There are many records of H. frenatus displacing or causing decline in native geckos throughout its introduced range ostensibly by competitive displacement. H. frenatus displaces endemic and 'Vulnerable (VU)' lesser night gecko (see Nactus coindemirensis in IUCN Red List of Threatened Species) and the endemic night gecko Nactus durrelli in the Mascarene Islands. It displaces both Nactus spp. from favored environments increasing their risk of predation and has proven to be a major cause in the decline of, the once thought extinct in the wild, N. coindemirensis (Cole et al, 2005; Jones & Cole, 2004). H. frenatus displaces Pacific island native Lepidodactylus lugubris in many locations and has demonstrated superior predation abilities. Experiments have demonstrated that H. frenatus consumes a disproportionately higher amount of insect prey than L. lugubris, thereby leaving it with less potential prey which decreases its body condition, fecundity, and ability to survive (Hanley et al 1995; Harvey et al 1998; Petren & Case, 1996). A similar predation study with Australian gecko Gehyra dubia also found H. frenatus to be a more formidable forager (Canyon & Hill, 1997). The displacement of Hemidactylus garnotii by H. frenatus throughout the Pacific basin has been attributed to behavioral interference from aggressive males. Furthermore, H. frenatus was also found to hybridize with H. garnotti in laboratory experiments (Dame & Petren, 2006).

The use of naturally or artificially occurring substrates with a crumbly/highly concentrated particulate surface may be used to exclude the pad-bearing H. frenatus from specific locations, allowing claw-bearing gecko species to forage unchallenged. This method of exclusion was tested in attempts to preserve populations of threatened Nactus spp in the Mascarene Islands. Simple habitat modifications through the addition of artificial refugia have been proposed as a means to enhance populations of endangered or displaced native reptiles (Cole et al 2005).\n

Chemical control: The use of Tricaine methanesulfonate (MS222) injected into the intracoelomic cavity of H. frenatus is a chemical euthanasia method consistent with conditions specified by The Public Health Service Policy on Humane Care and Use of Laboratory Animals which require that euthanasia of ectotherms be consistent with the American Veterinary Medical Association (AVMA) Guidelines on Euthanasia. Test subjects were administered a intracoelomic injection of 250 to 500 mg/kg of 0.7% to 1% sodium-bicarbonate–buffered MS222 solution followed by intracoelomic injection of 0.1 to 1.0 ml unbuffered 50% (v/v) MS222 solution. Test subjects were effectively made unconscious by the first injection and respiratory and cardiac functions were eliminated by the second (Conroy et al 2009).\n