Dasymutilla occidentalis

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Dasymutilla occidentalis
Dasymutilla occidentalis (female).jpg
Female
Dasymutilla occidentalis (male) 6184404.jpg
Male
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Mutillidae
Genus: Dasymutilla
Species:
D. occidentalis
Binomial name
Dasymutilla occidentalis
Synonyms [1]

Mutilla occidentalisLinnaeus, 1758

Dasymutilla occidentalis (red velvet ant, eastern velvet ant, cow ant or cow killer) [2] [3] [4] is a species of parasitoid wasp that can be found worldwide but are native to North America. [5] It is commonly mistaken for a member of the true ant family, as the female is wingless. The species ranges from Connecticut to Kansas in the north and Florida to Texas in the south. These insects live in environments such as pastures, meadows, fields, and forest edges, in warm and dry climates. They cohabitate with ground nesting bees and wasps. Adults are mostly seen in the summer months. [6]

The eastern velvet ant is the largest of the velvet ant species in the eastern United States, attaining an approximate length of 0.75 in (1.9 cm). Adults display aposematic coloration, consisting of black overall coloring with an orange-red pattern on the dorsal surface of the thorax and abdomen. Although known for their red coloration, their red coat can also appear black, gold, brown, or white. [7] They are covered in dense, velvet-like hair. [3] [4]

Characteristics and Description

Commonly mistaken for an ant, because of its appearance and its common name, it is a parasitoid wasp species in which the females are wingless, as is true for all females of Mutillidae. It can be recognized by its distinctive red coloring, with a black stripe that goes across the abdomen. [4] They are quick-moving and often take a defensive posture when threatened. Instead of creating nests, the females seek out the brood cells of Eastern cicada killers and horse guard wasps as well as other large ground-nesting members of Crabronidae, where they deposit an egg onto a host larva. The egg quickly hatches into a white, legless grub, which consumes the host and goes through several larval stages prior to pupation. Unlike the females, males have dark, translucent wings and do not possess a sting. [8] [2] [3] Males fly low over grass in search of mates. Both sexes make a squeaking noise (stridulation) to warn potential predators (another form of aposematism in females, and automimicry in males). [9]

Ecology

Dasymutilla occidentalis plays an ecological role as pollinators, parasites, and prey. Velvet ants may fall prey to insectivores like some toads and lizards, as well as some birds and small rodents. [10] The insect may evade predators' by previously stated defense mechanisms, as well as their aposematic coloration. In defense, they may sting, the female velvet ants have a stronger sting than the males. Velvet ants are not known to predate on other animals as their diet primarily consists of nectar as adults. [11] However, they do play a role as parasites, velvet ants will lay their eggs on larvae of other insects, once the egg hatches the velvet ant larvae will feed on the host larvae. [12]

Defense

The velvet ant has multiple defensive strategies, but is best known for its extremely painful sting, ranked 3 out of 4 on the Schmidt's sting pain index, earning it the nickname of "cow killer". [8] [13] Its defenses include a thickened exoskeleton, the ability to run fast and evasively, warning coloration, stridulatory warning sounds, a chemical secretion, and venom. [9] When stridulating, velvet ants rub their abdominal segments together in a rapid fashion. This is different than stridulation seen in insects such as crickets, in which the leg structures are rubbed against the abdomen. [14]

D. occidentalis and related species are well known for their high levels of Mullerian mimicry. Mullerian mimicry occurs when species with pre-existing defenses adopt similar colorations and patterns to increase the fitness of both all species involved. North American velvet ant species comprise one of the most intricate Mullerian mimicry rings in the natural world, being divided into eight separate rings of mimicry. [14] These complex rings of Mullerian mimicry allow predators to quickly learn to avoid any prey that resembles a velvet ant. Velvet ants occupying southern Texas and northern Mexico possess a characteristic orange "fur" on their most dorsal abdominal segment. Of the 351 species of velvet ants in North America, only 15 species do not easily fit into a Mullerian mimicry ring. [14]

Reproduction

Unlike most wasp species, velvet ants live solitary lives. Male velvet ants take to the air to detect pheromones released by female velvet ants. Males will fly towards female stridulation sounds as well. [15] Once a receptive female is located, the male will carry the female in his mandibles and move her to place he deems "safe" to mate. These mating spaces are often shaded and away from potential mating competitors. [15] Both males and females stridulate during the mating process. Once the mating process is finished, the female begins looking for eggs and larvae of host species. [15]

