ReviewThe value of comparative approaches to our understanding of puberty as illustrated by investigations in birds and reptiles
Section snippets
Introduction: sexual maturation in birds and reptiles
Puberty refers to the physiological processes by which an individual attains sexual maturity and is thus able to reproduce successfully as an adult. As such, it is a key component of the general process of development. Developmental biology has a long and distinguished history of employing a wide range of species in order to understand the complex sequence of events that underlies how a zygote is transformed into an adult (Wolper and Tickle, 2010). Curiously, although all vertebrate species go
The development of sexual maturity in birds
There are approximately 10,000 extant species of birds present on earth today (Clements, 2007). Nearly 50% of these are members of the order Passeriformes (songbirds; Clements, 2007). Passeriformes typically reach sexual maturity within one year. In temperate zone species this would mean that a nestling hatched in the late spring or summer would either migrate or overwinter and then be capable of breeding the following spring. This sort of pattern or some variant (depending on when breeding
What is the pattern of sexual development in birds that mature within their first year of life?
In seasonally breeding birds, the annual cycle of reproductive and non-reproductive activity can in many species be characterized by understanding how the birds' transition among three different physiological states that are defined based on their responsiveness to seasonal variation in photoperiod (Dawson et al., 2001, Nicholls et al., 1988). Lessons learned from the annual cycle of adults are then applied to thinking about the development of a mature reproductive state in juvenile birds. This
What is the pattern of sexual development in birds that mature in substantially less time than one year?
Some avian species breed in an opportunistic manner (Hahn et al., 2008). Opportunistic in this case, refers to the fact that some critical resources are unpredictable and species that rely on them respond with a rapid increase in reproductive physiological activity when these resources become available. Species exhibiting this pattern for the organization of reproductive activity can be contrasted with seasonally breeding species that generally track highly predictable resources such as the
What is the pattern of sexual development in birds that mature after their first year of life?
In birds that mature after their first year of life the most obvious hypothesis is that they have evolved a life history strategy of delayed maturity. If this is the case they would not breed in their first year because they are just not mature enough. However, several lines of evidence indicate that this is not the case. For example, seabirds such as Albatrosses do take a long time to mature but they still reach their full body size well before they reach sexual maturity. Also, studies of
The development of sexual maturity in reptiles
Like birds, almost 10,000 species of reptiles exist; the vast majority of which are squamates (lizards and snakes). However, the literature on puberty in reptiles is extremely thin. A PubMed search of “reptile and puberty” in November 2012 produced nine articles, three that are actually on human pediatrics. Only six relate to endocrine development in non-mammalian vertebrates (two of these are not in English and therefore may be of limited accessibility). Web of Science provided four
Discussion and conclusions
Birds and reptiles represent two diverse vertebrate taxa that exhibit a range of adaptations in their strategies of reproduction. This diversity has informed the field of reproductive neuroendocrinology about many fascinating questions, including those associated with sexual differentiation and the control of seasonal breeding cycles. However, puberty has received much less attention in these taxa than in mammalian vertebrates. In birds, model species such as starlings have been developed that
Acknowledgments
The authors would like to thank BK Follett and J. Balthazart for discussion and access to unpublished data. GFB's work on seasonal breeding is supported by NINDS (R01 NS 35467). JW's research is supported by NIMH (R01 MH 096705 & R01 MH 055488) and NSF (I0S 0742833).
References (24)
Gamete production, sex hormone secretion, and mating behavior uncoupled
Horm. Behav.
(1984)- et al.
Determinants of puberty in a seasonal breeder
Recent Prog. Horm. Res.
(1986) - et al.
Environmental regulation of annual schedules in opportunistically-breeding songbirds: adaptive specializations or variations on a theme of white-crowned sparrow?
Gen. Comp. Endocrinol.
(2008) Hormonal regulation and ovarian function in reptiles
- et al.
Hormonal regulation of testicular functions in reptiles
- et al.
Functional versus physiological puberty: an analysis of sexual bimaturism in the green iguana, Iguana iguana
Anim. Behav.
(1994) - et al.
Hormones and reproductive cycles in snakes
- et al.
Comparative insights of the kisspeptin/kisspeptin receptor system: lessons from non-mammalian vertebrates
Gen. Comp. Endocrinol.
(2012) - et al.
The genome of Anolis carolinensis, the green anole lizard and comparative analysis with birds and mammals
Nature
(2011) - et al.
Do primary males physiologically suppress subordinate males? An experiment in a cooperatively breeding passerine
Ethology
(2009)
Helping and Communal Breeding in Birds
Clements Checklist of Birds of the World
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Puberty in a Mesozoic reptile
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2017, Hormones and BehaviorCitation Excerpt :However, these studies did not measure testosterone production or other potential down-stream effects as a result of activation of these genes. Much of the functional research into kisspeptin has focused on the neuropeptide's effects on regulating puberty (Ball and Wade, 2013). However, the HPG axis controls a suite of hormones and down-stream effects, such as territorial behavior, that warrant further analysis.
Sex differences and rapid estrogen signaling: A look at songbird audition
2015, Frontiers in NeuroendocrinologyCitation Excerpt :While these organizational effects can be explained in part by long-term genomic actions of estradiol interacting with nuclear estrogen receptors, a more unified view of sexual differentiation proposes that genetic differences attributable to sex chromosome complement interact with hormonal and environmental factors to direct masculine vs. feminine development (Arnold et al., 2004; McCarthy and Arnold, 2011). Previous reviews have considered how organizational effects of testosterone and estradiol direct sexual differentiation during critical periods in mammals (Forger and de Vries, 2010; McCarthy, 2010) as well as birds and lizards (Ball and Wade, 2013; Balthazart et al., 1996). Here, we consider how neuroestrogens may shape auditory processing differently in male vs. female songbirds, which relies on this foundational framework.
Collection, Handling, and Preservation of Wild Bird Semen: Current Status, Challenges, and Perspectives
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2022, Journal of Experimental Zoology Part A: Ecological and Integrative Physiology