Variation in size at sex-change among natural populations of the protandrous hermaphrodite, Crepidula fornicata (Gastropoda, Calyptraeidae)

AbstractThe relationship between growth and sexual maturation is central to understanding the dynamics of animal populations which exhibit indeterminate growth. In sequential hermaphrodites, which undergo post-maturation sex change, the size and age at which sex change occurs directly affects reproductive output and hence population productivity. However, these traits are often labile, and may be strongly influenced by heterogenous growth and mortality rates. We analysed otolith microstructure of a protandrous (i.e., male-to-female) fish (barramundi Lates calcarifer) to examine growth in relation to individual variation in the timing of sex change. Growth trajectories of individuals with contrasting life histories were examined to elucidate the direction and extent to which growth rate influences the size and age individuals change sex. Then, the relationships between growth rate, maturation schedules and asymptotic maximum size were explored to identify potential trade-offs between age at female maturity and growth potential. Rapid growth was strongly associated with decreased age at sex change, but this was not accompanied by a decrease in size at sex change. Individuals that were caught as large females grew faster than those caught as males, suggesting that fast-growing individuals ultimately obtain higher fitness and therefore make a disproportionate contribution to population fecundity. These results indicate that individual-level variation in maturation schedules is not reflective of trade-offs between growth and reproduction. Rather, we suggest that conditions experienced during the juvenile phase are likely to be a key determinant of post-maturation fitness. These findings highlight the vulnerability of sex-changing species to future environmental change and harvest.

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Direct observations of protandrous sex change in the patellid limpet Patella vulgata

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315406012975 ◽

2006 ◽

Vol 86 (1) ◽

pp. 161-162 ◽

Cited By ~ 21

Author(s):

W.J.F. Le Quesne ◽

S.J. Hawkins

Keyword(s):

Sex Change ◽

Spawning Season ◽

Indirect Methods ◽

Patella Vulgata ◽

Direct Observations ◽

Protandrous Hermaphrodite

Direct observations of sex change were made on Patella vulgata, which has long been considered a protandrous hermaphrodite based on indirect methods. Thirty per cent of the male limpets that were marked during the spawning season in 2003 were female when they were re-examined during the spawning season in 2004. This confirms that protandry does occur within the superfamily Patellidae.

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Epigenetics underpins phenotypic plasticity of protandrous sex change in fish

10.22541/au.163352147.73004011/v1 ◽

2021 ◽

Author(s):

Alyssa Budd ◽

Julie Robins ◽

Olivia Whybird ◽

Dean Jerry

Keyword(s):

Phenotypic Plasticity ◽

Epigenetic Modification ◽

Strong Association ◽

Sex Change ◽

Ecological Processes ◽

Sea Temperature ◽

Protandrous Hermaphrodite ◽

Female Specific ◽

Response To Environmental Change ◽

Male To Female

Phenotypic plasticity is an important driver of species resilience. Often mediated by epigenetic changes, phenotypic plasticity enables individual genotypes to express variable phenotypes in response to environmental change. Barramundi (Lates calcarifer) is a protandrous (male-first) sequential hermaphrodite that exhibit plasticity in length-at-sex change between geographic regions. This plasticity is likely to be mediated by changes in DNA methylation (DNAm), a well-studied epigenetic modification. However, region-specific relationships between length, sex and DNAm in sequential hermaphrodites were previously unreported. To investigate these relationships, here we compare DNAm in four conserved vertebrate sex-determining genes in male and female barramundi of differing lengths from three regions of northern Australia. Despite a strong association between increasing length and male-to-female sex change, the data reveal that DNAm becomes more sex-specific (rather than more female-specific) with length. Significant differences in DNAm between males and females of similar lengths suggest that female-specific DNAm arises rapidly during sex change, rather than gradually with growth. The findings also reveal that region-specific differences in length-at-sex change are accompanied by differences in DNAm, and were concurrent with variability in remotely sensed sea temperature and salinity. Together, these findings provide the first in situ evidence for epigenetically and environmentally mediated sex change in a protandrous hermaphrodite, and offer significant insight into the molecular and ecological processes governing the marked and unique plasticity of sex in fish.

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Physical and Chemical Interactions with Conspecifics Mediate Sex Change in a Protandrous Gastropod Crepidula fornicata

Biological Bulletin ◽

10.1086/bblv229n3p276 ◽

2015 ◽

Vol 229 (3) ◽

pp. 276-281 ◽

Cited By ~ 5

Author(s):

Abigail E. Cahill ◽

Alia Rehana Juman ◽

Aaron Pellman-Isaacs ◽

William T. Bruno

Keyword(s):

Sex Change ◽

Chemical Interactions ◽

Crepidula Fornicata ◽

Physical And Chemical

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High-voltage electron microscopy of maxillary gland of spirochete-infected brine shrimp: lesion of efferent tubule

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103875 ◽

1988 ◽

Vol 46 ◽

pp. 362-363

Author(s):

G. E. Tyson ◽

M. J. Song

Keyword(s):

Electron Microscopy ◽

High Voltage ◽

Brine Shrimp ◽

Natural Populations ◽

Three Dimensional ◽

Dimensional Structure ◽

High Voltage Electron Microscopy ◽

Voltage Electron ◽

High Voltage Electron ◽

Infected Adult

Natural populations of the brine shrimp, Artemia, may possess spirochete- infected animals in low numbers. The ultrastructure of Artemia's spirochete has been described by conventional transmission electron microscopy. In infected shrimp, spirochetal cells were abundant in the blood and also occurred intra- and extracellularly in the three organs examined, i.e. the maxillary gland (segmental excretory organ), the integument, and certain muscles The efferent-tubule region of the maxillary gland possessed a distinctive lesion comprised of a group of spirochetes, together with numerous small vesicles, situated in a cave-like indentation of the base of the tubule epithelium. in some instances the basal lamina at a lesion site was clearly discontinuous. High-voltage electron microscopy has now been used to study lesions of the efferent tubule, with the aim of understanding better their three-dimensional structure.Tissue from one maxillary gland of an infected, adult, female brine shrimp was used for HVEM study.

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Effect of acid deposition on trichome morphology and dogwood anthracnose biology

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124604 ◽

1992 ◽

Vol 50 (1) ◽

pp. 840-841

Author(s):

Kyle T. Thornham ◽

R. Jay Stipes ◽

Randolph L. Grayson

Keyword(s):

Acid Deposition ◽

Disease Incidence ◽

Natural Populations ◽

Tree Disease ◽

Flowering Dogwood ◽

Discula Destructiva ◽

Disease Induction ◽

Dogwood Anthracnose ◽

Trichome Morphology ◽

Precipitation Events

Dogwood anthracnose, caused by Discula destructiva (1), is another new catastrophic tree disease that has ravaged natural populations of the flowering dogwood (Cornus florida) in the Appalachians over the past 15 years, and the epidemic is prognosticated to continue (2). An estimated 9.5 million acres have been affected, primarily in the Appalachian Mountains, from VA southwards, alone, and an estimated 50% of all dogwoods in PA have been killed. Since acid deposition has been linked experimentally with disease induction, and since the disease incidence and severity are more pronounced at higher elevations where lower pH precipitation events occur, we investigated the effect of acidic foliar sprays on moiphologic changes in the foliar cuticle and trichomes (3), the initial sites of infection and foci of Discula sporulation.

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