ИСТИНА

What are the ecological, spatial, behavioral and cytogenetic background for coexisting and evolution of parthenogenetic and bisexual rock lizards? The present study was held in central Armenia (40°31’ N, 44°23’ E; 1920 m), where two parthenogenetic species (Darevskia unisexualis, D. armeniaca) and bisexual species D. valentini coexist stably for many years. The data was collected during field studies in May–July 2013–2015 yrs. Identification of morphological differences and cytogenetic processes in gonads of meiosis prophaseofthree males originated from hybridization between parthenogenetic femalesD. unisexualis and males of D. valentini has been done. Data on population density, species composition and daily activity was collected on five transects (43.3 km; 2022 individuals registered). Three residential males (D. valentini and hybrids D. valentini x D. armeniaca; D. valentini x D. unisexualis) and 28 females (23 – D. armeniaca; 4 – D. unisexualis; 1 – D. unisexualis x D. valentini hybrid) within the area 3600 m2were marked and observed in May–July 2014. Hybrid males possessed 57 chromosomes (versus 38 chromosomes in 2n males of D. valentini) and anomaly developed sperm prevailed– two or three flagella, deformed and swollen heads, acrosome and neck anomalies. However, some spermatozoa had one flagellum, but deformed heads, thus, it is difficult to tell whether these 3n males sterile or not. Morphological study of the hybrids revealed their interplacement between parental species. The activity of all three species in 2014 yr started in mid May, animalswere active with maximums at 09:30 AM – 14:30 PM and at 16:00 PM–17:00 PM. Lizard terrestrial activity reduced in late July–August to almost zero. Lizards were patchily distributed within the study area, occupying mostly stony heaps and rocks, where population density reached 250 ind/ha. Number of parthenogenetic species prevailed on D. valentine (2.6%). The average percent of hybrids among adults was 10.2%. The adult male/female ratio was 1:20. Males with hybrid morphological feature prevailed (51.4 %) on males of D. valentini (48.6 %). Only few females of D. valentini were observed during the study period. Home ranges and core areas of lizards of different species and hybrids broadly overlapped and social interactions among them were common. Six successful copulations were observed for males D. valentini with females of D. valentini; D. armeniaca; D. unisexualis and for hybrid male D. valentini x D. armeniaca with female D. armeniaca. Our study supports the idea that parthenogenetic species are able to coexist with related bisexual species altogether being functionally single population in ecological, spatial, behavioural and, probably, in genetic way. Gene flow among species in such a population is a possible way to support variability and increase their selective opportunities.