The Mastery of Müllerian Mimicry in Mutillids

velvet ants
Adult female velvet ants: Western Mimicry ring. Photograph: Joe Wilson/Joe Wilson et al./Current Biology 2015

I have been seeing a lot about velvet ants (family Mutillidae) lately and that is totally cool because velvet ants are fuzzy little bundles of fabulous mimicry.  First time I saw one of the red species, I was struck by how bright and almost fake looking they seemed.  Just doing her thing, walking on the ground, not bothered by my incredulous staring.  Thankfully I was smart enough not to touch; the Schmidt Pain Index rates these as a 3 out of 4 and sensation lasting for about 30 minutes.  On my scale that is a five swear word string at a yell but not quite a scream.

Speaking of screaming, both males and females can produce a squeaking or chirping sound by stridulation when they are alarmed.  That’s a pretty neat defense mechanism.  Their other defense is the vivid coloration.  The aposematic coloration is The-Schmidt-Insect-Sting-Pain-Indexa warning to predators that they are dangerous.  This is beneficial to the ants (they don’t get eaten) and the predator (they don’t get stung).  This system of being potentially dangerous, and looking like something else that is potentially dangerous is Müllerian mimicry (vs. Batesian mimicry).  New research shows that of the 351 species studied (that’s just in North America!) all but 15 were morphologically similar.  The authors found that they could place all the species in eight “mimicry rings”.  Check out this really great article by GrrlScientist here.

The eight mimicry rings found in North American velvet ants. Morphological & geographic ranges of the 8 velvet ant mimicry rings. Each mimicry ring represented by 5 species, which are morphologically closest to the estimated mean for each mimicry ring
The eight mimicry rings found in North American velvet ants. Morphological & geographic ranges of the 8 velvet ant mimicry rings. Each mimicry ring represented by 5 species, which are morphologically closest to the estimated mean for each mimicry ring

Other facts about velvet ants:

  • Although in the wasp and ant order (Hymenoptera) they are not true ants and are solitary, not social.
  • Their stinger is nearly half the length of their body.
  • They have a very hard exoskeleton, thought to help with water retention in the dry environments they are endemic to.
  • They are extremely sexually dimorphic.  Males and females look so different from each other, males are often very hard to identify.
  • Female velvet ants attack other species of bees and wasps.  They lay their eggs on the other species larvae and pupae an the developing velvet ant larvae feeds on the other hapless larvae.
  • They are sometimes called “cow killers” due to the painful nature of their sting, but they cannot actually kill a cow.
DasyGlor1a-XL
Photo by Alex Wild

My personal favorite is the thistledown velvet ant (Dasymutilla gloriosa).  What’s yours?  Care to “share”?

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