What is burying dead earthworms?
August 14, 2018 1:39 AM   Subscribe

So it has been really really hot here for the past month or so, which caused tons of earth worms to come to the surface and then die. Recently I have noticed that many of the worm corpses are becoming half buried in little mounds. Well maybe buried is the wrong word. Little mounds of stuff surround the worm corpses like a wall. What is causing this?

So at first I noticed it in sandy areas and figured that there was some natural reason that sand would accumulate around a worm corpse. However, yesterday I saw a dead worm on a brick sidewalk that was encircled by tiny leaves and other stuff. It definitely looked like some other creature did this. Any one know what does this or how it happens?
posted by Literaryhero to Science & Nature (7 answers total) 8 users marked this as a favorite
Please please I need to see photos of this.
posted by amtho at 5:21 AM on August 14, 2018 [13 favorites]

Could be ants. They will excavate after a flood and leave little piles of earth around. The grain size varies by species but if the mounds are made up of little grains of packed dirt, it’s most likely ants.

The collocation could be because the ants experienced flooding in the same places worms do, but also it’s easy to not count all the little piles around that aren’t near a dead worm.

The other possibility is other worms: worm castings also form little piles.

Where in the world are you, and can you post a photo?
posted by SaltySalticid at 5:22 AM on August 14, 2018 [2 favorites]

I would imagine that worms would borrow deeper when it's hot, not come to the surface.

Has it been raining a lot? Worms will surface when the soil is saturated. Perhaps you're seeing small piles of debris that have been collected and moved about by little currents, and the dead worms are part of that.
posted by hydrophonic at 6:44 AM on August 14, 2018 [4 favorites]

Burying beetles (Nicrophorus) do this, although mostly with small vertebrates. Maybe some species tackle worms. Or maybe there is another insect with similar behavior.
posted by beagle at 10:17 AM on August 14, 2018

Here are some pictures. It is pretty clear to me now that ants are doing it, you can kind of see them working in the photos. What isn't clear is why. Anyone know?

Additional details. I live in Songdo, Korea. It is on reclaimed land (aka a man-made island) and it hasn't rained in a month, so I think it has to be the heat forcing them to the surface although I don't know why. It has been like 35c (95f) or hotter every day for the past month.

At any rate, I look forward to any answers that might come.
posted by Literaryhero at 3:09 PM on August 14, 2018 [1 favorite]

Maybe to keep other potential scavengers away from it?
posted by Preserver at 3:47 PM on August 14, 2018 [1 favorite]

Well, it might hide the food from other close-to-the-ground arthropods. From an ant's perspective, the worm would be invisible from outside the mound.
posted by amtho at 3:56 PM on August 14, 2018 [2 favorites]

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