A growth cost of experimentally induced conspicuous coloration in first-year collared lizard males

I used painted first-year collared lizard males in the field to test the hypothesis that conspicuous coloration imposes a growth cost, either because it makes lizards less cryptic to their prey or because conspicuous color attracts predators forcing increased refuging by lizards. To make males more conspicuous, I painted them green and yellow to match hues of older territorial males, made another group inconspicuous by painting males brown like females, and painted a control group with water. I then compared rates of travel, the frequency, and the percentage of strikes on prey that were successful. I recaptured males periodically to record cloacal and substrate temperatures, to measure growth rate, and to retouch paint. Time spent refuging, travel rate, and both cloacal and substrate temperatures were similar in the 3 groups. Males painted conspicuously had slower growth than males in the other treatment groups. Inconspicuous males initiated strikes on prey more than 4 times more frequently than conspicuous males, and the number of strikes that resulted in prey capture was higher in inconspicuous males, suggesting that conspicuous coloration reduces foraging opportunities because it makes first-year males more visible to their prey. Rapid growth during the first season is necessary for collared lizard males to become large enough to compete for breeding territories as 2 year olds. Therefore, conspicuous coloration may develop gradually in first-year collared lizard males to maintain crypsis, which promotes food intake sufficient for rapid growth to large size that has important consequences for future reproductive success.