Badisis ambulans
Encyclopedia
Badisis is a stilt-legged fly genus
with only one known species
, Badisis ambulans. This is a wingless, haltere-less fly
with an ant-like appearance
. It is only found in the Southwest Australia
n bioregion of Western Australia
. Dependent on the rare Albany Pitcher Plant (Cephalotus follicularis) for its development, this fly is also a rare species.
Despite its many apomorphic features, the details of its morphology
suggest a close relationship to the diverse genus Metopochetus, which is also in the tribe
Metopochetini. The fossil
stilt-legged fly "Electrobata" tertiaria from Baltic
amber
of the Paleogene
also shows some similarities; it may be a very basal member of the Metopochetini, close to the divergence between these and the Eurybatini.
, B. ambulans has a less unusual habitus
than other members of the Micropezidae
. Its body is stockier, with a petiolate
abdomen (like in ant
s and other Apocrita
), its middle and hind legs are less elongated, and its forelegs are less shortened than in its relatives. At a casual glance, it is easier to confuse with an ant than with other micropezid flies. The two sexes are almost identical; they can be told apart essentially just by microscopic
study of the tip of the abdomen. The larva is adapted to its strange habitat, the pitchers of the Albany Pitcher Plant. In third-instar
larvae (and likely in others too), the slits of the posterior spiracle
are entirely closed.
, many of which lack them altogether. The third antennal
segment of Badisis is elongate-oval. There are usually three bristles (seta
e) on each side of the "forehead". Rare among stilt-legged flies but also found in Metopochetus, there is a knob below the postvertical bristles. The prelabrum is large but not markedly projected forward at the lower margin.
sutures
across the centerline of the mesothorax
. The metathorax
has a dorsal
sclerite
shaped like a saddle.
is formed by the first two segments of the abdomen, the first of which has a slight bulge on the tergite. In the male the postabdomen is highly characteristic, the sternite of the 5th postabdominal segment is shallow divided into 2 lobes, each of which bears two or three stout bristles at the tip; the entire structure is very similar to that of "Electrobata" tertiaria. The 6th sternite is triradiate like in Metopochetus, but like in Eurybatini not compressed laterally and with a trough-like channel in the middle. The subepandrial sclerite of male Badisis has a very small prominence with a minute setula at its tip. The aedeagus
with its moderately long two-segmented distiphallus resembles that of Metopochetus subgenus
Crus
. On the other hand, the ejaculatory sclerite of Badisis is unlike that of any known Metopochetus, with a rod-like apodeme expanded at the tip like a mushroom-head. Females show the conventional postabdominal structure of stilt-legged flies.
Males are far more often seen than females; the latter were only described 8 years after the former. As far as is known, B. ambulans inhabits sclerophyll forest, where the males are occasionally encountered on flowers of the Myrtaceae
shrub
Astartea fascicularis
. If they feel threatened, they will try to escape by hopping and letting themselves drop down to the ground where they can hide.
The larvae have to date only been found in the pitchers of the Albany Pitcher Plant (Cephalotus follicularis). This carnivorous plant
has a limited range in southwestern Western Australia
, effectively restricting the fly's range also. Most significantly, the plant is found in the Warren
, Jarrah Forest
and Esperance Plains
biogeographic region
s.
The conservation status
of B. ambulans has not been evaluated yet. The Albany Pitcher Plant is classified as a Vulnerable species
by the IUCN. Its numbers are declining, mainly due to habitat destruction and collecting for horticulture
(though there is by now a good supply of culture-grown plants, which are also far easier to maintain than those collected from the wild). The Albany Pitcher Plant prefers somewhat moister habitat
than the fairly arid
locations where adult B. ambulans have been collected. Thus, either that the adult flies are more mobile than their winglessness suggests, able to walk for prolonged distances, and consequently more resilient to local extinctions of the Albany Pitcher Plant. On the other hand, the flies might be restricted to the dry spectrum of the plant's habitat, making them more localized and consequently even more threatened than the plant is.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
with only one known species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, Badisis ambulans. This is a wingless, haltere-less fly
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
with an ant-like appearance
Ant mimicry
Ant mimicry is mimicry of ants by other organisms. Ants are abundant all over the world, and insect predators that rely on vision to identify their prey such as birds and wasps normally avoid them, either because they are unpalatable, or aggressive. Thus some other arthropods mimic ants to escape...
