Poecilogony in Polydora hoplura (Polychaeta: Spionidae) from commercially important molluscs in South Africa
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Females of the polychaete Polydora hoplura (Claparède 1869) that produced planktotrophic and adelphophagic larvae were compared genetically to determine whether the different reproductive morphs represented sibling species or poecilogony. Worms were collected from Saldanha Bay, South Africa (33°0′37.71S, 17°56′59.74E), and cultured in a laboratory setting from November 2012 to April 2013. The results based on mitochondrial and nuclear DNA (Cyt b and ATPSα, respectively) showed shared haplotypes between reproductive morphs for both markers. Additionally, variation in mtDNA sequences was significantly higher within morphs than between morphs (95.8 and 4.2 %, respectively). A comparison of developmental modes found that broods of planktotrophic larvae were larger than broods of adelphophagic larvae, while the latter had larger eggs and larvae at hatching. Developmental time from oviposition to settlement for planktotrophic and adelphophagic larvae was 40.2 and 16.6 days, respectively. Polydora hoplura represents the fifth confirmed case of poecilogony in the Spionidae.
KeywordsPolychaete Developmental Mode Sibling Competition Larval Size Brooding Female
We thank James Blake and Jason Williams for advice on culture procedures, Glenys Gibson for valuable input, Tamara Robinson for suggestions and comments on the statistics, Sandy van Niekerk for taxonomic clarification of adult worms and Lee Gavin Williams for help with the genetic component of the study. We would like to thank Kevin Ruck for supplying oysters and Grant Pitcher and Alick Hendricks of the Department of Agriculture, Forestry and Fisheries of South Africa for supplying algae stock cultures and three anonymous reviewers for their input. The support of Stellenbosch University is also greatly appreciated. This study is part of a larger doctoral dissertation funded by the National Research Foundation (Thuthuka Programme) of South Africa.
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