Data from: Promiscuous mating in the harem-roosting fruit bat, Cynopterus sphinx

Observations on mating behaviours and strategies guide our understanding
of mating systems and variance in reproductive success. However, the
presence of cryptic strategies often results in situations where social
mating system is not reflective of genetic mating system. We present such
a study of the genetic mating system of a harem-forming bat Cynopterus
sphinx where harems may not be true indicators of male reproductive
success. This temporal study using data from six seasons on paternity
reveals that social harem assemblages do not play a role in the mating
system, and variance in male reproductive success is lower than expected
assuming polygynous mating. Further, simulations reveal that the genetic
mating system is statistically indistinguishable from promiscuity. Our
results are in contrast to an earlier study that demonstrated high
variance in male reproductive success. Although an outcome of behavioural
mating patterns, standardized variance in male reproductive success (I_m)
affects the opportunity for sexual selection. To gain a better
understanding of the evolutionary implications of promiscuity for mammals
in general, we compared our estimates of I_m and total opportunity for
sexual selection (I_m/I_f, where I_f is standardized variance in female
reproductive success) with those of other known promiscuous species. We
observed a broad range of I_m/I_f values across known promiscuous species,
indicating our poor understanding of the evolutionary implications of
promiscuous mating.