I live in NJ and have these teeny tiny pin size red bugs covering my concrete porch and steps. They’ve also started climbing up my house around the door frame but haven’t managed to get themselves inside yet. They appeared around this time last year and eventually went away, however this year there are many many more of them. They leave red stains when squished. They look similar to predatory running mites I’ve seen on your site, although I can’t tell if they are exactly the same. What are they, what can I do, how long will they last? Are they dangerous to children? I have a 2 year old that is obsessed with them and as much as I try to keep her away from them, I’m fearful she’ll get a hold of them sooner or later. Please help!
Generally, but not always, small predators need small prey. In the spring, newly hatched insects are small. Predatory Running Mites are more plentiful when their food supply abounds. As insects grow too large to be prey, the predator population will decline. These Predatory Running Mites will not harm your child.
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.