Insights From An Introduced Lizard On Coping With Environmental Change: Is It Better To Be Behaviorally Flexible Or Consistent?

Abstract

Brown anoles (Anolis sagrei) are native to Cuba and the Bahamas, but have been widely introduced to other Caribbean islands, the southeastern United States, Hawai‘i, and Japan. While some traits have been used to model their ability to become naturalized in new locations (Latella et al. 2011) behavior has been largely unexplored. Some studies have begun to test their learning ability (Storks and Leal 2020) and their behavioral consistency (called behavioral syndromes) (Lapiedra et. al. 2016) but both studies are limited by either low sample size or studying only one sex. I used non-native populations of brown anoles on the island of Oʻahu in the Hawaiian Islands, USA to test for the presence of a boldness syndrome and to test their learning ability. Behavioral syndromes are theorized to be favored in environments where one consistent behavior maximizes fitness. This could play an important role in responding to novel challenges and opportunities in urban habitats. Previous research indicates that urban individuals tend to be more aggressive, exploratory, and bold than their rural conspecifics (Sih et al. 2004a). I measured a behavioral syndrome along the bold-shy axis across eight populations along an urban gradient and compared boldness among sites, but boldness was not significantly different when comparing my urban and rural sites. A syndrome was detected, but was weak in strength, indicating low within-individual consistency in boldness. Behavioral flexibility via the ability to learn is another way for non-native animals to cope with new environments. Learning ability has mostly been studied in mammals and birds, but studies on reptiles are becoming more prevalent (e.g., Szabo et al. 2018, Storks and Leal 2020, De Meester et al. 2021). I measured problem-solving ability and learning-ability in 66 wild-caught lizards. I presented lizards with a detour task, a clear plastic tube with one entrance, over subsequent trials and measured their time to complete the task in each trial. About half of the lizards showed the ability to problem-solve by completing the task at least once. Only 9 of the 66 lizards decreased their solve-time over trials, indicating the ability to learn. I next evaluated the field of behavioral syndromes through a literature review and simulations. I found that, despite earlier recommendations to increase sample sizes (Garamszegi et al. 2012), many studies in this field are still underpowered. Simulations revealed that underlying mixtures of syndrome strength within a population can be obscured by correlation and mixed model analyses. I demonstrate and recommend the use of maximum pairwise differences to quantify these underlying patterns.