Dasymutilla occidentalis

Geographic Range

Red velvet ants (Dasymutilla occidentalis), inhabits the Nearctic region, specifically, the United States. Their range stretches northward from Florida to Connecticut and Pennsylvania. The range continues west towards the western edge of Texas and into the south-eastern parts of Colorado and Kansas. (Simbeck, 2020)

Habitat

Red velvet ants are commonly found in habitats that are sunny, warm, dry, and have sandy soil. These include pastures, fields, meadows, and along forest edges. Red velvet ants co-occur and parasitize ground nesting bees and wasps, like cicada killer wasps (Sphecius speciosus) and horse guard wasps (Stictia carolina). Male winged red velvet ants can be found on flowers eating nectar and the wingless females are ground-dwellers that search for nests to invade. The elevation and depth for this species is not reported. (Grissell, 2010; Schmidt, 2018; Simbeck, 2020; "Velvet Ants", 2022)

Physical Description

Red velvet ants range in size from 6 to 25 mms in length. Both sexes have black and red-orange hairy spots on the dorsal section of their abdomen, and their thorax looks like red velvet due to the thick abundance of red hairs. The rest of their body is mostly black. They closely resemble large ants even though they are a species of solitary wasp. Their bright colors are a form of aposematic coloration, which is a color pattern of bright colors to warn potential predators that the species is venomous or dangerous in some form. Red velvet ants posses a powerful sting and a tough, durable outer body that is difficult to pierce or break.

Red velvet ants are a sexually dimorphic species. Female red velvet ants are slightly larger than males. Females have a stinger with a powerful venom but lack wings. Male red velvet ants have black translucent wings, they are mostly black with the same patches of red-orange as the female, and closely resemble wasps rather than ants like the females. The males are incapable of stinging as they do not have a stinger. Both male and female red velvet ants display bilateral symmetry. Red velvet ants are ectothermic relying on the temperature of their environment to determine their body temperature.

Mass, wingspan, and basal metabolic rate for red velvet ants is not reported. (Abbott and Abbott, 2023; Carde and Resh, 2009; Eaton, 2021; Nellis, 1997; Schmidt, 1977; Schmidt, 2018; Simbeck, 2020; "Velvet Ants", 2022)

  • Sexual Dimorphism
  • female larger
  • sexes shaped differently
  • Range length
    6 to 25 mm
    0.24 to 0.98 in

Development

The life cycle of the red velvet ant is as follows: egg, larva, pupa, then adult going through complete metamorphosis. Female red velvet ants will seek out the nest of one of its host species to lay a singular egg. Once the egg is in place near or in the brood chamber of the host species, female red velvet ants will leave the egg and the host nest.

After roughly 3 days the egg will then hatch into the larval form and proceed to feed on the other larvae and pupae of the host species. The larva will continue to feed until it is ready to enter its pupal stage. The pupation process takes around 20 days to complete, while in the pupal stage the red velvet ants will remain in the brood chamber and will overwinter with the host species larvae and pupae. If it is still warm enough in the outside environment, the red velvet ants will leave the host nest before overwintering to look for a potential mate. When the ambient temperature increases as winter ends, adult red velvet ants will leave the host nest and proceed to find a mate. (Capinera, 2008; Simbeck, 2020; "Velvet Ants", 2022)

Reproduction

Male red velvet ants will fly over their surroundings to look for females for mating. Females will release a pheromone and stridulate to help attract the males to their location. After the males locate a female mate, male red velvet ants will use their mandibles to pick up the females and will either fly or run to a safe, shady area to begin the mating ritual.

Once the mating ritual begins, male red velvet ants will mount the females and then both the male and female red velvet ants will begin to stridulate. During the copulation process both sexes will continue to stridulate for the duration of mating. Once the mating process has been completed the males and females will part ways. The female red velvet ants will search for a nest of one of their host species to lay eggs. Male and female red velvet ants mate once and do not bond with each other, often males can become aggressive towards the females after copulating. (Capinera, 2008; Eaton, 2021; Schmidt, 1977; Simbeck, 2020)

Red velvet ants start reproducing in the warmer months of the year. Red velvet ants have only one egg clutch per year. Females and males do not take care of the eggs once they are laid, and female red velvet ants leave immediately after placing eggs in the host species' nests. Hatchlings are ectoparasites of their hosts, with a larval velvet ant feeding on its host larva. Velvet ant larvae pupate inside host nest and continue to feed on the host.

Juvenile red velvet ants of both sexes typically are mature ca. 23 days post-hatching. These individuals emerge as adults typically in July or August. However, not all individuals reach adulthood in the summer; some individual red velvet ants will remain and pupa over the winter months and instead emerge the following spring.

