Foraging distances and forager population sizes of the desert termite Gnathamitermes tubiformans (Buckley) (Isoptera: Termitidae)
The desert termite Gnathamitermes tubiformans and its unique foraging tubes are a common fixture in rangelands across Arizona, New Mexico, northern Mexico, and Texas. Although it is a native species and has thrived for millions of years, recent droughts have made its activity more visible and raised questions about its impact on vegetation. Since G. tubiformans prefers grasses as food, there has been a concern about competition between livestock and termites. Monitoring of desert termite activity was conducted through two experiments focusing on foraging distances and forager population sizes.
The foraging distances experiment used circular grids in 5 m x 5 m plots to map the movement of marked G. tubiformans released from the center of the grid. Analyses showed no significant correlations between distances moved and abundance or type of vegetation. Movement of marked termites did not favor any compass directions.
The second experiment used a mark-recapture estimation model to predict G. tubiformans forager populations in 5 m x 5 m plots. Linear regression analyses showed a significant positive correlation between size of the forager population and amount of total vegetation. In addition, linear regression analyses showed a significant positive correlation between total estimated number of collected termites during early recruitment and amount of vegetation cover, specifically grasses.
Desertification of rangelands used by G. tubiformans and livestock is a worry with few known solutions. Elucidating answers to this problem involves ferreting out the sources of the degradation. The results of this thesis shed light on the role G. tubiformans plays in its habitat, and infer that degraded habitats with low amounts of vegetation will exhibit low termite populations.