First record of carcass use as a refuge in lizards: the phyllodactylid gecko Homonota darwinii (Boulenger, 1885) in Argentina.

HILTON ENTRINGER; GEORGINA SQUARTINI; DANIEL UDRIZAR SAUTHIRE; LUCIANO J. AVILA; GABRIELA S. BLANCO

Herpetology Notes

Societas Europaea Herpetologica

Lugar: Bonn; Año: 2023

Darwin’s Marked Gecko, Homonota darwiniidarwinii (Boulenger, 1885), occurs mainly in Argentine Patagonia (Morando et al., 2014) and is the gecko with the southernmost distribution in the world. This small lizard (snout–vent length, SVL = 55 mm) is oviparous and its diet is composed predominantly of arthropods,such as insects and spiders (Kun et al., 2010). It exhibits nocturnal-twilight activity (Ibargüengoytía and Casalins, 2007) and generally uses rocks as daytimerefuges (Ibargüengoytía et al., 2007). The selection of these shelters is related principally to thermoregulation (Ibargüengoytía et al., 2007; Aguilar and Cruz, 2010).Thus, the quality of a shelter can guarantee a good level of metabolic maintenance during resting periods and improve performance during nocturnal activity (Aguilarand Cruz, 2010). Although shelter selection can play an important role in the survival of H. d. darwinii, few studies detail its behavioural specifics and microhabitat use (e.g., Aguilar and Cruz, 2010). This lack of information is an important knowledge gap, since understanding the level of plasticity regarding microhabitat use may have implications for the conservation and management of these geckos (e.g., Terán-Juárez et al., 2020; Jins et al.,2022). Among the currently known rest refuges for H. d. darwinii are rock fragments, fissures (Aguilar and Cruz, 2010; Breitman et al., 2014), and anthropogenic material (Breitman et al., 2014), such as plastic fishing boxes accumulated on beaches (Hilton Entringer Jr, pers. obs.). However, such elements represent only some of the potential refuges available in Patagonia. In order to increase the knowledge of the naturalhistory of H. d. darwinii, the main goal of this study was to validate the use of carcasses (dead penguins) as refuges by this lizard in two island environments, where the availability of this potential refuge is significantly high compared to other areas. In addition, we aimed to describe and quantify the characteristics of selected carcasses to evaluate their importance as refuges according to their suitability for the species. As H. d. darwinii shows a nocturnal-twilight pattern of activity and tends to select refuges according to its size (Ibargüengoytía et al., 2007), we hypothesize that carcasses can be used as daytime resting refuges when they represent the most suitable environmental elements available.