what's interesting about ticks is how they handle water
Imagine a tick.
No, wait, imagine a toddler. Big squishy cheeks, face like a new penny, waving their chubby little arms up in the air, begging to be picked up.
“Many tick species, particularly Ixodidae, lie in wait in a position known as ‘questing’. While questing, ticks cling to leaves and grasses by their third and fourth pairs of legs. They hold the first pair of legs outstretched, waiting to grasp and climb on to any passing host.” - Wikipedia
And like a toddler, the tick gets thirsty while it’s waiting for you to pick it up. But instead of constantly demanding “milk please?”, the tick drools a special saliva onto its face and then drinks it back.
“Atmospheric moisture is absorbed by the highly salty saliva and then sucked back into the body of the tick, thus helping ticks to stay hydrated, sometimes for years, while they wait for a host.” - The Role of Saliva in Tick Feeding
Y’know the whole thing about how you’re safe from lyme disease or whatever as long as you get the tick off fast enough? There’s truth there. Ticks transmit disease as a side effect of how they handle homeostasis during feeding. They drink so much blood, so fast, that after a certain point they need to filter out the excess water and spit it back into you while keeping only what they need.1 That backwash is the disease vector, and they gotta drink enough to need to spit before it becomes a problem for us.
ticks are beautiful
still, haters gonna hate
six legs good, eight legs bad
I think a 6-legged tick is less likely to get you sick than an 8-legged one? Here’s my logic:
A few tick-borne diseases are transmitted from mama tick to her eggs, but most only come to the tick via hosts they feed upon.
After hatching from their eggs, ticks go through three more life stages (larva, nymph, adult).
Ticks typically feed only once per post-egg life stage.
“Larval ticks hatch with six legs, acquiring the other two after a blood meal and molting into the nymph stage.” (Wikipedia)
Ergo: a 6-legged tick found feeding on you is a larva who has probably never had the chance to catch any diseases by feeding on a prior host, and so can only transmit a disease it may have been born with, which would be an unusual situation. Hooray!
you got a real pretty mouth
“a tick digs in using two sets of hooks. Each set looks like a hand with three hooked fingers. The hooks dig in and wriggle into the skin. Then these ‘hands’ bend in unison to perform approximately half-a-dozen breaststrokes that pull skin out of the way so the tick can push in a long stubby mouth part called the hypostome.”
- How A Tick Digs Its Hooks Into You (v. upsetting marvelous video here)
Breaststrokes, you say? Oh yes
“It's almost like swimming into the skin,” says Dania Richter (NPR)
The diagrams here are really quite something - "How ticks get under your skin: insertion mechanics of the feeding apparatus of Ixodes ricinus ticks"
and now for a romantic musical interlude
Female ticks are the ones doing the serious extended feedings. Males are just hanging around looking for love “will remain on the host for extended periods in order to find a mate” - UMaine Tick Lab
Ticks (lyrics) by Brad Paisley
(all of which is of course a prelude to the miracle of life)
some etymology
Ticks are arachnids, bucketed alongside mites in subclass Acari, which comes from the Greek word ακαρί and means “impossible to be cut”2.
Soft ticks (family Argasidae) are believed to have been named after Argos, Odysseus’s dog. This comes from the bit in the Odyssey where Argos is described as laying in a dung heap full of vermin (κυνοραιστέων).
“Which dog parasite did the author mean by κυνοραϊσταί? Its translation as vermin is too vague. Other candidates are lice or, better, ticks. Why do we opt for the latter rather than for the former? Note that dog lice are not as common as dog ticks. We have also in mind the folk conviction that excrements kill sucking lice and fleas. If so, Odysseus’ dog could not have them and, by this token, we are more inclined to admit that κυνοραϊσταί should be understood as ticks.”
- About the Greek origin of acarology: a short note on Argas and the Acari3
Hard ticks (family Ixodidae) otoh are named for ἰξός (Greek for birdlime (historically used for trapping birds), and ultimately anything sticky). Makes sense - a soft tick typically falls off after feeding for just a few minutes, but a hard tick is a stickier situation - their feedings last something like 3-10 days!)
More fun etymology - hard ticks have a hard plate on their back called the “scutum”, named after an ancient Roman shield.
And I’ll spare you the photo, but the Australian paralysis tick Ixodes holocyclus’s name comes from holocyclus, meaning 'complete circle’, because of “the complete pear-shaped encirclement of the anus by the anal groove.” Obviously.
thises and thats
Check out the amazing videos at Static electricity passively attracts ticks onto hosts!
“A common misconception about ticks is they jump onto their host; however, they are incapable of jumping, although static electricity from their hosts has been shown to be capable of pulling the tick over distances several times their own body length.” (Wikipedia)
Also worth a glance - this obituary of Jane Brotherton Walker, “the doyenne of African tick researchers”, who was “greatly distressed when it was proposed that the genus Boophilus become a subgenus of her beloved Rhipicephalus, a subject which the protagonists of this change preferred not to discuss with her.”
“It is unclear why ticks go to such lengths to obtain blood only to inject large parts of it back into their host.” - Wonders of tick saliva (full text)
I learned this around the time I’ve been reading Planet of the Ants by Susanne Foitzik and Olaf Fritzche, which mentions an unfortunate anecdote where they spent hours excavating a colony and when they finally found the brood chamber “the spade missed - slicing the queen in two”. I suppose it’s not terribly meaningful to point out that ticks used to be seen as too tiny to be cut, and yet an ant can be cut in half, but here we are, this is how my brain works, hi.
That paper also has a little callback to our discussion of Antoni Van Leeuwenhoek’s invention of lenses good enough to let him be the first person to ever see microorganisms. Before the invention of the microscope, storage mites were thought to be the tiniest organisms known!