EXAMPLES OF REVERSALS. “In birds, transitions in the level of specialization are rare. Yet in plants, there are many examples of reversals in specialization; for example, pollinator breadth exhibits little phylogenetic signal. Phytophagous insects also exhibit equivocal results with transitions occurring in either direction.”
http://rspb.royalsocietypublishing.org/content/281/1795/20142004.short