Mating and reproductive success associated with male body size in Stegastes acapulcoensis (Teleostei: Pomacentridae)

Molecular techniques enable the study of patterns and processes that are difficult to study using other methods. Specifically, population connectivity, taxonomic status and genetic mating systems can be clearly defined using these techniques. In this paper, the genetic mating system of Stegastes acapulcoensis (Fowler Fishes Acad Nat Sci Phila Monographs 6: 57–529, 1944 ) in the Mexican central Pacific (17–19°N, 101–105°W) was analyzed using four nuclear microsatellite loci. In this species, males are territorial and prepare a rocky substrate for spawning with the females, who oviposit tens of thousands of eggs that attach to the substrate with adhesive threads. Once a nest has been established, the male exhibits parental care to protect the eggs from predation until the larvae hatch. Twenty nests were collected from nest-guarding territorial males during the period from 2010 to 2011, and the numbers of female donors of the gametes in these nests were determined. The most common mating system found in this species was polygyny involving two to six females per nest. Larger males exhibited higher reproductive success than smaller males, guarding larger nests with more eggs from more females. Some males in this species exhibited parasitic behavior.