Meserani is a semi arid area in Monduli District in north east Tanzania that is prone to land degradation in terms of vegetation and soil degradation due to natural and anthropological factors. For a number of years the local community including extension officers had suspected that in certain locations of Meserani area bare lands, apart from grazing and farming activities were also created by grazing insects. The main objective of this paper was firstly, to identify the type of grazing insects that were creating bare lands, hence land degradation. Land degradation in this context is taken to mean the removal of herbaceous vegetation caver. Secondly, to determine the extent in which grazing insects are contributing to land degradation in the area. The harvester ants of species Messor cephalotes, Emmery were identified as the main insects that were foraging herbaceous vegetation cover thus creating bare lands in some of the locations in the study area. Areas with high intensity of human activities in terms of framing and grazing had more bare lands created by ants than the fallow or stony areas. Therefore in the Meserani harvester ants just like grazing or farming activities were contributing to land degradation through the creation of bare lands.