Age structure, growth, and survival rates of an insular population of hemidactylus turcicus

Abstract

The Mediterranean house gecko, Hemidactylus turcicus (Linnaeus, 1758), a widespread nocturnal lizard, exhibits diverse life-history traits, yet its insular populations in Türkiye are underexplored. This study examines how Bozcaada's insular environment shapes the age structure, body size, growth rates, and sexual dimorphism of H. turcicus, providing a detailed demographic and morphometric baseline. We sampled 30 individuals (19 males, 11 females) from Bozcaada, Çanakkale, Türkiye, measuring snout-vent length (SVL), body mass, and additional traits (head length, width, height, forearm, and hind leg length). Age was determined via skeletochronology, counting phalangeal Lines of Arrested Growth (LAGs). Results show a maximum longevity of 7 years for males (mean: 4.26 ± 0.33) and 6 years for females (mean: 3.91 ± 0.41). SVL averaged 45.19 ± 1.59 mm for males and 43.51 ± 2.33 mm for females, with growth rates of 3.10 ± 1.03 mm/year (males) and 3.58 ± 1.24 mm/year (females), modeled using the von Bertalanffy equation. Sexual dimorphism was subtle (SDI = 0.04, male-biased), with no significant differences in morphometric traits between sexes. Survival rates were 0.78 for males and 0.76 for females, yielding adult life expectancies of 6.06 years (males) and 5.80 years (females), indicating a stable population. These findings suggest that Bozcaada's insular conditions, including limited resources and reduced predation, influence size, growth, and survival. This study establishes a novel profile of H. turcicus in an insular habitat, highlighting ecological adaptations and providing a foundation for future research and conservation strategies for this adaptable species.