Selfing in Parvulastra exigua: an asterinid sea star with benthic development

Abstract

Parvulastra exigua, a species that lacks a dis-

Very fine-scale population genetic structure of sympatric asterinid sea stars with benthic and pelagic larvae: influence of mating system and dispersal potential

“…Many invertebrates with benthic development are simultaneous hermaphrodites with the potential for self‐fertilization and self‐seeding of populations (e.g. Amphipholis squamata : Sponer & Roy, ; Parvulastra exigua : Barbosa et al ., ). Given that isolated individuals can give rise to progeny and so have the potential to establish new populations (Sponer & Roy, ; Barbosa et al ., ), founder effects and inbreeding may also contribute to genetic structure (Avise, ; Yund & O'Neil, ).…”

“…Amphipholis squamata : Sponer & Roy, ; Parvulastra exigua : Barbosa et al ., ). Given that isolated individuals can give rise to progeny and so have the potential to establish new populations (Sponer & Roy, ; Barbosa et al ., ), founder effects and inbreeding may also contribute to genetic structure (Avise, ; Yund & O'Neil, ). Studies of the population genetic structure of sexually reproducing species that lack a dispersal stage frequently report significant genetic structure at fine spatial scales, from metres to < 10 km (Johannesson, ; Kyle & Boulding, ; Goldson, Hughes & Gliddon, ; Sokolova & Boulding, ; Grahame, Wilding & Butlin, ; Panova, Hollander & Johannesson, ).…”

“…In eastern Australia, P. exigua and M. calcar co‐occur within metres on the same rock platforms, and sometimes even in the same tide pool. Parvulastra exigua , an egg‐laying species with a benthic larva (Byrne, ; Barbosa et al ., ) is one of the world's most widespread sea stars occurring from southern Australia to South Africa (Dartnall, ; Dartnall et al ., ; Waters & Roy, ; Hart et al ., ). Populations in Australia and South Africa are taxonomically consistent with P. exigua (Dartnall et al ., ).…”

“…The extensive distribution of P. exigua in the absence of a pelagic phase has been the focus of several studies of population genetic structure in this species across large spatial scales (approximately 100–1000 km+) spanning oceanic (Waters & Roy, ; Hart et al ., ), regional (Colgan et al ., ; Sherman et al ., ; Ayre et al ., ), and intra‐regional distances (Hunt, ; Ayre et al ., ). Given its unusual life‐history traits, mixed mating system (selfing + outcrossing), pseudocopulation among closely‐related conspecifics (inbreeding), and an entirely benthic life cycle with a philopatric larva (Barbosa et al ., ), we hypothesized that P. exigua exhibits genetic structure at the spatial scale of tide pools (< 300 m apart) and of adjacent headlands (5–15 km apart). A recent study of the tide pool and headland populations investigated in the present study shows that individual P. exigua can give rise to juveniles in isolation, indicating the potential to self‐seed populations, although this selfing ability varied among populations (Barbosa et al ., ).…”

“…Given its unusual life‐history traits, mixed mating system (selfing + outcrossing), pseudocopulation among closely‐related conspecifics (inbreeding), and an entirely benthic life cycle with a philopatric larva (Barbosa et al ., ), we hypothesized that P. exigua exhibits genetic structure at the spatial scale of tide pools (< 300 m apart) and of adjacent headlands (5–15 km apart). A recent study of the tide pool and headland populations investigated in the present study shows that individual P. exigua can give rise to juveniles in isolation, indicating the potential to self‐seed populations, although this selfing ability varied among populations (Barbosa et al ., ).…”