page_title: Semelparity and iteroparity
section_title: Current evolutionary advantages hypothesis
hierarchical_section_title: Semelparity and iteroparity / Evolutionary advantages to semelparity / Current evolutionary advantages hypothesis
caption_attribution_description: Agile Antechinus (Antechinus agilis) showing offspring inside
context_page_description: Semelparity and iteroparity are two classes of possible reproductive strategies available to living organisms. A species is considered semelparous if it is characterized by a single reproductive episode before death, and iteroparous if it is characterized by multiple reproductive cycles over the course of its lifetime. Some botanists use the parallel terms monocarpy and polycarpy.
  In truly semelparous species, death after reproduction is part of an overall strategy that includes putting all available resources into maximizing reproduction, at the expense of future life. In any iteroparous population there will be some individuals who die between their first and second reproductive episodes, but unless this is part of a syndrome of programmed death after reproduction, this would not be called semelparity.
  This distinction is also related to the difference between annual and perennial plants. An annual is a plant that completes its life cycle in a single season, and is usually semelparous. Perennials live for more than one season and are usually iteroparous.
context_section_description: The evolution for semelparity in both sexes has occurred many times in plants, invertebrates, and fish. It is rare in mammals because mammals have obligate maternal care due to internal fertilization and incubation of offspring and nursing young after birth, which requires high maternal survival rate after fertilization and offspring weaning. Also, female mammals have relatively low reproductive rates compared to invertebrates or fish because they invest a lot of energy in maternal care. However, male reproductive rate is much less constrained in mammals because only females bear young. A male that dies after one mating season can still produce a large number of offspring if he invests all of his energy in mating with many females.
caption: Antechinus agilis showing offspring inside pouch
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