haven't heard of adeniums having nectar .... so am guessing here - it is the color of the blooms that *may* attract wildlife - what they do after they get there is anyone's guess (my best guess: hangout)
having said that - am not 100% sure how adeniums pollinate - am leaning towards self pollinate - although many say that's not possible
Adenium hangout - its not that unusual to see anoles, dragonflies & Carolina wrens during the day - and a few moths & Mediterranean geckos at night