Your opinion? Millipede
- Thread starter rcorteschile
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rcorteschile That's actually a defense mechanism against predators. Some millipedes can excrete cyanide compunds when they are attacked or annoyed. I was on a biology excursion in Costa Rica a few years ago. We experimented with this. If you annoy a living millipede enough they start excreting the chemical defence and will smell like this. At least in central america there are actually some Phoridae flies that use the smell to find and lay their eggs on them. I don't know if it happens in other places also.Just found a writeup describing this process: http://dailyparasite.blogspot.com/2017/07/myriophora-alexandrae.html
What we did was similar. We offered an annoyed millipede, and some chemicals found in their defense secretions in different petri dishes and counted for a set amount of time how many flies came to which spot.
The process of finding prey or a host for one's eggs by a chemical excretion of the host is called "Kairomone Signaling Pathway". A Kairomone is a so called semiochemical, which means that it is a chemical emitted by an organism that triggers a response in an organism of another species. The original purpose could be anything. In this case defense of the millipede. It's called a Kairomone when in a two species interaction the receiver of the signal (the fly) has a benefit (finding an egg host) and the sender has a disadvantage (dying by parastism). Normally the defense chemical has the exact different purpose, repelling predators. In this context it would be called an Allomone, positive for the sender (defense), negative for the receiver (poisoning/repelling). So this naming of chemical signals is always case specific.
