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Annual Reproductive Cycle and Unusual Embryogenesis of a Temperate Coral in the Mediterranean Sea.

Marchini C, Airi V, Fontana R, Tortorelli G, Rocchi M, Falini G, Levy O, Dubinsky Z, Goffredo S - PLoS ONE (2015)

Bottom Line: Not only females, but also sexually inactive individuals (without germ cells) and males were found to brood their embryos.Gametogenesis showed a strong seasonal influence, while embryos were found throughout the year in males and in sexually inactive individuals without a defined trend.This unusual embryogenesis suggests the possibility of agamic reproduction, which combined with sexual reproduction results in high fertility.

View Article: PubMed Central - PubMed

Affiliation: Marine Science Group, Department of Biological, Geological and Environmental Sciences, University of Bologna, Via F. Selmi 3, 40126 Bologna, Italy.

ABSTRACT
The variety of reproductive processes and modes among coral species reflects their extraordinary regeneration ability. Scleractinians are an established example of clonal animals that can exhibit a mixed strategy of sexual and asexual reproduction to maintain their populations. This study provides the first description of the annual reproductive cycle and embryogenesis of the temperate species Caryophyllia inornata. Cytometric analyses were used to define the annual development of germ cells and embryogenesis. The species was gonochoric with three times more male polyps than female. Polyps were sexually mature from 6 to 8 mm length. Not only females, but also sexually inactive individuals (without germ cells) and males were found to brood their embryos. Spermaries required 12 months to reach maturity, while oogenesis seemed to occur more rapidly (5-6 months). Female polyps were found only during spring and summer. Furthermore, the rate of gamete development in both females and males increased significantly from March to May and fertilization was estimated to occur from April to July, when mature germ cells disappeared. Gametogenesis showed a strong seasonal influence, while embryos were found throughout the year in males and in sexually inactive individuals without a defined trend. This unusual embryogenesis suggests the possibility of agamic reproduction, which combined with sexual reproduction results in high fertility. This mechanism is uncommon and only four other scleractinians (Pocillopora damicornis, Tubastraea diaphana, T. coccinea and Oulastrea crispata) have been shown to generate their broods asexually. The precise nature of this process is still unknown.

No MeSH data available.


Related in: MedlinePlus

Fraction of sexually mature individuals per size class (mm).Fraction of sexually mature individuals per size class in millimeters, collected at Elba Isle. The values above the bars indicate the number of sexually mature polyps (bold) out of the number of polyps analyzed per size class (N = 158).
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pone.0141162.g002: Fraction of sexually mature individuals per size class (mm).Fraction of sexually mature individuals per size class in millimeters, collected at Elba Isle. The values above the bars indicate the number of sexually mature polyps (bold) out of the number of polyps analyzed per size class (N = 158).

Mentions: Polyps up to 6 mm in length were immature and size at sexual maturity ranged from 6 to 8 mm in length (Fig 2). According to biometric analyses a polyp in this category has l = 5–7 mm, h = 5–6 mm, V = 146–206 mm3. The frequency of sexually mature polyps decreased in larger size classes (Fig 2).


Annual Reproductive Cycle and Unusual Embryogenesis of a Temperate Coral in the Mediterranean Sea.

Marchini C, Airi V, Fontana R, Tortorelli G, Rocchi M, Falini G, Levy O, Dubinsky Z, Goffredo S - PLoS ONE (2015)

Fraction of sexually mature individuals per size class (mm).Fraction of sexually mature individuals per size class in millimeters, collected at Elba Isle. The values above the bars indicate the number of sexually mature polyps (bold) out of the number of polyps analyzed per size class (N = 158).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4625958&req=5

pone.0141162.g002: Fraction of sexually mature individuals per size class (mm).Fraction of sexually mature individuals per size class in millimeters, collected at Elba Isle. The values above the bars indicate the number of sexually mature polyps (bold) out of the number of polyps analyzed per size class (N = 158).
Mentions: Polyps up to 6 mm in length were immature and size at sexual maturity ranged from 6 to 8 mm in length (Fig 2). According to biometric analyses a polyp in this category has l = 5–7 mm, h = 5–6 mm, V = 146–206 mm3. The frequency of sexually mature polyps decreased in larger size classes (Fig 2).

Bottom Line: Not only females, but also sexually inactive individuals (without germ cells) and males were found to brood their embryos.Gametogenesis showed a strong seasonal influence, while embryos were found throughout the year in males and in sexually inactive individuals without a defined trend.This unusual embryogenesis suggests the possibility of agamic reproduction, which combined with sexual reproduction results in high fertility.

View Article: PubMed Central - PubMed

Affiliation: Marine Science Group, Department of Biological, Geological and Environmental Sciences, University of Bologna, Via F. Selmi 3, 40126 Bologna, Italy.

ABSTRACT
The variety of reproductive processes and modes among coral species reflects their extraordinary regeneration ability. Scleractinians are an established example of clonal animals that can exhibit a mixed strategy of sexual and asexual reproduction to maintain their populations. This study provides the first description of the annual reproductive cycle and embryogenesis of the temperate species Caryophyllia inornata. Cytometric analyses were used to define the annual development of germ cells and embryogenesis. The species was gonochoric with three times more male polyps than female. Polyps were sexually mature from 6 to 8 mm length. Not only females, but also sexually inactive individuals (without germ cells) and males were found to brood their embryos. Spermaries required 12 months to reach maturity, while oogenesis seemed to occur more rapidly (5-6 months). Female polyps were found only during spring and summer. Furthermore, the rate of gamete development in both females and males increased significantly from March to May and fertilization was estimated to occur from April to July, when mature germ cells disappeared. Gametogenesis showed a strong seasonal influence, while embryos were found throughout the year in males and in sexually inactive individuals without a defined trend. This unusual embryogenesis suggests the possibility of agamic reproduction, which combined with sexual reproduction results in high fertility. This mechanism is uncommon and only four other scleractinians (Pocillopora damicornis, Tubastraea diaphana, T. coccinea and Oulastrea crispata) have been shown to generate their broods asexually. The precise nature of this process is still unknown.

No MeSH data available.


Related in: MedlinePlus