Saturday, July 13, 2019

Western Fence Lizards (Blue Bellies) -- Lyme Disease Control in Ticks ???

In 1998, a pioneering study led by UC Berkeley entomologist Robert Lane found that a protein in the Western fence lizard’s blood killed Borrelia bacteria, and as a result, Lyme-infected ticks that feed on the lizard’s blood are cleansed of the disease-causing pathogen.
Image - John Lindsey

Image - John Lindsey
As a kid I was always went nuts about catching both lizards and snakes. But lizards more often and different kinds of lizards. Amazing how even today as you look at the photo above, little boys are still attracted with catching and holding lizards. Sadly the modern world's time wasting electronic devices has captured the attention of most kids and generally being outdoors is in many cases not an option. Of course the most common lizard where I come from is the Western Fence Lizard (Sceloporus occidentalis). They are everywhere. We also called them Blue Bellies because of the deep pretty blue on their under bellies. But back in 2011 researchers discovered something even I never knew about the abundantly common Western Fence Lizard. They play an ecological role in hosting ticks at a small juvenile stage of the tick's life cycle. And ticks that feed off Western Fence Lizard blood acquire aa protein which destroys the Borrelia bacteria which causes Lyme Disease. Here are some quotes from the article and I'll provide a link so you can read the entire research report.
"Western fence lizard’s blood killed Borrelia bacteria, and as a result, Lyme-infected ticks that feed on the lizard’s blood are cleansed of the disease-causing pathogen. Moreover, research has found that up to 90 percent of the juvenile ticks in this species feed on the Western fence lizard, which is prevalent throughout California and neighboring states."  
"The lizard is thus often credited for the relatively low incidence of Lyme disease in the Western United States. The new UC Berkeley-led study put that assumption to the test experimentally."
Photo - Gary Nafis
Interestingly, the researchers found that the Lizards accommodate ticks with a specialized fold in their neck called a “mite pocket.” Wow, I never knew that when I was a kid in the 60s and never knew to look for any ticks period. But remember, we're not talking about adult ticks, these are tinier ticks in the infancy stage of life known as nymphal stage. So in a nutshell, in 4 or 5 plots where those lizards were already being studied, many were removed from an area and substitute animals like woodrats and pocket mice were checked to see if they became the new host for the juvenile ticks.
"The researchers found that in plots where the lizards had been removed, ticks turned to the female woodrat as their next favorite host. On average, each female woodrat got an extra five ticks for company when the lizards disappeared.  However, the researchers found that 95 percent of the ticks that no longer had lizard blood to feast on failed to latch on to another host. 
“One of the goals of our study is to tease apart the role these lizards play in Lyme disease ecology,” says Swei, who is now a post-doctoral associate at the Cary Institute of Ecosystem Studies in New York. “It was assumed that these lizards played an important role in reducing Lyme disease risk. Our study shows that it’s more complicated than that.”  
Notwithstanding the results in this new study, Lane pointed out that the Western fence lizard are key to keeping infection rates down among adult ticks. “This study focused only on the risk from juvenile ticks, specifically those in the nymphal stage,” he said. “The earlier finding that adult ticks have lower infection rates because they feed predominantly on the Western fence lizard at the nymphal stage still holds.”  
“In attempting to decrease infectious disease risk, we need to remember the law of unexpected consequences,” said Sam Scheiner, program director in the National Science Foundation Division of Environmental Biology, which funded the research through the joint NSF-NIH (National Institutes of Health) Ecology of Infectious Diseases Program. “This study demonstrates the complexity of infectious diseases.”
(Berkeley News)
Lizards in your yard are a really good thing
Image - Orange County Register

