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Weeks, Stephen C.; Marcus, Vivien; Alvarez, Sheila

doi:10.1023/a:1003106702451

Cited by 44 publications

(4 citation statements)

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“…Given this constraint, we nonetheless replicated our comparison of reproductive types (dioecious vs. androdioecious) to disassociate reproductive mode comparisons from species differences. We compared two dioecious species Encysted eggs of all four species were hatched from previously collected field soil samples (Table 1) lights and had an air-stone to provide aeration (Weeks, Marcus, & Alvarez, 1997). Once per day the tanks were fed a portion of food mixture made with a 0.5 g brewer's yeast and 0.5 g of ground algae fish food flakes dissolved in 100 ml of water.…”

Section: General Methodsmentioning

confidence: 99%

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Intersexual conflict in androdioecious clam shrimp: Do androdioecious hermaphrodites evolve to avoid mating with males?

Ford

Weeks

2018

Ethology

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A recent sexual conflict model posits that a form of intersexual conflict may explain the persistence of males in androdioecious (males + hermaphrodites) populations of animals that are being selected to transition from dioecious (gonochoristic) mating to self‐compatible hermaphroditism. During the evolutionary spread of a self‐compatible hermaphrodite to replace females, the selective pressures on males to outcross are in conflict with the selective pressures on hermaphrodites to self. According to this model, the unresolved conflict interferes with the evolutionary trajectory from dioecy to hermaphroditism, slowing or halting that transition and strengthening the otherwise “transitory” breeding system of androdioecy into a potentially stable breeding strategy. Herein, we assess this model using two dioecious and two androdioecious clam shrimp (freshwater crustaceans) to ask two questions: (1) Have hermaphrodites evolved so that males cannot effectively recognize them?; and (2) Do androdioecious hermaphrodites avoid males? Androdioecious males made more mistakes than dioecious males when guarding potential mates suggesting that androdioecious males were less effective at finding hermaphrodites than dioecious males were at finding females. Similarly, in a three‐chambered experiment, focal hermaphrodites chose to aggregate with their same sex, whereas focal dioecious males chose to aggregate with the alternate sex. Together, these two experiments support the sexual conflict model of the maintenance of androdioecy and suggest that hermaphrodites are indeed evolving to avoid and evade males.

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Section: General Methodsmentioning

confidence: 99%

“…The clam shrimp were then allowed to sexually mature before being used in the experiments. Shrimp are considered mature once the presence of claspers on males and eggs on hermaphrodites/females were seen (Weeks et al, 1997).…”

Section: General Methodsmentioning

confidence: 99%

Intersexual conflict in androdioecious clam shrimp: Do androdioecious hermaphrodites evolve to avoid mating with males?

Ford

Weeks

2018

Ethology

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“…Table 2). Hermaphrodites have both testes and ovaries, while males have only testes; additionally, hermaphrodites typically store up to several hundred large eggs in their carapace prior to ovipositioning (Weeks, Marcus, and Alvarez 1997).…”

Section: Annotation and Differential Expressionmentioning

confidence: 99%

A new standard for crustacean genomes: the highly contiguous, annotated genome assembly of the clam shrimp Eulimnadia texana reveals HOX gene order and identifies the sex chromosome

Baldwin-Brown

Weeks

Long

2017

Preprint

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Vernal pool clam shrimp (Eulimnadia texana) are a promising model system due to their ease of lab culture, short generation time, modest sized genome, a somewhat rare stable androdioecious sex determination system, and a requirement to reproduce via desiccated diapaused eggs. We generated a highly contiguous genome assembly using 46X of PacBio long read data and 216X of Illumina short reads, and annotated using Illumina RNAseq obtained from adult males or hermaphrodites. 85% of the 120Mb genome is contained in the largest 8 contigs, the smallest of which is 4.6Mb. The assembly contains 98% of transcripts predicted via RNAseq. This assembly is qualitatively different from scaffolded Illumina assemblies: it is produced from long reads that contain sequence data along their entire length, and is thus gap free. The contiguity of the assembly allows us to order the HOX genes within the genome, identifying two loci that contain HOX gene orthologs, and which approximately maintain the order observed in other arthropods. We identified a partial duplication of the Antennapedia gene adjacent to the few genes homologous to the Bithorax locus. Because the sex chromosome of an androdioecious species is of special interest, we used existing allozyme and microsatellite markers to identify the E. texana sex chromosome, and find that it comprises nearly half of the genome of this species. Linkage patterns indicate that recombination is extremely rare and perhaps absent in hermaphrodites, and as a result the location of the sex determining locus will be difficult to refine using recombination mapping.

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“…The presence of growth bands of variable widths in spinicaudatans and their biological (sex, growth rate, life span and senility) and ecological (food resources, environmental stability, permanent or ephemeral pools) controls have been discussed by various authors (Tasch, 1969;Webb, 1979;Frank, 1988). Weeks et al (1997) and Stigall & Hartman (2008) suggested that these variable increments are linked to the onset of the sexual maturity and the transition between rapid juvenile growths to reproductive phase. The species studied here shows two categories of growth band, one in the younger growth stage and the other in the older stage, both with a set of wide to narrow growth bands.…”

Section: Carapacementioning

confidence: 99%

Reassignment of Lioestheria codoensis Cardoso (Spinicaudata, Anthronestheriidae) from the Lower Cretaceous of Brazil: systematics and paleoecology

Gallego¹,

Monferran²,

Astrop³

et al. 2013

Rev. bras. paleontol.

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Lioestheria codoensis Cardoso was described from materials originally collected from the Codó Formation (Lower Cretaceous, Parnaíba Basin, Piauí State), northeastern Brazil. Since its discovery L. codoensis has been assigned to different genera by different authors [as Estheriina (Nudusia) and Cyzicus (Lioestheria)]. In this paper, previous systematic assignments are reviewed and discussed in light of new scanning electron microscopy studies of new material. As a result of this research, the species is assigned to a new genus of the Family Antronestheriidae, and the study integrates palaeontological, biological and ecological approaches to provide a robust description for the species. Previous assignments to other genera (Estheriina, Lioestheria and Cyzicus) are also assessed and comparisons with other related genera of the Family Anthronestheriidae (Pseudestherites, Etmosestheria, Anthronestheria and Paleolepthestheria? chinensis) are made. Detailed stratigraphical (Codó, Santana, Itapecuru, Rio da Batateira and Missão Velha formations) and geographical (seven localities) records are compiled. Finally, the autecology and within-species morphological variation are also addressed.

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Cited by 44 publications

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Intersexual conflict in androdioecious clam shrimp: Do androdioecious hermaphrodites evolve to avoid mating with males?

Intersexual conflict in androdioecious clam shrimp: Do androdioecious hermaphrodites evolve to avoid mating with males?

A new standard for crustacean genomes: the highly contiguous, annotated genome assembly of the clam shrimp Eulimnadia texana reveals HOX gene order and identifies the sex chromosome

Reassignment of Lioestheria codoensis Cardoso (Spinicaudata, Anthronestheriidae) from the Lower Cretaceous of Brazil: systematics and paleoecology

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