The social feather duster worm Bispira brunnea (Polychaeta: Sabellidae): aggregations, morphology and reproduction

ABSTRACT

The fan worm Bispira brunnea is one of the most attractive sabellid polychaetes from Caribbean coral reef areas and it is exploited for ornamental purposes. An understanding of the structure of its aggregations, morphology and reproductive biology will provide information required to facilitate artificial propagation of this species. Ten aggregations were collected in October 2013, February and March 2014 in the Majahual reef lagoon, Mexican Caribbean. Whole aggregations were examined under light microscopy and scanning electron microscopy and the histology of oogenesis was determined. Aggregations were composed of 24–56 individuals and included juveniles and adults. The adults (5–20 mm) did not display any noticeable form of sexual dimorphism. In B. brunnea both sexual (hermaphroditism or gonochorism) and asexual reproduction occurred at the same time within the population: 92.71% reproduced sexually and 52% by architomy. The buds produced by architomy were inside the parental tube, at three regenerative stages. The sex ratio was 36.75% males, 33.11% females, 22.84% hermaphrodites and 7.28% unknown (gametes not seen). Gametes were distributed in the last thoracic segments and throughout the abdomen. Oogenesis was extra-ovarian, development followed four discrete stages and the oocytes were small and asynchronous (60.97 μm in diameter). Sperm morphology was adapted to external fertilization in the water column. Sequential (protandrous) hermaphroditism is suggested to occur in B. brunnea. The pyramidellid ectosymbiont mollusc Odostomia (Eulimastoma) caniculatum is recorded here for the first time as being associated with a sabellid worm.

RESPONSIBLE EDITOR:

• Danny Eibye-Jacobsen

KEYWORDS:

• Cluster duster
• gonochorism
• hermaphroditism
• architomy
• regeneration
• oogenesis

Acknowledgements

We greatly appreciate José Luis Bortolini Rosales and Silvia Espinosa Matías (Facultad de Ciencias, UNAM) for providing access to facilities and guidance on histology and SEM procedures. Thanks are given to Fabio Moretzsohn (Texas A&M University at Corpus Christi) for help in identification of the mollusc species associated with B. brunnea. Nuria Méndez Ubach (ICMyL-UNAM) provided useful observations and comments on earlier versions of the manuscript. Ann Grant and Dave R. Bybee (Brigham Young University, Hawaii) revised the English style of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Yasmín Dávila-Jiménez http://orcid.org/0000-0001-8926-0412

Additional information

Funding

Yasmín Dávila-Jiménez (PCMyL-UNAM) was supported by CONACyT scholarship no. 308594. Field collections were part of the Biodiversity of Southern Gulf of Mexico Project, funded by the Harte Research Institute for the Gulf of Mexico Studies. Collection was authorized by permit SAGARPA–CONAPESCA–PPF/DGOPA.127/14.