An odorant receptor which affects chemotaxis to the volatile odorant diacetyl. Specifies AWA neuronal cell fate via the odr-7 pathway. Interacts with odr-4. Strongly expressed in the sensory cilia of AWA olfactory neurons, and at low levels in the CEP neurons. Expressed in AWA olfactory neurons at the L3 larval stage in males and hermaphrodites, but expressed decreases in males from the L4 stage to adulthood. Induced upon exposure to the volatile odorant diacetyl. Defective response to diacetyl with wild-type response exhibited to other ketones and odorants sensed by AWA. Belongs to the nematode receptor-like protein str family.