairs. I began by examining if social environment impacts development of skink behavioural traits across their first year of life. I found strong evidence that skink behavioural development was plastic depending on their social experience, and isolation itself did not hinder E. striolata behaviour in a similar manner as found in previous research. I then assessed how social isolation impacted skink cognitive ability. Contrary to previous research, I found no effect of social environment on individual learning ability in multiple cognitive tasks (e.g., spatial, motor and discrimination tasks). Additionally, juvenile tree skinks did not use social information from adults regardless of their early social environment. Finally, I studied if social environment affects skink social competence using repeated behavioural observations in a laboratory and semi-natural setting. Isolated skinks were initially more social than socially-raised skinks, but they decreased in their sociability over time once exposed to a social environment. This is evidence that E. striolata can flexibly alter their social behaviour in response to the environment they are exposed to, even after long-term social isolation. Overall, this thesis presents evidence that isolation rearing does not consistently result in negative impacts on behaviour across all social taxa, and instead, that E. striolata behavioural development responds flexibly, and potentially adaptively, to the social environment in which they are raised.

Thesis Citation

Riley JL (2017) Social environment impacts behavioural development of a family-living lizard. PhD thesis, Macquarie University, Sydney, New South Wales, Australia.


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