ABSTRACT
A vast majority of animals are iteroparous; in them, the reproductive episode recurs and is distributed over space and time. Contrastingly, semelpares reproduce only once in a ‘big bang’ during their entire lifetime. The number of iteroparous species was arrived by subtracting the number of semelparous species from the total species number. From an analysis on shelled and non-shelled molluscs, Pandian found that the presence of shell(s) afforded iteroparity and a relatively longer life in prosobranch, pulmonates and bivalves but in its absence, semelparity occurs in opisthobranchs and cephalopods. Aside from the sporadic incidences of male semelparity, it occurs in all the social insects. However, this account is limited to the semelparity alone.
