Bispira brunnea Breeding Guide

How the social feather duster Bispira brunnea forms colonies and reproduces both sexually by broadcast spawning and asexually by architomy, with most of a population doing both.

Overview

Bispira brunnea, the social feather duster, is a Caribbean sabellid polychaete that lives in groups and is common off the Caribbean islands and the Bahamas. Each worm bears a crown of 18 to 28 radioles in two semicircular whorls and feeds on plankton filtered from the water, secreting a soft, non-calcareous tube about 40 mm long with white sand grains cemented to the outside. Aggregations can include both juveniles and adults.

Reproductive Mode

Both sexual and asexual reproduction occur within a population at the same time. In one study, about 92.7% of individuals reproduced sexually while about 52% reproduced by architomy; whole colonies are described as either male, female or hermaphrodite, and the worms are likely protandrous hermaphrodites that begin life as males and become female when larger.

Asexual Reproduction

Asexual reproduction is by architomy: buds are produced inside the parental tube at several regenerative stages. This budding, together with the worm's ability to regenerate a crown nipped off by a predator within a few weeks, drives the dense social aggregations that give the species its name.

Sexual Reproduction

Sexual reproduction follows the sabellid pattern of external fertilisation after gametes are shed into the water, with a planktonic larval phase before settlement; the sex composition of studied populations included males, females and hermaphrodites.

Common Challenges

In aquaria these worms multiply mainly through architomy within the cluster rather than through larval rearing, which is not practical at home. They depend on plankton-rich water, and stress can trigger crown shedding that is usually followed by regeneration.