sex reversal

…free-living nematodes are capable of sex reversal—if the sex ratio in a given population is not optimal or if environmental conditions are not ideal, the ratio of males to females can be altered. This sometimes results in intersexes; i.e., females with some male characteristics. Hermaphroditism occurs in nematodes, and self-fertilization…

…the young are males; their subsequent sex, however, is determined by their nearest neighbour. They remain males as long as they are near a female but change into females if isolated or placed near another male.

…functional males but, after a transitional phase, spend their remaining life span as females. Crepidula species, for example, form stacks of as many as 19 individuals. The younger ones on top are male, the old ones on the bottom female, and those in the middle are intermediate in sex. Isolated…