Ticks and Mites (Order Acari)

The Order Acari comprises a "huge, diverse group of about 300 families and 30,000 species", "are found in every habitat, including aquatic ones, and have a wide range of lifestyles." (McGavin, cited on main Arthropod page, p. 223) Most of them are quite small, and their bodies have no distinctive divisions. Their fossils go back to the Devonian Period (417-354 Mya) of the Palaeozoic Era.

Visually most striking in our area are the Velvet Mites (Trombidium spp), shown below, whose reddish bodies have myriad hairs giving them a velvety appearance. Click on each image to enlarge it.


In the image at right, the body looks like a lumpy blob. This lumpiness is evident in many of these species. When we handled this specimen, it went into a dormant/defensive state as seen here. In the enlargement of the image you can also clearly see the many hairs.

In the images below, the creature has been turned over, showing the underside in this dormant/defensive state. Again, in the left-hand image the hairs are clearly visible.


The background dots in 3 of the images are glove-marks, which facilitate measuring the creature at just under a centimeter in size. Most Trombidium species are smaller than this. We see these creatures walking on the ground in July after the Monsoon rains begin. This is typical for the group -- the adults emerge from the soil after heavy rain to mate and lay their eggs. The larvae of some species are parasitic on various arthropods, while the adults feed on small arthropods as well.

The Department of Entomology of the University of Nebraska-Lincoln kindly makes available the following image of a specimen from their area, photographed by Jim Kalish:

The species in our area looks much more heavily furred than this one, but the general shape is similar and you can see the pedipalps in this image. We will work to provide better imagery in the future.

These velvet mites are found worldwide, especially in the Tropics. As you might expect for such a visually striking creature, Trombidium is widely in demand for Homeopathic remedies, and in India these insects, also called "rain insects", are intensively collected to be sold as a sex tonic (the "Indian Viagra") and for making an oil said to enlarge women's breasts.