Tag Archives: mites

Nature pics from Martin Forest

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For some reason I forgot to post this last year. Luckily, nature photographs aren’t particularly time sensitive. These are all from a warm day in November after a good rain. The Martin Forest is a 30-acre tract near Smedley Park, not too far from the Springfield Mall in Springfield, PA. The tract is owned by Swarthmore College.

Up first is a large trombiid mite that was lumbering along the trail. I’m assuming this is in the genus Tombidium and not Allothrombium, but nowhere within the 1000s of IDs on iNaturalist and BugGuide is a single useful comment about what distinguishes them. The only key I could find is on page 43 of Banks’ The Acarina or Mites published in 1915, and apparently Allothrombium has “pedunculate eyes”. For a great introduction to the group, see Zhang 1998.

Here’s another mite (Rhagidiidae) that was racing around a rotting log covered with moss and liverworts, likely looking for springtails and other small arthropods to eat. Its speed made it nearly impossible to photograph, so the above is just a lucky frame out of dozens of fails. BugGuide and iNaturalist generally just leave these mites at family level, which is a shame because I’d love to know more about what they do for a living.

This is a dark fishing spider (Dolomedes tenebrosus), I think. Likely just overwintering under the protection of loose bark (which I replaced).

I think this is Pogonognathellus dubius (Tomoceridae), a rather fetching elongate springtail. In searching for information on this species I discovered you can buy them. One site describes them as follows: “Among the largest springtails in the hobby. Blow on their antenna to see them curl into spirals, a unique characteristic of the genus. They have very relaxed personalities and mostly sit still, great pet invertebrate species.”

I’ve noticed this for years but have never before photographed it: mica with some sort of alga or lichen in between the layers. I wasted several hours trying to find out what it might be but came up with nothing. Which means I’ll probably need to collect a sample and put it under a compound microscope.

If you enjoyed any of the above, I also post nature pics and esoteric facts on Mastodon. And occasionally on Bluesky. I still have a Twitter account but it’s silent except for periodic updates on Spartan Mosquito (the company suing me for exposing its scam).

Bats with red spots

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During a 2008 trip to La Selva Biological Station in Costa Rica, I took a terrible photograph of some lesser sac-winged bats (Saccopteryx leptura) roosting on the underside of a tree.

Roosting bats covered with red dots

I kept the photograph because the bats seemed to sporting some strange red dots that were the color of giant red velvet or trombidium mites, and I was curious. But I looked online (for years) and for the life of me couldn’t find any reports of something that large on a bat in Costa Rica. All I succeeded in discovering was that quite a few smaller mites seem to be found on bats (Banks 1915; Klimpel and Mehlhorn 2013), with new species found all the time.

One person suggested that they might be chigger mites (Trombiculidae). Each spot, perhaps, would be composed of hundreds of mites feeding together. Chiggers feeding in a group isn’t rare, apparently. If you search for “trombiculidae aggregation” you’ll get lots of images of seething groups (e.g.) on all variety of animals. But it begs two questions. Why does each bat have only one clump, and of the same size.

UPDATE: After posting and sharing on Twitter, Sean McCann sent me a message asking whether my dots might be marking bands. He also sent a photograph (a good one) in which the locations of the bands exactly matched where my dots are in my photograph. So I contacted Dr Carlos de la Rosa, the Director at La Selva Biological Station, to see if anyone was banding bats at the time, and he responded that it was likely … and is checking to see exactly who. I’ll post an update if I hear back. 

UPDATE II: Dr de la Rosa spoke with Dr Martina Nagy, who claimed those bats as part of her research (as well as corrected my species identification; they are not rhinoceros bats). She even recognized the tree (“SOR 170 Sendero Oriental”). These individuals (two males, one female) had been banded by Dr Barbara Caspers. The tree eventually fell and then the bats disbanded to someplace else. 

It took me almost 10 years, but I’m glad I finally know what was going on. That photograph had really been bugging me. Thanks, everyone!