<Tr> <Td> </Td> <Td> This section needs expansion . You can help by adding to it . (April 2016) </Td> </Tr> <P> In redlip blennies, only the male fish develops an organ at the anal - urogenital region that produces antimicrobial substances . During parental care, males rub their anal - urogenital regions over their nests' internal surfaces, thereby protecting their eggs from microbial infections, one of the most common causes for mortality in young fish . </P> <P> Most flower plants are hermaphroditic but approximately 6% have separate males and females (dioecy). Males and females in insect - pollinated species generally look similar to one another because plants provide rewards (e.g. nectar) that encourage pollinators to visit another similar flower, completing pollination . Catasetum orchids are one interesting exception to this rule . Male Catasetum orchids violently attach pollinia to euglossine bee pollinators . The bees will then avoid other male flowers but may visit the female, which looks different from the males . </P> <P> Various other dioecious exceptions, such as Loxostylis alata have visibly different genders, with the effect of eliciting the most efficient behaviour from pollinators, who then use the most efficient strategy in visiting each gender of flower instead of searching say, for pollen in a nectar - bearing female flower . </P>

Refers to differences between the phenotypes of males and females of the same species