A description of the spermatheca of<i>Spirorbis spirorbis</i>(L.) (Polychaeta: Serpulidae) and evidence for a novel mode of sperm transmission

Daly, J.M.; Golding, D. W.

doi:10.1017/s0025315400021366

Cited by 50 publications

(33 citation statements)

References 17 publications

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“…Exchange of sperm might or might not have occurred during the experiment. Some sperm stored over winter in a specific organ of the head could have been used to fertilize the eggs [86], [87]. Likewise, some embryos in dormancy at the beginning of the experiment could have reactivated their development.…”

Section: Discussionmentioning

confidence: 99%

Differential Responses of Calcifying and Non-Calcifying Epibionts of a Brown Macroalga to Present-Day and Future Upwelling pCO2

Saderne

Wahl

2013

PLoS ONE

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Seaweeds are key species of the Baltic Sea benthic ecosystems. They are the substratum of numerous fouling epibionts like bryozoans and tubeworms. Several of these epibionts bear calcified structures and could be impacted by the high pCO2 events of the late summer upwellings in the Baltic nearshores. Those events are expected to increase in strength and duration with global change and ocean acidification. If calcifying epibionts are impacted by transient acidification as driven by upwelling events, their increasing prevalence could cause a shift of the fouling communities toward fleshy species. The aim of the present study was to test the sensitivity of selected seaweed macrofoulers to transient elevation of pCO2 in their natural microenvironment, i.e. the boundary layer covering the thallus surface of brown seaweeds. Fragments of the macroalga Fucus serratus bearing an epibiotic community composed of the calcifiers Spirorbis spirorbis (Annelida) and Electra pilosa (Bryozoa) and the non-calcifier Alcyonidium hirsutum (Bryozoa) were maintained for 30 days under three pCO2 conditions: natural 460±59 µatm, present-day upwelling1193±166 µatm and future upwelling 3150±446 µatm. Only the highest pCO2 caused a significant reduction of growth rates and settlement of S. spirorbis individuals. Additionally, S. spirorbis settled juveniles exhibited enhanced calcification of 40% during daylight hours compared to dark hours, possibly reflecting a day-night alternation of an acidification-modulating effect by algal photosynthesis as opposed to an acidification-enhancing effect of algal respiration. E. pilosa colonies showed significantly increased growth rates at intermediate pCO2 (1193 µatm) but no response to higher pCO2. No effect of acidification on A. hirsutum colonies growth rates was observed. The results suggest a remarkable resistance of the algal macro-epibionts to levels of acidification occurring at present day upwellings in the Baltic. Only extreme future upwelling conditions impacted the tubeworm S. spirorbis, but not the bryozoans.

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Section: Discussionmentioning

confidence: 99%

Differential Responses of Calcifying and Non-Calcifying Epibionts of a Brown Macroalga to Present-Day and Future Upwelling pCO2

Saderne

Wahl

2013

PLoS ONE

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“…In those cases in which the secretion is made up of lipoproteins or phospholipids it has been hypothesised that, besides its trophic importance, it has a role as the source of material necessary for the modifications that take place in the plasmalemma of the spermatozoa during their stay in the female genital tracts (Daly & Golding 1977;Giusti & Selmi 1985;Selmi & Giusti 1986). This does not seem to be the case in A. granulatum, since the spermatozoa do not appear to undergo a notable structural modification of any type while they are in the seminal receptacle.…”

Section: Discussionmentioning

confidence: 99%

Ultrastructure of seminal receptacle and sperm storage inArmadillidium granulatumBrandt (Isopoda: Oniscidea)

Longo¹,

Trovato²

2008

Italian Journal of Zoology

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The aim of this study was to evaluate the efficacy of sperm storage in the seminal receptacle in females of Armadillidium granulatum after the first mating and in the absence of further mating. Females of A. granulatum were bred in the laboratory, isolated from males, until they were sexually mature, and then they were allowed to mate. They were then isolated again from the males and observed to evaluate their reproductive behaviour until their natural death. Some females were sacrificed at various time intervals to carry out ultrastructural observations of the seminal receptacle and of the spermatozoa inside. All the females had the first brood at about 20 days after mating; a little less than 50% of the females had a second brood during the first reproductive season; only 10% of the females had another brood during the second reproductive season. The average number of juveniles produced by each female was about 25 at the first brood, but fall with the successive broods; the sex ratio of juveniles was about 1 male : 4 females. The ultrastructural observations showed some variations in the seminal receptacle wall over time with respect to reproductive activity while there was no appreciable modification as regards the spermatozoa present in the organ, the number of which progressively decreased during the period of reproductive activity.

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“…A small number of polychaetes produce ent-aquasperm, such as Micromaldane spp. [40], Spirorbis morchi [41], Spirorbis spirorbis [42] and Tomopteris helgolandica [43]; however, the structure of their testes has not been studied at present. Therefore, in light of the given information, the complex testes in polychaetes could be possibly related to the production of introsperm and the adoption of internal fertilisation strategy.…”

Section: Discussionmentioning

confidence: 99%

Detailed analysis of the male reproductive system in a potential bio-indicator species – The marine invertebrate Galeolaria caespitosa (Polychaeta: Serpulidae)

Aitken

Lin

2017

PLoS ONE

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For the first time, this study has systemically investigated the male reproductive system in a sessile broadcast-spawning marine invertebrate, Galeolaria caespitosa (Polychaeta: Serpulidae), which has significant potential as a bio-indicator species of coastal marine pollution. The abdomen of G. caespitosa was divided by intersegmental septa into over 80 trunk segments. Each segment served as a germinal chamber with a C-shaped gonadal arrangement consisting of several distinct compartments: a seminiferous epithelium (SE) compartment located in the centre of the chamber, with each of its two ends connecting to a nurse cell (NC) compartment and then an efferent duct (ED) compartment. The SE compartment contained a multilayered seminiferous epithelium where spermatogenesis was initiated. Spermatids were released in pairs into the lumen of the SE compartment and then transported to the NC compartment where they underwent spermiogenesis with the support of secretory vesicles released by the nurse cells. Spermatozoa were stored in the ED compartment and subsequently released into the seawater through the vas deferens. Unlike vertebrates where germ cells differentiated in close proximity to the nurse cell population (i.e. Sertoli cells), the spermatogenic cells of G. caespitosa exhibited no direct contact with supporting cells at any spermatogenic stage. This finding suggested that the spermatogenesis in G. caespitosa was more dependent on intrinsic developmental programming than most species. Notwithstanding such differences, there were clear parallels between the male reproductive system of G. caespitosa and mammals, in terms of the structure and function. The independence of spermatogenic cells from supporting cells in G. caespitosa raised the possibility of inducing spermiogenesis in vitro, which would provide a useful tool to dissect the mechanisms underlying this complex cell differentiation process in invertebrates and other higher order animals.

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A description of the spermatheca ofSpirorbis spirorbis(L.) (Polychaeta: Serpulidae) and evidence for a novel mode of sperm transmission

Cited by 50 publications

References 17 publications

Differential Responses of Calcifying and Non-Calcifying Epibionts of a Brown Macroalga to Present-Day and Future Upwelling pCO2

Differential Responses of Calcifying and Non-Calcifying Epibionts of a Brown Macroalga to Present-Day and Future Upwelling pCO2

Ultrastructure of seminal receptacle and sperm storage inArmadillidium granulatumBrandt (Isopoda: Oniscidea)

Detailed analysis of the male reproductive system in a potential bio-indicator species – The marine invertebrate Galeolaria caespitosa (Polychaeta: Serpulidae)

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