The Reproductive Cycle of the Female American Alligator (Alligator mississippiensis)

Lj, Guillette; Ar, Woodward; Da, Crain; Gr, Masson; Bd, Palmer; Cox, Maria Christina; You‐Xiang, Qui; Ef, Orlando

doi:10.1006/gcen.1997.6953

Cited by 100 publications

(85 citation statements)

References 40 publications

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“…First, E2 is the primary hormone responsible for stimulating the liver to produce vitellogenins, or egg-yolk proteins (reviewed in Ho et al, 1982), and increases in E2 are correlated with vitellogenic activity in turtles (Ott et al, 2000), alligators (Guillette et al, 1997), lizards (Edwards and Jones, 2001;Radder et al, 2001;, and snakes (Bonnet et al, 1994;Whittier et al, 1987). Second, in creases in E2 commonly occur during the mating season because E2 can stimulate attractivity or receptivity of female reptiles Whittier and Tokarz, 1992).…”

Section: Discussionmentioning

confidence: 99%

“…Increases in circulating B during the mating period and vitello genesis have been noted in many reptile species (reviewed in Moore and Jessop, 2003;Romero, 2002), and this in crease in B may involve its role in energy mobilization for vitellogenesis (Grassman and Crews, 1990;Wilson and Wingfield, 1992). However, other squamate species show peaks in B during the later stages of gestation (DauphinVillemant et al, 1990;Guillette et al, 1997). In mammals, plasma B is elevated during the late stages of gestation because glucocorticoids are key components of the physiological changes leading to parturition (Gibb and Challis, 2002).…”

Section: Discussionmentioning

confidence: 99%

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Seasonal steroid hormone levels and their relation to reproduction in the Western Diamond-backed Rattlesnake, Crotalus atrox (Serpentes: Viperidae)

Taylor

DeNardo

Jennings

2004

General and Comparative Endocrinology

107

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We report seasonal variation in steroid hormone levels in blood samples from free ranging Western Diamond backed Rattle snakes (Crotalus atrox), and the relationship between these hormones and events in the reproductive cycle. At a field site in the Sonoran Desert of south central Arizona, we collected monthly blood samples over the course of two active seasons from 17 ra diotelemetered females, and over three active seasons from 103 randomly encountered males. We used radioimmunoassay to measure plasma levels of 17b estradiol, progesterone, corticosterone, and testosterone in samples from females, and corticosterone and testosterone in samples from males. Non reproductive females have consistently low levels of circulating 17b estradiol, pro gesterone, and testosterone throughout the year. In reproductive females, 17b estradiol levels increase dramatically and testosterone levels increase modestly during vitellogenesis in April and May, while progesterone levels increase dramatically at ovulation in June and then steadily decline until parturition in August. Corticosterone levels appear relatively constant in non reproductive females, whereas reproductive females show increased levels at the end of gestation. Plasma testosterone levels in males are low in early summer and are elevated during spring and late summer, corresponding to the two mating periods of C. atrox. Plasma cortico sterone levels in males did not vary seasonally and were not related to testosterone levels.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Seasonal steroid hormone levels and their relation to reproduction in the Western Diamond-backed Rattlesnake, Crotalus atrox (Serpentes: Viperidae)

Taylor

DeNardo

Jennings

2004

General and Comparative Endocrinology

107

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“…A great deal has been learned about the reproductive biology of the American alligator (Alligator mississippiensis) in recent decades, fueled in part by increased research efforts following precipitous population declines in the 1960s (Groombridge 1987, Joanen & McNease 1989, Guillette et al 1997, Lance et al 2009). While the majority of American alligators reside in freshwater and have been the focus of much of this research, comparatively little data are available detailing the geographical variation that exists in the reproductive endocrinology of adult alligators, especially of alligator populations living in barrier island locales.…”

Section: Introductionmentioning

confidence: 99%

“…Studies on adult female alligators carried out in Florida lakes, as well as those carried out near coastal Louisiana, show that courtship and breeding take place in April and May, coincident with elevated concentrations of plasma 17b-estradiol (E 2 ) and testosterone and to a lessor extent progesterone (P 4 ) (Lance 1989, Guillette et al 1997, Lance et al 2009). Eggs are laid in June, which aligns with a rapid decline in plasma E 2 and testosterone and an elevation in plasma P 4 concentration.…”

Section: Introductionmentioning

confidence: 99%

The reproductive hormone cycle of adult female American alligators from a barrier island population

Hamlin

Lowers²,

Kohno

et al. 2014

Reproduction

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Comparatively, little data are available detailing the geographic variation that exists in the reproductive endocrinology of adult alligators, especially those living in barrier islands. The Merritt Island National Wildlife Refuge (MI) is a unique barrier island environment and home to the Kennedy Space Center (FL, USA). Seasonal patterns of sex steroids were assessed in adult female American alligators from MI monthly from 2008 to 2009, with additional samples collected at more random intervals in 2006, 2007, and 2010. Plasma 17b-estradiol and vitellogenin concentrations peaked in April, coincident with courtship and mating, and showed patterns similar to those observed in adult female alligators in other regions. Plasma concentrations of progesterone, however, showed patterns distinctly different than those reported for alligator populations in other regions and remained relatively constant throughout the year. Plasma DHEA peaked in July around the time of oviposition, decreased in August, and then remained constant for the remaining months, except for a moderate increase in October. Circulating concentrations of DHEA have not been previously assessed in a female crocodilian, and plasma concentrations coincident with reproductive activity suggest a reproductive and/or behavioral role. Interestingly, plasma testosterone concentrations peaked in May of 2008, as has been shown in female alligator populations in other regions, but showed no peak in 2009, demonstrating dramatic variability from year to year. Surveys showed 2009 to be particularly depauperate of alligator nests in MI, and it is possible that testosterone could serve as a strong indicator of breeding success.

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“…Assim, dos trabalhos publicados sobre o tema, alguns se referem a populações em cativeiro, ou a umas poucas espécies de crocodilianos, como Crocodilus porosus, Crocodylus palustris, Alligator mississippiensis, Caiman yacare e Caiman latirostris (FOGGIN, 1987;MILLAN et al, 1997;GUILLETTE et al, 1997;WHITAKER, 2000;MOURA et al, 1999;ZAYAS et al, 2011). Isto faz a interpretação dos resultados mais desafiadora, principalmente no caso do jacaré-de-papo-amarelo (Caiman latirostris), porque poucos estudos prévios têm sido realizados no estabelecimento das taxas normais dos valores hematológicos e bioquímicos do sangue dessa espécie, e mesmo assim, consideráveis discrepâncias têm sido observadas nestes experimentos.…”

Section: Introductionunclassified

Estado sanitário do jacaré-de-papo-amarelo (<i>Caiman latirostris</i>) em paisagens antropizadas no Estado de São Paulo

Basset¹

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The Reproductive Cycle of the Female American Alligator (Alligator mississippiensis)

Cited by 100 publications

References 40 publications

Seasonal steroid hormone levels and their relation to reproduction in the Western Diamond-backed Rattlesnake, Crotalus atrox (Serpentes: Viperidae)

Seasonal steroid hormone levels and their relation to reproduction in the Western Diamond-backed Rattlesnake, Crotalus atrox (Serpentes: Viperidae)

The reproductive hormone cycle of adult female American alligators from a barrier island population

Estado sanitário do jacaré-de-papo-amarelo (<i>Caiman latirostris</i>) em paisagens antropizadas no Estado de São Paulo

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