There was a great article in the Orange County Register in 2010 about the benefits of having various Lizard species living as residents within your garden and landscape. Amazing photo above where a Western Fence Lizard is gulping down a Jerusalem Cricket, which frankly to me looking at one up close, is one of the most sinister looking bugs I've never wanted to touch. Wicked looking jaw and mouth parts and stickery claws which clasp onto anything tightly. Hence I've always refused to touch one. But look at that lizard. No apparent fear there. Here's parts of the article:
"Settle down everybody. A backyard lizard invasion has not begun. OK, maybe it has, but no reason to panic. Alligator lizards, Western Fence lizards and even the occasional side-blotched lizard are feasting on summer bugs and living large reptilian lives in our residential back yards. Yay for lizards!" 
“Lizards are not poisonous, harmful or anything other than interesting,” said Steve Bennett, vector ecologist at Orange County Vector Control. “In fact, during the mating season it is fun to watch the males doing their push-ups to show off, or squabbling over girlfriends.”  
Lizards are considered beneficial companions consuming more than their share of crickets, cockroaches, ants, beetles and sometimes flies if they can catch them.  But most lizards are usually more prey than predator. “In the wild they don’t live more than a year or two,” Bennett said. “In captivity they can live much longer.”  
Cats, birds, even black widows will make a meal out of a lizard, especially when the lizards are young and small. To the gardener the lizard is a constant companion, sitting on rocks, scurrying under shrubs, getting out of the way when the garden hose goes on. Or not. Lizards don’t seem to mind the occasional squirt from the hose, perhaps because like other reptiles, lizards can’t control their body temperature. A cool sprinkle in August probably feels good.
(Orange County Register)
But getting back to these ticks. The adult ticks dangle on the tips of grass and other low-lying vegetation like shrubs in a host-seeking posture called “questing.” In this position, they spread their two front clawed limbs wide open and wait patiently for hours, or even days, for unsuspecting critter to brush by so they can dig their metal-like mouth parts into their host and gorge themselves on it's blood. Contrary to what some people may believe, ticks don’t jump or fly. And when it comes to keeping an eye out for ticks, at least the adult ticks can easily be seen, unlike ticks in the nymph or juvenile life stage, when the tick is about the size of a poppy seed and difficult to spot. Juveniles usually do not climb grass or shrubs while host-seeking. Instead, they lurk closer to the ground on top of leaf litter on the forest floor, a perfect location to attach to lizards. In fact, research has shown about 90 percent of hosts for tick nymphs are reptiles rather than small mammals or birds. This is truly amazing, because I never knew this before and would never have suspected lizards all this time offered such an amazing checks & balances service in the natural world.
Some Other Interesting Facts About Lyme Disease & Ticks

Opossums: Where Lyme disease goes to die
Where foxes thrive, Lyme disease doesn’t
PoughKeepsie Journal

Taal Levi, a researcher at Cary Institute

The interesting thing here is Coyotes will kill foxes, not for food, but as a competing predator. Where that happens there is a rise in Lyme disease because the Fox (Red & Grey) are small mammal (mice, rats, etc) predators which are often carriers & spreaders of the disease. While I don't like those Coyote hunting contests, there is nevertheless an incredible out of control overpopulation of Coyotes. Removal of Wolves a century ago brought this on. 
Poughkeepsie Journal Archive: Where foxes thrive, Lyme disease doesn't
"Taal Levi, a researcher at Cary Institute of Ecosystem Studies, talks about Lyme disease and how ecology — specifically, the interplay between wildlife species — affects the spread of infectious disease. Mice are especially good carriers of Lyme disease because their immune systems don't fight off the pathogen and they don't groom ticks off their bodies. (unlike opossums that remove as much as 96 percent). Foxes are highly effective at killing mice - statistical data shows that as fox populations go down, the incidence of Lyme goes up."
Great Vimeo Video: Where foxes thrive, Lyme disease doesn’t
Image - Matthew Twombly (NPR)
Clearly there are literally millions of things about our planet's natural world that scientists flat out do not understand. What possitive role do ticks play in Nature ? Yeah I know, Ticks ? There are countless synthetics that industrial science has invented to rid us of what appear to be pests, without considering what role humans may have played in ecosystem imbalance and whether it could be reversed. Our entire human experience of life is one of either cooperation or competition with all the other living things on Earth. But when humans alter their environment, they also alter the behaviour of other living things. Take for example the Zika Virus & the mosquito, Aedes aegypti. Wasn't always a pest and in fact most mosquitoes weren't until people altered environments they shouldn't have. In fact scientists now know that mosquitoes didn't always attack or bother humans, rather the mosquito's specific targets were almost exclusively animals and even then they played a role in ecosystem management. But something changed and humans were the cause of that change. The reality is that all such parasites and aggressor pests grew out of a system that was originally designed to be completely sustainably cooperative but was suddenly transformed and turned into a competitive disarray.
Fabricating Unscientific Fables for Corporate Business Interests
Throughout history people have killed whatever annoyed or inconvenienced them, even other humans. Hence the practices of killing what we don't like or cause us to lose profit has only escalated with the invention of synthetic science-based pesticides. The ignorance on how nature really works became further distorted when a scientific label was attached to many living things about 150 years ago when something called "Argument from Poor Design" was fabricated to prop up a new worldview and given as a gift to mankind by Charles Darwin. Darwin never used science for all his examples of poor design, but rather he employed metaphysical and faith-based religious concepts to justify the new worldview. I get the idea of being turned off to much of Christendom's track record, etc, I do I get it. But to trash nature to justify an argument for another worldview ??? 😕

“Folks who ain’t got ideas of their own should be mighty careful whose they borrow…”
Old Cowboy Saying 
No truer words than that. Look throughout history at all the supposedly intellectual ideas and philosophies mandated as truth by this world's elites which later turned out to be purely based on gross human ignorance and incompetent understanding of how they think Nature really works and we've all been paying a high price ever since as a result. 
More Reading References on the Subject
Murray Suuer M.D. - "Lyme Disease and Lizards Los Angeles"