The female will enter the ground nest of a host species, typically a wasp or bee species, and lay her eggs near the host's larvae. As D. occidentalis' larvae develop, the species' true parasitoid nature is shown. The larvae grow and develop by feeding on and killing the larvae of the host species. [13] Velvet ant larvae will continue to feed until they enter the pupal stage. In this stage, larvae continue to grow into adults. Pupation typically takes 23 days, and most velvet ants are mature and ready to reproduce themselves after this. [15] Velvet ants have an interesting mating style compared to other Hymenopteran species. The male has no parental care responsibilities and the female leaves as soon as she lays her eggs. This is not out of the ordinary for a Hymenopteran species, but velvet ants are though to be monogamous and semelparous. [15] This means females mate just once in their lifetime with only one male. Many entomological organizations suspect velvet ants to mate only once in their lifetime. [16]

Economic Importance

D. occidentalis poses no real positive or negative economic effects on humans. However, their behavior and coloring has been used to study how aposematic coloration works in the wild. Additionally, the species high levels of Mullerian mimicry are of great interest to evolutionary biologists. [17] The sting of this species is extremely painful, but is not lethal to humans. Pest control efforts could be inhibited by the life cycle of velvet ants. Since velvet ants parasitize the larvae of predatory species, prey species could grow to unsustainable numbers if velvet ants become too reproductively successful. [18] However, there is no record of this occurring.

Velvet ants are extremely successful at keeping yellow jackets and other Hymenopteran species at bay. Females search for the larva of ground nesting species to lay her eggs on. Once the host's larvae is killed, the velvet ants are fully developed. Velvet ants keep ant populations in check as well. Multiple studies have shown the alert pheromones released from the mandibles of velvet ants contain ketones that act as allomones. [19] These allomones are used to "control" ant species to perform actions that benefit the velvet ant. Velvet ant allomones are commonly used in research to better understand the use of allomones in other species.

Dasymutilla occidentalis have both negative and positive effects on humans and economics as a whole. Negatively, their is an injury to humans as the sting is painful. Positively, they are a topic of research. Their behaviors and adaptations are being studied. They also provide insight into parasitism and aposematic coloration. [15] The larvae of dasymutilla occidentalis are parasitic to bumblebees, bees are the worlds biggest source of pollination, this can be a concern if the parasitic velvet ant larvae take over a large portion of bees. [20] However, dasymutilla occidentalis are not aggressive and their venom is not very toxic, overall this species poses no real threat to humans, animals, or our world beside a harmful sting and larvae affecting bees. [21]

Related Research Articles

<span class="mw-page-title-main">Mimicry</span> Imitation of another species for selective advantage

In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. Often, mimicry functions to protect a species from predators, making it an anti-predator adaptation. Mimicry evolves if a receiver perceives the similarity between a mimic and a model and as a result changes its behaviour in a way that provides a selective advantage to the mimic. The resemblances that evolve in mimicry can be visual, acoustic, chemical, tactile, or electric, or combinations of these sensory modalities. Mimicry may be to the advantage of both organisms that share a resemblance, in which case it is a form of mutualism; or mimicry can be to the detriment of one, making it parasitic or competitive. The evolutionary convergence between groups is driven by the selective action of a signal-receiver or dupe. Birds, for example, use sight to identify palatable insects and butterflies, whilst avoiding the noxious ones. Over time, palatable insects may evolve to resemble noxious ones, making them mimics and the noxious ones models. In the case of mutualism, sometimes both groups are referred to as "co-mimics". It is often thought that models must be more abundant than mimics, but this is not so. Mimicry may involve numerous species; many harmless species such as hoverflies are Batesian mimics of strongly defended species such as wasps, while many such well-defended species form Müllerian mimicry rings, all resembling each other. Mimicry between prey species and their predators often involves three or more species.

<span class="mw-page-title-main">Mutillidae</span> Family of wasps

The Mutillidae are a family of more than 7,000 species of wasps whose wingless females resemble large, hairy ants. Their common name velvet ant refers to their resemblance to an ant, and their dense pile of hair, which most often is bright scarlet or orange, but may also be black, white, silver, or gold. Their bright colors serve as aposematic signals. They are known for their extremely painful stings,, and has resulted in the common name "cow killer" or "cow ant" being applied to the species Dasymutilla occidentalis. However, mutillids are not aggressive and sting only in defense. In addition, the actual toxicity of their venom is much lower than that of honey bees or harvester ants. Unlike true ants, they are solitary, and lack complex social systems.

