Influence of endogenous and exogenous factors on the reproductive output of a cryptogenic calcareous sponge

Abstract

The propagule pressure exerts an important role during the bioinvasion process. However, this biological characteristic of invasive species is still poorly understood for marine invertebrates. Here, we investigated aspects of the propagule pressure of the cryptogenic calcareous sponge Heteropia cf. glomerosa in the northeastern coast of Brazil. The investigated population was continuously reproductively active. Oocytes were present mainly during the rainy season, while embryos and larvae only during the dry season. The reproductive effort of this species was among the highest observed for sponges. The wet weight of the species did not influence on the reproductive output, but the number of tubes with apical osculum comprising the sponge was related to the number of oocytes. The reproduction of H. cf. glomerosa seemed to be driven by temperature, tides, and photoperiod. Our findings indicate that this species presents an opportunistic life history strategy enabling it to reproduce early in its life cycle with abundant propagules. As photoperiod is one of the drivers of its reproduction, it is expected that in higher latitudes (where this species has been found), the reproductive effort may exert an even higher pressure for the establishment and dispersion of the species. If H. cf. glomerosa is confirmed as a non-native in the study area, our results indicate that the best time to apply field efforts to avoid the expansion and establishment of the species is during the rainy period, when fewer larvae are found.