Male social niche conformance? Effects of manipulated opportunity for extra-pair mating on behavior and hormones of male zebra finches

Transcriptomic changes in the testes and brain associated with sperm competition risk in male zebra finches

“…Our treatment affected the transcriptomes in both brain tissues, indicating responses in neural functions that regulate behavioural phenotypes. As reported in our accompanying paper 44 , zebra nch males adjusted their behavioural phenotypes to the manipulated social environment indicating social niche conformance 4 . However, contrary to our pre-registered expectations 43 , there was no evidence that these behavioural adjustments were related to the elevated sperm competition risk.…”

“…We expected the Double-pair males to show more courtship displays, including songs directed towards their social mate, more a liative and copulation behaviour with their social mate and more aggression towards competitors than the control group 43 . On the contrary, males of the Double-pair treatment group decreased courtship rates (song), and when confronted with an unfamiliar intruder, they responded less aggressively than Single-pair males 44 . No other behavioural measures revealed signi cant treatment effects (see 44 for all details).…”

“…On the contrary, males of the Double-pair treatment group decreased courtship rates (song), and when confronted with an unfamiliar intruder, they responded less aggressively than Single-pair males 44 . No other behavioural measures revealed signi cant treatment effects (see 44 for all details). These unexpected effects suggest that in our study, we observed adjustment of social behaviour to social factors other than the elevated sperm competition risk, e.g., reactions to mild social isolation.…”

“…Finally, we detected signi cant correlations between the expression of several gene network modules in individual transcriptomes and among-individual variation in aggression and hormone levels. In the following, we discuss our results for each target tissue and in relation to the hormonal and behavioural results, which were reported in detail in our complementary paper 44 .…”

“…1). The effects of this treatment on the behavioural and hormonal pro les of zebra nch males have been reported in a complementary paper, which revealed individual phenotypic plasticity to be induced by the social environment 44 . For example, males decreased within-pair interactions (i.e., time spent courtship singing and time spent near their social mates) and aggression towards an unfamiliar intruder under the Double-pair treatment 44 .…”