Reproduction and development in the pycnogonid Pycnogonum littorale

Jarvis, J. H.; King, P. E.

doi:10.1007/bf00366565

Cited by 43 publications

(33 citation statements)

References 13 publications

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“…Behavioural observations of a morphologically similar congener ( Jarvis & King 1972) led us to hypothesize that male P. stearnsi, owing to the substantial egg masses they carry, would show limited capacity for multiple mating. However, our genetic appraisals demonstrate unambiguously that males routinely acquire multiple mates by adding additional egg masses to their bodies, even before previous ones have finished developing.…”

Section: Discussionmentioning

confidence: 99%

“…Our study was motivated in part by previous observations on P. litorale, a related species that displays several features suggestive of sex-role reversal owing to limited male brooding space: males are markedly smaller than females (Tomaschko et al 1997)-each male carries one large egg mass that he receives from a single female (Jarvis & King 1972)-and a male does not remate until all the eggs have hatched, which can take up to ten weeks ( Jarvis & King 1972;Tomaschko et al 1997). P. litorale and P. stearnsi have similar morphologies and egg-mass configurations.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative measures of sexual selection reveal no evidence for sex-role reversal in a sea spider with prolonged paternal care

Barreto

Avise

2010

Proc. R. Soc. B.

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Taxa in which males alone invest in postzygotic care of offspring are often considered good models for investigating the proffered relationships between sexual selection and mating systems. In the pycnogonid sea spider Pycnogonum stearnsi, males carry large egg masses on their bodies for several weeks, so this species is a plausible candidate for sex-role reversal (greater intensity of sexual selection on females than on males). Here, we couple a microsatellite-based assessment of the mating system in a natural population with formal quantitative measures of genetic fitness to investigate the direction of sexual selection in P. stearnsi. Both sexes proved to be highly polygamous and showed similar standardized variances in reproductive and mating successes. Moreover, the fertility (number of progeny) of males and females appeared to be equally and highly dependent on mate access, as shown by similar Bateman gradients for the two sexes. The absence of sex-role reversal in this population of P. stearnsi is probably attributable to the fact that males are not limited by brooding space but have evolved an ability to carry large numbers of progeny. Body length was not a good predictor of male mating or reproductive success, so the aim of future studies should be to determine what traits are the targets of sexual selection in this species.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantitative measures of sexual selection reveal no evidence for sex-role reversal in a sea spider with prolonged paternal care

Barreto

Avise

2010

Proc. R. Soc. B.

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“…The formation of electron‐dense bodies within the cisternae and/or vesicles of rER was documented in earlier papers on pycnogonid oogenesis (King & Jarvis 1970; Jarvis & King 1972, 1975, 1978), in which the authors suggested that these bodies represent structures analogous to the “disc‐shaped bodies” described for the first time in the oocytes of the crayfish, Cambarus , Orconectes , and Procambarus spp. (Beams & Kessel 1963).…”

Section: Discussionmentioning

confidence: 82%

Ultrastructural investigations of the ovary and oogenesis in the pycnogonids Cilunculus armatus and Ammothella biunguiculata (Pycnogonida, Ammotheidae)

Miyazaki

Biliński

2006

Invertebrate Biology

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Abstract. Ovarian ultrastructure and oogenesis in two pycnogonid species, Cilunculus armatus and Ammothella biunguiculata, were investigated. The ovary is morphologically and functionally divided into trunk and pedal parts. The former represents the germarium and contains very young germ cells in a pachytene or postpachytene phase, whereas the latter houses developing previtellogenic and vitellogenic oocytes and represents the vitellarium. Intercellular bridges were occasionally found between young (trunk) germ cells. This indicates that in pycnogonids, as in other animal groups, at the onset of oogenesis clusters of germ cells are generated. As nurse cells are absent in the ovaries of investigated species, the clusters must secondarily split into individual oocytes. In the vitellarium, the oocytes are located outside the ovary. Each oocyte is connected to the ovarian tissue by a stalk composed of several somatic cells. The stalk cells directly associated with the oocyte are equipped with irregular projections that reach the oocyte plasma membrane. This observation suggests that the stalk cells may play a nutritive role. The ooplasm of vitellogenic oocytes comprises mitochondria, free ribosomes, stacks of annulate lamellae, active Golgi complexes, and vesicles derived from these complexes. Within the latter, numerous electron‐dense bodies are present. We suggest that these bodies contribute to yolk formation.

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“…Mating was reported to be as brief as a few minutes (Cole, 1901) and as long as 5 weeks in the shallow-water Pycnogonum littorale (Jarvis and King, 1972). Bain (2003) and Bogomolova (2007) indicated that the male pycnogonid generally carries the egg masses on special ovigerous legs and takes care of the offspring.…”

Section: Introductionmentioning

confidence: 98%