Interactions: What eats itUsed with permission

Although critical, the Western Fence Lizard’s placement on the food chain is by no means dominant.  Due to their sunbathing nature, Sceloporus occidentalis often find themselves easy prey for their numerous predators: snakes, birds, shrews, and California Striped Racers are just a few.  Interestingly enough, some lizards may even fall victim to an incredible turn of events. Black widow spiders have been known to snack on young lizards that are small enough to be stuck in their web (Nafis, 2013).  Fortunately, many lizards get the opportunity to escape their hunters.        
Western Fence Lizards do not possess many resources or tricks to protect themselves from these predators.  One thing they do have is the advantage of camouflage.  Their dark, earthy colors and coarse, spiny skin gives them a slight opportunity to be disguised from the eyes of their foe.  Sceloporus occidentalis also hold the power of speed.  Their powerful hind legs contribute to their rapid sprint speed and quick movements.  Lizards also have the ability to hop or jump short distances and are excellent climbers, which could be deemed useful at a time of an attack (Buckley et al, 2010).      
The most fascinating and beneficial interaction shared with S. occidentalis is that of the common tick.  Ticks are a known carrier of Lyme disease which is very dangerous to humans, other animals, and forests.  Amazingly, when ticks feed on the Western Fence Lizard, a protein in the lizard’s blood kills the Lyme disease bacteria, hindering any further opportunity of that tick to spread the disease.  This phenomenon is statistically proven based on rates of infected human’s with Lyme disease.  In regions where Sceloporus occidentalis is very abundant, such as California, rates of the disease are drastically lower than regions without the lizard, like Northeastern United States (Swei et al, 2011a).             

Used with permissionDr. Ostfeld and fellow researchers performed a study to test if these statistics hold legitimate truth.  Researchers attempted to remove S. occidentalis from certain areas to see what effect it would have on tick density, but more important the abundance of the Lyme disease pathogen.  They also rid areas of deer mice, dusky-footed wood rats and Columbian black-tailed deer which all possess some sort of host relationship with infected ticks.  It was found that the ticks preferred the lizards’ blood and often had difficulty locating another host when the lizards were removed.  Therefore, an overall lower productivity of the tick species was found.  Not surprisingly, this made the hypothesis hard to accept or reject.  However, the scientists in this study-as well as many others across the world-can agree that increasing the amount of lizards in a given location can reduce the Lyme disease pathogen in ticks (Swei et al, 2011b).             

 Although it is difficult for S. occidentalis to avoid their predators, their interactions with disease pathogens present a very beneficial symbiosis.  Not only can they run, jump, and hide, but they can also eliminate harmful bacteria. 

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