Such cases are highly important, for they prove that the capacity in any two species to cross is often completely independent of their systematic affinity, that is of any difference in their structure or constitution, excepting in their reproductive systems.
Horrelako kasuek garrantzi handia dute, honako hau frogatzen dutelako, alegia, zeinahi bi espeziek duten gurutzatzeko ahalmenak ez duela maiz inolako zerikusirik ahaidetasun sistematikoarekin, hau da, egitura edo osaerako edozein ezberdintasunekin, ugal-aparatuko aldeak salbu.