Biology Reference
In-Depth Information
CHAPTER 9
Mating Systems
Photo © Alexander T. Baugh
Our main theme in the last two chapters has been conflict; conflict over mating and
fertilization (Chapter 7) and conflict over parental care (Chapter 8). We now explore the
outcomes of these conflicts in terms of mating systems, which refer to how mates are
acquired, how many mates and associated patterns of parental care. At first sight, the
variety in nature appears bewildering (Table 9.1). How can we explain this diversity?
Beginning with an influential paper by Stephen Emlen and Lewis Oring (1977), a
fruitful approach has been to view mating systems as outcomes of the behaviour of
individuals competing to maximize their reproductive success. Different mating systems
might emerge depending on two factors: (i)
male and female dispersion in space and time
(which will influence how easy it is for either sex to gain access to mates); (ii)
patterns of
desertion by either sex
(which will depend on the costs and benefits of parental care).
Two factors
influencing
mating system
diversity
Mating systems with no male
parental care
We begin with cases where the male does not provide parental care. In theory, the mating
system should result from a two-step process (Fig. 9.1). Firstly, female reproductive success
will be limited most by access to resources (Chapter 7), so female distribution should
depend primarily on resource dispersion (e.g. food, breeding sites), modified by the costs
and benefits of associating with other individuals (e.g. through influences on predation
and resource competition; Chapter 6). On the other hand, male reproductive success will
be limited more by access to females (Chapter 7), so the second step in the sequence is that
males should then distribute themselves in relation to female dispersion. Males could
