​Petite Pests: Part of the Natural Balance

Expressions like “Mother Nature”, “crime against nature”, and “back to nature” suggest a wholesomeness to the natural world.  The reality, though, is that ‘nature’ is not inherently good or bad.  We realize this and, therefore, only selectively expose ourselves to it.  ​

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We enjoy the beauty of the sunset, but slather on SPF 30 to protect our skin.  We absorb the vibrant color of the blooms as we pop antihistamines to deal with the pollen.  We listen to the bird songs and curse their droppings on our cars. ​

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As I enjoy my outdoor pursuits, I, too protect myself with long sleeves and pants, a hat, insect repellent, and sunscreen.  But that has not been enough!  One evening a few weeks ago I discovered I had a “passenger”.  It was a wee worrisome wild thing:  a tick.  

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​Since then, I have been reading about these itty-bitty invertebrates.  They are related to spiders, scorpions, and mites.  My greater understanding of these teeny arachnids prompted me to give my passenger a name.

Tucker Bloodsucker:  Form Follows Function

​Like fleas and mosquitoes, ticks feed on blood.  But ticks are not insects.  Like other arachnids, Tucker did not have wings, nor antennae, but SHE did have eight legs.
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The part of a hard tick that looks like a head is called a capitulum.  The capitulum contains the tick’s “mouth”.  It has two palps, which the tick uses to brace itself when feeding.  Two chelicerae cut through the host’s skin.  The needle-like, barbed hypostome exchanges fluids.  ​

Stylized image of tick by Rebecca Smith Paul.

During feeding, some ticks secrete substances that help anchor it to the host, act as an anesthetic to mask the pain from the bite, and prevent blood from coagulating. The cement-like substances make it hard to remove a feeding tick.  Unlike a flea’s saliva, the substances ticks secrete don’t usually include compounds that cause itching and swelling.  ​

As ticks feed, their idiosoma (the main body part) expands. Female ticks need energy from blood to grow, develop, and lay eggs. Male ticks blood feed briefly, but do not become engorged with blood. After a brief attachment, males detach and wander on in search of an attached feeding female to mate with.  When I met Tucker, SHE was busy eating.

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Ticks Quest for Hosts

Ticks typically use a passive behavior known as questing to seek out their hosts. When questing, a tick will perch at the end of a piece of vegetation with front legs extended and latch on to a host as it passes by. The arachnids are susceptible to drying out and need a habitat with high humidity to survive. In general, they tend to be found in tall grass, leaf litter, and around stone walls and wood piles where small mammals live. Eliminating tick habitat around your property is an excellent way to reduce your exposure to these tiny tormentors.

Tick enlarged and stylized to show Questing behavior. Image by Rebecca Smith Paul.

Ticks Can Transmit Pathogens While Feeding

If a host has a blood borne infection, the tick will ingest the pathogen with its meal.  An acquired disease can be transmitted to a new host at the tick’s next feeding, since saliva from the tick may enter the host while it is affixed.  Since ticks are so small, they often go unnoticed.  The longer a tick carrying a pathogen stays attached, the greater the likelihood that a disease can be transmitted to its host.

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One kind of tick commonly found in Dutchess County is Ixodes scapularis, the black-legged tick.  It is commonly on white-tailed deer, but will also parasitize other animals.  It is a vector for several diseases, including Lyme.

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Unwelcome, but Necessary

Although infections that ticks may spread can cause misery, they are important in population control as an element of natural selection.  By transmitting disease, they remove weak members from populations, providing opportunities for younger and healthier animals to thrive.  With the understanding that all organisms are interconnected, scientists study tick and other animal populations to help monitor potential environmental problems.  The extinction of any animal population, including ticks, could cause unwanted effects within the biosphere. 

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