Because females live just one year and males do not always overwinter, it is suspected that these velvet ants mate just once in their lifetimes (semelparous). (Capinera, 2008; Eaton, 2021; Schmidt, 1977; Simbeck, 2009; Simbeck, 2020; "Velvet Ants", 2022)

  • Breeding interval
    Red velvet ants breed once yearly
  • Breeding season
    Warmer months during the year
  • Average time to independence
    0 minutes
  • Range age at sexual or reproductive maturity (female)
    23 (low) days
  • Range age at sexual or reproductive maturity (male)
    23 (low) days

Males have no parental involvement beyond the act of mating. Once female red velvet ants lay the eggs on the host larva, females leave the eggs and do not return. (Capinera, 2008; Simbeck, 2020)

  • Parental Investment
  • no parental involvement

Lifespan/Longevity

Red velvet ants live for up to one year in the wild, and females are known to overwinter. It is unclear is males live as long as females; in other species in the family, males may live just 22 days past the act of mating. Due to their solitary nature red velvet ants are difficult to locate and track. There has not been a formal measure of red velvet ants' lifespan in captivity as they are often caught in the wild for research purposes and are difficult to age properly with this method. (Gall, et al., 2018; Schmidt and Blum, 1977; Wilson, et al., 2012)

  • Average lifespan
    Status: wild
    1 years
  • Average lifespan
    Status: wild
    1 years

Behavior

Red velvet ants are a solitary species meaning that they do not form nests or reside together in any fashion. The only time that red velvet ants come into contact with any member of its species is to mate. Red velvet ants are generally not aggressive and will not seek out other species to attack. However, red velvet ants will deploy a variety of tactics to avoid predation. Most often the red velvet ants will scurry away from anything that is perceived as a threat or dangerous, but once attacked they will stridulate (rub body parts together to make a squeaking sound) to try and scare the attacker. If these tactics fail female red velvet ants will use very powerful and painful sting to deter predators. Males will utilize their wings to fly away as they are unable to sting predators. Females lack wings are are instead terricolous. They may be fossorial while laying eggs in host nests.

Red velvet ants are diurnal and will rest during the night time and will be active during the day, seeking shade to cool off on warmer days while searching for mates. Being active during the day also allows the female red velvet ants to search for potential host species' nest to lay their eggs while populations of these hosts are away from the nest. The adults feed on nectar from plants, while the larval stage of the red velvet ants parasitize the larval and pupal stages of their host species.

Some individuals will overwinter as pupa. Some females will overwinter as adults; it is unclear of the patterns for adult males, but their lifespans may be markedly shorter (as is true for most males in the family). (Abbott and Abbott, 2023; Borror and White, 1970; Capinera, 2008; Eaton, 2021; Schmidt, 1977; Schmidt, 2018; Schmidt and Blum, 1977; Simbeck, 2009; Simbeck, 2020)

Home Range

Red velvet ants do not have an indicated or recorded home range. This is most likely due to their solitary nature and lack of building a nest. Red velvet ants spending the majority of their adult life looking for a mate. (Capinera, 2008)

Communication and Perception

Red velvet ants have a number of ways to communicate with conspecifics when encountering potential mates. In this case, female and male red velvet ants will stridulate to identify as conspecifics, and the females use pheromones to help the males locate them. Red velvet ants also use this stridulation (rubbing body parts together to make a squeaking noise) to warn predators of their presence when the predators get too close. Both male and female red velvet ants use their sense of sight to spot potential predators and areas of shade to run to and hide if danger is sensed. Red velvet ants also used vibrations in their environment to sense potential dangers.

Red velvet ants have very bright and noticeable orange-red coloration to warn predators away from trying to eat or attack them. If the aposematic coloration fails to deter the predators, female red velvet ants have a very powerful and painful sting. (Eaton, 2021; Gall, et al., 2018; Schmidt and Blum, 1977; Wilson, et al., 2012)

Food Habits

Adult female red velvet ants spend most of their time seeking out nests of ground dwelling cicada killer wasps (Sphecius speciosus) and horse guard wasps (Stictia carolina), among other bees and wasps, to lay their eggs so that their parasitic larvae can feed on the mature pupae of these species. Red velvet ant larvae will remain in these nests feeding on their hosts until after they pupate and reach their adult stage. Once the adolescent red velvet ants reach their adult stage, they feed on the nectar of plants and drink water to sustain themselves. (Abbott and Abbott, 2023; Eaton, 2021; Grissell, 2010; Schmidt, 2018; "Velvet Ants", 2022)

  • Animal Foods
  • insects
  • Plant Foods
  • nectar

Predation

Red velvet ants have a wide variety of anti-predator adaptations. Red velvet ants have the ability to stridulate to deter predators from attacking them. Females have a very powerful sting to defend themselves if a predator gets too close. Red velvet ants also have aposematic coloration to deter predators that spot them with their brightly colored hair. This coloration is also part of a specific type of mimicry called Mullerian mimicry where different harmful species have the same coloration tactics to mutually benefit each other. (Capinera, 2008; Gall, et al., 2018; Schmidt, 1977; Wilson, et al., 2012)

