Temperature-Dependent Rates Of Larval Development In Limnoperna Fortunei (Bivalvia: Mytilidae)

Laboratory-reared larvae of Limnoperna fortunei (Dunker) were monitored until the morula stage at 26°C, and from there on until settlement at 20, 25 and 28°C. The first polar lobe is produced c. 40 min after spawning, and the first division occurs 14 min later. Slightly over an hour after spawning, the second polar lobe appears and the second division yields a 4-cell stage. The third division occurs 90 min after spawning, and the fourth 115 min after spawning. The morula stage is reached 3.5 h after spawning. The trochophore stage (size: 95-110 μm) is reached 20, 6.3 and 6 h after spawning at 20, 25 and 28°C, respectively. Straight-hinged veligers (115-175 μm) start appearing at 45, 26, and 24 h after spawning; umboned veligers (156-220 μm) at 287, 165 and 118 h after spawning; and pediveligers (>200 μm) at 480, 313 and 265 h after spawning. Implications of these findings for the dispersion of the species and for its fouling impact are discussed. © The Malacological Society of London 2005, all rights reserved.