Strategies, patterns and environmental cues for reproduction in two temperate haliclonid sponges

Abstract

The reproductive biology of 2 haliclonid sponges was examined over a 2 yr period. Histological samples of Haliclona sp. 1 (green Haliclona) and Haliclona sp. 2 (brown Haliclona) from tagged and haphazardly sampled individuals of both species were examined using light microscopy. Interest in these 2 sympatric species is high, due to the potent and unique bioactive compound (salicylihalamide A) they produce, hence the need to understand the reproductive biology of both species to ensure their proper conservation and management. Green Haliclona is viviparous, with both gonochoric and hermaphroditic individuals in the sponges sampled. Brown Haliclona is also viviparous and is clearly a gonochoric species. Only decreasing wave height showed a significant correlation to gametogenesis, but the onset and progression of reproduction in both species coincided with increases in water temperature and photoperiod. Oogenesis for both species extended from November to April. Spermatogenesis extended over 3 mo for green Haliclona (January to March) and 4 mo for brown Haliclona (January to April). Embryogenesis within brood chambers started in January and extended over 4 mo in green Haliclona and 5 mo in brown Haliclona. The parenchymellae larvae of green Haliclona were observed in tissue samples for 2 mo compared to 4 mo for brown Haliclona. The reproductive output of each species was similar; however, female reproductive output at 2.9% (green Haliclona) and 2.4% (brown Haliclona) of the mesohyl was much lower than that of other viviparous species. Male reproductive output (2.3 and 2.4% for green and brown Haliclona, respectively) compares favourably to that of oviparous species. The high reproductive output of males and the timing of reproduction in both species of sponge appears to help in reducing the risk of unsuccessful fertilisation and lower the probability of larvae being released into unfavourable conditions. KEY WORDS: Haliclona · Sexual · Fecundity · GametogenesisResale or republication not permitted without written consent of the publisher OPEN PEN ACCESS CCESS

Interference of asexual and sexual reproduction in the green hydra

“…The hypothesis that sexual reproduction may be a strategy employed to survive insufficient food conditions may be supported by the finding that starvation has been reported as an inductive factor of sexual differentiation in many hydra species (e.g., H. littoralis, H. magnipapillata, H. oligactis, and H. viridissima ;Loomis 1964;Fukuhori et al 2005;Habetha et al 2003;Rutheford et al 1983;Sugiyama 1983). Unfavorable conditions (e.g., insufficient food supply or oxygen depletion) or prognostic factors (e.g., temperature or photoperiod) have been shown to induce sexual reproduction in hydras and other animals able to reproduce asexually and sexually (e.g., sponges, hydroids, and oligochaetes; Abdo et al 2008;Braverman 1963;Christensen 1984;Frost et al 1982;Loden 1981).…”

New species of Haliclona (Demospongiae: Haplosclerida: Chalinidae) from Western Australia

“…The species also differed in their reproductive biology (Abdo et al 2008a), and growth patterns, with H. djeedara having distinct seasonal growth in summer and loss of volume in winter, while H. durdong did not have seasonal growth (Abdo et al 2008b).…”

“…Haliclona djeedara is viviparous and gonochoric, reproducing in the Austral summer (Abdo et al 2008a). It is characterized by numerous large apical oscules, brown colour and a more dense and compact mesohyl than Haliclona durdong, with a consequent compressible and springy texture.…”

“…nov. is viviparous, with both gonochoric and hermaphroditic individuals, and reproduces in the Austral summer (Abdo et al 2008a). It is characterized by wide apical, funnel-like oscules and large internal canals, green colour, compressible texture, fibre only at the nodes of the skeletal reticulation, never forming sheaths, and ready fragmentation.…”

“…nov. with a uniformly heavily ciliated body and lacking a posterior flagellated band. Larvae first observed annually in February (Abdo et al 2008a).…”