Fig 1.
Two life cycle types of Aurelia spp.
Fig 2.
Stars on the left bottom map indicate observatories from which global horizontal irradiance data were obtained. A circle and black triangles on the right map indicate stations where environmental parameters were observed.
Fig 3.
Temporal variations in environmental parameters.
Chlorophyll fluorescence was averaged throughout the water column. Error bars in the copepod density indicate SD.
Fig 4.
Two types of ontogenetic development of planulae in Maizuru Bay.
Transformation process of the direct-development type from planula (A) to ephyra (F). The images B–F were taken 2, 6, 10, 12, and 15 days after the onset of incubation at 10°C, respectively. Transformation process of the metagenetic type from planula (G) to polyp (H). The image H was taken 7 days after the onset of incubation at 28°C. In B–E and H, A. coerulea attached to the wall of 24-well plates located in the lower part of the pictures. The scale bars indicate 1 mm.
Fig 5.
Temporal variations in proportion of direct development from planulae.
Bars and error bars in the top figure are mean values and SD. No planula indicates that no female bore planulae. Dark and light shades indicate the direct-development and metagenetic periods, respectively.
Fig 6.
Duration required for direct development from planula to ephyra in relation to temperature.
Fig 7.
Temporal variations in the bell diameter of medusae, proportion of planula-bearing medusa, and the number of planulae per medusa and per ovary weight.
In the top figure, boxes and bars in boxes indicate the first and third quartile and median values, respectively, and bars outside boxes indicate the minimum and maximum values. Bars and error bars in the bottom figure are mean values and SD, respectively. Dark and light shades indicate the direct-development and metagenetic periods, respectively.
Fig 8.
Seasonal change in oocyte diameter.
Two boxes with dashed lines indicate the direct-development and metagenetic periods.
Fig 9.
Temporal variations in the length of the major axis of the planulae, diameter of the top 5% of oocytes, and volume of the planulae and top 5% of oocytes.
Bars and error bars are mean values and SD. * in the bottom figure indicates a significant difference (P < 0.05). No planula indicates that no females bore planulae. Dark and light shades indicate the direct-development and metagenetic periods, respectively.
Fig 10.
COI phylogenetic relationships among Aurelia of the two life cycle types in Maizuru Bay and A. coerulea from the North Pacific.
The tree with the highest log likelihood (-862.22) is shown. Circle, triangle, and square indicate haplotypes that include specimens from the direct-development period, metagenetic period, and both periods, respectively. The letters following the symbols indicate the number of specimens from the direct-development (D) and metagenetic types (M). Bootstrap values > 50% are shown adjacent to branches. The scale bar indicates the number of substitutions per site. A. limbata was used as an outgroup.
Fig 11.
Schematic diagram of the seasonal life cycle of A. coerulea in Maizuru Bay.
The timing of strobilation is inferred from Miyake et al., Makabe et al. and Watanabe & Ishii [53–55]. The copepod biomass is treated as prey abundance, with the assumption that it changes linearly from July to October. Risks of predation and spatial competition are inferred from the abundance and filtration rates of filter-feeding sessile organisms, according to Kim & Moon and Ishii & Katsukoshi [56,57].
Table 1.
Life cycle type of Scyphozoa in relation to their egg sizes.