Author: Putter Tiatragul

I'm a graduate student in the Warner Lab broadly interested in how animals adapt to urban environments and other human disturbances. Learn more about my research at stiatragul.weebly.com

Where Do Anolis Lizards Lay Their Eggs?

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On February 8, 2019

In All Posts

Searching for anole eggs

In this southern city where the heat is on, and the parties last ‘til the break of dawn, residents are busy patrolling territories, showing off their physique, and courting each other. With all this activity going on, South Miami, FL surely takes the crown for the best people anole-watching destination. All these anoles surely have different stories for how they got to Miami, and some research has shed light on this issue. But what is unknown about anoles in this city is how they manage to proliferate when the temperature can be unforgiving to developing embryos (Sanger et al. 2018; Hall and Warner 2018).

Anolis lizards have attracted the attention of many anolologists that are mesmerized by their conspicuously beautiful dewlap displays, superb clinging abilities (Donihue et al. 2018; Winchell et al. 2018), and an urge to show off their physiology (Battles and Kolbe 2018). However, one aspect of their biology that is much less conspicuous is their nesting behavior. Even biologists that have devoted countless hours studying their behaviors know very little about where females lay eggs, what microhabitats they prefer, and how those nesting behaviors impact embryonic development. In this recently published study, we unveil the mystery of where these city slickers’ nests are located compared to their forest-dwelling counterparts.

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Anole Embryos Don’t Mind the Heat

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On March 26, 2017

In Introduced Anoles

Adult male A. cristatellus in survey position on a tree next to an urban street. Photo credit: Renata Brandt

Walking down “Red Road” in Pinecrest neighborhood of Miami, FL, it is hard to miss a myriad of lizards on trees and street lamps. Among the many city-dwelling residents, the Cuban brown anole (A. sagrei) and the Puerto Rican crested anole (A. cristatellus) are seen virtually everywhere. While there is evidence that anoles are adapting to urban landscapes, most past studies have focused on adult stages (Kolbe et al., 2012; Winchell et al., 2016; Lapiedra et al., 2017) and early life stages have been largely ignored. Our recently published study in the Journal of Thermal Biology (Tiatragul et al., 2017) was the first to address how anole embryos could facilitate establishment of populations in cities.

The transformation of natural habitats into urban landscapes dramatically alters thermal environments, which in turn, can impact local biota. For ectothermic organisms that are oviparous (like anoles), developing embryos are particularly sensitive to these altered environments because they cannot behaviorally thermoregulate and are largely left to the mercy of their surrounding environment. Yet, we know little about how thermal environments in urban and forested areas affect embryo development and hatchling phenotypes.

Figure 2. Mean incubation duration is shorter when eggs are incubated at urban temperatures (hotter). See publication for full results.

Mean incubation duration is shorter when eggs are incubated at urban temperatures (hotter). See publication for full results.

To determine if embryos from urban and forested sites are adapted to their respective thermal environments, we incubated eggs with temperature regimes that mimic likely nest conditions in both urban and forested environments. Our results show that for two species (A. sagrei and A cristatellus), urban thermal environments accelerated development, but had no impact on egg survival or any hatchling phenotypic traits measured (including body size, running performance, and locomotor behavior). Furthermore, there is no evidence that embryos from either habitat are adapted to their respective thermal environments. Rather, this lack of major effects suggests that both anole species are physiologically robust to novel environments. This may explain their success in establishing populations in human-modified landscapes.

Physiological adaptation by embryos are not required for a population to establish successfully. Maternal behaviors, like maternal nest site selection could shield embryos from lethal conditions. Hence, our next study is going to involve quantifying maternally selected nest sites in the urban and forested landscapes.

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