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Mallophora fautrix

By Matthew Ewing

Geographic Range

Mallophora fautrix, a species of bee-killing robber fly, is native to Neoartic and Northern Neotropical regions. In the US, they are found as far East as Louisiana, and West through Oklahoma, Texas, New Mexico, Arizona, Nevada, and California. In Mexico, they have been documented as far South as Veracruz. (Estrada and Nápoles, 2020; Pant and Mopper, 2020)

Habitat

Mallophora species commonly are found occupying prairies, pastures, grassy fields, and gardens. They usually situate themselves on tall plant stalks or branches in sunny areas. This gives them a vantage point with which to spot their prey. (Steck, 2004)

Physical Description

All species in the genus Mallophora imitate bees. Mallophora fautrix mimics the workers of an American Bumble Bee species. (Bombus sonorus) Males and females of the species are both around 15-20mm in length. They have brown wings, with patches of yellow, white, and black hair on their body. Bodies of this species also feature a black thorax, with brown legs covered in black hairs. Their face is full of yellow hair, with two large compound eyes, and small reddish antennae. As is the case with all robber flies, they have a small indent between their two eyes. (Finn, 2003; Pant and Mopper, 2020; Steck, 2004)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    15mm to 20mm mm
    to in

Development

While the knowledge on much of the development of many Mallophora species is unknown, what is known is that Mallophora eggs are laid in the ground. These eggs hatch into larvae. Some Mallophora species' larvae are ectoparasites on scarabaeid beetle grubs. The larvae, after going through several instars, pupate, and become adults. (Finn, 2003; Steck, 2004)

Reproduction

While the reproduction behavior of Mallophora is undocumented, it is known that robber flies have minimal courtship behavior, where the males prefer to pounce on females and reproduce with them through tail-to-tail copulation. (Finn, 2003)

Mallophora fautrix individuals reproduce after the emergence of the adult stage. Reproduction is seasonal, since adults are active from April to November. (Finn, 2003; Pant and Mopper, 2020)

  • Breeding interval
    Mallophora fautrix breed once a year

The extent of parental investment in Mallophora is laying eggs in soil in order to give the larvae a suitable environment to grow. (Steck, 2004)

Lifespan/Longevity

While the life span of Mallophora fautrix is unknown, many robber fly species' life-spans take more than a year to complete. ("Robber Fly", n/a)

  • Range lifespan
    Status: wild
    1 to 2 years

Behavior

Mallophora fautrix are a solitary, diurnal species. They hunt alone during the day, perched vertically or horizontally on a stem or branch, waiting to spot prey. When moving from perch to perch, or when pursuing prey, these bee-killers fly using their pair of wings. Male robber flies are known to be highly territorial, which is likely to apply to Mallophora fautrix as well. (Finn, 2003; Pant and Mopper, 2020)

Home Range

There is no information currently about the home range of Mallophora fautrix.

Communication and Perception

All species of Robber flies, Mallophora fautrix included, have sharp vision, as characterized by their two large, compound eyes. These high powered eyes are especially useful when hunting, since the flies can spot their targets and attack with deadly precision. They also use their eyes to search for a mate to reproduce with. The two mates reproduce by attaching reproductive organs on their tails. (The University of Cambridge, 2017)

Food Habits

Mallophora fautrix, like all Mallophora species, is known as a "bee killer". This is because these robber flies are specifically adapted to hunt bees and wasps. Mallophora fautrix would be classified as a carnivore, but more specifically an insectivore. Adults pounce on their prey from the air, subduing prey with their strong legs. They then inject their prey with digestive enzyme filled saliva, liquefying the insides of the bee or wasp. The fly then perches in a safe area with its meal. Mallophora fautrix is known to feed on just about every bee species, such as the common honey bee species Apis mellifera. (Finn, 2003; Pant and Mopper, 2020)

  • Animal Foods
  • insects

Predation

Mallophora fautrix has no documented predation defenses, though robber flies are known for being able to deliver a painful bite. There are no documented predators of Mallophora fautrix, though robber flies are known to be prey to insect-eating birds. (Finn, 2003)

  • Known Predators
    • Birds

Ecosystem Roles

Adult Mallophora fautrix are both predator and prey as adults. They act as predators, eating bees, wasps, and other insects, and fall prey to insect-eating birds. As larvae, some Mallophora species act as parasites, though it is unknown if Mallophora fautrix larvae exhibit these same behaviors. (Steck, 2004)

Economic Importance for Humans: Positive

There are no documented economic benefits of Mallophora fautrix.

