Chatty females and quiet males: complex vocal communication in the Northern dtella, Gehyra dubia

Vocal communication is widely used by vertebrates to transfer complex information to conspecifics. Although most birds, mammals, frogs, and crocodilians communicate vocally, most squamate reptiles are mute and unable to broadcast sound signals. Notable exceptions are gekkonid lizards, in which vocal communication is phylogenetically widespread. We describe the vocal repertoire of a house gecko native to tropical Australia, the Northern Dtella (Gehyra dubia). Male and female Gehyra dubia vocalize at a high frequency range (from 6,000-13,000 Hz, almost above the limits of human hearing), and produce at least five different vocalizations. Both sexes produce single chirp calls more often than more complex call types, suggesting that these serve as broadcast signals. More complex vocalizations (multiple single chirps, multiple double chirps, and triple chirps) are frequently used in the presence of another individual. Multiple single chirp calls appear to be used exclusively by males, whereas the other four calls are made by both sexes. Female geckos vocalized significantly more often than males, both when alone and when paired with a conspecific, especially a male. The calling rates of paired geckos are strongly correlated, suggesting active vocal communication between individuals. The vocal repertoire of G. dubia is among the most complex yet studied among squamate reptiles, and individuals modify calling rates according to sex, body size, and social context. Such complexity in vocal communication may help nocturnal geckos efficiently establish and maintain territories, find mates, and avoid direct conflicts with conspecifics