common house gecko

The Common House Gecko (Hemidactylus frenatus) is recently being reported from multiple islands across the Lesser Antilles: Antigua, Dominica, St. Barthélemy, St. Eustatius, St. Kitts, St. Lucia, and St. Martin (Brisbane et al. 2021, Dewynter et al. 2022, Griffing et al. 2022, Thorpe 2022, Questel et al. 2023, Thibaudier et al. 2023, Lindsay et al. 2023). Here, we report on the establishment of the species on Saba, Dutch Caribbean.

On 27 November 2023, between 19.30–20.30 h, we surveyed buildings, walls, rock crevices and piles of wood, brick, concrete, and metal, including building supplies, on the Fort-Bay Road, adjacent to the Fort Bay harbor on Saba (17.61615, -63.25039). We found H. frenatus at eight locations along a 520-meter stretch of road, either on walls, next to the road between rocks, or between aforementioned materials. At each location one animal was captured, totaling four adults and four juveniles. The lamellae on the 4th and 5th digit were used to confirm species identity (Krysko and Daniels 2005). We collected one adult (Figure 1) that has been provided to Naturalis Biodiversity Center, Leiden, The Netherlands, for deposition in their collections. We note that Hemidactylus mabouia was also found at three sites within the 520-meter stretch, but never closer than ~30 meters to Hemidactylus frenatus, which is a known competitor of other gecko species (Petren & Case 1996).

Within the northern Lesser Antilles, the island of Saint Martin, including the Dutch part (St. Maarten, a constituent country of The Netherlands) and the French part (the Collectivity of Saint Martin), is considered the main hub for established non-native reptiles, currently numbering ten species (Table 1) (Dewynter et al. 2022; Thorpe 2022). The islands of Saba and St. Eustatius are special municipalities of The Netherlands and frequently trade with St. Maarten. During the last five years, several new non-native reptile species have been reported on Saba and St. Eustatius, which originate from the non-native populations already present on Saint Martin: the Green Iguana, Iguana iguana (van den Burg et al. 2018, 2022) on St. Eustatius, and the Brahminy Blindsnake, Indotyphlops braminus (van den Burg et al. 2021) and Smooth-scaled Tegulet, Gymnophthalmus underwoodi on Saba (van den Burg et al. 2021). It is believed that these newly established populations have been facilitated by poor biosecurity between the islands. Here, we describe the establishment of two species, G. underwoodi and the Common House Gecko, Hemidactylus frenatus, on St. Eustatius.