breeding

Two modes of sex determination occur in squamates: genotypic sex determination (GSD) and temperature-dependent sex determination (TSD). Within each of these two major modes, there are many different variants, or mechanisms. Male heterogamety, female heterogamety, multiple sex chromosome systems, and homomorphic sex chromosome systems are all types of GSD found in squamates. Two patterns of TSD have been reported.Only three snakes have been investigated for their sex-determining mechanisms, each having GSD, although incubation temperature does cause differential mortality and affects post-hatching physiolom. Less than 50 lizard species have been investigated, but there is considerable diversity in the sex-determining mechanisms reported thus far. Apparently, TSD (and/or GSD) has evolved multiple times within a given taxon. Presently, both GSD and TSD are found in the Agamidae, Eublepharidae, and Gekkonidae, and possibly in the Iguanidae, Lacertidae, and Varanidae as well. Only GSD has been reported for the Scincidae and Teiidae.Correlations within the Eublepharidae suggest an adaptive explanation for the evolution of sexdetermining mechanisms; a shift from male-larger dimorphism to female-larger (or no sexual size dimorphism) is accompanied by a shift in sex-determining mode. These shifts are in agreement with similar correlations observed in turtles. b

show abstract

Sex‐determining mechanisms in squamate reptiles

Viets

et al. 1994

View full text Add to dashboard Cite

show abstract

Dominance hierarchies in male lizards: Implications for zoo management programs

Alberts

1994

Zoo Biology

View full text Add to dashboard Cite

Depending on spatial requirements and the distribution of key resources in the environment, social behavior among lizards varies from defense of exclusive territories to the establishment of dominance hierarchies. In captivity or under conditions where dispersal is not possible, dominance hierarchies often emerge in species that are otherwise territorial. This review explores some of the morphological, behavioral, and hormonal determinants of social status in male lizards and how these may lead to differential reproductive function in dominant and subordinate individuals. Emphasis is placed on the importance of population density, local resource dispersion, and the composition and stability of social groups in promoting hierarchical behavior. Results of these studies have ramifications for several aspects of zoo management, including exhibit design, choice of animals to be housed together, provision of resources in space and time, and orientation of enclosures within captive breeding facilities. o 1994 Wiley-Liss, lnc.

show abstract

Environmental (and Random?) Sex Determination in Endangered and Invasive <i>Phelsuma</i> Geckos

Peš,

Straková,

Kratochvíl

2024

Sex Dev

View full text Add to dashboard Cite

Introduction: Sex is a fundamental characteristic of an individual. It is therefore puzzling why in some systems sex is precisely determined by a genotype, while in others it is influenced by the environment or even subtle, not to say random, factors. Some stochasticity in sex determination would be expected if environmental conditions did not have a large sex-specific effect on fitness. Although data are only available for a small fraction of species, geckos show exceptional variability in sex determination. Methods: We tested the effects of three incubation temperatures on sex ratio and adult body size in the invasive gecko Phelsuma laticauda and the vulnerable gecko Phelsuma nigristriata. Results: We document temperature-dependent sex determination (TSD) in both species. Only females hatched at a low temperature (24 °C), whereas male production peaked at an intermediate temperature (29 °C) and declined, at least in P. laticauda, again at the highest temperature (31 °C). Interestingly, full siblings hatched from eggs glued together during the incubation at temperatures producing both sexes are often of the opposite sex. We found no significant effect of incubation temperature on adult body length. Conclusions: Documentation of TSD in the day geckos has implications for conservation practice in environmental management of endangered species or eradication of invasive species. However, it appears that a very subtle (random?) factor may also be involved in their sex determination. In line with this, we found no significant effect of incubation temperature on adult body length, suggesting that, at least in this trait, there is no strong selection against producing females at “male” temperatures.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

breeding

Cited by 3 publications

References 2 publications

Sex‐determining mechanisms in squamate reptiles

Sex‐determining mechanisms in squamate reptiles

Dominance hierarchies in male lizards: Implications for zoo management programs

Environmental (and Random?) Sex Determination in Endangered and Invasive <i>Phelsuma</i> Geckos

Contact Info

Product

Resources

About