Research highlights for issue 10: understanding complex lifecycles

Many parasites, including those of relevance to human health, use multiple hosts in order to complete their lifecycle. These complex lifecycles are somewhat mysterious from an evolutionary perspective, as the reliance on more than one host species seems likely to make the parasite more vulnerable to ecosystem perturbation and to restrict its range (Lopez et al. 2015). There have been a number of intriguing hypotheses put forward to explain how selection could favor such strategies – ranging from somewhat neutral explanations, such as selection to simply survive predation of hosts, to elaborately adaptive ones, such as selection to exploit hosts of larger size by moving up the food chain (Parker et al. 2015a; Poulin and Lagrue 2015). However, finding evidence to support these hypotheses – and especially to craft generalizable explanations – has proved difficult.