Foils of flexion: the effects of perch compliance on lizard locomotion and perch choice in the wild

Abstract

Summary1. Animals in the wild must navigate habitats that vary in structure and complexity. For arboreal animals, perch compliance (flexibility) is a common and variable characteristic, but the effects of perch compliance on arboreal behaviour and locomotion, specifically jumping, have only been examined for primates in the wild. 2. In this study, we observed jumping behaviour of green anole lizards (Anolis carolinensis) at a site with perches ranging from highly compliant palm leaflets to sturdy trunks and branches. We measured the characteristics, including compliance, of perches found throughout this habitat, those generally used by the green anole and those used for jumping within this population. We then compared the characteristics of these perch types to better understand how green anoles interact with compliant perches in the wild. 3. We found that green anoles used perches ranging across all compliances found in the habitat, but they selectively jumped from relatively non-compliant perches. Green anoles also tended to jump farthest from relatively sturdy, low-lying perches. Therefore, green anoles avoided the most compliant perches when jumping, likely due to the performance costs associated with compliant perch use. 4. In addition, we discovered that generally, perches become more compliant as they become narrower, but variance in compliance for a given diameter does not allow for the use of diameter as a proxy for compliance in this type of habitat. Thus, studies of compliance effects on small animal movement should include direct measurements of perch compliance. 5. We assert that perch compliance is an important habitat characteristic that influences behaviour and performance in green anoles, and likely many other small jumping animals.

City slickers: poor performance does not deter Anolis lizards from using artificial substrates in human‐modified habitats

“…). The substrates on which lizards perch have an important impact on their locomotor performance (Losos & Sinervo ; Gilman & Irschick ). We assessed the effects of inclination and roughness on performance because of the higher frequency of smooth, vertical substrates, such as buildings, fences and walls, in urban areas.…”

“…Previous studies have found that habitat characteristics influenced locomotor behaviour in green anoles: despite using perches with a range of compliances, green anoles selectively jumped from less compliant (less flexible) perches (Gilman & Irschick ). Other research shows anoles tend to jump less often from broad surfaces (Pounds ; Losos & Irschick ) and when nearby perches are lacking (Moermond ; Avilés‐Rodríguez ).…”

Effects of support diameter and compliance on common marmoset (Callithrix jacchus) gait kinematics

“…Specifically, compliant substrates absorb some of the mechanical work that would be otherwise employed to redirect and accelerate the CoM during steady locomotion, and compromise stability by undermining the animal's ability to estimate body orientation (MacLellan and Patla, 2006). Previous research has shown that increasing branch compliance significantly compromises the locomotor performance of leaping primates (Crompton et al, 1993;Demes et al, 1995;Warren and Crompton, 1997;Walker, 2005;Channon et al, 2011) and lizards (Gilman et al, 2012;Gilman and Irschick, 2013), and necessitates numerous postural and locomotor adjustments in orangutans (Thorpe et al, 2009;Myatt and Thorpe, 2011). However, relative to the breadth of research on the effects of substrate diameter, studies of how perch compliance affects quadrupedal gait mechanics are sparse (but see Stevens et al, 2001;GosselinIldari, 2010).…”

Robust jumping performance and elastic energy recovery from compliant perches in tree frogs

“…A rigid Teflon rod, 9 cm long, was inserted within the tubing midway along the perch to provide a rigid area for frogs to jump from. The perch was stretched to 0, 2 and 4 cm beyond the slack length, creating three different compliance levels (2.3, 1.8 and 1.1 cm deformation under 1 N vertical load; unloaded resonant frequencies of 8.4, 9.5 and 12.1 Hz, respectively) within the range of arboreal substrate compliance observed in their introduced range (Gilman and Irschick, 2013). For rigid perches, frogs jumped from a wooden dowel of equal diameter.…”

“…Animals moving through natural habitats commonly encounter compliant substrates (Demes et al, 1995;Gilman et al, 2012;Gilman and Irschick, 2013), which yield when subjected to force, resulting in the absorption of mechanical energy. While some substrates, such as mud, may only dissipate energy, others, such as small-diameter plant branches, are elastic and may return a significant portion of their energy upon recoil (Cannell and Morgan, 1987).…”