The white-bellied lizards are also emphasizing a different pheromone chemical as their sexual attractant and territorial marker, which will likely over time make them unattractive to the other versions, reproductively isolating that population into its own separate gene pool.
The white morph, by contrast, is smaller but is more resistant to parasites, and because it is hardier it is able to lay fewer eggs and still maintain its population. The red morph for instance is larger and stronger on average, but is more vulnerable to parasites. Overall, then, each of the color morphs seems to be settling on a dissimilar set of characteristics which gives them different ecological advantages and disadvantages. But the white-bellied populations seem to exhibit a distinctly higher level of resistance to this infection, while the red-bellied morphs seem to be particularly vulnerable. Wall Lizards are often infected by a group of microscopic blood parasites called haemogregarines. Females in yellow-bellied areas tend to lay a larger number of smaller-sized eggs: white-bellied females, by contrast, tend to produce smaller clutches of larger eggs, while the females in areas where red bellies predominate seem to be able to vary their clutch and egg size according to local conditions.Īnother interesting variation deals with resistance to parasites. The various populations also differ in their reproductive strategy. The white-bellied males, by contrast, have low levels of tocopherols but a higher concentration of different chemicals called furanones.
The males of all Wall Lizards have special pores on the inside of their thighs that produce chemicals called tocopherols for marking their territory and attracting females, but the chemical markers found in the reddish-bellied populations tend to be stronger and longer-lasting than those of the yellow morphs. The reddish “morphs” tend to be the largest, reaching up to ten inches. More significantly, however, are the color differences that seem to separate them into distinct geographic regions: some local populations have reddish scales on their bellies, some have yellowish, and some have white.īut there are other genetic differences associated with these color variations which are, in the evolutionary sense, much more important. To the human eye, the most noticeable difference is color: some individuals of Wall Lizard throughout their range have greenish scales on their backs, and others have grayish or brownish. Within its wide geographic range, the reptiles encounter a variety of climatic and ecological conditions, and the populations in each area have adapted themselves to their own particular circumstances. It makes its home in stone walls, rock piles, construction rubble, or among ancient Roman ruins.įor biologists, the lizard is interesting because it seems to be in the process of speciation-of dividing itself into a number of different species. A greenish ten-inch lizard with a long tail and a pointed snout, the Wall Lizard likes to be around human cities and is seldom found far away from buildings, parks or parking lots. The Common Wall Lizard, Podarcis muralis, is, as the name implies, a familiar sight in most of southern Europe from Spain to Turkey. Realizing that there must be an entire population of them here, I went searching online, and found the “Lazarus Lizard". So I figured it must have been a pet that escaped or was released. But I saw enough of it to realize it was a lacertid, and that stopped me in my tracks as I thought, “What the heck is THAT doing here?” There are no lacertid lizards native to North America.
The first time that I saw a Wall Lizard in Cincinnati, it was only for an instant as it ran across the walkway in front of me.
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