Like all other decapods, the grapsid crab, Metopograpsus messor has mouth
parts composed of six pairs of modified appendages. The present study revealed the structural significance of this complexity and the feeding habits of this species.
Scanning electron microscope was used for examination of the mouth parts of the
specimens collected from two different habitats. No differences were found neither in
the structure of mouth parts nor in food analyses. The feeding habits showed that M.
messor is opportunistic omnivore feeding on a wide variety of benthic organisms
including algae, epifaunal animals as well as dead fish and other decayed animals in
addition to higher plants particularly decomposed sea grass leaves and mangrove.