TEMPERATURE-DEPENDENT RATES OF LARVAL DEVELOPMENT IN LIMNOPERNA FORTUNEI (BIVALVIA: MYTILIDAE)

摘要

Laboratory-reared larvae of Limnoperna fortunei (Dunker) were monitored until the morula stage at 26 deg C, and from there on until settlement at 20, 25 and 28 deg 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 3.5h after spawning. The trochophorc stage (size: 95-110 mum) is reached 20, 6.3 and 6 h after spawning at 20, 25 and 28 deg C respectively. Straight-hinged veligers ( 115—175 mum) start appearing at 45, 26, and 24h after spawning; umboncd veligers (156 —220 mum) at 287, 165 and 118h after spawning; and pediveligers (>200 mum) 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.