Ecosystem Roles

Red velvet ants are an ectoparasites of many ground-dwelling species of bees and wasps. There are very few that have been observed by researchers, but of those observed are cicada killer wasps (Sphecius speciosus) and horse guard wasps (Stictia carolina). It is possible that while the females and males are climbing on plants to drink the nectar the red velvet ants by proxy pollinate these plants, but it is uncertain. (Grissell, 2010)

Species Used as Host

Economic Importance for Humans: Positive

Red velvet ants are a topic of research to better understand their adaptations and behavior. Red velvet ants provide an insight into parasitism and aposematic coloration as an evolutionary trait, along with the Mullerian mimicry they pose. There is no other economic importance for humans stated or recorded. (Gall, et al., 2018; Schmidt, 1977; Wilson, et al., 2012)

  • Positive Impacts
  • research and education

Economic Importance for Humans: Negative

Female red velvet ants have a very painful sting; if agitated by humans, they will sting. The sting is very painful but non-lethal to humans and pets. There are no related economic costs due to this species. (Schmidt, 2018; "Velvet Ants", 2022)

  • Negative Impacts
  • injures humans
    • bites or stings

Conservation Status

Red velvet ants have not been evaluated by the IUCN Red List. They have no special status from the US Fish and Wildlife Service, CITES, or on the State of Michigan List.

They have no known threats to existing populations.

Given this lack of information, no conservation measures are in place.

Contributors

Caleb Smith (author), Radford University, Candice Amick (editor), Radford University, Katherine Gorman (editor), Radford University, Karen Powers (editor), Radford University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

aposematic

having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

diurnal
  1. active during the day, 2. lasting for one day.
ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

herbivore

An animal that eats mainly plants or parts of plants.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

mimicry

imitates a communication signal or appearance of another kind of organism

monogamous

Having one mate at a time.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nectarivore

an animal that mainly eats nectar from flowers

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

parasite

an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

seasonal breeding

breeding is confined to a particular season

semelparous

offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

venomous

an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

References

Virginia Cooperative Extension. Velvet Ants. ENTO-539NP. Blacksburg, Virginia and Petersburg, Virginia: Virginia Tech, Virginia State University. 2022. Accessed January 26, 2023 at https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/ENTO/ENTO-22/ENTO-539.pdf.

Abbott, J., K. Abbott. 2023. Insects of North America. Princeton, New Jersey: Princeton University Press.

Borror, D., R. White. 1970. Peterson Field Guides: Insects. New York, New York: Houghton Mifflin.

Capinera, C. 2008. Red velvet ants. Pp. 4073-4076 in C Capinera, ed. Encyclopedia of Entomology, Vol. 1, 2nd Edition. New York, New York: Springer Publishing.

Carde, R., V. Resh. 2009. Defensive behavior. Pp. 255 in R Carde, V Resh, eds. Encyclopedia of Insects, Vol. 1, 2nd Edition Edition. Amsterdam, Netherlands: Elsevier Publishing.

Eaton, E. 2021. Wasps: The Astonishing Diversity of a Misunderstood Insect. Princeton, New Jersey: Princeton University Press.

Gall, B., K. Spivey, T. Chapman, R. Delph, E. Brodie, J. Wilson. 2018. The indestructible insect: Velvet ants from across the United States avoid predation by representatives from all major tetrapod clades. Ecology and Evolution, 8/11: 5852-5862.

Grissell, E. 2010. Bees, Wasps, and Ants: The Indispensable Role of Hymenoptera in Gardens. Portland, Oregon: Timber Press.

Hertz, J. 2015. "Mutillidae (Insecta: Hymenoptera)" (On-line). Accessed February 02, 2023 at https://entnemdept.ufl.edu/creatures/misc/wasps/mutillidae.htm#top.

Nellis, D. 1997. Poisonous Plants and Animals of Florida and the Caribbean. Sarasota, Florida: Pineapple Press.

Schmidt, J. 1977. Defensive Strategies of Wasps and Ants: Dasymutilla occidentalis and Pogonomyrmex badius. Athens, Georgia: University of Georgia‚ÄČ.

Schmidt, J. 2018. The Sting of the Wild. Baltimore, Maryland: Johns Hopkins University Press.

Schmidt, J., M. Blum. 1977. Adaptations and responses of Dasymutilla occidentalis (Hymenoptera: Mutillidae) to predators. Entomologia Experimentalis et Applicata, 21/2: 99-111.

Simbeck, R. 2009. "For Wildlife Watchers: Red velvet ant" (On-line). South Carolina Wildlife Magazine. Accessed May 28, 2023 at https://www.dnr.sc.gov/magazine/articles/julyaug2009/redvelvetant.html#:~:text=Fertilized%20females%20dig%20through%20the,larva%20begins%20eating%20the%20host..

Simbeck, R. 2020. The Southern Wildlife Watcher: Notes of a Naturalist. Columbia, South Carolina: University of South Carolina Press.

Wilson, J., K. Williams, M. Forister, C. Von Dohlen, J. Pitts. 2012. Repeated evolution in overlapping mimicry rings among North American velvet ants. Nature Communications, 3: 1272.