Fitness costs as well as benefits are important when considering responses to anthropogenic noise

Trade-offs lie at the heart of behavioral ecology, with our ultimate understanding of many behaviors reliant on an assessment of both fitness benefits and costs. However, the rapidly expanding research literature on the impacts of anthropogenic noise (a recently recognized global pollutant) tends to focus on the benefits likely to be accrued by any resulting behavioral adaptations or plasticity. In particular, although studies investigating acoustic communication (the topic receiving the most attention to date) invariably discuss, and occasionally attempt to measure, the perceived benefits in terms of reduced masking that might arise from vocal adjustments by signalers, only rarely are the potential fitness costs even mentioned. The bias toward benefits prevents a full understanding of the consequences of anthropogenic noise, including the implications for population viability and community structure. Here, we argue for a greater consideration of fitness costs, outline a number of specific examples (reduced transmission distances, increased risk of predation/parasitism, altered energy budgets, loss of vital information), make suggestions about how to move forward, and showcase why a balanced view is as crucial in this field as any other aspect of behavioral ecology.