Badisis outpatient
| Badisis outpatient | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Badisis | ||||||||||||
| McAlpine , 1990 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Badisis outpatient | ||||||||||||
| McAlpine , 1990 |
Badisis ambulans is the only species of its genus from the family of stilt flies (Micropezidae). It can only be found in Southwest Australia in the distribution area of the dwarf jug ( Cephalotus follicularis ), a carnivorous plant , because its larvae develop in their traps.
Badisis ambulans has neither wings nor holders , in appearance it resembles an ant .
Regardless of their numerous apomorphic features, many morphological properties indicate a close relationship with the genus Metopochetus . It also shares some similarities with the fossil stilt fly Electrobata tertiaria of the Paleogene found in Baltic amber , so it could turn out to be a basal species of the Metopochetini tribe .
features
Badisis ambulans reaches a body length of 3.6 to 5.6 mm, with about 1.5 mm being accounted for by the thorax . It is the only known species within the stilt fly with completely reduced wings and holders. Besides her, only one other species, Calycopteryx moseleyi , is known with reduced wings, which, however, has at least rudiments. There is no pronounced sexual dimorphism, both sexes are almost identical, they can only be identified on the basis of microscopic examinations of the apex of the abdomen. The basic color of Badisis ambulans is yellow to dark brown, with the surface partially shiny and more or less frosted. The head is dorsally black-brown, the face is partially drawn gray. The thighs of the legs are gray-black with sandy brown roots and protrusions. The lower legs of the front legs are also gray-black, the tarsi and the rest of the legs are sand-yellow. The first two abdominal segments are also sandy brown, the third to fifth are brown-black, and parts of the sixth to eighth are differently brown.
Morphologically, the species differs significantly from other stilt flies due to its ant-like appearance, but is significantly less conspicuous in stature. The body is more compact and the abdomen is similar to ants and waist wasps petiolate , which means that the first abdominal segment fused with the thorax and the second abdominal segment is shaped like a handle, similar to a wasp waist. Accordingly, Badisis ambulans is more likely to be confused with an ant than with any other stilt fly. Since it occurs together with ants where it was found, this is probably a mimicry . When it was first described, it was found together with a species of glandular ants (Dolichoderinae) to which it is very similar and which has been identified as the Iridomyrmex species.
head
The head of Badisis ambulans is rounded and significantly wider than the thorax. The forehead region is clearly sclerotized and the back of the head is clearly thickened above the neck. The compound eyes are just as large as in Metopochetus species and thus unusual for wingless two-winged birds , where they are usually reduced. The first sensor element is clearly protruding, the second very short and the third elongated-oval. On each side of the forehead there are three bristles and a number of other bristle features characterize the species or genus.
Unusual for stilt flies, but also present in Metopochetus , is a knot below the post-vertical bristles. The prelabrum is large but not conspicuously directed forward at the lower edge, the palpus and trunk are not enlarged.
Thorax and legs
The metathorax has a very heavily sclerotized dorsal sclerite that is saddle-shaped and unique for the family. The pronotum is very short, the scutellum is relatively small but clearly visible. As with most other Eurybatinae, there is no pit connecting the sutures running along the mesoscutum to the midline of the mesothorax . In addition, the bristle arrangement on the thorax is typical of the species or genus, although this is limited to a few areas such as the pleura .
The middle and the rear pair of legs are less elongated and the front legs are not shortened as much as in other stilt flies. The legs are shorter than those of most stilt flies with the exception of the Calypteryx species. The hind legs are longer than the middle ones in all sections. The coxae of the forelegs are compressed and have a noticeably serrated lobe on the lower front end, a feature that is only found in Badisis and Metopochetus . They are placed close to the thorax in the resting position. The anterior tarsi is almost as long as the tibia, flattened at the end and equipped with powerful claws. The tarsi of the other legs are significantly slimmer and also flattened at the foot end. The tibia of the middle legs typically has two spines on the ventral side.
abdomen
The petiolus of the abdomen is the most noticeable characteristic of the species in addition to the complete winglessness. It is formed by the first two segments of the abdomen, the first showing a slight bulge of the tergite . The post-abdomen is characteristic of the males : the sternite of the fifth post-abdominal segment is deeply split and forms two lobes, each of which has two or three compressed bristles at the tip. This structure is very similar to the fossil stilt fly Electrobata tertiaria , which is believed to be related to it. The sixth sternite is rounded and triangular as in Metopochetus , but as in the Eurybatini not laterally flattened and with an almost continuous channel in the middle. The Aedeagus has a long and two-segment distiphallus , which corresponds to that of the subgenus Crus of the Metopochetus . In contrast, the ejaculatory sclerite of Badisis, with a rod-shaped outgrowth that widens towards the tip like a mushroom, is different from that of all known Metopochetus species. The females have the post-abdominal structures typical of stilt flies.
Larval features
The larvae are specially adapted to their habitat, the trap leaves of the dwarf jug. In the third larval stage (presumably also in others) the posterior spiracles are closed.
distribution
The maximum distribution area of Badisis ambulans is limited to the distribution area of the dwarf jug ( Cephalotus follicularis ) in Southwest Australia, in whose jugs the larvae develop. The adults can be found on the flowers of the Astartea fascicularis shrub . The male holotype and 25 other male specimens ( paratypes ) were collected near the Warren River , 10 kilometers south of the city of Pemberton .
Systematics
Badisis ambulans was first described in 1990 by David McAlpine, the generic name is derived from the Greek βάδισις = "gait" and refers to the current way of life of the species.
Despite the strongly modified form of B. ambulans , it shares a number of anatomical features with the Metopochetus species, due to which it is closely related to this genus. Together with them, it forms the tribe Metopochetini within the stilt fly subfamily Eurybatinae, which is predominant in Australia. A closer relationship with Calycopteryx moseleyi as the only species in which the wings are also reduced, however, is excluded. A relationship with the species Apterosepsis basilewskyi , which is widespread in Tanzania , whose assignment is unclear and which McAlpine assigned to the Anthomyzidae , is also excluded despite the similarities in habitus.
Individual evidence
literature
- David K. McAlpine: A new apterous micropezid fly (Diptera: Schizophora) from Western Australia. Systematic Entomology 15, 1990: pages 81-86.
- David K. McAlpine: Review of the Australian stilt flies (Diptera: Micropezidae) with a phylogenetic analysis of the family. Invertebrate Taxonomy 12 (1), 1998: pages 55-134. doi : 10.1071 / IT96018 (HTML abstract)
- D. Yeats: Immature stages of the apterous fly Badisis ambulans McAlpine (Diptera: Micropezidae). Journal of natural history 26, 1992; Pages 417-424