Spiroplasmas are bacteria in the Class Mollicutes that are frequently associated with insects and/or plants. This electron micrograph shows symbiotic/ commensal spiroplasma-like organisms (SLOs) in the midgut of a leafhopper, Macrosteles quadrilineatus. SLOs found in this insect are long and tubular shaped with a tip structure (t). These SLOs (S) were found in great numbers in the gut lumen (lu) frequently associated with gut microvilli, but unlike the plant-pathogenic mollicutes, they did not seem to invade the gut epithelium (ec) or other tissues in their leafhopper hosts. This image is related to Fig. 1 in Arch. Microbiol (2011) 193:35-44.