Hoverfly

Last updated

Syrphidae
Temporal range: Eocene–Present
Syrphidae poster.jpg
Sixteen different species of hoverflies
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Section: Aschiza
Superfamily: Syrphoidea
Family: Syrphidae
Latreille, 1802
Subfamilies

Hoverflies, also called flower flies or syrphids, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while the larvae (maggots) eat a wide range of foods. In some species, the larvae are saprotrophs, specifically detritivores, [1] eating decaying plant and animal matter in the soil or in ponds and streams. In other species, the larvae are insectivores, preying on aphids, thrips, and other plant-sucking insects.

Contents

Insects such as aphids are considered crop pests, so the aphid-eating larvae of some hoverflies are economically and ecologically important. The larvae are potential agents for use in biological control, while the adults are pollinators.

About 6,000 species in 200 genera have been described. Hoverflies are common throughout the world and can be found on all continents except Antarctica. Hoverflies are harmless to most mammals, though many species are mimics of stinging wasps and bees, a mimicry which may serve to ward off predators.

Hoverfly hovering behavior is unlike that of hummingbirds since they do not feed in midair. Hovering in general may be a means of finding a food source. Male hovering is often a territorial display seeking females, [2] while female hovering serves to inspect ovipositing sites. [3] [4] [5]

A hoverfly on flowers in Japan

Description

The size of hoverflies varies depending on the species. [6] For example Paragus tibialis [7] [8] [9] is 3–5 mm (1⁄8–13⁄64 in) long, while Criorhina nigriventris is 13.6–20.6 mm (17⁄32–13⁄16 in) long. [10] Some, such as members of the genus Baccha , are small, elongated, and slender, while others, such as members of Criorhina , are large, hairy, and yellow and black. As members of the Diptera, all hoverflies have a single functional pair of wings, with the hind wings reduced to balancing organs. [11] Many species are brightly colored, with spots, stripes, and bands of yellow or brown covering their bodies. [11] Due to this coloration, they are often mistaken both by insect-eating birds and by humans for wasps or bees; they exhibit Batesian mimicry. Despite this, hoverflies are harmless to humans. [6] Drone flies, Eristalis tenax, are an example of a species of hoverfly who exhibit Batesian mimicry. [12]

With a few exceptions, [13] Hoverflies are distinguished from other flies by having a spurious vein, located parallel to their fourth longitudinal wing vein. [6] Adults feed mainly on nectar and pollen. [11] Many species also hover around flowers, lending to their common name. [6]

Bee flies of the family Bombyliidae often mimic Hymenoptera and hover around flowers, as well, rendering some bombyliid species hard to tell apart from Syrphidae at first glance. Hoverflies can, nevertheless, be distinguished in the field by anatomical features such as:[ citation needed ]

Their wariness of people is surprisingly low, and their behaviour can be observed up close. hanaabu.jpg
Their wariness of people is surprisingly low, and their behaviour can be observed up close.

Reproduction and life cycle

Midair mating of Simosyrphus grandicornis Hoverflies mating midair.jpg
Midair mating of Simosyrphus grandicornis

Unlike adults, the maggots of hoverflies feed on a variety of foods. Some are saprotrophs, eating decaying plant or animal matter, while others are insectivores, eating aphids, thrips, and other plant-sucking insects. [6] [14] Predatory species are beneficial to farmers and gardeners, because aphids destroy crops, and hoverfly maggots are often used in biological control. That includes one of the most common widespread hoverfly species, Episyrphus balteatus , the larvae of which feed on aphids.

Hoverfly depositing egg on Epipactis helleborine which has ants farming aphids Hoverfly depositing egg.jpg
Hoverfly depositing egg on Epipactis helleborine which has ants farming aphids

An example of a well-known hoverfly maggot is the rat-tailed maggot of the drone fly, Eristalis tenax . It has a breathing siphon at its rear end, giving it its name. [6] The species lives in stagnant water, such as sewage and lagoons. [15] The maggots also have a commercial use, and are sometimes sold for ice fishing. [16]

An ichneumonid wasp ovipositing inside a hoverfly larva Parasitoid wasp oviposits inside hoverfly larva.jpg
An ichneumonid wasp ovipositing inside a hoverfly larva

