Sex Change by a Polychaete: Effects of Social and Reproductive Costs

Ecology ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 837-845 ◽  
Author(s):  
Anders Berglund
Keyword(s):  
Sex Change ◽  
Reproductive Costs

scholarly journals The earliest example of sexual dimorphism in bivalves—evidence from the astartid Nicaniella (Lower Jurassic, southern Germany)

2021 ◽  
pp. 1-10
Author(s):  
Baran Karapunar ◽  
Winfried Werner ◽  
Franz T. Fürsich ◽  
Alexander Nützel
Keyword(s):  
Principal Component Analysis ◽  
Life History ◽  
Shape Analysis ◽  
Principal Component ◽  
Sex Change ◽  
Lower Jurassic ◽  
Allocation Of Resources ◽  
Fourier Shape Analysis ◽  
Lower Height ◽  
Male To Female

Abstract Protandrous sex change (sex change from male to female) is one of the diverse sexual expressions exhibited by bivalves, but its expression in the shell is quite rare. Previous studies on living and fossil astartids suggest a relationship between protandrous sex change and the formation of crenulations on the ventral shell margin at later ontogenetic stages. Here we report the formation of such crenulations in the Early Jurassic astartid Nicaniella rakoveci (Kuhn, 1935) from the Amaltheenton Formation at Buttenheim, Franconia. This is the earliest known record of protandrous hermaphroditism in fossil bivalves, predating previous reports by at least 13 Myr. A principal component analysis of linear size measurements and Fourier shape analysis of the shell outlines revealed that the outline of Nicaniella rakoveci specimens varies from subquadrate to subcircular, but this variation is independent of the presence or absence of crenulations and therefore not associated with sex. Crenulated specimens exhibit a lower height/inflation ratio than non-crenulated ones, suggesting that the protandrous females have more inflated valves than the males. The formation of crenulations was probably related to allocation of resources for reproduction. The most likely function of the crenulations was to increase the internal shell volume in the female stage to accommodate more eggs rather than being an adaptation against predation as often assumed for other bivalves. The formation of crenulations is part of the protandrous life history and probably is controlled by a genetic mechanism that is also responsible for sex change.

Gonopore development and sex change in the Antarctic shrimp Chorismus antarcticus (Caridea: Hippolytidae)

Polar Biology ◽  
1997 ◽  
Vol 17 (4) ◽  
pp. 384-388 ◽  
Author(s):  
Piero Mascetti ◽  
Rodrigo Fernandez de la Reguera ◽  
Luis Albornoz ◽  
Silvia Oyarzún ◽  
Matthias Gorny ◽  
...  
Keyword(s):  
Sex Change ◽  
The Antarctic

scholarly journals Epigenetic Modifications During Sex Change Repress Gonadotropin Stimulation of Cyp19a1a in a Teleost Ricefield Eel (Monopterus albus)

Endocrinology ◽  
2013 ◽  
Vol 154 (8) ◽  
pp. 2881-2890 ◽  
Author(s):  
Yang Zhang ◽  
Shen Zhang ◽  
Zhixin Liu ◽  
Lihong Zhang ◽  
Weimin Zhang
Keyword(s):  
Dna Methylation ◽  
Binding Protein ◽  
Sex Change ◽  
Gonadal Development ◽  
Proximal Region ◽  
Histone Deacetylation ◽  
Epigenetic Mechanisms ◽  
Gonadal Differentiation ◽  
Stimulation Of

