breeding

#4
Or aggression might run so high in the male that he kills the only female he has. Not uncommon at all which is why more females is usually recommended. I have, however, done just fine with single pairs. Even with species you'd think would be hard to keep satiated with only one female like L. fuelleborni, M. crabro, M. greshakei, P. demasoni and currently M. sp. Zebra Chilumba. Of course it's taking chances and through personal experience I'd rather be safe than sorry. :)