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At the most fundamental level, biological invasions hinge on the fate of individuals surviving and reproducing in novel environments. If individuals are able to reproduce at a higher rate than they die, the invader will increase in numbers and can eventually become established and spread; if the balance is negative, however, the population will decrease over time and end up extinct. Because the rates of birth and death are ultimately determined by how organisms allocate their limited time and energy to reproduction and survival (Stearns, 1992), life history theory has long been deemed essential to understanding the success of invaders (Lewontin, 1965). Surprisingly, however, life history theory has achieved little success in predicting the outcome of organisms’ introduction (Blackburn et al., 2009; Sol et al., 2012b). One reason is the excessive focus on the small population paradigm, implicitly assuming that demographic stochasticity is the main driver of extinction in introduced populations. This has led to the widespread belief that successful invaders are characterized by high fecundity that reduces the exposure to demographic stochasticity by enhancing population growth (Moulton et al., 1986). Nevertheless, for an invader coming from a distant region, unfamiliarity and insufficient adaptation to the new resources, enemies and other hazards are also likely to increase the risk of extinction by negative population growth. Life history theory offers additional mechanisms that may help mitigate these effects, such as bet-hedging (Starrfelt and Kokko, 2012) and the storage effect (Warner and Chesson, 1985; Caceres, 1997). As we argue in this chapter, if …