HOUSE HUNTING: HARVESTER ANT (POGONOMYRMEX BARBATUS) COLONIES IN AN URBAN GRADIENT

Harvester ants are granivorous insects that reside in arid to semi-arid climates and are prone to

establish themselves in rural to semi-urban regions. Though efforts have been made to remove

their presence in agricultural settings, no published research has documented their preferences for

colony establishment in South Texas urban areas. Harvester ants are considered pests in the U.S.

due to their painful stings and removal of vegetation around colony entrances. This behavior

jeopardizes the aesthetic of the traditional American lawn, leading to increased use of insecticides

to remove established colonies. Data for the study consisted of National Agriculture Imagery

Program (NAIP) images, digital elevation models (DEMs), and collection of soil moisture levels

within our colonies of interest. NAIP and DEMs were downloaded from the Texas Natural

Resources Information Systems (TNRIS) website. Soil moisture data (n = 22) was collected from

the UTRGV (University of Texas Rio Grande Valley) Intramural fields (26°18'35.5"N

98°10'47.4"W), and values were inputted to ArcMap 10.2.2 for interpolation of soil moisture

within the area using kriging. Determining the specific conditions ants establish themselves could

help citizens take proper measures to reduce the likelihood of colony establishment on their

property. From the data collected, we observed that 47% of the colonies in the intramural fields

were found to be established in soil moisture levels of 28-28.5% volumetric moisture content. Of

the group, 48% were situated within 10m of a road, and at the 5m radius around the colonies 47%

had an area of pervious material above 80%, while less than 23% have an area of pervious material

above 70%. Finally, 90% of the colonies were located at an elevation range of 28.5-30m.