Data from: Molecular evolution of sour tolerance in birds

Taste is crucial in shaping animals’ perception. Sourness, one of the
primary tastes, is aversive in mammals, whereas many birds frequently
consume acidic fruits, suggesting a potential tolerance. Our study
uncovers a mechanism enabling sour tolerance in birds involving changes to
the sour receptor (Otopetrin1, OTOP1). We demonstrate sour tolerance is a
conserved trait in birds, with avian OTOP1 exhibiting acid-induced
inhibition, and OTOP1 modulation affects sour perception and tolerance.
Ancestral reconstruction reveals that the increase in acid tolerance
evolved at the same point in the songbird phylogeny--before the last
common ancestor of honeyeaters and other songbirds, and after the
divergence of Australian treecreepers--as the regain of sweet sensing in
this clade. We propose this shift might have enabled songbirds to feed on
a wider range of fruits, expanding their ecological niches, and may play a
role in the evolution and diversification of the songbird
radiation.