Gregariousness and protandry promote reproductive insurance in the invasive gastropod Crepidula fornicata : evidence from assignment of larval paternity

摘要: According to the size-advantage hypothesis, protandric sequential hermaphroditism is expected when increase in reproductive success with age or size small for males but large females. Interestingly, some protandrous molluscs have developed gregarious strategies that might enhance male at cost of intraspecific competition. The gastropod Crepidula fornicata, a European invading species, ideal investigating mating patterns hermaphrodite relation grouping behaviour because individuals different (age) live perennial stacks, fertilization internal and embryos are brooded. Paternity analyses were undertaken stacks sampled three close recently invaded sites Brittany, France. assignment 239 larvae, from set 18 brooding females carried out using five microsatellite loci, revealed 92% crosses occurred between located same stack. These thus function as independent groups which may reproduce consecutively female over short time period, pattern explained by sperm storage capacity. Gregariousness sex reversal promoting insurance this species. In addition, usually fertilized several (78% broods multiply sired) occupying any position within stack, result reinforcing hypothesis Our study pointed behaviours gender allocation varied concert across suggesting multiple paternities depending on competition intensity.