Unisexual rock lizard might be outcompeting its bisexual progenitors in the Caucasus

Abstract

We compared the distributions, abundances and ecological requirements of parthenogenetic lizard Darevskia 'dahli' and its bisexual progenitors, D. portschinskii and D. mixta, in Georgia. We developed a regression model relating the species abundances with the distribution of climates. Darevskia portschinskii lives in warmer and drier climates than D. mixta; D. 'dahli' has the intermediate requirements. Temperature is more important than humidity for D. portschinskii, humidity is more important for D. mixta and both temperature and humidity are important for D. 'dahli'. Suitable habitats of all three species overlap broadly; however, the observed ranges partly overlap only for D. 'dahli' and D. portschinskii. The observed abundance of each species, related to its predicted abundance, is lower at the sites with potential competitors. Darevskia 'dahli' occupies a higher proportion of the suitable habitats and has higher abundances than the progenitor species. Competition with D. 'dahli' is an important factor determining current distribution pattern of D. portschinskii and D. mixta. The parthenogen is a stronger competitor than the bisexual breeders and potential advantages of the bisexual reproduction remain unrealized in the given temporal and spatial scale. To explain domination of bisexually breeding lizards on the global scale, considering climate changes in geological timescale is necessary.

Comparing developmental stability in unisexual and bisexual rock lizards of the genusDarevskia

“…In conclusion, considering the nature of our data, we can assume that parthenogenetic hybrids of the genus Darevskia may benefit more from high heterozygosity, which is maintained through clonal reproduction, rather than suffer from potential side effects of genetic uniformity or outbreeding depression (Jančúchová‐Lásková et al, ). In parthenogenetic Darevskia , this has been reported for their ability to cope with parasites (Danielyan et al, ) or environmental disturbances (Murphy et al, ; Tarkhnishvili et al, ). Darevsky () documented an increased amount of aberrant, nonviable embryos in parthenogenetic Darevskia , which already died during embryogenesis or shortly after hatching.…”

Sex produces as numerous and long-lived offspring as parthenogenesis in a new parthenogenetic insect

“…However, oribatid mites did not (Domes et al 2007). In fact, parthenogenetic lizards seem to be good competitors, instead of colonizers (Tarkhnishvili et al 2010), and parthenogenetic fishes (Riesch et al 2012) and mayflies (Sekiné and Tojo 2010) show equal fecundity and similar offspring. Our data add to these conflicting results.…”

Phylogeography and morphological variation in a narrowly distributed Caucasian rock lizard, Darevskia mixta

“…During 2009-2014 our team members studied several hundred rock lizard locations in Georgia and NE Turkey (Tarkhnishvili et al, 2010;Tarkhnishvili, 2012;Tarkhnishvili, Murtskhvaladze and Gavashelishvili, 2013;Tarkhnishvili et al, unpublished). All previously recorded locations for D. mixta (Darevsky, 1967;Murphy et al, 2000;Tarkhnishvili et al, 2010) were included, and augmented with additional populations.…”

“…All previously recorded locations for D. mixta (Darevsky, 1967;Murphy et al, 2000;Tarkhnishvili et al, 2010) were included, and augmented with additional populations. We identified 26 locations of D. mixta, and collected tissue samples from thirteen locations ( fig.…”

“…1). Each individual was photographed as described in Tarkhnishvili et al (2010); Tarkhnishvili, Murtskhvaladze and Gavashelishvili (2013), tail-tips were collected in the study were stored in 95% ethanol to preserve the DNA for later extraction and analysis.…”