First use of a non-invasive technique for determination of sex hormones in the queen conch Lobatus gigas, Mollusca Gastropoda

Sánchez, Fabiola Chong; Díaz, Martha Enriquez; Rodríguez, Eric Murillo; Aranda, Dalila Aldana

doi:10.1007/s10499-018-0336-1

Cited by 8 publications

(7 citation statements)

References 45 publications

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“…In marine species, including mollusks, environmental triggers including rapid changes in water temperature or the detection of conspecific gametes in the water are often implicated in the initiation of gametogenesis and reproductive activities [ 72 ]. For queen conch, multiple studies have identified increasing water temperature and photoperiod as the stimulus for reproductive migrations and the subsequent initiation of mating [ 5 , 11 ], and recent evidence has verified the presence of sex hormones in conch feces [ 73 ]. Concentrations of estrogen, progesterone, and testosterone increase in conjunction with each phase of the conch reproductive season, indicating that these hormones are linked to the reproductive process [ 73 ].…”

Section: Discussionmentioning

confidence: 99%

Limiting factors for queen conch (Lobatus gigas) reproduction: A simulation-based evaluation

Farmer

Doerr

2022

PLoS ONE

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Queen conch are among the most economically, socially, and culturally important fishery resources in the Caribbean. Despite a multitude of fisheries management measures enacted across the region, populations are depleted and failing to recover. It is believed that queen conch are highly susceptible to depensatory processes, impacting reproductive success and contributing to the lack of recovery. We developed a model of reproductive dynamics to evaluate how variations in biological factors such as population density, movement speeds, rest periods between mating events, scent tracking, visual perception of conspecifics, sexual facilitation, and barriers to movement affect reproductive success and overall reproductive output. We compared simulation results to empirical observations of mating and spawning frequencies from conch populations in the central Bahamas and Florida Keys. Our results confirm that low probability of mate finding associated with decreased population density is the primary driver behind observed breeding behavior in the field, but is insufficient to explain observed trends. Specifically, sexual facilitation coupled with differences in movement speeds and ability to perceive conspecifics may explain the observed lack of mating at low densities and differences between mating frequencies in the central Bahamas and Florida Keys, respectively. Our simulations suggest that effective management strategies for queen conch should aim to protect high-density reproductive aggregations and critical breeding habitats.

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Section: Discussionmentioning

confidence: 99%

Limiting factors for queen conch (Lobatus gigas) reproduction: A simulation-based evaluation

Farmer

Doerr

2022

PLoS ONE

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“…For queen conch, multiple studies have identified increasing water temperature and photoperiod as the stimulus for reproductive migrations and the subsequent initiation of mating [5,11], and recent evidence has verified the presence of sex hormones in conch feces [74]. Concentrations of estrogen, progesterone, and testosterone increased in conjunction with each phase of the conch reproductive season, indicating that these hormones are linked to the reproductive process [74]. Active hormone detection by conspecifics would positively influence encounter rates of low-density populations and could explain our model outcomes for scent-tracking simulations where mating success increased at lower densities.…”

Section: Discussionmentioning

confidence: 99%

“…In marine species, including mollusks, environmental triggers including rapid changes in water temperature or the detection of conspecific gametes in the water are often implicated in the initiation of gametogenesis and reproductive activities [73]. For queen conch, multiple studies have identified increasing water temperature and photoperiod as the stimulus for reproductive migrations and the subsequent initiation of mating [5,11], and recent evidence has verified the presence of sex hormones in conch feces [74]. Concentrations of estrogen, progesterone, and testosterone increased in conjunction with each phase of the conch reproductive season, indicating that these hormones are linked to the reproductive process [74].…”

Section: Discussionmentioning

confidence: 99%

Limiting factors for queen conch (Lobatus gigas) reproduction: A simulation-based evaluation

Farmer

Doerr

2021

Preprint

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Queen conch are among the most economically, socially, and culturally important fishery resources in the Caribbean. Despite a multitude of fisheries management measures enacted across the region, populations are depleted and failing to recover. It is believed that queen conch are highly susceptible to depensatory processes, impacting reproductive success and contributing to the lack of recovery. We developed a model of reproductive dynamics to evaluate how variations in biological factors such as population density, movement speeds, movement restrictions, rest periods between mating events, sexual facilitation, and perception of conspecifics affect reproductive success and overall reproductive output. We compared simulation results to empirical observations of mating and spawning frequencies from conch populations in the central Bahamas and Florida Keys. Our results confirm that low probability of mate finding associated with decreased population density is the primary driver behind observed breeding behavior in the field, although additional factors also play important roles. In particular, sexual facilitation and perception of conspecifics may explain observed lack of mating at low densities and differences between mating frequencies in the central Bahamas and Florida Keys, respectively. Our simulations suggest densities greater than 200 adults/ha are needed for high levels of spawning output, supporting the suggestion that effective management strategies for queen conch should aim to protect high-density reproductive aggregations and critical breeding habitats.

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“…However, when making comparisons between phyla, this widely-held view could lead to incorrect assumptions about an organism’s biology. One prime example of this is the view that molluscs use vertebrate sex steroids, such as testosterone, in their reproductive endocrinology 2–6 . Currently this is an area of controversy, with some researchers measuring vertebrate sex-steroids in molluscan tissues and equating these values to de novo synthesis and a physiological role 7–12 .…”

Section: Introductionmentioning

confidence: 99%

Early embryonic exposure of freshwater gastropods to pharmaceutical 5-alpha-reductase inhibitors results in a surprising open-coiled “banana-shaped” shell

Baynes

Pino

Duong

et al. 2019

Sci Rep

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In vertebrates, the steroidogenesis enzyme 5α-reductase converts testosterone to the more potent androgen 5α-dihydrotestosterone. Homologues of 5α-reductase genes have been identified in molluscs. However, recent findings suggest that vertebrate-type steroid androgens are not utilised in molluscan reproductive development. Genomic searches have revealed that molluscs do not possess many of the steroidogenic enzymes required to make testosterone, nor a nuclear androgen receptor. Consequently, the role of 5α-reductase in molluscs presents a mystery. Here, developmental exposures of Biomphalaria glabrata to selective pharmaceutical 5α-reductase inhibitors elicited a strong, highly reproducible phenotypic response characterised by the development of elongated “banana-shaped” shell morphology. In comparison to untreated snails, the shells are open-coiled and the whorls are unattached. Dutasteride (5α-reductase inhibitor) is approximately 10-times more potent at provoking the banana-shaped shell phenotype than finasteride, paralleling the pharmaceuticals’ efficacy in humans. Other enzyme inhibitors with different modes of action were tested to investigate the specificity of the phenotype. However, only the pharmaceutical 5α-reductase inhibitors provoked the response. Dutasteride elicited the same phenotype in a second gastropod, Physella acuta. In the absence of evidence for de novo androgen steroidogenesis in molluscs, these findings suggest that novel substrates for 5α-reductase exist in gastropods, lending support to the contention that molluscan endocrinology differs from the well-characterised vertebrate endocrine system.

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First use of a non-invasive technique for determination of sex hormones in the queen conch Lobatus gigas, Mollusca Gastropoda

Cited by 8 publications

References 45 publications

Limiting factors for queen conch (Lobatus gigas) reproduction: A simulation-based evaluation

Limiting factors for queen conch (Lobatus gigas) reproduction: A simulation-based evaluation

Limiting factors for queen conch (Lobatus gigas) reproduction: A simulation-based evaluation

Early embryonic exposure of freshwater gastropods to pharmaceutical 5-alpha-reductase inhibitors results in a surprising open-coiled “banana-shaped” shell

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