Diet Analysis Of Texas Horned Lizards (Phyrnosoma Cornutum) In Two Small Texas Towns Using Morphological And Genetic Methods

Alenius, Rachel

Publication

Diet Analysis Of Texas Horned Lizards (Phyrnosoma Cornutum) In Two Small Texas Towns Using Morphological And Genetic Methods

Alenius, Rachel

Date

2016

Additional date(s)

2016-05-19

Abstract

Texas Horned Lizards (Phrynosoma cornutum) are considered threatened within Texas, due to their high vulnerability to habitat changes. In particular, horned lizards are believed to be sensitive to the loss of harvester ants (Pogonomyrmex), which make up a large portion of their diet. Thus, dietary studies are important in assessing the reliance of horned lizards on harvester ants . This study focuses on the diets of horned lizards in two populations from Kenedy and Karnes City, TX, to determine if their diets differ from previously studied populations. Additionally, this study explores the effectiveness of genetic analysis in dietary studies of horned lizards. Twenty-three fecal samples from Kenedy and Karnes City, TX were analyzed using a combination of morphological and genetic methods. In morphological analysis, desert termites (Gnathamitermes tubiformans) accounted for 50.5% of all prey items observed, while only 4.8% were harvester ants. Furthermore, genetic analysis of 12 samples from Kenedy revealed diets containing 21 different families from 7 orders (Araneae, Coleoptera, Diptera, Hemitptera, Hymenoptera, Isoptera, and Orthoptera). The diversity of prey items and the abundance of termites suggest that the diets of horned lizards from Kenedy and Karnes City differ significantly from previously studied populations. Additionally, genetic sequencing proved to be a useful technique for dietary analysis, due to its ability to accurately distinguish between different taxa.