Welcome to Word of the Week! Stay tuned for a new word each Friday to amp up your nature vocabulary!
Semelparous [SE-mal-pe-rus] (noun): A species that only reproduces once in its lifetime. It is the opposite of an iteroparous species which can have many offspring multiple times throughout their life cycle.
Semelparous comes from the Latin root words semel, meaning 'a single time' and pario, meaning 'to beget'.
In nature, semelparous organisms are present across both sexes commonly in many plants, invertebrates, and fish. In mammals, it is usually only present in the males of some species of Quoll and Opossum. Reasons and for being a semelparous organism may include a physically taxing reproductive method, such as salmon which expend all of their energy migrating hundreds of kilometers to spawn. It may also have to do with prey abundance and short breeding windows, as well as insects that may have evolved from more parasitic ancestors and therefore lack biological functions that would allow them to survive multiple breeding cycles.
In High Park, we have many examples of semelparous species. Insects such as cicadas may have a long life cycle underground, however once they reach maturity and breed they die soon after. Other insect examples in the park include the invasive gypsy moth, which after reaching adulthood lay one clutch of eggs on the bark of a tree and die soon after.
Fun Fact: Despite a wide array of spider species being semelparous, a study published by Nordic Society Oikos found that females that lose their brood will produce a second clutch. These experimental females were protected from predation, and were capable of laying a second clutch and raising the young of both.