Most animal species are characterised by being either semelparous or iteroparous. Less commonly, some populations are iteroparous while others are semelparous (e.g., American Shad, Alosa sapidissima, Hasselman et al. 2013), one sex is iteroparous and the other semelparous (e.g., some populations of capelin, Mallotus villosus, Huse 1998; four genera of marsupials, Fisher et al. 2013), some individuals are semelparous while others are iteroparous (e.g., the sea squirt, Botryllus schosseri, Grosberg 1988; New Zealand stocks of chinook salmon, Oncorhynchus tshawtscha, Unwin et al. 1999; the European earwig, Forfi cula auricularia, Meunier et al. 2012) or semelparity may be a facultative trait, as suggested for the invertebrate Nephelopsis (Davies and Dratnal 1996), the spider, Stegodyphus lineatus (Schneider et al. 2003) and the fi sh, Mallotus villosus (Christiansen et al. 2008). Salmonids are generally classifi ed as iteroparous or semelparous with the former reproductive mode being the ancestral state (Crespi and Teo 2002) as has also been shown for insects in the order Dermaptera (Guillet and Vancassel 2001). It seems probable that among animals in general, iteroparity is the original reproductive mode with semelparity being an evolved state from iteroparity.