Summary
Physical Description
Ecology
Life History & Behaviour
Reproduction
Experiment: Cell Aggregation
Nutrition
Anatomy & Physiology
Evolution & Systematics
Biogeographic Distribution
Conservation & Threats
References & Links |
REPRODUCTION
Sponges can reproduce asexually and sexually, depending on the species. Clonal asexual reproduction can either occur by fragmentation, budding or by the formation of so called gemmules that are internal buds (Ruppert et al., 2004). Both, asexual and sexual reproduction, can be found in the algae phylum as well. Sexual and asexual reproduction was observed in the Haliclona/Ceratodictyon association (Fromont, 1994; Trautman et al., 2000; Trautman et al., 2003).
Haliclona/Ceratodictyon: asexual reproduction
It is assumed that fragmentation is the primarily way of reproduction in the Haliclona/sp association (Trautman et al., 2000). Currents or waves usually are the main reasons for sponge fragmentation. In order to regenerate successfully, sponges need an exceptional remodeling capacity (Ruppert et al., 2004). The sponge fragments attach on solid substrata and reorganize themself into a functional sponge (Ruppert et al., 2004).
Haliclona/Ceratodictyon: sexual reproduction
Sexual reproduction in Haliclona/Ceratodictyon takes place independently of one another (Trautman et al., 2000; Fromont, 1994). Haliclona cymaeformis shows a very short period of reproductive activity from December till mid-January (Fromont, 1994). Reproductive activity is triggered by factors such as rainfall, sunlight and an increase in water temperature. As viviparous, gonochoric or at least successive hermaphrodites, oocytes, embryos and larvae are present at the same time in Haliclona cymaeformis. Incubated eggs, embryos and larvae can be found along the central axis of the algae branches whereas sperm cysts are distributed throughout the mesohyl (Fromont, 1994). Sperm cysts form when sperm arise from choanocyte chamers sink into the mesohyl and become enclosed in a thin cellular wall (Ruppert et al., 2004). The mature larvae are creamy white in colour and oval shaped.
Ceratodictyon spongiosum shows reproductive products throughout the year except of the winter months June, July and August. Reproductive and vegetative peaks occur in the middle of summer, at the same time that Haliclona cymaeformis reaches its maximum reproductive activity (Fromont, 1994). The parameters which lead to the establishment of the symbiosis are unknown.
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