Light matters: testing the “Light Environment Hypothesis” under intra- and interspecific contexts Angelica Hernandez-Palma School of Renewable Natural Resources, Louisiana State University Agricultural Center, Louisiana State University, Baton Rouge, Louisiana Keywords Abstract Dichromatism, Furnariides, model of color discrimination, species recognition, The “Light Environment Hypothesis” (LEH) proposes that evolution of inter- tetrahedral color space model, visual specific variation in plumage color is driven by variation in light environments signaling. across habitats. If ambient light has the potential to drive interspecific variation, a similar influence should be expected for intraspecific recognition, as color sig- Correspondence nals are an adaptive response to the change in ambient light levels in different Angelica Hernandez-Palma, School of habitats. Using spectrometry, avian-appropriate models of vision, and phyloge- Renewable Natural Resources, Louisiana State netic comparative methods, I quantified dichromatism and tested the LEH in University Agricultural Center, Louisiana State University, Room 227 RNR Building, Baton both intra- and interspecific contexts in 33 Amazonian species from the infraor- Rouge, Louisiana 70803. der Furnariides living in environments with different light levels. Although Tel: 225 578 4228; these birds are sexually monochromatic to humans, 81.8% of the species had at Fax: 225-578-4227; least one dichromatic patch in their plumage, mostly from dorsal areas, which E-mail:
[email protected] provides evidence for a role for dichromatism in sex recognition. Furthermore, birds from habitats with high levels of ambient light had higher dichromatism Funding Information levels, as well as brighter, more saturated, and more diverse plumages, suggest- National Science Foundation (Grant/Award Number: ‘0545491’, ‘1257340’) ing that visual communication is less constrained in these habitats.