Florida’s subtropical climate and extensive network of ports support a vast array of reptile life. This high biological diversity includes numerous native species, but the environment is also highly susceptible to the introduction and establishment of non-native wildlife. Lizards have flourished in the state’s warm, humid conditions, resulting in a complex food web. Understanding the diets of these reptiles is crucial for comprehending their influence, especially as invasive species compete with native inhabitants for resources.
Common Florida Lizard Species
Florida is home to both native and numerous introduced species, which often coexist in the same habitats. The native Green Anole (Anolis carolinensis) is an iconic species, recognized by its ability to shift colors from brown to bright green. It is typically an arboreal lizard, spending most of its time high in trees and shrubs. The Florida Scrub Lizard (Sceloporus woodi) is another native resident, found in specialized habitats like pine scrub and sandhill communities.
The introduced species are far more numerous and widespread. The most commonly encountered is the invasive Brown Anole (Anolis sagrei), which arrived over a century ago and is now the most prolific lizard in Florida. Larger invasive species include the omnivorous Argentine Black and White Tegu (Salvator merianae) and the herbivorous Green Iguana (Iguana iguana). Other established non-native lizards include the Northern Curly-tailed Lizard (Leiocephalus carinatus) and the Mediterranean House Gecko (Hemidactylus turcicus).
Typical Dietary Components
The diets of Florida lizards are separated into three main categories: insectivorous, omnivorous, and herbivorous. Most smaller species are specialized insectivores, such as the native Green Anole and the invasive Brown Anole, which primarily consume arthropods. Their diet includes spiders, crickets, flies, and small beetles, captured through active hunting or opportunistic ambush.
Insectivorous diets serve an important ecological function by regulating local populations of various invertebrates. Small lizards also consume minute invertebrates, including earthworms and insect larvae. Prey size is typically proportional to the lizard’s head size, ensuring safe consumption.
Omnivorous species, often the larger lizards, supplement their insect and invertebrate intake with plant matter. This broader diet includes flowers, soft fruits, and seeds available in the subtropical environment. The largest lizards, such as the Green Iguana, are predominantly herbivorous, focusing on foliage, blooms, and plant buds. Juvenile iguanas and other large lizard hatchlings often start as insectivores, shifting to a plant-based diet as they mature.
Dietary Shift: Consumption of Invasive Prey
Florida’s invasive lizard populations have created a complex web where non-native species frequently consume other non-native organisms. The invasive Brown Anole is a generalist predator that consumes numerous arthropods, inadvertently controlling various non-native insect pests. This includes preying on mosquitoes, which can indirectly reduce the transmission of mosquito-borne diseases to humans and wildlife. The invasive Mediterranean Gecko also prefers nuisance insects, often hunting around outdoor lights near human structures.
A more direct example of invasive-on-invasive consumption occurs among larger introduced lizards. The Northern Curly-tailed Lizard, an established non-native species, is a known predator of the smaller, invasive Brown Anole. This intra-invasive predation creates a localized population check-and-balance system. The invasive Knight Anole has also been documented preying on the Brown Anole.
The invasive Red-headed Rock Agama also preys on Brown Anoles, which reduces the anole population. While this eliminates another non-native species, it carries an ecological cost. If the Brown Anole population declines, the number of lizards available to consume mosquitoes decreases, potentially shifting disease risk toward native wildlife and people.
The Ecological Role of Invasive Lizard Diets
The dietary habits of Florida’s non-native lizards create significant pressure on the native ecosystem through competition and direct predation. The Brown Anole directly competes with the native Green Anole for insect resources. The Brown Anole’s preference for lower perches often forces the native species higher into the canopy, placing the Green Anole in less-optimal foraging areas. This habitat shift can lead to a decline in the native population density, compounded by the fact that the Brown Anole preys on the native Green Anole’s hatchlings.
The dietary breadth of the state’s largest invasive lizards presents a serious threat. The Argentine Black and White Tegu and the Nile Monitor are opportunistic omnivores that target the eggs of native ground-nesting animals. These large predators consume the eggs of gopher tortoises, alligators, and threatened sea turtle species, directly impacting the reproductive success of Florida’s indigenous fauna. This predation on eggs and vulnerable hatchlings disrupts the native food web.
The presence of a large invasive predator, such as the Curly-tailed Lizard, can also alter the feeding behavior of other species. The threat of predation forces smaller lizards into safer, yet more crowded areas, intensifying competition for food. This fear-induced competition demonstrates how an invasive species can negatively affect native wildlife even without direct consumption.