title of learn-about section on goose barnacles of A SNAIL'S ODYSSEY
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Larval biology


Topics on reproduction include larval biology, considered here, and EGG RELEASE & BROODING and SETTLEMENT considered in other sections.

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Research study 1

outline drawings of the 6 naupliar larval stages of a goose barnacle Pollicipes polymerusdrawing of cypris larva of a goose barnacle Pollicipes polymerusDevelopment of goose barnacles Pollicipes polymerus is similar to that of acorn barnacles in that eggs of 100┬Ám diameter are released into the mantle cavity where they are fertilised, and where development to hatching occurs.  Hatching occurs about 20-30d after fertilisation at 14oC. The eggs hatch to feeding nauplius larvae that eventually transform into the settling cypris stage at about 70d post-fertilisation. Six naupliar stages are passed through before moulting to a cypris stage. the cypris is non-feeding and within a day or two is seeking out a place to settle. Settlement and metamorphosis occur at 10-11wk of age in laboratory culture.

In laboratory culture best growth and survival of nauplii is obtained on a combined diet of the microalgae Platymonas sp. and Prorocentrum micana.  Other phytoplankton species, especially photograph of a cluster of goose barnacles Pollicipes polymerus taken in a cavebristly diatoms, may clog the feathery setae that the nauplii use to strain the particles from the water, thus causing the larvae to weaken and die. Other algal species are eaten but fail to promote good growth.  Absence of large oil droplets common in the cyprids of other barnacle species suggests that the cyprids of P. polymerus may be extremely short-lived in the plankton.  Settlement of competent cyprids is stimulated only by the presence of healthy adult peduncles of the same species.  In the field, juveniles are often common on the stalks of adults. Lewis 1975 Mar Biol 32: 127; Lewis 1975 Mar Biol 32: 141.

NOTE alternatively, the author suggests that the cyprids of P. polymerus may possibly feed from the plankton

Cluster of goose barnacles Pollicipes polymerus
photographed on a cave. Note the 2 juveniles
attached to a stalk in the 5-o'clock position

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