1. BreAnna Grantham
Entomology
Term paper
The Unique Ecology of Velvet Ants
Abstract
Velvet ants, Mutillidae, are a very unique family under the order of Hymenoptera. Velvet ants
are not as common as most insects, so they are understudied. Velvet ants have a vast diversity in
ecology as well as unique behavioral tendencies. There are very few observational studies about
the mating system employed by velvet ants. Velvet ants also have unique characteristics that
greatly reduce their rate of predation, including a cuticle that is sturdier than that of most insects.
There is also a high likelihood of many undiscovered species of velvet ants, including cryptic
species which look morphologically similar and therefore assumed to be the same species.
Further studies about the ecological niches of velvet ants are important for conservation reasons.
Body
Velvet ants, Mutillidae, are a family of insects in the order Hymenoptera. Most diurnal velvet
ant species have an appearance of brightly colored large fuzzy ants and are very conspicuous
when encountered. In spite of many species being visually obvious, velvet ants are not so
commonly encountered by humans as much of their life history is spent underground, leaving
much to be learned about this insect group. Unlike most families of wasps, velvet ants are
solitary and are not found in colonies. There are many different species of velvet ants in various
shapes, sizes, and colors with various behavioral tendencies and utilization. Many velvet ant
species have some unique behavioral traits as well as ecological niches.

2. Multillidae are often classified as a type of wasp in spite of their appearance being unlike
that of a wasp. Known species of Multillidae are parasitoids of other families of Hymenoptera.
Most species of Multillidae specialize in one or more wasp species as hosts during larva and/or
pupa stages for egg laying purposes (Wilson, J. S., 2010). Mating behavior is not often observed
in this species, so it is much understudied, especially in male velvet ants. Female velvet ants are
known to search for the nest of a potential host, entering it when the host parent is absent. The
female velvet ant then oviposits on the larvae and/or pupae within the nest. There have been
some observations of male velvet ants entering the host nest with the female. Mating habits in
velvet ants vary greatly from species to species. Some species have obvious sexual dimorphism,
and often times this involves male velvet ants having wings while the females do not. Most
known velvet ant species are known for the ability to make high pitched noises with parts of their
thorax; this behavior is called stridulation and is used in both sexes to attract mates as well as a
response to potential predation. In general, female velvet ants search for host nests, while males
look for female mates; a behavior sometimes observed in females as well. In many winged
species of velvet ants, males seek mates by flying close to the ground and walk rather than fly
under lower temperature conditions. Males tend to gather in shaded areas rather than near
potential host nests where the females would be expected, which is likely due to surviving in
desert climates. Many species of velvet ants have a male biased sex ratio, which leads to intense
male to male competition as well as females regarding in multiple mating events for often times,
a few to several males will gather around a female velvet ant and either the victorious male drags
the female away from other suitors, or immediately copulates with her after fighting. In many
species, the male is smaller than the female and is unable to drag her away from the other suitors.
In some species the male is about the same size or larger than the female and carries her off

3. during flight. Velvet ants have also evolved survival adaptations for the possible scenario of the
parent of the hosts nest returning and attacking, such as a thick cuticle as well as a powerful sting
in females. (Polidori, C., 2013) These characteristics are also advantageous for minimizing
predation in velvet ant species.
Velvet ants have many characteristics making them unpalatable and unappealing to most
insectivores. Velvet ants have bright coloration, which is a common indication of the presence
of a toxic substance within the organism. Velvet ants also make high-pitched noises with parts
of their thorax that are unusually loud for their small size. Female velvet ants have stingers that
are about half as long as their total body length. Most velvet ants have a fuzzy texture, as well as
chemical secretions that can easily irritate mucus membranes if a predator attempts to ingest
them. Additionally, velvet ants have a sturdy and slippery cuticle that makes it difficult for even
very insensitive predators to consume them. Velvet ants have characteristics that prevent initial
contact such as fast and unpredictable movement patterns that make them difficult to catch and
possibly be intimidating to would-be predators. An experiment regarding velvet ant predation
was done with skinks by comparing the feeding behavior skinks have when presented with
crickets to their behavior when presented with velvet ants (Vitt, L., J., 1988). Most of the skinks
ate the crickets, but not the velvet ants. Some of the skinks tried to eat the velvet ant, but
released it quickly. Skinks often eat other types of stinging wasps as well as other insects with
tough cuticles, suggesting that velvet ants are an exceptionally difficult prey item for many
insectivores.
Within the family Hymenoptera, Multillidae not only have unique characteristics within
the family but also have an abundant diversity of lifestyles that vary from species to species.
There are nocturnal species which are smaller and have more pale coloration than in the