Very rarely, hoverfly larvae have caused accidental myiasis in humans. That occurs when the larvae are accidentally ingested from contaminated food. [15] [17]

Evolution

The oldest known fossils of crown group Syrphidae are from the Eocene aged Florissant Formation, Green River Formation and Baltic amber. The genus Prosyrphus , found in Late Cretaceous (Cenomanian) Burmese amber, appears to represent a stem group to the family. [18]

Distribution and habitat

Hoverflies are a cosmopolitan family found in most biomes, except extreme deserts, tundra at extremely high latitudes, and Antarctica. [19] [20] Certain species are more common in certain areas than others; for example, the American hoverfly, Eupeodes americanus, is common in the Nearctic realm, and the common hoverfly, Melangyna viridiceps, is common in the Australasian realm. About 6,000 species and 200 genera are in the family. [21]

While some hoverfly larvae are aquatic and are often found in stagnant water, those of species that prey upon aphids and other plant parasites are usually terrestrial, residing on leaves. [22] Adults are often found near flowers, their principal food source being nectar and pollen. [11] Some species are inquilines; for instance, members of the genus Volucella can be found in bumblebee nests, while members of Microdon are myrmecophiles, found in ant or termite nests. [6] Others can be found in decomposing vegetation.

Pollination

Episyrphus balteatus on a daisy Hoverfly October 2007-21.jpg
Episyrphus balteatus on a daisy
Eupeodes corollae ComputerHotline - Syrphidae sp. (by) (3).jpg
Eupeodes corollae

Hoverflies are important pollinators of flowering plants in many ecosystems worldwide. [23] Syrphid flies are frequent flower visitors to a wide range of wild plants, as well as agricultural crops, and are often considered the second-most important group of pollinators after wild bees. Relatively little research into fly pollinators has been conducted, compared to bees. [23] Bees are thought to be able to carry a greater volume of pollen on their bodies, but flies may be able to compensate for this by making a greater number of flower visits.

Like many pollinator groups, syrphid flies range from species that take a generalist approach to foraging by visiting a wide range of plant species through those that specialize in a narrow range of plants. [24] Although hoverflies are often considered mainly nonselective pollinators, some hoverflies species are highly selective and carry pollen from one plant species. [25] Cheilosia albitarsis is thought to only visit Ranunculus repens.

Specific flower preferences differ among species, but syrphid fly species have repeatedly been shown to prefer white- and yellow-coloured flowers. [26] Nonvisual flower cues such as olfactory cues also help these flies to find flowers, especially those that are not yellow. [27] Many syrphid fly species have short, unspecialized mouth parts and tend to feed on flowers that are more open as the nectar and pollen can be easily accessed. [28]

Also, a number of interactions occur between orchids and hoverflies. The orchid species Epipactis veratrifolia mimics alarm pheromones of aphids which attracts pollinating hoverflies. [29] Another plant, the slipper orchid in southwest China, also achieves pollination by deceit by exploiting the innate yellow color preference of syrphids. [30]

Systematics

Relationship with humans

Hoverfly nectaring on a small flower bud covered with dew drops. Hoverfly in rain by prasan shrestha.jpg
Hoverfly nectaring on a small flower bud covered with dew drops.

Adult syrphid flies are pollinators.

Larvae of many hoverfly species prey upon pest insects, including aphids and leafhoppers, which spread some diseases such as curly top, so they are seen in biocontrol as a natural means of reducing levels of pests. Gardeners, therefore, sometimes use companion plants to attract hoverflies. Those reputed to do so include Alyssum spp., Iberis umbellata , statice, buckwheat, chamomile, parsley, and yarrow. [31] Many syrphids, such as Toxomerus marginatus , are attracted to herbivore-induced plant volatiles, and there are commercial formulations of said volatiles, like methyl salicylate, which can be used to attract them for biocontrol purposes. [32] Larvae in the subfamily Eristalinae live in semi-aquatic and aquatic environments, including manure and compost, and can filter and purify water.

