Worm lions
| Worm lions | ||||||||||||
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Lampromyia sp. |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Vermileonidae | ||||||||||||
| Nagatomi , 1975 |
The worm lions (Vermileonidae) are a family of flies (Brachycera) within the two-winged birds (Diptera). They are notable for the larvae 'prey trapping technique, which create funnels in loose sand. The scientific name comes from the genus Vermileo , it is derived from the Latin vermis : worm and leo : lion.
features
Imagines the worm lions are medium-sized, slender and graceful built birds with a body length of about 5 (European in most species) to a maximum of 18 millimeters. They are colored pale brown to dark black-brown. Your body is almost free of bristles. The head has two rather short antennae with a distinct antenna whip which is slightly tapered towards the tip. The mouthparts can be long and remarkably ( Lampromyia ) or short ( Vermileo be). The abdomen is cylindrical and elongated, the legs long and slender, their splints ( tibia ), especially the front splints, with end spurs or spine-like bristles. The wings are clearly narrowed towards the base, they can be crystal clear (hyaline) or have darker drawing elements.
The larvae are slender and elongated, soft-skinned and predominantly white in color. As is typical for flies, its head capsule is partially reduced and retracted far into the torso, usually a dorsal sclerite and the mouthparts are visible. Their posterior segments are noticeably enlarged, their integument has a warty structure. The body is scattered with bristles with a striking transverse row of thorn bristles dorsally on the seventh segment of the abdomen, which help to anchor the animal in the sand. The first abdominal segment has protruding pseudopods. The posterior spiracles lie on the eighth segment. In Vermileo this ends in four conical extensions. In Vermileo , adult larvae reach a body length of about 12 to 14 millimeters, compared to about 5 millimeters in the adults.
Life cycle
Worm lion adults only live for a few days. They are flower visitors and feed on nectar. The predatory larvae, on the other hand, have a very long and slow development of typically three to four years. The pupal stage goes through quickly, within nine to ten days.
Way of life
The worm lion larvae build funnel-shaped pitfalls in the sand in which they live. This hunting behavior is very similar to that of the ant lions , the larvae of the ant maid family (Myrmeleontidae). Since the two are not closely related to each other (the ant lions belong to the insect order of the reticulated wings) this is an example of convergent evolution. The funnels of both groups look the same at first glance and can appear next to each other. The differences are: the worm lions' trap funnels are somewhat narrower and steeper, the larvae prefer somewhat finer substrate.
The larvae then sit at the bottom of this pit and wait for prey (prey hunters). This consists of small insects that fall into the pit and are embraced by the larva with the front end. They are numbed and digested by the secretions of the saliva . The larva then soaks up the dissolved food pulp. William Morton Wheeler described the behavior when building funnels : the larva pushes the curved body into the sand and stretches it with a jerky muscle movement, which throws the sand upwards. By rotating movements between the throws, the excavation is distributed in all directions, so that a regular funnel is created. In the finished funnel, the larva rests stretched out on its back, the rear end hidden in the sand. The front end in the center of the funnel is covered by a very fine veil of sand. The size of the trap funnel is fairly constant and independent of the size and age of the lavas.
The larvae build their trap funnels, often in large numbers next to each other, in fine sand without vegetation, always in rain-protected areas, for example between tree roots, in cave entrances, but also under protruding roofs in settlement areas, where they can be very common, for example in Israel. They prefer shaded areas.
distribution
The very small family includes around 80 species in eleven genera. There are only two genera in Europe ( Vermileo and Lampromyia ).
- Alhajarmyia Stuckenberg : Two species, one in Arabia ( Hajar Mountains , Oman), one in the Taita Hills , Kenya.
- Isalomyia Stuckenberg: Only one species, Isalomyia irwini . Madagascar.
- Lampromyia Macquart: 13 species. Palearctic : France, Spain, Canary Islands, North Africa (Morocco and Algeria) and Afrotropic : South Africa and Zimbabwe.
- Leptynoma Westwood: 7 species. Namibia, South Africa.
- Namaquamyia Stuckenberg: Only one species: Namaquamyia manselli . South Africa.
- Vermileo Macquart: 10 species. Mediterranean region (Greece, Balkans, southern France, Iberian Peninsula), Africa: Sudan, America: Mexico, Jamaica, Cuba, southern USA (two species from California to Colorado).
- Vermilynx Stuckenberg: 2 species: South Africa, Namibia.
- Vermiophis Yang: 7 types. China.
