Linked from
The 15 pages that link to Mating system, each with the reason it gives.
AardwolfRelated: Aardwolves commonly form pairs, while females may also mate with neighboring males.
Nephrops norvegicusRelated: Mating follows female molting, when the new shell is still soft.
CopulationRelated: Mating systems shape who copulates with whom and how often.
Emperor dragonflyRelated: Males patrol water and compete for access to females and breeding sites.