4. conspicuous diurnal counterparts. Velvet ants also are diverse in their methods for obtaining
food. Some species have been observed drinking artificial nectar when it was provided as a food
source under laboratory conditions. In the field, they have been observed taking nectar from
flowers. There also have been observations of females of an African species drinking liquid from
host wounds after attacking it (Wilson, J., 2010). Different velvet ant species specialize in
different wasp hosts for reproductive purposes, as well as food sources. Data are limited
regarding the overall ecology of velvet ants, but some ideas of ecological roles they play can be
formed by compiling observations from multiple studies. Velvet ants are a parasitoid that may
prevent other species of wasps from becoming overly abundant. Velvet ants also are unique in
their many adaptations that have lead to a decreased number of predators in contrast to other
insects, which leads to a higher survival rate of individuals (Wilson, J. S., 2010). Therefore,
fewer individuals are required to maintain the population. Velvet ant populations are balanced by
the populations of hosts they depend on for reproduction, so they are less likely to cause
ecological imbalance resulting from immersed populations than most other insect species. Some
species of velvet ants are likely pollinators since they have been observed taking nectar from
flowers and getting pollen on their bodies in the process (Wilson, J., 2013). Velvet ants could
have many more unobserved ecological purposes, as well as undiscovered species.
There are many species of Mutillidae that look so morphologically similar that it is
assumed they are the same species. In such cases, the morphologically similar species are called
cryptic species. Such species are found out through DNA testing as well as habitat comparison
to understand whether or not these possibly separate species are capable of interbreeding. A
cryptic species can have distinct ecological niches from its morphologically similar counterparts.

5. There are probably many more species of velvet ants than previously thought, which could also
many undiscovered ecological niches as well. (Wilson, J., 2012)
Concluding remarks
Data concerning velvet ants are limited, as they are understudied in contrast to most other
families of wasps and other insects. There are most likely many species in the Mutillidae genera
yet to be discovered. Further studies on Mutillidae would increase our understanding of their
ecology in a unique and overlooked perspective as well as better understand evolution in insects.
Mutillidae have various unique adaptations for different niches as well as environments. Further
studying Mutillidae would also be helpful for understanding how characteristics in insects evolve
specifically among Hymenoptera. It also is important to learn more about Mutillidae with regard
to conservation as many species are rare yet may play important ecological roles that we remain
unaware of due to lack of observations.

6. References
Polidori, C., Beneitez, A., Asis, J., & Tormos, J. (2013). Scramble competition by males of the
velvet ant Nemka viduata (Hymenoptera: Mutillidae). Behaviour, 150(1), 23-37.
Vitt, L. J., & William E. Cooper, J. r. (1988). Feeding responses of skinks (Eumeces laticeps) to
velvet ants (Dasymutilla occidentalis). Journal Of Herpetology, 22(4), 485-488.
Wilson, J. S., Williams, K. A., & Pitts, J. P. (2010). Preliminary assessment of velvet ant
(Hymenoptera: Mutillidae) diversity in the deserts of Southern California. Western North
American Naturalist, 70(2), 224-232.
Wilson, J.S., Clark, L.S., Williams A.K., & Pitts, J.P. (2012). Historical biogeography of the
arid-adapted velvet ant Sphaeropthalma arota (Hymenoptera: Multillidae) reveals cryptic species.
Journal of Biogeography, 39(2), 336-352.
Wilson, J., Williams, K., Tanner, D., & Pitts, J. (2010) Nectaring by nocturnal velvet ants
(Hymenoptera: Mutillidae). Southwestern Naturalist, 55(3), 441-443.