a male calls or is silent, whereas the arm girth does not regulate whether a male uses the tactic of calling or being silent nor does it effect whether the male engages in singular or multimale amplexus. Thus, male density is positively associated with multimale amplexus and sperm competition and male density is negatively associated with the advantage of arm strength for mating. This would indicate that there would be increased investment in testes mass and sperm production, which is supported by the density of males in choruses. Since a female can mate with multiple males, the sperm from different males must compete for fertilization of the ova, meaning that there is continued competition post copulation. Reproduction and development Hibernation Quacking frogs hibernate during summer and autumn. They use rocks and logs for cover when they are hibernating. Fertilization Crinia georgiana breeds mainly in the winter months, from July to October, usually near granite outcrops, in shallow murky pools. Breeding has also been known to occur in puddles and wheel ruts. Amount of rainfall affects the timing of breeding, as this species usually breeds in temporary ponds that are only full after rain. Temperature can affect the rate of egg lying, which slows when ambient temperatures are very low. However, since water temperature is usually warmer than air temperature, it is unlikely that the water temperature will drop below 2 °C, the temperature necessary to significantly decrease breeding activity. Lunar phasing also affects mating, with higher rates occurring around the full moon. Although it is unclear why this is so, it can be inferred that the sexual activity of both males and females is synchronised by this variable. Mating usually occurs during the night. When a female arrives at a chorus, she seeks out the calling male by moving under their body, allowing for fertilization in inguinal amplexus. However, females may be intercepted by a silent male, which are usually smaller and tend to be close to the calling male. Fertilisation occurs via amplexus, which lasts about 23 minutes. Amplexus is a form of copulation in which the male grasps the female with his front legs while she lays her eggs and he simultaneously releases fluid containing sperm. Matings in this species are relatively unique in that quacking frogs are polyandrous; about half of all matings involve more than one male, and possibly up to nine, resulting in a brood