<span class="mw-page-title-main">Yellowjacket</span> Common name for two genera of wasps

Yellowjacket or yellow jacket is the common name in North America for predatory social wasps of the genera Vespula and Dolichovespula. Members of these genera are known simply as "Wasps" in other English-speaking countries. Most of these are black and yellow like the eastern yellowjacket and the aerial yellowjacket ; some are black and white like the bald-faced hornet. Some have an abdomen with a red background color instead of black. They can be identified by their distinctive markings, their occurrence only in colonies, and a characteristic, rapid, side-to-side flight pattern prior to landing. All females are capable of stinging. Yellowjackets are important predators of pest insects.

<span class="mw-page-title-main">Paper wasp</span> Vespid wasps that gather fibers from dead wood and plant stems

Paper wasps are vespid wasps and typically refers to members of the vespid subfamily Polistinae, though it often colloquially includes members of the subfamilies Vespinae and Stenogastrinae, discussed elsewhere, which also make nests out of paper. Paper wasp nests are characterized by open combs with down pointing cells. Some types of paper wasps are also sometimes called umbrella wasps, due to the distinctive design of their nests.

<span class="mw-page-title-main">Apocrita</span> Suborder of insects containing wasps, bees, and ants

Apocrita is a suborder of insects in the order Hymenoptera. It includes wasps, bees, and ants, and consists of many families. It contains the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" (petiole) formed between the first two segments of the actual abdomen; the first abdominal segment is fused to the thorax, and is called the propodeum. Therefore, it is general practice, when discussing the body of an apocritan in a technical sense, to refer to the mesosoma and metasoma rather than the "thorax" and "abdomen", respectively. The evolution of a constricted waist was an important adaption for the parasitoid lifestyle of the ancestral apocritan, allowing more maneuverability of the female's ovipositor. The ovipositor either extends freely or is retracted, and may be developed into a stinger for both defense and paralyzing prey. Larvae are legless and blind, and either feed inside a host or in a nest cell provisioned by their mothers.

<span class="mw-page-title-main">Spider wasp</span> Family of wasps

Wasps in the family Pompilidae are commonly called spider wasps, spider-hunting wasps, or pompilid wasps. The family is cosmopolitan, with some 5,000 species in six subfamilies. Nearly all species are solitary, and most capture and paralyze prey, though members of the subfamily Ceropalinae are kleptoparasites of other pompilids, or ectoparasitoids of living spiders.

<i>Sphecius speciosus</i> Species of wasp

Sphecius speciosus, often simply referred to as the cicada killer or the cicada hawk, is a large, solitary digger wasp species in the family Crabronidae. The name may be applied to any species of crabronid that preys on cicadas, though in North America, it is typically applied to this species, also referred to as the eastern cicada killer in order to further differentiate it from the multiple other examples of related wasp species. Sometimes, they are called sand hornets, although they are not hornets, which belong to the family Vespidae. This species can be found in the Eastern and Midwest U.S. and southwards into Mexico and Central America. They are so named because they hunt cicadas and provision their nests with them. Cicada killers exert a measure of natural control on cicada populations, and as such, they may directly benefit the deciduous trees upon which the cicadas feed.

<span class="mw-page-title-main">Müllerian mimicry</span> Mutually beneficial mimicry of strongly defended species

Müllerian mimicry is a natural phenomenon in which two or more well-defended species, often foul-tasting and sharing common predators, have come to mimic each other's honest warning signals, to their mutual benefit. The benefit to Müllerian mimics is that predators only need one unpleasant encounter with one member of a set of Müllerian mimics, and thereafter avoid all similar coloration, whether or not it belongs to the same species as the initial encounter. It is named after the German naturalist Fritz Müller, who first proposed the concept in 1878, supporting his theory with the first mathematical model of frequency-dependent selection, one of the first such models anywhere in biology.

