Dewlap size in male water anoles associates with consistent inter-individual variation in boldness

Abstract

Male sexually selected signals can indicate competitive ability by honestly signaling fitness-relevant traits such as condition or performance. However, behavior can also influence contest outcomes; in particular, boldness often predicts dominance rank and mating success. Here, we sought to determine whether male ornament size is associated with consistent individual differences in boldness in water anoles Anolis aquaticus. We measured the relative size of the dewlap, a flap of skin under the chin that is a sexually selected ornament in Anolis lizards, and tested for associations with responses to a novel and potentially risky environment: time to emerge from a refuge into an arena and number of head scans post-emergence. We found that individuals consistently differed in both time to emerge and head scanning (i.e., individual responses were repeatable), and that dewlap size was negatively related to number of head scans. This suggests that ornament size could indicate male boldness if scanning represents antipredator vigilance. We found that males that had larger relative dewlaps were also in better body condition, but boldness (i.e., head scanning) was not related to condition. Lastly, we found consistent differences in behavior between trials, showing that anoles were becoming habituated or sensitized to the testing arena. Overall, our study shows that in addition to indicating condition and performance, dewlap size could also honestly indicate male boldness in Anolis lizards.

You’re Just My Type: Mate Choice and Behavioral Types

“…Many of the sometimes arbitrary-seeming attributes that females use to make mate choice decisions have been theorized to indicate fitness-relevant traits via good genes or direct benefits. Many of these attributes, including coloration [73][74][75] and dewlap size [76], are also correlated to BT. Females may be selecting based on ornaments but if those ornaments are correlated to a male's BT, she will indirectly select BT.…”

Clothing color mediates lizard responses to humans in a tropical forest

“…Anoline dewlaps can be used as an honest indicator of health (Cook, Murphy, & Johnson, ; Driessens, Huyghe, Vanhooydonck, & Damme, ), can convey bite force (Baeckens, Driessens, Huyghe, Vanhooydonck, & Damme, ; Henningsen & Irschick, ), and are used for intra‐ and inter‐sexual interactions (Steffen & Guyer, ). In water anoles, specifically, dewlap size scales with traits implicated in intrasexual combat and is likely used as an honest signal of fighting ability (Petelo & Swierk, ; Putman, Azure, & Swierk, ). Because the dewlap is an integral form of communication, we predicted that anoles would be less apprehensive and allow researchers to approach them at closer distances, increasing capture, and encounter rates, when researchers wore orange.…”

Physiological Stress Integrates Resistance to Rattlesnake Venom and the Onset of Risky Foraging in California Ground Squirrels

“…We used close proximity to snakes, tail-flagging rate, and latency to feed as three separate measures of boldness, which we defined as willingness to take risks during a predator presentation test [ 82 ]. Yet, we did not find that these three behaviors were similarly impacted by the same effectors, implying that they represent functionally different traits for squirrels [ 83 ]. For instance, approaching snakes closely may allow squirrels to more accurately assess the threat posed by the snake, tail-flagging modifies snake hunting behavior [ 1 ], and feeding latency associates with resource acquisition.…”