Multiple paternity in a natural population of a salamander with long‐term sperm storage

Abstract

Sperm competition appears to be an important aspect of any mating system in which individual female organisms mate with multiple males and store sperm. Post-copulatory sexual selection may be particularly important in species that store sperm throughout long breeding seasons, because the lengthy storage period may permit extensive interactions among rival sperm. Few studies have addressed the potential for sperm competition in species exhibiting prolonged sperm storage. We used microsatellite markers to examine offspring paternity in field-collected clutches of the Ocoee salamander (Desmognathus ocoee), a species in which female organisms store sperm for up to 9 months prior to fertilization. We found that 96% of clutches were sired by multiple males, but that the majority of females used sperm from only two or three males to fertilize their eggs. The high rate of multiple mating by females suggests that sperm competition is an important aspect of this mating system. Comparison of our data with those of other parentage studies in salamanders and newts reveals that multiple mating may be common in urodele amphibians. Nevertheless, the number of males siring offspring per clutch in D. ocoee did not differ appreciably from that in other species of urodeles with shorter storage periods.

Molecular evidence for historical and recent population size reductions of tiger salamanders (Ambystoma tigrinum) in Yellowstone National Park

“…However, there is some evidence that low genetic diversity increases the susceptibility of amphibians to disease (Pearman and Garner 2005). We reviewed several salamander microsatellite studies and found that the average expected heterozygosity was 0.519 (range 0.14-0.937; Curtis and Taylor 2003;Myers and Zamudio 2004;Adams et al 2005;Jehle et al 2005;Storfer, unpublished). The expected heterozygosity for Yellowstone populations was 0.317 (Table 2), the second lowest of any of these studies.…”

Population size, structure and phenology of an endangered salamander at temporary and permanent breeding sites

“…This may reflect the species mating system and inter-sex conflicts as different selection pressures shape each gender's reproductive behaviour. Salamandra demonstrate multiple paternity (Steinfartz et al 2006) -i.e., males are capable of multiple mating with different females during a single season (Adams et al 2005). Females however are capable of long-term sperm storage and thus may not be limited by copulation every year to reproduce each year (Sever 2002).…”

Parentage and sibship exclusions: higher statistical power with more family members

“…In marker-assisted parentage analyses, it is common that a mother and a number of her offspring (or fertilized eggs/seeds) are genotyped to infer their paternity (Kichler et al, 1999;Adams et al, 2005;Bretman and Tregenza, 2005;Chapple and Keogh, 2005;Gosselin et al, 2005;Madsen et al, 2005). Some of the offspring sampled from a mother may be full siblings fathered by the same male, and their genotypes can be used jointly to infer the paternity more accurately.…”