It is not only humans that may feed on sea pumpkin leaves! As can be seen here, the leaf margins show mutilation by hungry locals. It is thought that sand fleas found in their thousands along the beach in the habitat of Prenia vanrensburgii cause these indentations along the leaf margins.
There must surely be other freeloaders as well, not counting the small insects to be seen inside these flowers. They are pollination contractors exacting their nectar rewards. Maybe even some of the coastal birds find something to eat here, albeit not always the plant itself, but some of the competing scroungers?