Herbivory by Lizards

Abstract

The extent of herbivory in lizards is influenced by several factors. Plant tissues are more difficult to digest than invertebrates due to the presence of cellulose. Thus, so many lizards exhibit carnivorous diet. Nevertheless, some species consume vegetables. Essentially herbivorous diet occurs in about 3% of lizards, while most omnivores add plants in their diets. Omnivorous species tend to eat more fruits, flower, and nectar, because they are easier to digest and provide more nutrients than leaves, which are rich in cellulose. The main factors influencing the consumption of plant material are related to the habitat of the species. Insular and arid environments favor the consumption of plants because such locations have low amount of arthropods available and present water scarcity. It is also possible to observe ontogenetic changes in the lizard's diet, in such a way that young individuals consume only invertebrates, whereas the adults supplement their diet with plant material. When consuming fruits and nectar, lizards become potential dispersers and pollinators. In this sense, some studies have already corroborated seed dispersal and pollination events by lizards. In islands where other species are absent, these interactions are essential for the maintenance of communities.

Multiple evolutionary origins and losses of tooth complexity in squamates

“…In contrast with tooth complexity ancestral states reconstructions, extant data allow the formulation of informed hypotheses on possible dietary transitions in squamates. Insects are an important food resource for the juveniles of many squamate species, and several extant species of plant consumers show an ontogenetic dietary shift from insectivorous juveniles to omnivorous or herbivorous adults 57,94,113,114 . Moreover, extant data show that predatory squamates may rely on plant material depending on environmental conditions 50,94,[115][116][117] .…”

Multiple evolutionary origins and losses of tooth complexity in squamates

“…In contrast with tooth complexity ancestral states reconstructions, extant data allow the formulation of informed hypotheses on possible dietary transitions in squamates. Insects are an important food resource for the juveniles of many squamate species, and several extant species of plant consumers show an ontogenetic dietary shift from insectivorous juveniles to omnivorous or herbivorous adults 36,64,81,82 . Moreover, extant data show that predatory squamates may rely on plant material depending on environmental conditions 34,64,83-85 .…”

Diet influences latitudinal gradients in life‐history traits, but not reproductive output, in ectotherms

“…For carnivorous lizards, larger body sizes may not be supported at higher latitudes because of the challenges associated with balancing the energetic costs of foraging for sparsely distributed prey along with increased total energetic requirements in colder and more seasonal areas (Carbone et al, 2007;Pough, 1973). Herbivores may be further limited by the lower nutritional content of plant food at higher latitudes, and their lower digestive efficiency, lower assimilation rate and longer gut passage times in those colder and more seasonal environments (Harlow et al, 1976;McConnachie & Alexander, 2004;Pietczak & Vieira, 2017;Pough, 1973;Zimmerman & Tracy, 1989).…”

“…In lizards, diet and temperature affect various digestive processes. Compared to protein rich animal-based diets of carnivores, plant material is less nutritious and more difficult to digest (McConnachie & Alexander, 2004;Pietczak & Vieira, 2017;Pough, 1973;Zimmerman & Tracy, 1989). And thus, herbivorous lizards typically have longer gut passage times and lower assimilation efficiency compared to carnivorous lizards (McConnachie & Alexander, 2004;Pough, 1973;Zimmerman & Tracy, 1989).…”