Ticks in pictures

Some more about ticks.  No, not The Tick comic or the movie Ticks … both may be entertaining, but they feature completely inaccurate depictions of ticks.

Let’s talk about real ticks:  Ticks are rather large mites. To demonstrate this, here is a family portrait:

family portrait of Ixodes pacificus, California Dept. of Public Health

Family portrait of Ixodes pacificus, California Dept. of Public Health [public domain]

From left to right, larva (6 legs), nymph (8 legs), male and female of Ixodes pacificus, the Western black-legged tick, from the west coast (you can see them with the naked eye, therefore they are big).

All members of the family feed on host blood using highly modified mouthparts, but only larvae, nymphs, and females engorge (feed to the point where their body truly swells up).

close-up of mouth parts of Amblyomma extraoculatum, U.S. National Tick Collection (USNMENT00956315)

Close-up of mouth parts of Amblyomma extraoculatum, U.S. National Tick Collection (USNMENT00956315)

Here are some nice examples of engorged females.  Keep in mind that while engorged ticks are easy to find, they are often difficult to identify.

Most of the ticks we encounter in Ohio have females that feed only once.  They engorge, convert all that host blood into a single mass of hundreds to thousands of eggs, and die.

tick with eggs (c) Univ. Nebraska, Dept. Entomology

Tick with eggs, Univ. Nebraska, Dept. Entomology

Ticks in general get really bad press.  Kind of sad, because ticks are very good at quite a few things, like surviving (some can survive hours under water or years without food), or manipulating your immune system (using a dizzying array of chemicals often found only in ticks). On second thought, that may not strike most people as positive, so let me end with a few pictures of beautiful creatures. I already introduced Amblyomma americanum, which occurs in Ohio, the others are African, A. chabaudi on tortoises in Madagascar, A. variegatum usually on cattle. Amblyomma variegatum is the main vector of heartwater, a disease making cattle herding impossible in parts of Africa, but still, very pretty.

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See some more of these specimens close-up, but at a safe distance through microscopes at our Annual Open House, April 22, 2017.

 

Dr. Hans Klompen, Professor EEOBiology at OSUAbout the Author: Dr. Hans Klompen is professor in the department of Evolution, Ecology and Organismal Biology and director of the Ohio State University Acarology Collection.

*** Which of these ticks is your “favorite”? Let us know on Facebook ***

 

Strange things to do with ticks

When most of us think of natural history collections we see well-labeled, nicely arranged rows of jars, sets of herbarium sheets, or pinned insects, and this is certainly a curator’s ideal. But this does not acknowledge the occasional outburst of mis-applied creativity leading to a novel approach to preserving specimens. Every collection probably has a few examples, and I thought I should share some from the acarology collection. The collection includes some ticks processed in ways that are simultaneously novel, creative, and useless.

The standard way to preserve ticks is in fluid, mostly 70-95% ethanol. Ideally in good vials with complete labels, and a barcode linked to a properly functioning database.

vial of ticks (Ixodes lemuris) with proper labeling

vial of ticks (Ixodes lemuris) with proper labeling

One less than great alternative is diluted formalin, at least for a brief period of time. This mixture does not evaporate as fast as ethanol (good in warm regions and in the absence of good containers) but it diminishes the value of the specimens because it destroys DNA. Still, this is not very odd. “Weird” would be one word for the option of pinning ticks.

pinned and slightly shriveled ticks

pinned and slightly shriveled ticks

 

We have a few of these in the OSU Acarology Collection. These specimens are essentially useless. Insects, with their hard cuticles, do quite well on pins, but generally soft-bodied organisms like ticks just shrink and shrivel, in the process destroying many valuable characters.

 

 

 

While tick adults and (usually) nymphs are fluid preserved, tick larvae are small enough that they can also be put on slides. A well-prepared slide of an unengorged tick larva can be a thing of beauty.

slide of larval Haemaphysalis lemuris

slide of larval Haemaphysalis lemuris

Under a microscope you can observe very fine detail of the cuticle structure, leg hairs, mouthparts, etc. Of course not everybody is as narrow-minded as the above lines suggest. For example, one specimen of an engorged adult dog tick (Dermacentor variabilis) in our collection shows a reckless disregard of the rule that slide mounting is only for larvae. The specimen is encased in a 2mm high wooden “box” placed on a slide, filled with mounting medium and topped with a glass cover slip.

side view of slide with female Dermacentor variabilis

side view of slide with female Dermacentor variabilis

The overall resulting structure is far too thick and too opaque to be usable, but the craftsmanship exhibited in making this “box” can only be described as exquisite.

 

I would like to close with a salute to those among us that are not bound by conventions and that bravely go where nobody has gone before. Just don’t do it again.

 

About the Author: Dr. Hans Klompen is professor in the department of Evolution, Ecology and Organismal Biology and director of the Ohio State University Acarology Collection.