Predatory Running Mites

bugman

April 23rd, 2006 at 12:00 am

Categories

Mites

Red bugs on the porch
Hello,
Great site! I live in Richmond, VA and the weather has been fairly warm for the last month. I’ve ventured out onto porch for the first time this year only to find several hundred little red bugs crawling over the painted wooden railing of my historic Fan district apartment. I am concerned that these bugs might be harmful in some way. It appears they are or are related to mites, but I was hoping you could confirm that with the attached macro shots. Sharpening in Photoshop has whitening the edges of their bodies slightly. Thanks,
Doug

Hi Doug,
They are Mites, but not all Mites are troublesome. These look like Predatory Running Mites that eat other small arthropods including young spiders and insects. They would be considered beneficial. We have been getting numerous letters lately without images from people complaining about the little red spiderlike creatures running around on their window sills. When squashed they leave a red mark. Thank you for supplying us with an image.

Update From Barry M. OConnor (05/23/2006)
Predatory running mites. All of the mites in the photos you call by this name are species in the family Erythraeidae, genus Balaustium. I think you have these confused with species in the family Anystidae, genus Anystis. Both of these mites are relatively large (for mites!), red in color, and commonly occur in aggregations. Anystis are the very fast moving, predatory mites. Their body is almost circular in outline. They run in what appears to be a random fashion until they encounter small arthropod prey. These are harmless to people. Balaustium, on the other hand, are more elongate as seen in your photos, with a distinct gap between the 2nd and 3rd legs. Species of Erythraeidae have piercing mouthparts and are also predatory on small arthropods or eggs in their post-larval stages, but Balaustium are unusual in being pollen feeders. They can be found in large numbers in flowers, but are most often seen by people on flat surfaces where pollen falls. These mites have been reported to bite people, causing some irritation, although why they do this is uncertain since they’re not parasitic.