In the wild, male chameleon grasshoppers (Kosciuscola tristis) are frequently observed mounted on the back of females even when not in copula, and will fight off other usurping males. If this behaviour is mate guarding and reflects investment in male mate choice, then we expect males to preferably guard females based on reliable cues of quality. Cues for female quality likely include female size and egg development that together may indicate fecundity. We investigated male mate choice in the field expressed as mate-guarding preference, by comparing size and egg development in guarded and unguarded females. We found no difference between guarded and unguarded females in measures of fecundity or body size. The majority of females sampled did not contain any viable eggs. This finding suggests that male K. tristis indiscriminately guard females in a scramble mating system.