<span class="mw-page-title-main">Aposematism</span> Honest signalling of an animals powerful defences

Aposematism is the advertising by an animal, whether terrestrial or marine, to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defenses which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or smell, sharp spines, or aggressive nature. These advertising signals may take the form of conspicuous coloration, sounds, odours, or other perceivable characteristics. Aposematic signals are beneficial for both predator and prey, since both avoid potential harm.

<span class="mw-page-title-main">Eucharitidae</span> Family of wasps

The Eucharitidae are a family of parasitic wasps. Eucharitid wasps are members of the superfamily Chalcidoidea and consist of three subfamilies: Oraseminae, Eucharitinae, and Gollumiellinae. Most of the 55 genera and 417 species of Eucharitidae are members of the subfamilies Oraseminae and Eucharitinae, and are found in tropical regions of the world.

<i>Phidippus johnsoni</i> Species of spider

Phidippus johnsoni, the red-backed jumping spider or Johnson jumping spider, is one of the largest and most commonly encountered jumping spiders of western North America. It is not to be confused with the unrelated and highly venomous redback spider.

<i>Philanthus gibbosus</i> Species of wasp

Philanthus gibbosus, the hump-backed beewolf, is a species of bee-hunting wasp and is the most common and widespread member of the genus in North America. P. gibbosus is of the order Hymenoptera and the genus Philanthus. It is native to the Midwestern United States and the western Appalachians. P. gibbosus are often observed to visit flowers and other plants in search of insect prey to feed their young. The prey that P. gibbosus catches is then coated in a layer of pollen and fed to the young wasps.

<i>Dasymutilla</i> Genus of wasps

Dasymutilla is a wasp genus belonging to the family Mutillidae. Their larvae are external parasites to various types of ground-nesting Hymenoptera. Members of this genus are highly variable in sting intensity, ranging from a 1 (D. thetis) to a 3 in the Schmidt sting pain index.

<i>Dasymutilla gloriosa</i> Species of wasp

Dasymutilla gloriosa, sometimes referred to as the thistledown velvet ant, is a member of the genus Dasymutilla. Only females are wingless, as in other mutillids. Compared to other mutillids, it is mid-sized, being larger than some of the smallest known species like Dasymutilla vesta but smaller than some of the largest known species like Dasymutilla klugii. It ranges from Utah, Nevada, California, Arizona, New Mexico, Texas and south into Mexico.

<span class="mw-page-title-main">Wasp</span> Group of insects

A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. The wasps do not constitute a clade, a complete natural group with a single ancestor, as bees and ants are deeply nested within the wasps, having evolved from wasp ancestors. Wasps that are members of the clade Aculeata can sting their prey.

<i>Mutilla europaea</i> Species of wasp

Mutilla europaea, the large velvet ant, is a species of parasitoid wasps belonging to the family Mutillidae. It is a parasitoid on various species of bumblebees and is found in Europe, Asia, and North Africa.

<i>Hemipepsis ustulata</i> Species of wasp

Hemipepsis ustulata is a species of tarantula hawk wasp native to the Southwestern United States. Tarantula hawks are a large, conspicuous family of long-legged wasps that prey on tarantulas by using their long legs to grapple with their prey and then paralyze them with a powerful sting. They are solitary, displaying lekking territorial behavior in their mating rituals.

<i>Pepsis grossa</i> Species of wasp

Pepsis grossa is a very large species of pepsine spider wasp from the southern part of North America, south to northern South America. It preys on tarantula spiders, giving rise to the name tarantula hawk for the wasps in the genus Pepsis and the related Hemipepsis. Only the females hunt, so only they are capable of delivering a sting, which is considered the second most painful of any insect sting; scoring 4.0 on the Schmidt sting pain index compared to the bullet ant's 4.0+. It is the state insect of New Mexico. The colour morphs are the xanthic orange-winged form and the melanic black winged form. In northern South America, a third form, known as "lygamorphic", has a dark base to the wings which have dark amber median patches and a pale tip.

<i>Euspinolia militaris</i> Species of wasp

Euspinolia militaris is a species of wasp in the family Mutillidae. Though it is a wingless wasp, it has sometimes been referred to by the name panda ant.

<i>Dasymutilla eminentia</i> Species of wasp

Dasymutilla eminentia is a species of parasitoid wasp in the family Mutillidae. Members of this family of wasps are often mistaken for true ants, especially since females are wingless. Unlike ants, however, their bodies are covered by a dense pile of velvet-like hair, and they lack petiole nodes.

References

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