Today, I was at my local patch of woods (NC, US) when I noticed something strange; roughly every 5 minutes, I would hear a rustling sound in the fallen leaves near me. I would veer in the direction of the sound, expecting to find a lizard or even a small mammal, only for a Narceus millipede to emerge (here’s the observation of one of these); a majority of these seemed almost disoriented, tumbling down the slopes. Although I often find Narceus millipedes, I usually see them under fallen logs, and I’ve never seen them as frequently as today. Have there been any previous reports of this? After I noticed the pattern, my mind immediately went to the reports of Japan’s “train millipedes”, although obviously these weren’t the absolute swarms noticed from that species.
Seismic activity? Just a fun thought.
That’s a beautiful animal; I hope this is not an adverse even for them.
Maybe it’s mating season for them? Or they were just heading downhill in search of the shady and moist spots they prefer? I’ve read they crawl up the slopes during rain and down in dry weather. I see a lot of them out in the open crawling across trails during rainy weather. Not sure though what they were doing, I’m just guessing.
I remember seeing a large number of Narceus millipedes one year at a park I frequent a lot in MD. It was maybe five years ago, and there were dozens each visit. Every subsequent year has only produced a handful there overall. I figured at the time that they emerged in broods somewhat like cicadas. Interesting to see this happening in other places too.
Has your weather recently warmed considerably? It could be specimens emerging from winter hide-aways.
Yeah, it definitely has.
I wouldn’t describe Narceus activity as an “emergence” or “broods” since they are slow growing, long-lived animals that live for many years. There’s probably just something about the time of year and/or weather conditions that’s making them stir. They’re most often hidden under bark and leaf litter and in warm weather come out and climb tree trunks at night but its not uncommon for them to wander during the day either.
There is a zombifying fungus that attacks at least flat-back millipedes, from what I can remember from some obs here. Infection makes them go up onto exposed sites to die, presumably so that spores can spread easier. If they are disoriented-looking, maybe it’s the same one or a related one going for this type?
Edit: Found the one I was thinking of Arthrophaga myriapodina
I don’t suspect that’s the case, since numbers of Narceus moving around out in the open and climbing things is a common occurrence and i’ve never seen/heard of it being associated with large numbers of dead ones that could’ve been killed by fungus, but thanks for alerting me about this fungus since it explains why I saw a ton of dead Apheloria sitting exposed on rocks last summer