Mediates recognition and avoidance of Streptomyces species by detecting dodecanoic acid secreted by the bacteria. Also mediates avoidance of decanoic acid which is not secreted by Streptomyces species but this may represent an additional important avoidance response in the environment. Expressed in the ADL, ADF and ASH chemosensory neurons in the head and in the PHA and PHB chemosensory neurons in the tail. Low expression also observed in the egg-laying structures in the mid-body region. RNAi-mediated knockdown results in defective head and tail avoidance responses to Streptomyces and to dodecanoic acid. It also results in severely reduced calcium influx into ASH neurons in response to both S.avermitilis and dodecanoic acid. Belongs to the nematode receptor-like protein srb family.