Harvestmen

2017 January 4

These are two different specimens of what I think are almost certainly the same species, one from June 25, 2016 and the other from July 9, 2016. If it weren’t for the date stamps on the photos, I’m not sure I’d be able to tell which one was which. Well, that and the fact that the one from July is missing a leg.

harvestman-b-full-dorsal

harvestman-a-full-dorsal

These are Harvestmen[1], in the order Opiliones, and these particular ones look to be in the family Phalangiidae.

harvestman-a-dorsal-body

harvestman-b-closer-dorsal

Normally, identifying harvestmen down to even the genus, let alone the species, is very difficult due to variability in their color pattern and the fact that they mostly have pretty much the same body shape. However, I think maybe we can make an exception in this case. I am reasonably confident that these are both Phalangium opilio.

harvestman-a-side-body

Why am I willing to identify these as that particular species? Well, mainly because this species is (a) very common in human-disturbed habitats, (b) found all around the northern part of the Northern Hemisphere, where they evidently followed the margins of the glaciers all around the world, and (c) at least one of the specimens on BugGuide that looks nearly identical to mine was found on Isle Royale, which is an island in Lake Superior only about 60 miles north of here (and that particular one was identified to species by an expert).

So, anyway, these are:
-Not spiders. There is no division into discrete body segments. If anything, they are probably more closely related to scorpions.
-Not dangerous. Unlike a lot of other arachnids, harvestmen don’t even have venom.
-Extremely fragile. They shed legs at the slightest provocation. The legs even keep wiggling for a while after they come off. This is a defense mechanisms, as any predator that grabs them is most likely to get a leg, and if it comes off they will be distracted enough that the body gets away.
-Not, as far as I know, objectionable to have around in any way. They eat all sorts of soft-bodied creatures (aphids, small caterpillars, mites, slugs, and the like), many of which are pests. And, they eat them early enough that the pests don’t have a chance to get large and damaging.
-Not edible. While they don’t have venom, most species do have chemical glands that make them distasteful.

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[1] Yes, I know that many (perhaps most) people call these “daddy-long-legs”. I do not, for reasons that I explained the first time that I posted pictures of harvestmen. I still stand by that.

2 Responses
  1. January 6, 2017

    It looks like one of those specialty vehicles at a construction site, designed to do one specific task and nothing else. All of the other spiders and whatnot are ordinary backhoes and bulldozers and then there’s this thing.

  2. Katbird permalink
    January 6, 2017

    Excellent photos!!! Thank you.

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