- Vermipardus Stuckenberg: 13 species. South Africa.
- Vermitigris Wheeler: 4 types. Orientalis : Borneo, Sumatra, South India, South China ( Guangxi ).
There is also a fossil representative:
- Protovermileo Hennig: Baltic amber from the Baltic coast.
Phylogeny and Taxonomy
A worm lion was already known to the founders of modern taxonomy. Carl De Geer described the way of life of the larvae in 1752, the corresponding species was named by Carl von Linné Musca vermileo in 1758 . Later it was transferred to the genus Rhagio (later to the genus Leptis ) by Johann Christian Fabricius . The worm lions were then considered to belong to the Rhagionidae or snipe flies until the 1970s . Justin Pierre Marie Macquart established the genus Vermileo ( Vermileo degeeri , today Vermileo vermileo ) for what was still the only known species in 1834 . Samuel Wendell Williston established the subfamily Vermileoninae for the genus in 1886, but without giving a formal diagnosis. The subfamily was raised to an independent family Vermileonidae by Akira Nagatomi in 1977. The South African researcher Brian Roy Stuckenberg (1930–2009) made significant progress in the family's taxonomy from its distribution center in southern Africa .
The family caused taxonomic difficulties for a long time due to their unusual combination of characteristics. Graham CD Griffiths therefore placed them in 1994 in a monotypical (only this family comprising) suborder Vermileonomorpha. Later studies indicate that they should probably be included as a basal branch in the Tabanomorpha instead. According to the genetic data, a sister group relationship to the Rhagionidae, similar to the traditional classification, also seems quite conceivable.
Sources and literature
- Pjotr Oosterbroek: The European Families of the Diptera: Identification - Diagnosis - Biology. KNNV Publishing (Brill), 2006. ISBN 9789004278066 . P. 170.
- E. Séguy: Diptéres Braychptéres (Stratiomyidae, Erinnidae, Coenomyiidae, Rhagionidae, Tabanidae, Codidae, Nemestrinidae, Mydaidae, Bombyliidae, Therevidae, Omphralidae). Faune de France 13. Fédération des sociétés françaises de sciences naturelles. Office central de faunistique. Paris, 1926.
- David K. Yeates, Brian M. Wiegmann (editors): The Evolutionary Biology of Flies. Columbia University Press, New York 2005. ISBN 9780231501705 .
- Ross H. Arnett Jr .: American Insects: A Handbook of the Insects of America North of Mexico. CRC Press (Taylor & Francis), Boca Raton 2nd edition 2017. ISBN 9781482273892 . P. 875.
- S. Shin, KM Bayless, SL Winterton, T. Dikow, DK Yeates, BD Lessard, BM Wiegmann, MD Trautwein (2018): Taxon sampling to address an ancient rapid radiation: a supermatrix phylogeny of early brachyceran flies (Diptera). Systematic Entomology 43 (2): 277-289. doi: 10.1111 / syen.12275
- Charles Morphy Dias Santos (2008): Geographical Distribution of Tabanomorpha (Diptera, Brachycera): Athericidae, Austroleptidae, Oreoleptidae, Rhagionidae, and Vermileonidae. EntomoBrasilis 1 (3): 43-50.
- William Morton Wheeler: Demons of the Dust. WW Norton & Company, New York 1930.
- Dušan Devetak (2008): Wormlion Vermileo vermileo L. (Diptera: Vermileonidae) in Slovenia and Croatia. Annales, Series Historia Naturalis 18 (2): 283-286.
- Dušan Devetak & Zoltán Soltész (2019): First record of wormlion Vermileo vermileo (Diptera: Vermileonidae) from Greece. Entomologica Hellenica 28: 5-10.
- Roi Dor, Shai Rosenstein, Inon Scharf (2014): Foraging behavior of a neglected pit-building predator: the wormlion. Animal Behavior 93: 69-76.
- Yehonatan Samocha & Inon Scharf (2019): Comparison of wormlion behavior under man-made and natural shelters: urban wormlions more strongly prefer shaded, fine-sand microhabitats, construct larger pits and respond faster to prey. Current Zoology zoz006, 1-8 doi: 10.1093 / cz / zoz006 .
- Brian R. Stuckenberg (1998): A revision of the Palaearctic species of Lampromyia Macquart (Diptera, Vermileonidae), with the description of a new Iberian species and a cladogram for the genus. Bonn Zoological Contributions 48 (1): 47–96.
