Many animals communicate using multiple signals. Historically, most attention was paid to how these traits evolve and function in isolation, but recent work has focused on how signals may interact with one another and produce unique signal interaction properties. These interaction properties vary within species, but little is known about how they vary among species, especially with regards to how the expression of particular signals may drive different signal interaction mechanisms. We studied the evolutionary relationships between iridescent plumage, courtship (shuttle) displays, solar environment, and male color appearance during a display (i.e. the signal interaction property) among six species of North American "bee" hummingbirds. We found that color appearances co-vary with behavioral and plumage properties, which themselves negatively co-vary, such that species with more exaggerated displays appeared flashier during courtship, while species with more exaggerated plumage appeared brighter/more colorful with minimal color-changes. By understanding how signal interaction properties co-vary with signals, we were able to discover the complex, multi-layered evolutionary relationships underlying these traits and uncover new potential drivers of signal evolution. Our results highlight how studying the interaction properties between animal signals provides a richer understanding of how those traits evolved and diversified.
|Date made available
|Apr 30 2019