Sometimes the hormones from one species breeding in the tank gets other species to breed as well. I imagine spawning cues are similar in west Africa and south America, so all the more reason to assume so. I've heard of people using easy livebearers to get harder plecos to spawn because of the hormones from the livebearers, but I've never heard of it going the other way, so I'm not entirely sure in this case, but could be that.
