INVITED TALKS 5 & 6

SENSORY ECOLOGY OF KELP FOREST FISHES

Cummings, Molly Elizabeth<sup>1

1</sup>University of Texas 2400 Speedway, University of Texas, Austin, TX, 78712, United States

A spectrally variable environment can tell us much about the ideal design for visual detection and visual communication. It is under such constrained environments that selection acts directionally on traits. I examine the evolutionary solutions to the problem of target detection and signal design in an optically variable environment by studying a group of closely related fish (surfperch: Embiotocidae) that inhabit the California kelp forest. Using species-specific measurements of habitat spectral irradiances collected over 3 years, visual pigment absorptances, and foraging target and color pattern reflectances along with simple visual detection models, I evaluate the direction of visual evolution in this system. The results show that photoreceptor peak sensitivity covaries with changes in optical habitat and that this divergence produces detectional biases. The evolutionary divergence in visual detection performance across this group of dichromats suggest that some species favor luminance contrast detection while others favor chromatic contrast. Divergence in sensory biases follows divergence in habitat optical properties—specifically the variation in signal:to:noise in particular detection channels. Signal design properties and display behaviors also show parallel divergence to exploit receiver biases, with signal design divergence observed across three different chromatophore types favoring species-specific biases.