Does niche centrality predict trait variation in the Antioquia Wren?

Resumen

The niche centrality hypothesis predicts that individuals near the niche centroid have higher fitness due to more favorable environmental conditions. In this study, we evaluated the effect of the niche structure of the Antioquia Wren on 20 different traits grouped into four datasets: morphology, genetic diversity, coloration and acoustics. We tested the relationship with distinct niche configurations using minimum volume ellipsoids, and evaluated the relationship between the distance to the niche centroid and trait values through ordinary linear and generalized linear squared regression models. We found positive relationships for variables associated with beak morphology and crown feathers hue. Conversely, we found a negative relationship with birdsong frequency and the distance between longest primary and first secondary flight feathers. All effects of the niche structure on traits were weak (<0.2). We found no consistency in the relationship between niche structure and the remaining 13 traits. We identify potential mechanisms underlying both positive relationships and the absence of trait–niche relationships. Our findings emphasize that factors such as biotic interactions, climatic heterogeneity, range size, niche breadth, centroid position, and intrinsic trait variability are likely to shape how species conform to the niche centrality hypothesis.