Eastern side blotched lizard

Uta stansburiana stejnegeri

Side-blotched lizard

Uta stansburiana

  1. Master’s research

Morphology and resource use of two agamid lizards in Taiwan

For my master’s thesis, I studied sexual dimorphism in two congeneric agamid lizards that co-occur in northern Taiwan. I also collected data on their resource use. It turned out that one species, Japalura swinhonis, are more sexually dimorphic than the other species, J. polygonata xanthostoma. Despite morphological differences, the two species occupied similar perch habitats and utilized the same set of food items. The two species might be competitors at my study site because subsequent observations showed that the population of J. polygonata xanthostoma was declining. It would be very interesting to elucidate the ecological relationship between the two species. Also, both species have conspicuous color patterns at their throat region. Those color patterns might serve as sexual signals, but no one really knows. I would like to unravel the function(s) of those color patches in the two agamid lizards.

  1. Other recent projects

  1. PhD research

The multitude of antipredator traits represents a fascinating facet of phenotypic diversity. Animals in particular have evolved all kinds of antipredator defense. The expression of defense traits often depends heavily on the intricate balance between costs and benefits and can vary substantially among species/populations. Tail autotomy (the ability to voluntarily discard the tail) in lizards is a great system for asking all kinds of interesting questions, especially along the lines of how the use of defense traits might respond to changes in the underlying cost-benefit dynamics. Here’s why:

First, autotomy is a very costly defense trait. A lizard without the tail may suffer from reduced locomotor performance, lower social status, lower mating success, etc. Moreover, some of those costs can persist for an extended period of time before the tail fully regenerates. Severe fitness consequences following tail loss implies that tail autotomy may be a labile defense trait, whose expression is highly sensitive to changes in the associated costs and benefits.

Second, although we already know that the propensity for tail autotomy (i.e., how easy it is to induce tail autotomy) varies substantially in nature, we still haven’t fully figured out what might be responsible for this variation. For example, we know that in some cases the variation has much to do with local predation intensity, but there are other factors that may also influence the cost-benefit dynamics of tail autotomy. Some of those factors are related to local ecological environments, such as the amount of available resources, whereas some are intrinsic to the individuals, such as sex, age and risk-taking behavioral tendencies (personalities).

The main goal of my dissertation is to understand the dynamics behind the variation in the propensity for tail autotomy, for which I have the following three projects:

  1. Modeling the cost-benefit dynamics of tail autotomy

  2. The relationship between risk-taking behavior and the propensity for tail autotomy under different food availabilities. Click to read more

  3. Comparative field study on the variation in tail autotomy among Uta stansburiana populations in western North America

I am currently collecting data for these projects. Check back soon for more updates!

Toepads, tendons and gecko adhesion

Geckos are amazing climbers, and the secret lies in their toes. Most geckos have millions of microscopic hair (setae) aligned neatly in fields on the surface of their toes. Those setae are the structures that generate adhesive force that allows geckos to stay on vertical surfaces. Although setae are essential for adhesion, a pair of tendons in each toe may also have a role to play. In collaboration with Dr. Anthony Russell at the University of Calgary, I will examine how tendon morphology might contribute to adhesive ability in several gecko species. More to come soon.

Kuo C-Y, Lin Y-T, Lin Y-S. 2009. Sexual size and shape dimorphism in an agamid lizard, Japalura swinhonis (Squamata: Iguania: Agamidae). Zoological Studies 48(3): 351-361 (cover)    pdf

Kuo C-Y, Lin Y-S, Lin Y-T K. 2007. Resource use and morphology of two sympatric Japalura lizards (Iguania: Agamidae). Journal of Herpetology 41(4): 713-723    pdf

Loading effects on jump performance in green anole lizards

Jumping is an energetically demanding behavior. However, things can get even harder, when animals have to jump with a substantial amount of weight gain. This can happen when an animal has to escape from a predator right after eating a meal, or when a female is pregnant. To explore how situations like these would affect an animal’s locomotor capacity, I added weights (30% body mass) on green anole lizards Anolis carolinensis to simulate weight gain after a regular meal and examined its influences on jump performance and kinematics. When jumping with loads, green anoles were unable to jump as far (declined by 18%) and also took off at a lower speed (declined by 10%), indicating that weight gain from eating a meal can pose a severe locomotor challenge. It also implies an interesting conflict between fulfilling energetic requirement and moving efficiently in the environments.

Kuo C-Y, Gillis GB, Irschick DJ. 2011. Loading effects on jump performance in green anole lizards, Anolis carolinensis. Journal of Experimental Biology 214: 2073-2079    pdf