What is implied about the evolutionary relationship between *C. chrysomelas* and the plants it feeds upon?

A deep, enduring co-evolutionary bond exists where the bird acts as a seed disperser optimized for local fruit morphology.

The feeding niche evolution of the Black-and-Yellow Tanager points toward a classic example of co-evolution within its specific lowland tropical biome. Since its diet includes fruits, it is highly probable that this frugivory involves a mutualistic relationship with the local flora, where the tanager functions as a primary seed disperser. Over vast stretches of evolutionary time, this relationship drives reciprocal adaptation: the bird's beak morphology and digestive efficiency would fine-tune to efficiently handle the size and toughness of indigenous fruits, while simultaneously, the plants would evolve fruits optimized specifically for ingestion and dispersal by birds like *C. chrysomelas*. This mutual dependency anchors the bird strongly to its specific habitat type. A decline in key fruit species would severely challenge the bird's fine-tuned, balanced diet, testing its secondary reliance on insect prey.