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Sexual reproduction in S arcotragus spinosulus from two different shallow environments
Author(s) -
Maria Mercurio,
Giuseppe Corriero,
Miriam Gherardi,
Rossella Baldacconi,
Gaino Elda
Publication year - 2013
Publication title -
marine ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 58
eISSN - 1439-0485
pISSN - 0173-9565
DOI - 10.1111/maec.12039
Subject(s) - biology , sponge , reproduction , embryo , reproductive season , anatomy , sexual reproduction , reproductive biology , embryogenesis , ecology , botany , fishery
The reproductive cycle of the demosponge S arcotragus spinosulus from two different shallow environments ( L a P ierta and L a S trea) of the I onian coasts of A pulia ( SE I taly) was studied from F ebruary 2006 to F ebruary 2007 in 20 tagged specimens. The sponge is viviparous. All the monitored specimens showed sexual reproduction, even if the process usually involved small portions of the sponge tissue. Most of the specimens showed hermaphroditism, with contemporaneous production of oocytes and spermatic cysts in the same reproductive season. Young oocytes occurred from J une to S eptember in specimens from L a P ierta and from J une to O ctober in those from L a S trea. Large mature eggs, measuring up to 200 μm, showed a peak in A ugust to S eptember, concomitant with the appearance of spermatic cysts, whose density values were about 100 times higher than those estimated for female elements. At L a P ierta, embryos were present for 11 months, whereas at L a S trea they were very scarce during the first 4 months of observation, with the results that there was a significant difference in the production of embryos between the two groups of sponges. Embryo development occurred in patches inside the choanosomal region. Cleavage started in S eptember and led in J une to a solid stereoblastula, which, only at L a P ierta, produced parenchymella larva (371.3 + 31.3 μm on average) from J une to J uly. In the specimens from L a S trea, larvae were never observed. The slight differences in the reproductive cycle between the two groups of sponges may be explained in the light of the major variability of the environmental parameters which could have affected the specimens from L a S trea negatively.