If you’ve ever looked at ant cocoons, you may have noticed they always have a dark spot at one end:

What’s up with the spot?
There is no way to put it delicately: it’s poop. The dark spot is at the butt end of the developing ant. But this spot is not just any old poop. It’s a rather special one called a meconium.
Although young ants have been alive and eating for many weeks by the time they spin a coccoon, they never once passed their food all the way through. Ant larvae are massively constipated. Their waste builds up in the digestive tract as a strong, concentrated mass clearly visible through their translucent bodies:

Larvae hold the pellet in as it gets larger through several molts, and don’t expel it as a meconium until they transition to the pupal stage. So, young ants only poop once.
Of course, there is good reason for the extended constipation. Living in large groups in fixed nests, ants have a public health interest in not continuously soiling their nurseries.
Speaking as an expectant father myself, I admit to a little bit of jealousy of a species that manages but a single diaper change per offspring.
Awesomely cool information!
The first human larvae poop is called meconium as well. And it’s is pretty gross. After that it gets better for awhile until they start solids.
At some point as a parent, you become a digestive tract expert…
Hahaha, well written! Made me laugh.
At least little humans don’t molt!
Educational and funny, excellent! Thanks, Alex.
YOPO
As a parent of 3, I suppose I should envy the ants in this. But I actually never minded the loads of poopy diapers. The strong, hormonally induced parental bond was very effective at blocking out those moments.
Fantastic findings, and thanks!
Interestingly, we observed in Leptothorax acervorum ants, that larvae did “poop” with assistance of workers, which then transported the pellet to the dump site. Leptothorax don’t spin a cocoon, maybe that’s the reason? If so, I would wonder if all Myrmicinae do “poop”? Perhaps you know, if it then happens only once during larva phase, or more times? We didn’t observe larvae separately for long, so we couldn’t tell…
That’s the interesting thing about insects: there always seems to be an exception to the poopy rules !!
Anarchists (and in the case of ants … syndicalists)
This “poopobiology” is characteristic of all Aculeata, at least, and is interpreted as a means of only minimally soiling the pupation cell. I wonder two things about it:
– Is it characteristic of all Hymenoptera? – Would certainly make sense for endoparasitoids, too.
– I wonder if it might also increase the efficacy of absorption of nutritive material from the larval food?
I seem to recall seeing info about varied meconia in most all holometabolous insects. Some species eject the meconia during the prepupal phase. Some butterflies expel theirs immediately after pupal eclosion and I read that some hymenoptera (Trichogramma) do that also.
The energetics would be pretty difficult to access separately from normal processes, I would think.
Alex,
A quick and informal survey shows that I am the ONLY member of my household who finds this information fascinating and wonderful.
That’s too bad. Does your focus group suggest that information about the poop of other animals might be more interesting than that of ants?
Alex,
NO!!! They were even LESS impressed and even MORE disgusted when I was baiting my dung beetle traps with a variety of bait from various species, and asked me where I’d gotten my “human bait”.
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Congratulations on your imminent fatherhood! A well written article.
Best wishes,
Alex
Fire Ant Control Centre (Biosecurity Qld)
Brisbane
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I poop a lot these days. 😛
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