How Developmental and Behavioural Plasticity in the Field Cricket is Influenced by the Acoustic Social Environment and Anthropogenic Noise

The social environment is an important driver of developmental plasticity in juveniles and behavioural plasticity in adults. An individual’s ability to accurately assess cues during development and predict its future social dynamics plays an important role in ensuring that its phenotype at adulthood will match their anticipated environment. However, because the overall plasticity of an individual is the result of a concomitant interaction between development, environment, and behaviour over the entire lifetime, constraints arising from development may hinder adult behaviour. My dissertation examines the influence of the developmental social environment on life-history traits and fitness-conferring adult behaviours to enhance our understanding of how these two life phases interact in the fall field cricket Gryllus pennsylvanicus. Through play-back experiments that altered the density of adult male acoustic signals, my findings reveal that male and female development time decreases and female residual mass at adulthood increases in higher perceived population densities. Contrary to my expectations, neither adult male aggressive nor mate attraction signalling were significantly influenced by developmental social environments. Adult female mate preference behaviour was influenced by developmental social environment, as females raised in social isolation were more responsive than females raised exposed to signals. Furthermore, the acoustic social environment experienced during development had significant indirect effects on all adult behaviours through constraints imposed on adult body size. Crickets reared in the high density environments developed faster, and a faster development time resulted in larger body sizes. Because body size significantly influenced male aggression and signalling behaviour, and female mate preference behaviour, the ability to express behavioural plasticity at adulthood may have been limited. However, my experiment that switched acoustic social environments between juvenile and adult stages showed that males who experienced a switched environment were able to adjust specific aspects of their signalling to match the unanticipated adult social dynamics. I also examined whether anthropogenic noise pollutes the bioacoustics network. Anthropogenic noise influenced male development time and signalling behaviour, and female residual mass and preference functions. Further, anthropogenic noise sometimes interacted with the acoustic social environment experienced during rearing, causing individuals to be mismatched with their social environment in adulthood.