Abstract In vertebrates, cytochrome P450 aromatase, encoded by cyp19a1, converts androgens to estrogens and plays important roles in gonadal differentiation and development. The present study examines whether epigenetic mechanisms are involved in cyp19a1a expression and subsequent gonadal development in the hermaphroditic ricefield eel. The expression of the ricefield eel cyp19a1a was stimulated by gonadotropin via the cAMP pathway in the ovary but not the ovotestis or testis. The CpG within the cAMP response element (CRE) of the cyp19a1a promoter was hypermethylated in the ovotestis and testis compared with the ovary. The methylation levels of CpG sites around CRE in the distal region (region II) and around steroidogenic factor 1/adrenal 4 binding protein sites and TATA box in the proximal region (region I) were inversely correlated with cyp19a1a expression during the natural sex change from female to male. In vitro DNA methylation decreased the basal and forskolin-induced activities of cyp19a1a promoter. Chromatin immunoprecipitation assays indicated that histone 3 (Lys9) in both regions I and II of the cyp19a1a promoter were deacetylated and trimethylated in the testis, and in contrast to the ovary, phosphorylated CRE-binding protein failed to bind to these regions. Lastly, the DNA methylation inhibitor 5-aza-2′-deoxycytidine reversed the natural sex change of ricefield eels. These results suggested that epigenetic mechanisms involving DNA methylation and histone deacetylation and methylation may abrogate the stimulation of cyp19a1a by gonadotropins in a male-specific fashion. This may be a mechanism widely used to drive natural sex change in teleosts as well as gonadal differentiation in other vertebrates.

scholarly journals Variation in plumage response of brown leghorn capons to oestrone I-intramnuscular injection

1935 ◽  
Vol 118 (807) ◽  
pp. 97-122 ◽  
Keyword(s):  
Environmental Factor ◽  
Sex Change ◽  
Similar Response ◽  
Definite Manner

During a study on the ability of certain synthetic oestrus-producing compounds to induce a sex change in the feather pigmentation of the Brown Leghorn capon (Cook, Dodds, and Greenwood, 1934) it was noted that injections of the same preparation at varying times did not always cause a similar response in the feathers. That such irregular feather responses may be obtained limits the usefulness of the capon test, it was therefore necessary that more should be known of the reaction and an attempt made to determine some, at least, of the factors causing the variation in response. An analysis of our previously collected data on the action of oestrone confirmed the opinion of Lillie and Juhn (1932) that the reactivity of the feathers of test animals varied considerably, but there was no evidence to show whether variable responses to the same stimulus occurred in one and the same individual or, if this were so, whether the changes behaved in a definite manner correlated with a varying environmental factor, such as season for example.

Riverine characteristics and adult demography influence female lake sturgeon (Acipenser fulvescens) spawning behavior, reproductive success, and ovarian quality

2019 ◽  
Vol 76 (7) ◽  
pp. 1147-1160 ◽  
Author(s):  
Kari J. Dammerman ◽  
Molly A.H. Webb ◽  
Kim T. Scribner
Keyword(s):  
Reproductive Success ◽  
Behavioral Plasticity ◽  
Lake Sturgeon ◽  
Operational Sex Ratio ◽  
Plasma Testosterone ◽  
Acipenser Fulvescens ◽  
Reproductive Costs ◽  
Arrival Date ◽  
Factors Influencing ◽  
Yearly Means

Abiotic conditions and demographic factors can influence the timing of spawning. Behavioral plasticity allows females to select spawning conditions that are conducive to offspring development; however, reproductive costs associated with delaying spawning are not well understood. In this study, factors influencing timing of female spawning, residence time (RT), and reproductive success (RS) during two seasons were determined, and plasma testosterone concentrations were used to quantify atretic rates in a wild, lake sturgeon (Acipenser fulvescens) population. For the 123 females monitored, RT ranged from 1 to 23 days and was influenced by arrival date, temperature, discharge, and male number, with the latter having the largest influence. RS varied due to arrival date, temperature, discharge, male number, male length, and operational sex ratio. Two females had testosterone levels indicative of atresia and RS estimates lower than yearly means; however, most females had normal ovaries, suggesting little reproductive costs of plasticity in spawning ground residency time. Results demonstrate the multitude of factors influencing female reproductive behavior and RS, highlighting the importance of abiotic and demographic conditions to recruitment in wild populations.

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