Pufferfish mating ritual

The white-spotted pufferfish is a relatively small () fish that was named in 2014 by a research group for the National Museum of Nature and Science. The fish has a brownish-yellow body with white spots and the ventral part of the body is translucent. The species was first discovered to be the manufacturers of highly ordered, large, circular sand structures on the sea floor in 2013. These structures have been observed by local scuba divers since 1995, although it was not yet known how they were formed. In 2012 an underwater photographer observed a pufferfish forming this structure. Torquigener albomaculosus was thought to be the only species of pufferfish to engage in this behaviour, until similar sand structures were found off the coast of Western Australia beyond water depth, which are believed to be pufferfish nests from an uncertain species of Torquigener. == Description ==

These structures are found at depths of on the seabed off the south coast of the Amami Ōshima Island. Each circle, two meters in diameter, has a huge cost of construction for the relatively small () fish. The fish begins making the structure by forming a simple circle shape in the sand using its belly. == Purpose of the "mystery circles" ==

Female choice This behavior is an example of a mating ritual, because it is used to attract mates and raise their young. It is assumed that the nest is important in female choice; however, there are no definitive factors known to influence the females' choice. There are a number of possible factors to consider, such as size and number of peaks/valleys, size of circle, sand composition, and color. This is also believed to be the most geometrically ordered structure created by any fish. There is evidence that females may be able to predict male body size and thus health of the fish from the structure formed. Larger males were shown to push sand further than smaller males, thus making larger spaces between peaks of the outer ring structure than those of a smaller male's nest. Females may be able to recognize these differences and assess whom she wants to mate with. In addition to this, two more courtship behaviors are carried out by the males before spawning. When females approach the nest, the males stir up the sand in the nest, and then perform a rush and retreat behavior to the females. It is hypothesized that the stirring of the sand is to show females the quality and quantity of the sand in the structure. For the rush and repeat behavior, the males would move to the outer portion of the nest, then rush towards the females, and then retreat back to the outer ring. After these courtship behaviors, the female will decide whether or not to spawn. Mating Spawning occurs from spring to summer. If a female decides to mate after the male performs the courtship behaviors, she will descend to the floor of the nest and the male will approach her. Mating occurs in pairs, and they will press their bodies together and vibrate until the female releases her gametes in the nest. Males may mate with multiple females in one day. Parental care After mating, the females leave the nest and the males stay. The males will no longer perform maintenance on the nest once the eggs are deposited. Males will care for the eggs and protect them until they hatch. They will chase off predators or other rival males that come to the nest. Eggs hatch around five days after mating, and the nest slowly deteriorates over this time. After hatching, males leave and will not use the same nest again. == See also ==