Faster but Not Stickier: Invasive House Geckos Can Out-Sprint Resident Mournful Geckos in Moorea, French Polynesia

The House Gecko, Hemidactylus frenatus, is one of the world's most invasive vertebrate species and is spreading rapidly across the South Pacific, displacing other species of geckos that are native or were already resident. We studied the adhesion and locomotor capabilities of H. frenatus and the resident Lepidodactylus lugubris on the island of Moorea in French Polynesia where they are syntopic. Our goal was to determine whether H. frenatus could stick or sprint faster than L. lugubris, two types of performance measures that could underlie superiority of H. frenatus in foraging and agonistic interactions hypothesized in other studies. The clinging ability of H. frenatus and L. lugubris are comparable suggesting that the potential for sticking to vertical and over-hanging surfaces as geckos move through their environments does not differ between species. In contrast, H. frenatus have maximal sprint speeds that are approximately fourfold higher than L. lugubris, an advantage in speed that is even greater than that measured previously for the two species running on horizontal surfaces. Proposed superiority in foraging and agonistic interactions of H. frenatus compared to L. lugubris are potentially traceable to performance characteristics such as adhesion and locomotion. We demonstrate that comparatively high maximal locomotor speeds may contribute to the observed success of H. frenatus over resident geckos in French Polynesia, and possibly in other areas where they have been introduced.