The goal of this study was to investigate stridulation behavior in Solenopsis invicta and S. richteri during nest mate and non-nest mate interactions. The frequency and incidence of stridulation was recorded during different behavioral events and compared with video and audio recordings. Non-nest mate interactions could be divided into three categories: pre-engagement, engagement and finally restraint. Pre-engagement consisted of the time before the ants encountered each other and stridulation was not observed during this time. Engagement was the time between encountering the other ant and restraint. Most of the stridulatory activity took place in the restraint category. Stridulation also occurred after initial restraint, with periods of stridulation bursts followed by non-stridulating periods. Stridulation in non-nest mate interactions is similar to the distress signals seen in ants restrained with forceps: an initial burst of stridulation followed by periods of non-stridulation and stridulatory bursts. This is similar to laboratory observations of restrained ants, which showed extreme variation in time between bursts and number of signals within the burst. Stridulation does not appear to serve any mechanical function in this behavior, in that the restrained ant does not appear to be stridulating in an attempt to loosen the mandibles of the other ant.