GUT CONTENT ANALYSIS OF AGAMA & CURLY-TAILED LIZARDS

Juliana Anderson & Jessica Wimmer

Florida Oceanographic

29 July, 2025

• Human activity has become a dominant force shaping the planet's environment.
• Climate change
• Local and regional extinctions
• Changes in migration patterns of organisms
• Introducing non-native species

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New Planetary Era: Anthropocene

Burmese Python

Brown Anole

• We are using these nonnatives as a model species to ask:
• Are they competing with one another?
• Are they competing or predators with our native species?
• Are they threats or simply filling an unoccupied niche?

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Non-native species are not always invasive

• Northern curly-tailed lizards are native to the Bahamas, Cayman Islands, and Cuba.

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• Introduced to the United States as intentional releases through the pet trade in the early 1940s.

Distribution of Curly-tails

EDDMapS, 2025. www.eddmaps.org

• The Peter’s Rock Agama (Agama picticauda) is native to tropical, sub-Saharan Africa.

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• First introduced to Florida in 1976 through the pet trade.

Distribution of Agamas

Female Agama

Male Agama

EDDMapS, 2025. www.eddmaps.org

• People often assume all nonnative species are harmful, but impacts can be complex or undetectable.

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Impacts are Not Obvious

Florida Oceanographic

• People often assume all nonnative species are harmful, but impacts can be complex or undetectable.

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• Peters’s Rock Agama and Northern Curly-tail may be interacting ecologically, competing for similar food resources or habitat space -- controlling each other‘s population naturally.

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Impacts are Not Obvious

Florida Oceanographic

• People often assume all nonnative species are harmful, but impacts can be complex or undetectable.

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• Peters’s Rock Agama and Northern Curly-tail may be interacting ecologically, competing for similar food resources or habitat space -- controlling each other‘s population naturally.

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• Gut content analysis helps investigate whether they are preying on native insects or reptiles, an indicator of possible ecosystem disruption.

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Impacts are Not Obvious

Florida Oceanographic

Hypothesis

• The diets of A. picticauda and L. carinatus in shared habitats will not significantly differ in prey type composition, reflecting similar use of available prey resources.

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Hypothesis

• The diets of A. picticauda and L. carinatus in shared habitats will not significantly differ in prey type composition, reflecting similar use of available prey resources.

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• They may be consuming native lizard species, such as green anoles.

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Methodology

• Six A. picticauda and six L. carinatus were captured at the same coastal site in Martin County, Florida.

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• Stomach contents were dissected under a stereomicroscope and separated by prey type.

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Study Sites & Sampling

Gut Content Identification

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A. picticauda (female)

Immature Male

Mature Male

A. picticauda (male)

Male

tail regrowth

Female

gravid

L. Carinatus

Sampling

Stomachs were removed through a mid-ventral incision and immediately preserved in 90% ethanol for subsequent gut content analysis.

Lizard Leftovers

A Closer Look Inside

Data Analysis

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Dietary composition will be summarized using:

• Frequency of occurrence (% of stomachs containing each prey category),
• Numerical abundance (count of prey items per category)
• Similarity percentages analyses (most commonly shared prey)

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Take Home Messages

• Only 12 samples – no strong conclusions can be drawn yet

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• This study suggests that Agamas and Curly-tails omnivores

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• No green anoles found in stomachs yet

Florida Oceanographic

29 July, 2025

THANK YOU

SPECIAL THANKS TO:

Florida Oceanographic

and the Research Team