Fredrik Sjöberg's  [ sv ] book The Fly Trap concerns his enthusiasm for hoverflies on the island of Runmarö in the Baltic Sea. [33] The island is a hotspot for hoverflies and other insects; Sjöberg has collected 58 species of butterflies there, and (in seven years of hunting) 202 species of hoverflies, including 180 in his garden. [34]

Identification guides

Regional lists

Related Research Articles

<span class="mw-page-title-main">Bombyliidae</span> Family of flies

The Bombyliidae are a family of flies, commonly known as bee flies. Some are colloquially known as bomber flies. Adults generally feed on nectar and pollen, some being important pollinators. Larvae are mostly parasitoids of other insects.

<i>Eristalis</i> Genus of flies

Eristalis is a large genus of hoverflies, family Syrphidae, in the order Diptera. Several species are known as drone flies because they bear a resemblance to honeybee drones.

<span class="mw-page-title-main">Nectar guide</span>

Nectar guides are markings or patterns seen in flowers of some angiosperm species, that guide pollinators to their rewards. Rewards commonly take the form of nectar, pollen, or both, but various plants produce oil, resins, scents, or waxes. Such patterns also are known as "pollen guides" and "honey guides", though some authorities argue for the abandonment of such terms in favour of floral guides. Pollinator visitation can select for various floral traits, including nectar guides through a process called pollinator-mediated selection.

<i>Eristalis tenax</i> Species of fly

Eristalis tenax, the common drone fly, is a common, migratory, cosmopolitan species of hover fly. It is the most widely distributed syrphid species in the world, and is known from all regions except the Antarctic. It has been introduced into North America and is widely established. It can be found in gardens and fields in Europe and Australia. It has also been found in the Himalayas.

<i>Melangyna viridiceps</i> Species of fly

Melangyna viridiceps is an Australian hoverfly, known as the common hover fly.

<i>Eupeodes americanus</i> Species of fly

Eupeodes americanus, the American hoverfly, is found throughout North America and inhabits meadows, and fields with flowers and foliage. Adults feed on nectar, whereas their larvae feed on aphids. The adult fly is black to metallic green, and has three yellow bands on its abdomen. Its face is a light yellow with large black compound eyes on either side, and its wings are clear; it is 9–12 mm in body length. The larvae are mature at around 11 mm, and they are yellow-white to salmon brown, with markings of black and white or yellow-white. The lighter markings consist of a transverse rectangular bars on segments 6 to 11, and a narrow line along each side of the larvae. Early instars have visible black setae. The larvae are active feeders. They are being considered as suitable biological control agents for aphids and scale insects. This species is considered highly migratory, moving from Canada to the southeastern United States during autumn

<span class="mw-page-title-main">Eristalinae</span> Subfamily of flies

Eristalinae are one of the four subfamilies of the fly family Syrphidae, or hoverflies. A well-known species included in this subfamily is the dronefly, Eristalis tenax.

<i>Eristalis arbustorum</i> Species of insect

Eristalis arbustorum, the European drone fly, is an abundant Northern Hemisphere species of syrphid fly, originally officially described by Linnaeus in 1758 as Musca arbustorum. The name "drone fly" is related to its similar appearance to the drone of the honeybee. Hoverflies get their names from the ability to remain nearly motionless while in flight. The adults are also known as flower flies as they are commonly found on and around flowers from which they get both energy-giving nectar and protein rich pollen. The larvae are aquatic filter-feeders of the long-tailed type.

<i>Syritta pipiens</i> Species of fly

Syritta pipiens, sometimes called the thick-legged hoverfly, is one of the most common species in the insect family Syrphidae. This fly originates from Europe and is currently distributed across Eurasia and North America. They are fast and nimble fliers, and their larvae are found in wet, rotting organic matter such as garden compost, manure, and silage. The species is also commonly found in human-created environments such as most farmland, gardens, and urban parks, wherever there are flowers. This species is an important part of its native ecosystem as adult Syritta pipiens flies are critical pollinators for a variety of flowering plants and the species supports parasitism by various parasitic wasp species. Thus, they play an important role in environmental functionality, and can serve as bio-indicators, in which their abundance can reflect the health of the environment. Syritta pipiens looks like many predatory hoverfly species, yet is not predatory.

<i>Helophilus</i> Genus of flies

Helophilus are a diverse genus of moderate to large hoverflies, that appear somewhat bee-like. This genus comprises two subgenera: Helophilus and Pilinasica. Larvae filter-feed in organic rich water. All Helophilus adults have a distinctive lengthwise striped thorax and a transverse striped abdomen.

