Use of Faecal Testosterone Concentrations to Monitor Male Florida Manatee (&lt;I&gt;Trichechus manatus latirostris&lt;/I&gt;) Reproductive Status

Larkin, Iskande L.V.; Gross, Timothy S.; Reep, Roger L.

doi:10.1578/am.31.1.2005.52

Cited by 17 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is possible that such individuals are in a state of long-term or even permanent cessation of reproductive activity; it is also possible, even likely, that adult manatees enter periods of greater or lesser spermatogenic activity and fertility associated with intensive bouts of promiscuous breeding behaviour and sperm competition. Similarly, Larkin et al (2005) used a radioimmunoassay kit to assess testosterone levels in captive and some free-ranging manatees; these authors independently confirmed the relationship of hormone levels and season. Interestingly, there was some overlap in testosterone levels of adult male and female manatees sampled.…”

Section: Discussionmentioning

confidence: 90%

“…The effect of seasonality on reproductive activity or capacity of male manatees was explored based upon observations of reduced mating behaviour (O'Shea & Hartley 1995, Rathbun et al 1995, reduced spermatogenesis (Hernandez et al 1995), smaller testicular mass (Reynolds et al 2004) and lower faecal testosterone concentrations (Larkin et al 2005) in adult males during winter months.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Secretion of anti-Müllerian hormone in the Florida manatee Trichechus manatus latirostris, with implications for assessing conservation status

Wilson¹,

Reynolds

Wetzel³

et al. 2011

Endang. Species. Res.

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Secretion of anti-Müllerian hormone in the Florida manatee Trichechus manatus latirostris, with implications for assessing conservation status

Wilson¹,

Reynolds

Wetzel³

et al. 2011

Endang. Species. Res.

View full text Add to dashboard Cite

“…Changes in testicular histology were also observed by Hernandez et al (1995) in wild Florida manatees during the winter season when compared with non-winter seasons. However, Larkin et al (2005), evaluating faecal androgens from captive Florida manatees, observed some hormonal differences between months, but those authors did not find a clear seasonal pattern. Therefore, future studies regarding the salivary testosterone pattern during all months of the year, the alteration in testicular morphology between seasons, and the hormonal variations between captive and wild populations are necessary to confirm the absence of reproductive seasonality in male Amazonian manatees.…”

Section: Table 2 Probability Values For the Main Effects Of Year (Fimentioning

confidence: 94%

Seasonal variation in urinary and salivary reproductive hormone levels in Amazonian manatees (Trichechus inunguis)

Amaral

Rosas

Silva

et al. 2015

Reprod. Fertil. Dev.

View full text Add to dashboard Cite

The Amazonian manatee (Trichechus inunguis) is a threatened aquatic mammal endemic to the Amazon basin. The aim of this study was to evaluate the urinary and salivary reproductive hormone levels of captive Amazonian manatees collected during two seasons of the year. Salivary samples from four males and urinary and salivary samples from three females were collected during two seasons (March-June and September-November) over two consecutive years. Salivary testosterone in males was measured by radioimmunoassay and reproductive hormones in females (salivary progesterone and oestradiol and urinary progestogens, oestrogens and luteinising hormone) were measured by enzyme immunoassay. The data were analysed in a 2×2 factorial design, where the factors were year and season. There was no effect of year or season for salivary testosterone. All female hormones showed a seasonal effect (higher hormone levels during March-June than September-November) or an interaction between year and season (P<0.05). These results strongly indicate the existence of reproductive seasonality in Amazonian manatees; however, apparently only females exhibit reproductive quiescence during the non-breeding season. Further long-term studies are necessary to elucidate which environmental parameters are related to reproductive seasonality in T. inunguis and how this species responds physiologically to those stimuli.

show abstract

“…For another sirenian species, the physiological relevance of using fecal samples to measure testosterone levels was demonstrated by showing that the injection of exogenous GnRH to adult male Amazonian manatees (Trichechus inunguis) led to significant increases in excreted androgen concentrations (Amaral et al 2009). Fecal testosterone concentrations have also been used to gain information on reproductive patterns in male Florida manatees (Trichechus manatus latirostris) in captive facilities and in the wild, confirming seasonal and gender variation in androgen production (Larkin et al 2005). In dugongs, Lanyon et al (2005) conducted a preliminary study to examine testosterone concentrations in fecal samples from seven male and three female wild dugongs.…”

Section: Introductionmentioning

confidence: 92%

Testosterone and tusks: maturation and seasonal reproductive patterns of live, free-ranging male dugongs (Dugong dugon) in a subtropical population

Burgess

Lanyon²,

Keeley³

2012

Reproduction

View full text Add to dashboard Cite

Knowledge of male reproductive status and activity in free-ranging animals is vital to understanding reproductive patterns and population dynamics. Until now, almost all information regarding reproductive behavior of the dugong, a cryptic marine mammal, has relied on post-mortem examination. We examined the relationships between body length, tusk eruption (secondary sexual characteristic), seasonality, and group association on fecal testosterone metabolite concentrations in 322 free-ranging dugongs (159 males, 163 females) in subtropical Moreton Bay, Australia. Fecal testosterone concentrations demonstrated biologically meaningful differences in testicular activity between sexes and across reproductive/age classes, and were correlated with circulating concentrations in serum. Male dugongs have a pre-reproductive period that persists until a body length of 240 cm is achieved. Puberty apparently occurs between 240 and 260 cm body length when fecal testosterone levels increase fourfold (O500 ng/g) over juvenile levels, and is associated with tusk eruption. However, social maturity may be delayed until male dugongs are larger than 260 cm with well-developed tusks. In mature males, the lowest (!500 ng/g) fecal testosterone concentrations occur in the austral autumn months with maximal concentrations in September-October, coincident with the onset of a spring mating season. During spring, solitary mature males had fecal testosterone concentrations double those of mature males sampled within groups, potentially suggesting a mating strategy involving roving of reproductively active males. This study demonstrates that single-point physiological data from individuals across a population have value as indicators of reproductive processes. Our approach provides an efficacious non-lethal method for the census of reproductive status and seasonality in live male dugongs.

show abstract

Use of Faecal Testosterone Concentrations to Monitor Male Florida Manatee (<I>Trichechus manatus latirostris</I>) Reproductive Status

Cited by 17 publications

References 0 publications

Secretion of anti-Müllerian hormone in the Florida manatee Trichechus manatus latirostris, with implications for assessing conservation status

Secretion of anti-Müllerian hormone in the Florida manatee Trichechus manatus latirostris, with implications for assessing conservation status

Seasonal variation in urinary and salivary reproductive hormone levels in Amazonian manatees (Trichechus inunguis)

Testosterone and tusks: maturation and seasonal reproductive patterns of live, free-ranging male dugongs (Dugong dugon) in a subtropical population

Contact Info

Product

Resources

About