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| Photos: Wilfredor (iguana) and Alan R Walker (mite)- Creative Commons |
Pockets are pretty cool things. We put our belongings in them, warm our hands on cold days in them. Some lizards have them too, but they aren’t storing cell phones in them. Chiggers live in these pockets, although sometimes a tick finds its way in there too.
Chiggers are the larvae of trombiculid mites, which feed on tissue fluid and cell debris, and they are not choosy when it comes to who they infest. They are found on amphibians, birds, mammals (including us), and some lizards. And for anyone who has had a chigger encounter, it’s definitely not a good time. That’s because when these little things eat, they pierce the skin, inject saliva which causes cell breakdown and increase in tissue fluid. Thus, the inflammation and itchiness.
For lizards, the pockets the chiggers dine in are found usually on the side of the neck, the armpit area, groin, and base of the tail. Luckily, most lizard species have pockets in only one location. Chiggers like these places because they provide humid and warm places to feed. In some cases, the scales in this area are smaller than normal and the blood supply is better, meaning, these parasites have a much easier time getting dinner.
The infestation cycle goes like this: the tiny chigger enters the pocket and starts to feed. It increases size and then when it has had its fill, it leaves the pocket, drops to the ground where it will become an adult, mate, and the cycle starts all over again.
Mite pockets have been found more than 150 lizard species and in five distinct lizards families including Iguanidae, Chamaeleonidae, Gekkonidae, Lacertidae, and Scincidae.
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| Mite infestation on a gecko (genus Cyrtopodion) photo: Drew Davis |
Some researchers believe these pockets actually help the lizard deal more efficiently with infestation. The pocket provides a single area where the chiggers gravitate and thus localize the irritation.
Read our other Parasitism Halloween Blogs
Part 1: mermithids and earwigs
SOURCES
Benton, Michael J. “The mite pockets of lizards.” Nature, vol. 325. January 29, 1987.
Reed, Jay Clark. “Analysis of the Function and Evolution of Mite Pockets in Lizards.” University of Michigan Library, Research Collections, Dissertations and Theses (Ph.D. and Master’s) 2014.
