Podarcis siculus (Rafinesque-Schmaltz, 1810)

Taxonomy and Naming

Podarcis siculus, first formally described by Rafinesque-Schmaltz in 1810, has an average snout–vent length of 150–250 mm (5.9–9.8 in).

Adult Body Length

Individuals typically have a green or brown back and a white or green belly.

General Coloration

Length and coloration vary widely across the species' many subspecies and populations.

Intraspecific Trait Variation

For example, some subspecies are melanic, with blue tints on parts of the back and belly; this color form occurs more often in island populations than in continental populations.

Sexual Dimorphism in Head Size

Head size is sexually dimorphic in this species: males have larger heads and stronger jaws than females.

Hypothesized Causes of Sexual Dimorphism

Researchers hypothesize this size difference arises partially from males' differing prey consumption needs, and from male-male aggressive competition.

Native Distribution in Italy

As its common associations suggest, P. siculus is native to Italy, where it is one of the most common lizard species.

Full Native Range

Its native range also extends to Bosnia and Herzegovina, Croatia, France, Montenegro, Serbia, Slovenia, and Switzerland.

Introduced Range

It has additionally been introduced to Spain, Turkey, the United States, and Canada.

Habitat Breadth

P. siculus is a habitat generalist that survives well in many natural and human-modified environments, including forests, grasslands, shrublands, rocky areas, and farmland.

Thermophily Trait

Its ability to thrive in open habitats comes from biological traits including high thermophily, or the ability to grow and survive well at high temperatures.

Activity Pattern Study Background

A 2005 study compared seasonal and daily activity patterns of an introduced P. siculus campestris population in New York (United States) to native populations in Rome, Italy.

Seasonal Activity Differences

Native P. siculus in Rome are active year-round, while the introduced New York population has a shorter overall activity period, limited to the months of April through October.

Driver of Seasonal Activity Difference

The lower mean temperatures of the New York habitat are thought to explain this reduced activity window.

Daily Activity Differences

The New York population is also active for fewer hours each day than the Rome population.

Support for Temperature Hypothesis

Photoperiod (day length) on Long Island, New York (the site of the introduced population) is similar to photoperiod in Rome, which supports the hypothesis that temperature differences are the main cause of differing activity patterns.

Reproductive Mode

P. siculus is oviparous (egg-laying).

Clutch Characteristics

Females can lay 3 to 4 clutches per year, with 4 to 7 eggs per clutch.

Intraspecific Clutch Variation

Clutch egg count varies between populations: for example, populations on small Croatian islands lay fewer eggs, which produce larger hatchlings.

Reproductive Season Timing

The species' reproductive season runs from May through July.

Gravid Female Behavior

Gravidity (egg development) does not create a major physical burden for females, but gravid females bask more frequently than non-gravid females.

Male Reproductive Enzyme Activity

In male P. siculus, P450 enzyme activity in the brain differs based on the individual's reproductive stage.

P450 Enzyme Function

P450 enzymes localize specifically to regions of the brain that control reproduction and behavior, so this enzyme is thought to be involved in regulating sexual behavior in the species.