Receptor for the Esp1 pheromone. Mediates the response to Esp1 which enhances female sexual receptive behavior (lordosis) upon male mounting, resulting in successful copulation. Expressed in the vomeronasal organ. No response of neurons in the vomeronasal organ or accessory olfactory bulb to Esp1 and no enhancement of lordosis following exposure to Esp1. Belongs to the G-protein coupled receptor 3 family.