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How do sour taste receptors respond to acids?

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Compound eye — Senses Vespid wasps (Vespidae), similar to other insects, have compound eyes that consist of thousands of tiny optical units known as ommatidia, which contain light-sensitive photoreceptor cells.

Sour taste receptors respond to acids primarily through the movement of hydrogen ions into the receptor cells. This process is thought to occur in a manner similar to the detection of salts, where the influx of ions alters the internal ionic concentration of the cell, thereby initiating an electrical signal.12

Additionally, acids may produce their characteristic sour sensation by opening specific ion channels that are sensitive to pH levels. While the concentration of hydrogen ions is a major factor in determining sourness, it is not the sole determinant; the rest of the acid molecule can influence the efficiency with which hydrogen ions stimulate the receptors, which explains why some weak organic acids taste more sour than their hydrogen ion concentration alone would predict.21