Arboreal walking performance in seven didelphid marsupials as an aspect of their fundamental niche

Abstract

Species of didelphid marsupials (Didelphimorphia, Didelphidae) differ in their use of the forest strata, but it is not clear whether these differences are in fundamental or realized niches. The fundamental niche of seven species of didelphids (Caluromys philander, Didelphis aurita, Gracilinanus microtarsus, Marmosops incanus, Metachirus nudicaudatus, Micoureus demerarae, and Philander frenatus) was compared using their performance in arboreal walking. The association between performance and vertical use of the forest also was tested accounting for phylogenetic and allometric effects. Tests consisted of making the animal cross five 3 m long horizontal supports of different diameters, 1 m from the ground. The cycle of maximum speed was chosen to measure stride length, frequency and velocity. Arboreal species performed better than the terrestrial ones, but a major part of the variation in stride length (70.95%) and stride frequency (88.10%) was associated with body size. Part of the variation in stride length independent of body size (14.05%) was associated with the degree of vertical use of the forest, after phylogenetic effects were accounted for. Fundamental niches of six of the seven species were discriminated with the performance tests used. Discrepancies between the realized and fundamental niches can be inferred for two of these species, D. aurita and P. frenatus.

In vivostrains in the femur of the Virginia opossum (Didelphis virginiana) during terrestrial locomotion: testing hypotheses of evolutionary shifts in mammalian bone loading and design

“…Glironia, Caluromys and Caluromysiops (Voss and Jansa, 2009)] exhibit arboreal habits and specializations (Nowak, 1991). However, although retaining features such as grasping feet and a prehensile tail, D. virginiana and the other opossum genera to which it is most closely related [Philander and Lutreolina (Voss and Jansa, 2009)] are primarily terrestrial rather than arboreal (Jenkins, 1971a;Nowak, 1991;Delciellos and Vieira, 2006;Delciellos and Vieira, 2009). As a result of this convergence back to terrestrial habits, D. virginiana may not represent the specific 'intermediate' between the locomotor patterns of non-avian reptiles and cursorial mammals, but they provide a functional analog of such an intermediate that is appropriate for comparison to other lineages in which limb bone loading has been evaluated.…”

Kinematics of quadrupedal locomotion in sugar gliders (Petaurus breviceps): effects of age and substrate size

“…This study contributes new data to a growing body of comparative literature addressing kinematic responses of (adult) small-bodied mammals to arboreal substrates, including those that are arboreally adapted with grasping extremities (Pridmore, 1994;Schmitt, 2003b;Schmitt and Lemelin, 2004;Delciellos and Vieira, 2006;Stevens, 2006;Delciellos and Vieira, 2007;Scheibe et al, 2007;Stevens, 2007;Nyakatura et al, 2008;Nyakatura and Heymann, 2010) and those that lack grasping capability and are predominantly terrestrial (Lemelin et al, 2003;Lammers and Biknevicius, 2004;Lammers, 2007;Lammers and Gauntner, 2008;Lammers, 2009;Schmidt and Fischer, 2010;Lammers and Zurcher, 2011). Much insight on L. J. Shapiro and J. W. Young arboreal adaptations has been gained from these studies, but this study is one of very few to provide ontogenetic kinematic data for mammals in an arboreal context (e.g.…”

“…Starting with the basic assumption that in arboreal mammals, stability is inversely related to relative body size, we hypothesized that sugar gliders would employ kinematic stabilizing mechanisms as body size increased relative to substrate diameter. Previous studies have tested for the effects of decreasing substrate diameter on quadrupedal kinematics in arboreal (Schmitt, 2003a;Delciellos and Vieira, 2006;Stevens, 2006;Delciellos and Vieira, 2007;Scheibe et al, 2007;Stevens, 2007;Lemelin and Cartmill, 2010) and non-arboreal (Lammers and Biknevicius, 2004; Lammers, 2007; Schmidt and Fischer, 2010) mammals, but these studies have been restricted to adult subjects at a given body size. By including both adults and juveniles in our sample, and by tracking kinematics longitudinally through ontogeny, our study has the added advantage of permitting the assessment of the effects of relative body (to substrate) size on locomotion across a more extensive range of body sizes within a single species (see also Young, 2009a).…”

“…Our data on sugar gliders is consistent with that prediction, supporting the association of these stride characteristics with navigation of relatively small substrates. Delciellos and Vieira compared relative stride lengths among seven species of terrestrial and arboreal didelphids moving across a flat surface vs cylindrical supports of four diameters (Delciellos and Vieira, 2006;Delciellos and Vieira, 2007). The arboreal taxa used relatively longer strides on the thinnest supports compared with terrestrial taxa, but differences in relative stride length within (Spezzano and Jayne, 2004).…”

“…However, few studies have examined locomotor ontogeny in an environment where the 481 Locomotor ontogeny in sugar gliders natural diversity of substrates is represented. Field and especially lab-based studies of arboreal mammals have identified detailed kinematic or kinetic locomotor adjustments to substrate variation in adults (McClearn, 1992;Vilensky et al, 1994;Lemelin et al, 2003;Schmitt, 2003a;Schmitt and Hanna, 2004;Delciellos and Vieira, 2006;Stevens, 2006;Scheibe et al, 2007;Stevens, 2007;Nyakatura et al, 2008;Carlson and Demes, 2010;Nyakatura and Heymann, 2010;Schmidt and Fischer, 2010) but much less extensively from an ontogenetic perspective (but see Young, 2009a;Young, 2009b). In contrast, naturalistic studies of locomotor ontogeny in arboreal taxa (mainly primates) have mostly focused on ontogenetic shifts in locomotor and substrate preferences (e.g.…”