section_path: Sex-determination systems/Environmental
section_name: Environmental
paragraph_text: Environmental
  
  For many species, sex is not determined by inherited traits, but instead by environmental factors such as temperature experienced during development or later in life.
  
  In the fern Ceratopteris and other homosporous fern species, the default sex is hermaphrodite, but individuals which grow in soil that has previously supported hermaphrodites are influenced by the pheromone antheridiogen to develop as male. The bonelliidae larvae can only develop as males when they encounter a female.