Quantity of social interaction influences preference learning and gene expression in a butterfly

Mate preference learning is pervasive across animal taxa, however little is known about preference learning temporal dynamics, particularly considering the variability in quantity of social exposure that occurs within species in nature. To uncover the temporal dynamics of preference learning from behavioural and transcriptional perspectives, we conducted learning and RNA-Seq time series using the butterfly Bicyclus anynana. We exposed females to an innately unpreferred male phenotype for five different exposure (training) durations, ranging from 30 minutes to three hours, and then tested female preference and brain gene expression in relation to naive females. We found that the longest exposure had the strongest effect on preference learning, however the effect of exposure duration on learning was non-linear. Also, the greatest number of differentially expressed genes (DEGs) between trained and naive females was after one hour of exposure, indicating that peak DEG did not coincide with optimal training time. While several genes were uniquely DE at each time point, one gene, associated with transcription initiation, was DE across all time points. Our results indicate that both gene expression and mate preference learning are temporally dynamic, and that stochasticity in quantity of social interaction may facilitate variance in realized mate preference.