Diet composition of omnivorous Mesopotamian spiny-tailed lizards (Saara loricata) in arid human-altered landscapes of Southwest Iran.

Abstract

The Mesopotamian spiny-tailed lizard, Saara loricata, is one of the largest lizard species in the Middle East. Here, we report on the diet of the lizard and their potential role in seed dispersal in Southwestern Iran. We analyzed lizard fecal pellet groups (n= 124) for their food item composition and seed content. We calculated the relative frequency of occurrence (FO%), relative volume (V%), and importance value (IV%) for each food item. Moreover, the number of seeds of each plant food item was counted. Our findings reveal the first solid evidence of omnivorous behavior in the lizard. In total, 16 plant food items and 14 animal food items were identified. Herbaceous plants (IV=110.2%) and invertebrates (4.8%) were the most important food groups. The plant food items with the highest FO% were Poaceae (56.4%), Centaurea sp. (43.5%), and Medicago polymorpha (27.4%); and the V% for these items were 53.6%, 30.9%, and 13.1%, respectively. Most of the seeds that were consumed by lizards were from Poaceae (547 seeds; 47.81%) and Fabaceae (285 seeds; 24.91%). We also found that each individual lizard could play an equal role in the seed dispersal of all plant families identified. Previous studies show that plant species density and richness are important features for the burrow site selection of Mesopotamian spiny-tailed lizard. This study highlights the potential role of lizards in influencing the vegetation communities around their burrows through seed dispersal.