<i>Toxomerus</i> Genus of flies

Toxomerus is a very large genus of hoverflies. They are found in many parts of North and South America. Most larvae are predators on soft bodied insects, though a few species have been shown to feed on pollen. Adults feed on the pollen of a wide range of flowers.

<i>Sericomyia chrysotoxoides</i> Species of insect

Sericomyia chrysotoxoides ,, the Oblique-banded Pond Fly , is a common species of syrphid fly observed across the eastern half of North America and in the Rocky Mountains. Syrphid flies are also known as Hover Flies or Flower Flies because the adults are frequently found hovering around flowers from which they feed on nectar and pollen. Adults are 9.6–1,315.3 mm (0.38–51.78 in) long, black with yellow bands, less prominent in the male. The larvae of this genus are known as rat tailed maggots for the long posterior breathing tube.

<i>Sericomyia militaris</i> Species of fly

Sericomyia militaria, commonly known as the narrow-banded pond fly, is a common species of syrphid fly observed across northern North America. Syrphid flies are also known as Hover Flies or Flower Flies because the adults are frequently found hovering around flowers from which they feed on nectar and pollen. Adults are 11.7–17.1 mm (0.46–0.67 in) long, mostly black with narrow yellow abdominal markings. The larvae of this genus are known as rat tailed maggots for the long posterior breathing tube.

Diptera is an order of winged insects commonly known as flies. Diptera, which are one of the most successful groups of organisms on Earth, are very diverse biologically. None are truly marine but they occupy virtually every terrestrial niche. Many have co-evolved in association with plants and animals. The Diptera are a very significant group in the decomposition and degeneration of plant and animal matter, are instrumental in the breakdown and release of nutrients back into the soil, and whose larvae supplement the diet of higher agrarian organisms. They are also an important component in food chains.

<i>Melangyna novaezelandiae</i> Species of fly

Melangyna novaezelandiae is a hoverfly endemic to New Zealand. It is a generalized pollinator of a large range of plants that are both native and exotic to the New Zealand flora. M. novaezelandiae is widespread throughout New Zealand, including in agricultural environments. The larvae of this species feeds on other arthropods and may have uses as a biocontrol agent.

The pollinators in New Zealand include bees, tūī birds, and syrphid flies, which all contribute to the ecology of New Zealand.

<i>Spilomyia longicornis</i> Species of fly

Spilomyia longicornis is a species of syrphid fly, also known as a flower fly or hoverfly, in the family Syrphidae. Although the appearance of S. longicornis is remarkably similar to a vespid wasp, it is a fly and cannot sting. It occurs in North America, east of the Rocky Mountains.

<i>Sericomyia lata</i> Species of fly

Sericomyia lata , the White-spotted Pond Fly , is a common species of syrphid fly observed across North America, concentrated in the east. Syrphid flies are also known as Hover Flies or Flower Flies because the adults are frequently found hovering around flowers from which they feed on nectar and pollen. Adults are 11.6–15.2 mm (0.46–0.60 in) long and black with large white abdominal spots. The larvae of this genus are known as rat tailed maggots for the long posterior breathing tube.

<i>Eristalis hirta</i> Species of fly

Eristalis hirta, the black-footed drone fly, is a common Western North American species of syrphid fly, first officially described by Loew in 1866. Hoverflies get their names from the ability to remain nearly motionless while in flight. The adults are also known as flower flies as they are commonly found on and around flowers, from which they get both energy-giving nectar and protein-rich pollen. The larvae are aquatic filter-feeders of the rat-tailed type.

<span class="mw-page-title-main">Eristalina</span> Subtribe of hoverflies

Eristalina is a subtribe of hoverflies with 17 genera. Several species are well-known bee mimics, such as the drone fly. The larvae live in aquatic and moist organic material, often with low oxygen levels using a posterior breathing tube, thus the common name—the "rat-tailed maggot".

