Meeting Abstract
Phyrynosoma cornutum is currently listed as a threatened species in Oklahoma and Texas. This species is known to inhabit both arid to semi-arid environments. However, relatively little data exist regarding the ecology and biology of this species in semi-arid prairie compared to more arid habitats such as desert scrub. This study investigates prey composition of Texas Horned Lizards in prairie habitat using fecal dissections (n=29) and compares it to published findings from desert scrub. Also, this research compares the digestive efficiency of Texas Horned Lizards consuming harvester ants (Pogonomyrmex) and beetles (Coleoptera), the two groups of prey items most prevalent in fecal samples. Total prey items found in feces are highly variable but prey composition is relatively consistent. This is presumably owing to variation in size of the horned lizard and prey availability. Ground beetles (Carabidae) were found in over 93% of all samples even though many other arthropods are encountered as frequently in the field, indicating that they may be selected for along with harvester ants, which made up the majority of every sample. Novel prey items, including Halictidae bees, Hister beetles, weevils, Caligrapha beetles, and vegetation were also noted in quantities that represent opportunistic or incidental consumption. Horned lizards are more efficient at digesting beetles than ants, which may indicate that they are required as a dietary supplement at least in times of high caloric requirements. Alternatively, they may represent periodic “treats” as an opportunistic additive to the diet. Future research will seek to resolve this speculation.
