Frank Sterns
Graduate Student, EEB, Section of Integrative Biology
The University of Texas at Austin

Frank Sterns is conducting research into how insects colonize new host plants and why that has important implications for both ecology and agriculture.  The vast majority of our invasive insect species and agricultural pest species are the result of successful host plant shifts.  The twice-marked thorn bug Enchenopa binotata is an ideal organism for research in this area.  This insect migrated from the tropics into North America and rapidly colonized eleven novel host plants, six of which are agricultural or ornamental trees.  Out of these eleven, only one is used by other thorn bugs, and most of the family is restricted to oaks.  The speed with which the twice-marked thorn bug has colonized these host plants and the diversity of colonized host plants indicates that this insect is comprised of biological traits that facilitate this process.  This species may provide valuable insights into the prevention and management of invasive and pest insects.

Populations of the twice-marked thorn bug have been located at Brackenridge Field Lab (BFL), Stengl Lost Pines (SLP), and Bee Caves Ecology Laboratory (BCEL).  All of these sites considerably extend the known range of this species.  At Brackenridge, insects have been found using nannyberry host plants (Viburnum rufidulum), wolly buckthorn or gum elastic (Sideroxylon langinosum) and pecan (Carya illinoinensis). 

At SLP, populations have been identified on two species of nannyberry (V. rufidulum and V. prunifolium) as well as gum elastic.  These insects have been found on gum elastic and pecan at BCEL. Populations on pecan are currently (Early April ’07) difficult to find as the trees are just now beginning to put out foliage, but the abundance of these plants at Stengl makes it likely that populations will be found there as well.    

Sterns intends to evaluate the causes and consequences of host plant colonization by the twice-marked thorn bug.  Determining what biological traits allowed this insect to incorporate a wide range of host plants into its diet will aid in identifying and managing potential invasive and pest insect species.  Evaluating the factors that caused the insect to include new host plants in its diet will help identify where and when a new invasive or pest species will likely occur, and thus prevent colonization.  With these goals in mind, he will investigate the sensory, feeding, and egg laying physiology of these insects.  Additionally, Sterns intend to induce artificial shifts under experimental field conditions.