Table 1.

Predictions of ‘outcome moderated’ and ‘engine of speciation’ theories for the effects of sexual conflict on species richness.

theory	potential for sexual conflict	mating pattern	prediction for species richness
‘outcome moderated’ (Parker & Partridge 1998)	high	male wins: polyandry	decreased; males promote gene flow
high	female wins: monandry	increased; females restrict gene flow
low	monandry	increased; both sexes restrict gene flow
‘engine of speciation’ (e.g. Gavrilets 2000)	high	polyandry	increased; high speciation potential
low	monandry	decreased; low speciation potential