Mutillidae (Velvet Ants) Facts!

Mutillidae (Velvet Ants) are Wasps

Velvet Ant, Cow Killer, Cow Ant, Mutilidae
Female. Image credit: Craig Pemberton CC-BY-SA-3.0; Released under the GNU Free Documentation License.

The Mutillidae are also referred to as “velvet ants”, they are not ants however; they are a family of wasps consisting of more than 3000 species. The female mutillidae are wingless and have very vibrantly coloured, hairy bodies, which makes them resemble ants (hence the name). The colors can be bright orange, scarlet, black, white, silver or even gold. These colors serve as aposematic signals – meaning the conspicuous colors help to warn off predators.

Cow Killers

Red Velvet Ant crop Also known as ‘cow killers’ these little guys are actually wasps with a pretty nasty sting. Image credit: Kerry Wixted cc2.0

Males have wings but no stingers and the females have stingers but not wings; therefore if a walking velvet ant is spotted then it is definitely a female. The sting of the velvet ant is very painful so they are sometimes also called cow killer or cow ant.

Armor Plated Exoskeleton

Surface of the exoskeleton which are really not hairs as in the mammalian sense. Public domain image

The velvet ants also possess an unusually strong exoskeleton that helps them to retain moisture and also to invade the nests of prey. This outer covering is like a suit of armor and is very hard to penetrate; there have even been incidents where entomologists have faced difficulty in trying to pierce the armor with steel pins so that the wasps may be hung up for display.


A female eastern velvet ant. Image credit: Pollinator GFDL

The mutillidae show large sexual dimorphism, i.e. the males and females are very different. The female invades the nest of an insect like a ground-nesting bee or wasp nest, and deposits one egg near each larva or pupa. Once the larva emerges it feeds on the host and reaches full size in several days time. The velvet ant pupa will convert the host’s now empty shell into a cocoon for itself. The size of the velvet ant depends on the size of its host during the development period.

Mutillidae (also known as Velvet Ants) are featured in the following book:
25 Beastly Bugs and Insects

The YouTube video playlist below contains videos about velvet ants. Details of the videos featured are underneath.

The Playlist:

  1. COW KILLER ANT – GIANT RED VELVET ANT (Dasymutilla – Mutillidae) by id780
  2. Hoplocrates specularis (Mutillidae) velvet ant “cow killer” formiga feiticeira by Diego da Cruz Pereira
  3. Cow Killer Ant – aka Mutillidae by Candy Graham
  4. Velvet Ant by dcc002


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