Geckos eat a variety of food items, including insects, arachnids, mollusks, small vertebrates and other small animals. Additionally, some geckos consume fruits and flower nectar. There are approximately 1,500 gecko species in the world, and the group displays a wide variety of dietary preferences.
Most geckos are relatively opportunistic predators, and they will eat virtually any animal they can catch that is small enough to consume. Some species tend to prefer a particular type of prey, while others primarily consume one species of prey because that particular prey species happens to be abundant. Geckos are usually ambush hunters that wait for prey to come within range.
Common insects eaten by geckos include ants, beetles, roaches, moths, butterflies, flies, mosquitoes and leafhoppers. Geckos do not normally predate upon large spiders, tarantulas or scorpions, but they frequently eat small species. Snails and slugs are common food items for some species, while the larger species eat other lizards, frogs or even nestling birds.
While most geckos are nocturnal, one group of geckos is active during the day. Called day geckos, this group of lizards consumes a lot of plant-based food. The geckos will lap up bits of overripe fruit and drink the nectar from within flowers. They likely had to evolve these dietary habits to become active during the day, when fewer insects are available to eat.