Post created by Kam
In most cases where an invasive species begins to kick grass and take turf from native inhabitants the causation can be chalked up to the invader’s being bigger, faster, stronger, or smarter, if not a combination of all thereof. However, while this can easily be the common rule, it does not mean that there are no exceptions to said rule. For instance, just off the Pacific coast of Mexico, in a dry, tropical forest there is an ongoing battle between two species wherein the upper hand belongs not to the biggest or strongest, but to the coolest.
That’s right, we’re talking about the life and death struggle between Mexico’s native Benedetti’s Leaf-toed Gecko (Phyllodactylus benedettii) and the invasive Common House Gecko (Hemidactylus frenatus) (Ok, so it’s not necessarily life and death, but its still pretty intense… For geckos… You know what we mean). A recent study found that, in fact, the Common Gecko’s superior ability to operate at all times without having to differentiate its own body temperature from that of the exterior climate provides it with a significant advantage over its Leaf-toed cousin (Romero-Baez et al., 2020).
Geckos, along with most other reptiles belong to a class of animals known as “ectotherms,” meaning, they depend on their environment or other external sources of body heat. Therefore, in an instance where two or more ectothermic species are competing within an ecosystem, whoever can spend the least amount of energy on regulating body temperature naturally has an upper hand (or foot? Pad? Whatever the technical term for a gecko’s locomotive extremities are…). Less energy spent on body temperature means more energy spend on things such as feeding, breeding, and oh yeah, not being eaten, all worthy causes.
In this case, the advantage goes to the Common House Gecko. While the Leaf-toed Gecko is form-fitted to the environment it has inhabited for centuries, the House Gecko is adapted for a broader range of habitats. Its ability to function and maintain normal activity levels while allowing its body temperature to mirror its environment allows it to conserve energy and expel it elsewhere. In fact, it was found that the House Gecko is able to remain active during the night as well as the day, increasing its ability to hunt patrol territory. This is completely contrary to the makeup and habits of the Leaf-toed Gecko, which has a very specific body temperature it strives to maintain and is only active during the day.
In the bigger scheme of things, it can be admitted that the fierce battle being raged between the native Benedetti’s Leaf-toed Gecko and the invasive Common House Gecko may not be as riveting or monumental as some may think. However, by understanding more about the competitive nature of these two species living in close proximity to each other we can begin to learn more about how other invasive and native ectotherms compete, or more specifically, how certain attributes that are characteristic of invasive species give them a greater ability to adapt and outcompete their native neighbors.
So, the next time you find yourself enjoying a day by the pool, soaking up the sun, think of our friends the ectotherms, and be grateful that you are in fact, and endotherm, and you don’t have to compete for territory with your cousin. I hope.
Source:
Romero-Baez, O., Santos-Bibiano, R., Dominguez-Godoy, M., Miles, D., Munoz-Nolasco, F. (2020). Thermal ecophysiology of a native and an invasive gecko species in a tropical dry forest of Mexico. Journal of Thermal Biology. https://doi.org/10.1016/j.jtherbio.2020.102607
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