Economic Importance for Humans: Negative

Though Mallophora fautrix does prey upon vital pollinators like bees, wasps, and other flying insects, as well as honey producing bees, there are no documented instances of the species having a negative economic impact. There have however been rare reports of other species in Mallophora, such as Mallophora bomboides, causing economic losses to beekeepers. Also, robber flies are known to have a painful bite to humans if handled incorrectly. (Bromley, 1930; Finn, 2003; Steck, 2004)

  • Negative Impacts
  • injures humans
    • bites or stings

Conservation Status

There is no special conservation status for Mallophora fautrix.

Contributors

Matthew Ewing (author), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

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

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

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

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

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

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.

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

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

oviparous

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

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

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

suburban

living in residential areas on the outskirts of large cities or towns.

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.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

Bee Killers. Encyclopedia of Life. Accessed February 13, 2022 at https://eol.org/pages/54637.

Integrated Taxonomic Information System. Mallophora. Accessed February 13, 2022 at https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=133767#null.

The Board of Regents of the University of Wisconsin System. 2022. "Robber Flies (Asilidae)" (On-line). Wisconsin Horticulture Division of Extension. Accessed February 13, 2022 at https://hort.extension.wisc.edu/articles/robber-flies-asilidae/.

Texas A&M. n/a. "Robber Fly" (On-line). Texas A&M Agrilife Extension. Accessed March 21, 2022 at https://texasinsects.tamu.edu/robber-fly/.

Bromley, S. 1930. Bee-Killing Robber Flies. Journal of the New York Entomological Society, Vol. 38 No.2: 159-176. Accessed February 13, 2022 at https://www.jstor.org/stable/25004364.

Dennis, S. 2015. "Oviposition, Eggs, and First Instar Larvae of Mallophora orcina (Wiedemann, 1828) (Diptera: Asilidae),". Proceedings of the Entomological Society of Washington, Vol. 117 No.3: 269-280. Accessed February 13, 2022 at https://doi.org/10.4289/0013-8797.117.3.269.

Estrada, A., J. Nápoles. 2020. New distribution records of Asilidae (Insecta: Diptera) for Mexico. Insecta Mundi A Journal of World Insect Systematics, 0783: 1-13. Accessed February 13, 2022 at https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2279&context=insectamundi.

Finn, E. 2003. "Featured creatures: Robber Flies" (On-line). Featured Creatures Entomology & Nematology. Accessed February 13, 2022 at https://entnemdept.ufl.edu/creatures/beneficial/flies/robber_flies.htm.

Pant, A., S. Mopper. 2020. "Earliest Record of the Bee-Mimic Robber Fly, Mallophora fautrix Osten Sacken 1887 (Diptera: Asilidae), in Louisiana,". Southeastern Naturalist, Vol. 19 No.2: 32-37. Accessed February 13, 2022 at https://doi.org/10.1656/058.019.0219.

Pollock, D. 2020. "New Records of Ground and Tiger Beetles (Coleoptera: Carabidae) As Prey for Asilidae (Diptera) in the High Plains of New Mexico and Texas,". The Coleopterists Bulletin, Vol. 74 No.1: 15-23. Accessed February 13, 2022 at https://doi.org/10.1649/0010-065X-74.1.15.

Steck, G. 2004. "Featured creatures: Bee Killers" (On-line). Featured Creatures Entomology & Nematology. Accessed February 13, 2022 at https://entnemdept.ufl.edu/creatures/misc/flies/bee_killers.htm.

The University of Cambridge, 2017. "The remarkable hunting ability of the robber fly" (On-line). phys.org. Accessed March 22, 2022 at https://phys.org/news/2017-03-remarkable-ability-robber.html#:~:text=The%20robber%20fly%20has%20incredibly,several%20thousand%20lenses%20per%20eye..

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