ABSTRACT
Growth and reproduction are competitive processes with the fi rst being an essential prerequisite for the second. In crayfi sh both of these processes continue until the animal dies although exactly how these are coordinated and scheduled remains poorly understood. They can be viewed as two cyclic intermittent processes, sometimes alternating sometimes not. Often in decapods growth and mating (the fi rst step in reproduction) are closely linked, but this is not the case in crayfi sh. Growth requires intermittent moulting, which in mature females aff ects sperm storage, a result that has consequences for both sexes because all stored sperm are lost and females are restored to a virginal state. Males in particular have to do something about this if they are to see any of their genes passed on to the next generation. Growth really only concerns the individual whereas mating is the concern of two individuals, male and female, whose interests may be diff erent. So if mating and moulting are not linked there has to be an alternative means of mate attraction to ensure that mating occurs. Signifi cant recent progress has been made into understanding the basis of mate attraction in crayfi sh and how urine-based signals are used for communication (Breithaupt 2011). An important consequence of the de-linkage of moulting and mating is that females can have multiple partners and thus there is the possibility of sperm competition. We have organized and summarized the data in this chapter so that it leads towards an understanding of the evolution of growth and mating behaviour in crayfi sh and how these are integrated. Such an evolutionary discussion needs to have in mind a sister group that helps to inform us about ancestral character states and derived characters that can be attributed to the colonization of freshwater. As will become evident we assume that the marine sister group for crayfi sh is the clawed nephropoid lobsters.