References

  1. ↑ Rotheray, G.E. (1993). "Colour Guide to Hoverfly Larvae (Diptera, Syrphidae) in Britain and Europe" (PDF). Dipterists Digest. 9: 155.
  2. ↑ Collett, T.S.; Land, M.F. (September 1978). "How hoverflies compute interception courses". Journal of Comparative Physiology. 125 (3). Springer-Verlag: 191–204. doi:10.1007/BF00656597.
  3. ↑ Almohamad, Raki; Verheggen, François J.; HaubrugeUniv, Éric (2009). "Searching and oviposition behavior of aphidophagous hoverflies (Diptera: Syrphidae): a review". Biotechnologie, Agronomie, Société et Environnement. 13 (3): 467–481.
  4. ↑ Vera Strader. "Hover Flies, a Gardener's Friend" (PDF). University of California Agriculture and Natural Resources.
  5. ↑ Peter Chen (December 6, 2023). "Allograpta exotica ovipositing - Allograpta exotica - Female". Bugguide. Iowa State University.
  6. 1 2 3 4 5 6 7 "hoverfly". Encyclopædia Britannica Online. 2009. Retrieved December 5, 2009.
  7. ↑ Stubbs, Alan E.; Falk, Steven J (1983). British Hoverflies: An Illustrated Identification Guide (2nd ed.). London: British Entomological and Natural History Society. pp. 253, xvpp. ISBN   1-899935-03-7.
  8. ↑ Ball, S.G.; Morris, R.K.A. (2000). Provisional atlas of British hoverflies (Diptera, Syrphidae). Monks Wood, UK: Biological Record Centre. pp. 167 pages. ISBN   1-870393-54-6.
  9. ↑ Van Veen, M.P. (2004). Hoverflies of Northwest Europe, Identification Keys to the Syrphidae (Hardback). Utrecht: KNNV Publishing. p. 254. ISBN   90-5011-199-8.
  10. ↑ Skevington, Jeffrey H. (2019). Field Guide to the Flower Flies of Northeastern North America. ISBN   9780691189406.
  11. 1 2 3 4 "Hoverfly". Hutchinson Encyclopedia. Helicon Publishing. 2009. Retrieved December 6, 2009.
  12. ↑ Heal, Jonathan (1979). "Colour patterns of syrphidae:". Heredity. 42 (2). Springer Science and Business Media LLC: 223–236. doi:10.1038/hdy.1979.24. ISSN   0018-067X.
  13. ↑ Reemer, Menno (2008). "Surimyia, a new genus of Microdontinae, with notes on Paragodon Thompson, 1969 (Diptera, Syrphidae)" (PDF). Zoologische Mededelingen . 82: 177–188.
  14. ↑ Schmidt, Martin; Thewes, Ulrich; Thies, Carsten; Tscharntke, Teja (2004). "Aphid suppression in mulched cereals". Entomologia Experimentalis et Applicata. 113 (2): 87–93. doi:10.1111/j.0013-8703.2004.00205.x. S2CID   85070615.
  15. 1 2 Aguilera A, Cid A, Regueiro BJ, Prieto JM, Noya M (September 1999). "Intestinal myiasis caused by Eristalis tenax". Journal of Clinical Microbiology . 37 (9): 3082. doi:10.1128/JCM.37.9.3082-3082.1999. PMC   85471 . PMID   10475752.
  16. ↑ Dictionary of Ichthyology; Brian W. Coad and Don E. McAllister Archived 2009-12-06 at the Wayback Machine at ww.briancoad.com
  17. ↑ Whish-Wilson PB (2000). "A possible case of intestinal myiasis due to Eristalis tenax". The Medical Journal of Australia . 173 (11–12): 652. doi:10.5694/j.1326-5377.2000.tb139374.x. PMID   11379520. S2CID   12898612.
  18. ↑ Grimaldi, David A. (2018-10-24). "Basal Cyclorrhapha in amber from the Cretaceous and Tertiary (Insecta: Diptera), and their relationships: Brachycera in Cretaceous amber Part IX". Bulletin of the American Museum of Natural History. 423 (423): 1–97. doi:10.1206/0003-0090-423.1.1. ISSN   0003-0090. S2CID   91679754.
  19. ↑ Barkemeyer, Werner. "Syrphidae (hoverflies)". Biodiversity Explorer. South Africa: Iziko Museum. Archived from the original on September 23, 2015. Retrieved December 11, 2009.
