Escape tactic plasticity of two sympatric Norops (Beta Anolis) species in Northeast Costa Rica

Abstract

Optimal Escape Theory (OET) has been used extensively to predict escape responses of lizards facing predation, yet few studies have examined the responses of two species that share the same habitat, even though such lizards may exhibit distinct patterns of spatial habitat use and behaviour. Furthermore, while OET may predict when escape behaviour should occur, it does not account for any variation in tactics used. Here, the escape behaviour of sympatric Norops humilis and N. limifrons lizards were studied. Lizard microhabitats were categorized and approach speeds were randomised such that each lizard was approached at one of two speeds, slow or fast. Approach speed of a simulated predator had no significant effect on approach distances for either species. Ambient and surface temperatures varied throughout the study period, yet had no significant effect on the escape responses of either species. Species differences in escape tactics correlated with microhabitat: Norops humilis were found more often on small shrubs and typically escaped by jumping to adjacent shrub branches or leaves. Norops limifrons, on the other hand, were typically found on tree trunks and thicker stems, and used squirrelling (horizontal movement around a trunk, branch, or stem) as a primary escape tactic. Additionally, all lizards encountered at ground-level ran. These results thus illustrate the variety of escape tactics used by sympatric N. humilis and N. limifrons within their structurally diverse habitat.

Delayed escape responses of male Basiliscus plumifrons (Squamata: Corytophanidae) during peak activity

“…Unlike time of day, I found no effect of the speed of my approach on any escape responses of B. plumifrons. Numerous studies support that approach speed can be an important risk factor affecting the escape responses of multiple species (e.g., Cooper Jr. 1997, 2003a, Cooper Jr. and Whiting 2007a, 2007b, but see also Lattanzio 2009). My methods are consistent with other studies (e.g., practiced approach speeds, similarly-colored clothing worn during all trials, etc.…”

“…My time periods therefore provide a useful contrast of B. plumifrons activity, with a period of high (morning) and low (early afternoon) activity. I approached lizards at one of two practiced, controlled paces: slow (~ 50 m/min) or fast (~ 150 m/min), following Lattanzio (2009). I conducted all surveys on sunny days, wore similarly-colored clothing throughout my experiment, and never explored the same area twice to avoid pseudoreplication.…”

“…Briefly, FID represents the distance between an approaching predator and the lizard prior to its escape and FD is the distance fled by the lizard during the initial escape response (e.g., Lailvaux et al 2003, Cooper Jr. andFrederick 2007). Empirical studies have revealed strong support for this model across several lizard taxa, supporting its utility for understanding the factors affecting escape decisions by this diverse clade (Cooper Jr. 2003a, Martín 2003, Vanhooydonck et al 2007, Lattanzio 2009, 2014, Brock et al 2015, Stellatelli et al 2015.…”

“…In addition, faster approaches reduce the time until a predator reaches its potential prey, which affects their time to initiate an escape response as well as the likelihood of success of that response (Cooper Jr. 2003a, 2003b. The escape responses of lizards should be susceptible to variable predator approach speeds (Stankowich and Blumstein 2005), and some studies have shown that faster approaches do elicit a more-rapid prey response (e.g., greater FID, reviewed by Samia et al 2015; but see Lattanzio 2009). Unlike FID, however, FD may not be as sensitive to variation in predator approach speed (e.g., Lattanzio 2009).…”

Temporal and ontogenetic variation in the escape response of Ameiva festiva (Squamata, Teiidae)

“…Optimal escape theory has been extensively used to generate predictions regarding the response of an organism to an approaching predator by focusing on the potential trade-offs between the risk of remaining and the costs of escape (Ydenberg and Dill 1986, Martín and López 1995, Cooper Jr. and Frederick 2007, Lattanzio 2009, Cooper Jr. and Avalos 2010. In most studies, the distance between predator and prey when the prey initiates escape (deemed flight initiation distance [FID]) is modeled as the escape response.…”