An atypical reproductive cycle in a common viviparous Asia Agamid Phrynocephalus vlangalii

Abstract

Viviparous lizards living in cold climate of high altitude often exhibit atypical reproductive cycles, in which mating and fertilization occur synchronously and annually with parturition occurring at the end of the year. Nevertheless, detailed case studies on atypical reproductive cycles are few. Using anatomical data combined with behavioral observations, we examined the reproductive cycle of a common Asian agamid, Phrynocephalus vlangalii, from a high‐elevation area in Sichuan, China. Male spermiation of P. vlangalii occurred in May, and spermatogenesis began in June and reached a maximum in October. For females, ovulation and fertilization occurred in May, and females developed gestation and pregnancy in 3 months from June to August, without vitellogenesis during this period. Females gave birth synchronously in late August, then vitellogenesis began and lasted until May of the next year. All adult males and females were synchronized in the same reproductive condition each month. The synchronous and annual reproductive cycle of P. vlangalii clearly represents an atypical cycle. The male courtship and mating behaviors were concordant with gonadal cycle and mainly happened in May and June. Despite the short growth period for neonates, they had a high over‐winter survival rate of 84.4%, suggesting that autumn parturition did not generate high costs to this reproductive cycle. We propose that the high over‐winter survival rate of neonates is likely linked with female delayed sexual maturity, female asynchronous vitellogenesis and gestation, large relative clutch mass (RCM), and adult‐offspring burrow sharing behavior during hibernation.

Proximate causes of altitudinal differences in body size in an agamid lizard

“…Many life history traits of this species show large amounts of geographic variation. Courtship occurs in May, and parturition occurs between mid‐July and late August (Wu, Fu, Yue, & Qi, ). Females at low‐elevation sites give birth earlier than those at high‐elevation sites (Li et al., ).…”

“…Lastly, if increased survivorship (~longevity) leads to a larger adult body size, adult lizards would survive longer and would be older in the high-elevation population than the low-elevation population. and parturition occurs between mid-July and late August (Wu, Fu, Yue, & Qi, 2015). Females at low-elevation sites give birth earlier than those at high-elevation sites (Li et al, 2014).…”

Reproductive cycles and reproductive strategies among populations of the Rose‐bellied Lizard Sceloporus variabilis (Squamata: Phrynosomatidae) from central Mexico

“…), Phrynocephalus (Wu et al. ), Anolis (Hernández‐Salinas and Ramírez‐Bautista ), and Sceloporus (Ouifero et al. ; Du et al.…”

“…Lately studies on several lizard species, such as Zootaca vivipara (Roitberg et al 2013) and species of the genus Takydromus (Du et al 2005), Phrynocephalus (Wu et al 2015), Anolis (Hern andez-Salinas and Ram ırez-Bautista 2015), and Sceloporus (Ouifero et al 2007;Du et al 2014;Lozano et al 2015) have found variation on several reproductive traits. In this sense, oviparous species which have wide distribution are good models to asses the changes on diverses life history characteristics, and mainly in the extension on reproductive cycles.…”

Reproductive strategies in males of the world's southernmost lizards

“…Seasonal reproductive cycles can be synchronous or asynchronous with the female reproductive cycle. In synchronous cycles spermatogenesis occurs simultaneously with vitellogenesis and is followed by testicular regression and a resting period (Crews & Gans 1992;Whittier & Tokarz 1992;Pudney 1995;Ibargüengoytía & Cussac 1999;Ibargüengoytía 2004;Villagrán-Santa Cruz et al 2009;Boretto et al 2012Boretto et al , 2014Wu et al 2015). In asynchronous cycles, male and female gametogenesis are not simultaneous and there is sperm storage in females and/ or males (Marion & Sexton 1971;Whittier & Tokarz 1992;Flemming 1993Flemming , 1994Swain & Jones 1994;van Wyk 1995;Jones & Swain 1996;Huang 1997;Murphy et al 2006).…”