. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FEEDING BY ECHINODERM LARVAE 23 under conditions where the mouth is jammed with par- ticles, or the particles are not desirable, or the larva is attempting to reject particles from its buccal cavity (Strathmann, 1971). Clearance rates Maximum clearance rates ranged from 1-2 n\ min~' for early larval stages (four-armed plutei and the simple bipinnaria-shaped larvae of asteroids and holothuroids) with short ciliated bands, to 6-10 v\ min~' for late larval stages (the large eight-armed plutei and the bipinnariae and auricularia
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FEEDING BY ECHINODERM LARVAE 23 under conditions where the mouth is jammed with par- ticles, or the particles are not desirable, or the larva is attempting to reject particles from its buccal cavity (Strathmann, 1971). Clearance rates Maximum clearance rates ranged from 1-2 n\ min~' for early larval stages (four-armed plutei and the simple bipinnaria-shaped larvae of asteroids and holothuroids) with short ciliated bands, to 6-10 v\ min~' for late larval stages (the large eight-armed plutei and the bipinnariae and auriculariae with large loops and folds of the ciliated band) with longer bands. Maximum clearance rate in- creases with the length of the ciliated band in all of these larvae (Strathmann, 1971; M. Hart, unpub. data). These clearance rates are similar to those of other larvae of comparable size and type, but measured by very dif- ferent techniques. Strathmann (1971) measured clearance rates for larvae by two methods: counting algal cells en- tering the mouths of swimming larvae, or counting cells in the guts of larvae left briefly in algal suspensions. Lucas (1982) measured clearance rates for groups of larvae by estimating the depletion of algal cells from suspension in prolonged feeding trials (of about 24 h duration). The similar range of clearance rates estimated for larvae of similar types clearing algal cells or polystyrene spheres from suspension suggests that the use of artificial sus- pended particles can give accurate estimates of clearance rates. Flavoring particles with some transferable factor from algal cells may enhance the rate of ingestion of poly- styrene spheres (Fenaux el al., 1985), but larvae capturing unflavored spheres, in my study, ingested almost all of Table II pruhahiliiY value-- /nrposi hoc paired comparisons «t mean lengths aiui / mean maximum clearance rales among lan'al stages of Strongylocentrotus droebachiensis. for di/t'emil st'xmail* of the ciliated ha
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
