Field of Science

Freak of the Week: Wingless, Legless Flies

I found this while looking up identification info for phorid flies, of which we currently seem to be receiving something of an influx in our samples.

Photoes from here.

Most of what you see in the lower of the two photoes above are larvae of army ants of the genus Aenictus. The odd one out is the whiter 'larva' in the centre—which is not a larva at all, but a fully adult female of the phorid fly Vestigipoda longiseta! (The upper photo shows the same animal in close-up.) This bizarre animal makes its living by imitating its host larvae and being fed by the larvae's deluded carers. Five species of Vestigipoda have been described to date from Malaysia (Disney et al., 1998; Murayama et al., 2008).

Close-up of head of Vestigipoda maschwitzi, from Disney et al. (1998).

Cases of neoteny, where insects develop full sexual maturity while still 'larvae', are not unknown among holometabolous insects (I earlier described a case involving the beetle Micromalthus). However, Vestigipoda cannot be regarded as neotenous because the female has a fully developed adult head.

So far, Vestigipoda seems to only be known from females. It is possible that males, when found, may turn out to be much more normal phorid flies. The challenge would be recognising them as related to their bizarre females.


Disney, R. H. L., A. Weissflog & U. Maschwitz. 1998. A second species of legless scuttle fly (Diptera: Phoridae) associated with ants (Hymenoptera: Formicidae). Journal of Zoology 246 (3): 269-274.

Maruyama, M., R. H. L. Disney & R. Hashim. 2008. Three new species of legless, wingless scuttle flies (Diptera: Phoridae) associated with army ants (Hymenoptera: Formicidae) in Malaysia. Sociobiology 52 (3): 485-496.


  1. Awesome. Are there any that live with a non-army ant sp., that might be raised in the lab to obtain a male...? What are they related to?
    And now a plug for my favourite ant symbiont - the tarsus mite. This is bizarre beyond belief...

  2. How do they know it's a Phorid if it's just a sausage...? Forgive my ignorance...

  3. No, the only known species so far are with army ants. As for how they know it's a phorid: I'm not actually sure, but the more normal phorids I've seen have a fairly distinctive appearance to their head. That would be my first guess for a connecting character.

  4. Great stuff. I bet the cuticular hydrocarbons of V. longiseta are just like those of the ants...


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