Platyarthrus hoffmannseggii (Ant Woodlouse) blog (updated 6/8/25)

Info on this species: Platyarthrus hoffmannseggii, commonly known as the ant woodlouse, is a species of isopod in the Family Platyarthridae. This species of small isopod is technically not native to North America, being introduced from Europe, however, it has an established population in the US and is not considered an invasive species as it does not threaten the environment or any endemic species. This isopod is absolutely tiny, adapted to living its life underground within the nests of ants, particularly those of Lasius spp. and Mymica spp., feeding on their feces or mildew.

I collected a group of 10 adults and juvenile P. hoffmannseggii back on 5/11/25. They range in measurement between 2-4mm long or 0.07-0.15in long.

Jun 8, 2025

In captivity, P. hoffmannseggii have been kept on rotting wood or sawdust when kept without an ant colony host. I don’t feed my group as I keep them with plenty of locally sourced wood chips and bark pieces. They seem to be doing fine as I haven’t noticed any deaths so far.

I keep them in a small setup, a 16-oz deli cup. I got this group in around 1.5in of substrate as well as a suitable amount of leaf litter, with the top of the substrate covered in rotting woodchips and bark. I gave them in a low ventilation lid, as I assume they wouldn’t get too much air in the tunnels of an ant colony. I keep them with some white springtails to feed on excess decaying matter. I spray down the setup once a week to keep the humidity somewhat high. I keep this colony in a dark environment (8 hours of dim indirect artificial light) as well as heated to around 78°F.

I’m probably not going to update this colony so regularly as they aren’t super active and I won’t be making any major changes to their husbandry, but I am happy to say that I have noticed some babies!