According to the theory proposed (the "reproductive load" theory), hermaphroditism is of advantage to the species in equitably distributing the "reproductive load" of the species. This is shown especially in insect-pollinated plants, in which the species produces relatively small amounts of pollen, because of the efficiency of insect pollination. Most of the reproductive energy of the species is therefore available for the production of seeds. If the sexes were separate in such plants and numerically equal then the species would be wasting much energy that might be available for the production of seeds (assuming that pollen production in such species requires less energy than seed production). Such waste can most efficiently be avoided by hermaphroditism. This method of distributing the reproductive load has therefore come about in evolution through natural selection, because of its advantage to the species.