C
onflict between the sexesis a driving force
in the evolution of mating patterns and reproduc-
tive behavior (Alonzo and Warner 2000). Each in-
dividual strives to maximize reproductive success, and since
each sex has different constraints on reproduction, males
and females generally have evolved different strategies for
mating. However, mating strategies are not the same thing
as mating systems. A mating strategy is all the tactics used by
an individual to maximize reproductive success, whereas a
mating system is characteristic of a population or a species.
Thus a mating system may reflect a variety of sex-specific
mating tactics. Mating systems are generally defined by
whether multiple mating (mating with 1 member of the
opposite sex) occurs in males, females or both. Descriptions
of monogamy and polygyny, for example, assume that fe-
males mate with a single male. Within a given mating sys-
tem (e.g., polygyny), males may adopt different strategies
(e.g., female defense or competitive searching for mates) to
try to maximize reproductive success.
Sexual selection theory predicts that when one sex (usu-
ally females) is limited in availability, the other sex com-
petes for access to members of that sex (Trivers 1972). Thus
research on mating systems has traditionally focused on the
strategies of males. Male strategies for maximizing repro-
ductive success have been viewed as a balance between the
advantage of copulating with as many females as possible
and the advantage of providing parental care (Clutton-
Brock 1989b). Under this scenario, the mating pattern is
determined by the distribution of receptive females in time
and space (Emlen and Oring 1977). Thus the behavior of
males is commonly the predominant factor used to describe
mating patterns.
However, a male’s ability to access additional females
is affected by a number of factors besides the distribution
of females, including competitive ability with other males,
habitat structure, and perhaps most important of all, fe-
male reproductive strategies. Most research has focused on
examining the environmental factors that influence male
reproductive success, and often ignores how female strate-
gies can influence male reproductive success (Ahnesjo et al.
1993; Lacey et al. 1997). Females may not often be passive
participants (see Solomon and Keane, chap. 4 this volume)
and females regularly multiply mate in several species that
have been described as polygynous. Multiple mating by fe-
males changes the competitive landscape for males.
In rodents, males use many different strategies to success-
fully fertilize females, including overt conflict and defense
of mates, competitive mate searching, and sperm competi-
tion (Schwagmeyer and Wootner 1985, 1986). This vari-
ety of mating strategies reflects the wide variation in spatial
and temporal distribution of receptive females. Female so-
cial organization ranges from solitary, dispersed, and rela-
tively asocial to highly clustered, colonial matrilineal groups
(Michener 1983a; Wolff 1985a, 1989; Schwagmeyer 1990;
Kalcounis-Rüppell and Ribble, chap. 6 this volume). Mul-
tiple mating by females, evidenced by genetic studies docu-
menting multiple paternity, may confound the strategies
used by males to maximize their reproductive success.
Among rodents, the mating tactics used by sciurids
probably are the best known, because their diurnal behav-