  20. ↑ Thompson, F. Christian (August 19, 1999). "Flower Flies". The Diptera Site. United States Department of Agriculture. Archived from the original on December 11, 2009. Retrieved December 11, 2009.
  21. ↑ Philip J. Scholl; E. Paul Catts; Gary R. Mullen (2009). "Myiasis (Muscoidea, Oestroidea)". In Gary Mullen; Gary Richard Mullen; Lance Durden (eds.). Medical and Veterinary Entomology (2nd ed.). Academic Press. pp. 309–338. ISBN   978-0-12-372500-4.
  22. ↑ Laura Smith. "Syrphidae, hoverflies". bumblebee.org.
  23. 1 2 Larson, B.M.H.; Kevan, P.G.; Inouye, D. W. (2001). "Flies and flowers: taxonomic diversity of anthophiles and pollinators". Canadian Entomologist. 133 (4): 439–465. doi:10.4039/ent133439-4. S2CID   55767580.
  24. ↑ Van Der Kooi, C. J.; Pen, I.; Staal, M.; Stavenga, D. G.; Elzenga, J. T. M. (2015). "Competition for pollinators and intra-communal spectral dissimilarity of flowers". Plant Biology. 18 (1): 56–62. doi:10.1111/plb.12328. PMID   25754608.
  25. ↑ Haslett, J.R. (1989). "Interpreting patterns of resource utilization: randomness and selectivity in pollen feeding by adult hoverflies". Oecologia. 78 (4): 433–442. Bibcode:1989Oecol..78..433H. doi:10.1007/bf00378732. PMID   28312171. S2CID   9178645.
  26. ↑ Sajjad, Asif; Saeed, Shafqat (2010). "Floral host plant range of syrphid flies (Syrphidae: Diptera) under natural conditions in southern punjab, Pakistan". Pakistan Journal of Biology. 42 (2): 1187–1200.
  27. ↑ Primante, Clara; Dotterl, Stefan (2010). "A syrphid fly uses olfactory cues to find a non-yellow flower". Journal of Chemical Ecology. 36 (11): 1207–1210. doi:10.1007/s10886-010-9871-6. PMID   20924654. S2CID   23245484.
  28. ↑ Campbell, Alistair, J.; Biesmeijer, J. C.; Varma, V.; Wakers, F. L. (2012). "Realising multiple ecosystem services based on the response of three beneficial insect groups to floral traits and trait diversity". Basic and Applied Ecology. 13 (4): 363–370. doi:10.1016/j.baae.2012.04.003.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  29. ↑ Stokl, Johannes; Brodmann; Dafni; Ayasse; Hansson (2011). "Smells like aphids: orchid flowers mimic aphid alarm pheromones to attract hoverflies for pollination". Proc. R. Soc. B. 278 (1709): 1216–1222. doi:10.1098/rspb.2010.1770. PMC   3049078 . PMID   20943694.
  30. ↑ Shi, J.; Luo, Y.B.; Ran, J.C.; Liu, Z.J.; Zhou, Q. (2009). "Pollination by deceit in Paphiopedilum barbigerum (Orchidaceae): a staminode exploits innate colour preferences of hoverflies (Syrphidae)". Plant Biology. 11 (1): 17–28. doi:10.1111/j.1438-8677.2008.00120.x. PMID   19121110.
  31. ↑ Ben-Issa, R., Gomez, L., & Gautier, H. (2017). Companion Plants for Aphid Pest Management. Insects, 8(4), 112. https://doi.org/10.3390/insects8040112
  32. ↑ Rodriguez-Saona, C., Kaplan, I., Braasch, J., Chinnasamy, D., & Williams, L. (2011). Field responses of predaceous arthropods to methyl salicylate: A meta-analysis and case study in cranberries. Biological Control, 59(2), 394-303. https://doi.org/10.1016/j.biocontrol.2011.06.017
  33. ↑ Sjöberg, Fredrik (2014). The Fly Trap. Particular Books. p. 197. ISBN   978-1-84614-776-0.
  34. ↑ Barkham, Patrick (14 June 2014). "Fredrik Sjöberg: 'I realised I had to write my book for people not interested in flies'". The Guardian. Retrieved 15 March 2015.

Species lists

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.