do millipedes spray cyanide? i relocated a couple while cleaning my yard and now i'm mildly concerned
the millipedes that release hydrogen cyanide release it as a gas. these include various flat-back millipedes, although there’s plenty of flat-backs that just use a benzoquinone-based fluid defense chemical, which is what many other common millipedes produce (including the round-backed juliforms one often finds in the yard). in either case, you’d need to swallow a millipede for it to do you any great harm.
Apheloria virginiensis is one local to me, and I am guilty of picking them up when on walks in the woods to smell the cyanide: it’s a fragrant scent of almonds or cherries.
cyanide-producing millipedes, since their defense chemical is gaseous, really can’t hurt you unless you’ve already ingested the millipede or are like huffing dozens of them, which would both be probably be actions deserving of consequences.
other millipedes’ liquid chemicals usually just smell foul, like burning rubber. most millipedes under 3-4 cm aren’t going to pack much of a toxic punch at all. some of the larger tropical species in the Spirobolida and Spirostreptida can cause caustic burns if it isn’t washed off soon with detergent or if you have very sensitive skin. I’ve harassed plenty a Narceus and gotten some yellow, later dark purple stains on my hands, but that was the extent of it.
The night blooming cereus had a second set of blooms this year. This time I got up early in the morning to see if it stayed open all night/ Here it is in full glory in early dawn.