Flexibility in extended phenotype sexual signals in great bowerbirds, Chlamydera nuchalis

Males employ a range of traits to signal their quality to attract mates, some of which can be very elaborate. Some individuals signal their quality via an extended phenotype display (an expression of their quality separate from their body). Signallers must adapt their sexual signals following disruption to maintain effective signal transmission, and males that signal via extended phenotype displays may be particularly sensitive to disruption given their unique reliance on the external environment to produce an effective display. Prior studies rarely consider this unique relationship when exploring flexibility in male signal adaptation. In this thesis, I explored how males displaying through extended phenotype sexual displays may adjust their display to environmental variability and variable female preferences. I studied populations of male great bowerbirds, Chlamydera nuchalis, which construct a complex bower display exclusively for mate choice. Urbanisation has increased the number of anthropogenic items available for males to use as decorations on their bower display. I demonstrated how males increased the salience and variance of their decoration display through their use and found a preference across males to use anthropogenic objects as decorations, irrespective of whether males were from an urban or rural site. I also assessed how males’ display environment may be impacted by another source of anthropogenic pollution (artificial light at night) and explored whether males altered their display behaviour in response. Artificial light altered the light environment at the bower during the night, dawn, and dusk, but males did not increase their display activity at the bower as a result. To determine how males manage multiple signals following disruption, I compared males’ behaviour at the bower before and after a portion of their wall was removed. I found that males manage signals simultaneously, rather than prioritising the restoration of the affected signal, and males appeared to make individual-specific decisions to optimise signal output. Finally, I assessed whether behavioural flexibility in response to female preferences may be an important consideration during sexual signalling using a reversal learning test. While we did not find this relationship when assessing a male’s decoration diversity, we suggest methods that may clarify this relationship. In conclusion, subject to constraints, males with extended phenotype sexual signals can make flexible adjustments to their signal in response to dynamic external conditions in ways that optimise the expression of their signals.<p></p>

Author dc:creator

• Caitlin Evans (21060518)

• sensory ecology
• sexual selection
• urbanisation
• flexibility
• cognition
• bowerbirds
• extended phenotype
• mate choice
• multiple signals
• construction
• signal management

Statement dc:rights

• All rights reserved
• Open Access after 2027-06-22

Identifier

10779/exe.32743338.v1

OAI identifier oai:identifier

oai:figshare.com:article/32743338