Intragonadal incubation of progeny in three viviparous asterinid sea stars that differ in offspring provisioning, lecithotrophy vs matrotrophy

Khan, Md. Mukhlesur Rahman; Whittington, Camilla M.; Thompson, Michael B.; Byrne, Maria

doi:10.1007/s00227-019-3507-3

Cited by 8 publications

(3 citation statements)

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“…Non-invasive imaging techniques such as micro-computed tomography (µ-CT) has been used to observe offspring inside the brood chamber non-destructively in situ in ophiuroids (Landschoff & Griffiths 2015). The asterinid sea star, Parvulastra parvivipara, exhibits a highly derived mode of matrotrophic incubation, sibling cannibalism, and a high level of offspring size variation (Byrne 1996;Khan et al 2019). This species care for its young within the gonads to an advanced juvenile stage that varies in size from 0.5-2.5 mm in diameter (Byrne 1996;Khan et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The asterinid sea star, Parvulastra parvivipara, exhibits a highly derived mode of matrotrophic incubation, sibling cannibalism, and a high level of offspring size variation (Byrne 1996;Khan et al 2019). This species care for its young within the gonads to an advanced juvenile stage that varies in size from 0.5-2.5 mm in diameter (Byrne 1996;Khan et al 2019). Adelphophagy provides significant nourishment for the juveniles, and gonad histology shows that cannibalism may mediate the position of juveniles within the gonads (Byrne 1996).…”

Section: Introductionmentioning

confidence: 99%

“…The extent to which the offspring size varies among and within gonads has not been characterised. Parvulastra parvivipara is a simultaneously hermaphroditic self-fertile species and has young in the gonad year-round with a range of developmental stages from embryo to juvenile (Byrne 1996: Khan et al 2019. The observation that the parents die after releasing all of the juveniles (Keough & Dartnall 1978) requires confirmation.…”

Section: Introductionmentioning

confidence: 99%

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Arrangement and size variation of intra-gonadal offspring in a viviparous asterinid sea star

et al. 2019

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Sibling competition and developmental asynchrony may greatly influence the arrangement and size of offspring of marine invertebrates that care for their young. In Parvulastra parvivipara, an asterinid sea star that incubates its young in the gonads, sibling cannibalism supports post-metamorphic development. Offspring size varies within (coefficient of variation, CV = 22.6 %) and among (CV = 17.7%) the gonads. Confocal microscopy was used to visualize early embryos and oocytes, and revealed the presence of several developmental stages within individual gonads. The eggs were a mean diameter of 84 μm. The observation of a gastrula at 86 µm smaller than the largest egg observed (134 µm) suggests that terminal egg size varies. The appearance of early embryos surrounded by somatic cells suggests that they may receive nutrients through histotrophy. Sibling competition intensifies once the digestive tract is functional in the tiny juveniles which then start to consume siblings. The arrangement of the offspring in the gonads was observed using micro-computed tomography. The juveniles were oriented with their oral surface facing each other, presumably as a defensive strategy to protect themselves from being eaten. Periodic release of offspring in single or several cohorts indicates continual reproduction. Released and retained juveniles varied in size. It is not known what initiates birth but it may be mediated by sibling competition. Larger adults had a greater allocation to female reproductive output than smaller adults.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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