Myxococcus xanthus bacteria spores (round), coloured scanning electron micrograph (SEM). M. xanthus is a rod shaped gram-negative bacterium that resides in the soil and feeds on other species of bacteria. It is found as single-species clusters, called swarms, which act as a collective unit and show coordinated movement in response to environmental cues. The bacteria are also able to differentiate to form inactive (resting) spores that are resistant to dessication (drying out). Magnification: x41700 when printed 10cm wide.