When Very Hungry Caterpillars go bad


From this week's Zoologger column in New Scientist:

In a grassy field on the edge of a patch of woodland, some ants are escorting a pink caterpillar to their home. Once it has been guided into the depths of their nest, the caterpillar begins feeding the ants with sweet fluids.

It may sound like a touching story of interspecies love, but it ain't. Over the following year, the caterpillar will eat its way through hundreds of ants, eggs and larvae. So voracious is the intruding caterpillar, there is a good chance that the ant colony will be wiped out.

This deceitful ant-muncher is the caterpillar of the large blue butterfly - in adult form, a strikingly beautiful creature with iridescent, spotted wings. But in order to reach adulthood, the caterpillars must infiltrate the ants' homes, and they have an arsenal of less than beautiful tricks for that purpose...

I like to imagine that lead being read by David Attenborough.

New Scientist: Zoologger: The very hungry caterpillar usurps a queen

Image courtesy Flickr user oddharmonic, via CC


  1. If only they could be bred or GM to live only on fire ants. But I hear they’ve begun releasing a specialized wasp for them already.

  2. @nanuq

    As with similar parasitic relationships there will be a delicate balance between those two species, i.e. there will be far more ant colonies than preying caterpillars.

    It’s similar with cleaner fishes and sabre-toothed blennies ( http://en.wikipedia.org/wiki/Sabre-toothed_blenny ). The latter look like cleaner fishes, but are in fact taking bites of healthy tissue from the larger fishes expecting to be cleaned.

    This also only works when there are far more real cleaner fishes than fake ones.

  3. The caterpillar relies on only a single species of ant – the ‘Myrmica’ ant. Obviously that lot aren’t too bright.

  4. David Attenborough DID do a segment on this caterpillar! I can’t remember which series… Life in the Undergrowth, I think.

  5. The caterpillar relies on only a single species of ant – the ‘Myrmica’ ant.

    Ah, too bad. I was going to see if I could get ahold of some of these caterpillars for the garden. But we have the ubiquitous Argentinian Supercolony, so we’re out of luck.

  6. @spike55151: I had forgotten about that Attenborough footage, but it’s so cool I added it to the original article. Thanks for the tip!

  7. The remarkable thing here is not the caterpillars, but the wasps. I’m surprised that Baker didn’t check out the video in the source. It is narrated by Attenborough.

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