. It is only found in the Southwest Australia
Southwest Australia
Southwest Australia is a biodiversity hotspot that includes the Mediterranean forests, woodlands, and scrub ecoregions of Western Australia. The region has a wet-winter, dry-summer Mediterranean climate, one of five such regions in the world...
n bioregion of Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
. Dependent on the rare Albany Pitcher Plant (Cephalotus follicularis) for its development, this fly is also a rare species.
Despite its many apomorphic features, the details of its morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
suggest a close relationship to the diverse genus Metopochetus, which is also in the tribe
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
Metopochetini. The fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
stilt-legged fly "Electrobata" tertiaria from Baltic
Baltic region
The terms Baltic region, Baltic Rim countries, and Baltic Rim refer to slightly different combinations of countries in the general area surrounding the Baltic Sea.- Etymology :...
amber
Amber
Amber is fossilized tree resin , which has been appreciated for its color and natural beauty since Neolithic times. Amber is used as an ingredient in perfumes, as a healing agent in folk medicine, and as jewelry. There are five classes of amber, defined on the basis of their chemical constituents...
of the Paleogene
Paleogene
The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...
also shows some similarities; it may be a very basal member of the Metopochetini, close to the divergence between these and the Eurybatini.
Description
Apart from its lack of wings and halteresHalteres
Halteres are small knobbed structures modified from the hind wings in some two-winged insects. They are flapped rapidly and function as gyroscopes, informing the insect about rotation of the body during flight....
, B. ambulans has a less unusual habitus
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
than other members of the Micropezidae
Micropezidae
The Micropezidae are a moderate-sized family of acalyptrate muscoid flies in the insect order Diptera, comprising about 500 species in about 50 genera and 5 subfamilies worldwide,...
. Its body is stockier, with a petiolate
Petiole (insect)
In entomology, the term petiole is most commonly used to refer to the constricted first metasomal segment of members of the Hymenopteran suborder Apocrita; it may be used to refer to other insects with similar body shapes, where the metasomal base is constricted...
abdomen (like in ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
s and other Apocrita
Apocrita
Apocrita is a suborder of insects in the order Hymenoptera.Apocrita includes wasps, bees and ants, and consists of many families. It includes the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" formed between the first two segments of the actual abdomen; the...
), its middle and hind legs are less elongated, and its forelegs are less shortened than in its relatives. At a casual glance, it is easier to confuse with an ant than with other micropezid flies. The two sexes are almost identical; they can be told apart essentially just by microscopic
Microscopic
The microscopic scale is the scale of size or length used to describe objects smaller than those that can easily be seen by the naked eye and which require a lens or microscope to see them clearly.-History:...
study of the tip of the abdomen. The larva is adapted to its strange habitat, the pitchers of the Albany Pitcher Plant. In third-instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
larvae (and likely in others too), the slits of the posterior spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
are entirely closed.
Head
The compound eyes are as large like in Metopochetus, an unusual feature among wingless DipteraDiptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...
, many of which lack them altogether. The third antennal
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
segment of Badisis is elongate-oval. There are usually three bristles (seta
Seta
Seta is a biological term derived from the Latin word for "bristle". It refers to a number of different bristle- or hair-like structures on living organisms.-Animal setae:In zoology, most "setae" occur in invertebrates....
e) on each side of the "forehead". Rare among stilt-legged flies but also found in Metopochetus, there is a knob below the postvertical bristles. The prelabrum is large but not markedly projected forward at the lower margin.
Thorax
The scutellum is distinctly visible but rather small. Like in most other Eurybatinae, there is no groove connecting the mesoscutal transverseTransverse plane
The transverse plane is an imaginary plane that divides the body into superior and inferior parts. It is perpendicular to the coronal and sagittal planes....
sutures
Suture (anatomical)
In anatomy, a suture is a fairly rigid joint between two or more hard elements of an animal, with or without significant overlap of the elements....
across the centerline of the mesothorax
Mesothorax
The mesothorax is the middle of the three segments in the thorax of an insect, and bears the second pair of legs. Its principal sclerites are the mesonotum , the mesosternum , and the mesopleuron on each side...
. The metathorax
Metathorax
The metathorax is the posterior of the three segments in the thorax of an insect, and bears the third pair of legs. Its principal sclerites are the metanotum , the metasternum , and the metapleuron on each side...
has a dorsal
Dorsum (biology)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
sclerite
Sclerite
A sclerite is a hardened body part. The term is used in various branches of biology for various structures including hardened portions of sponges, but it is most commonly used for the hardened portions of arthropod exoskeletons....
shaped like a saddle.
Abdomen
The petiolePetiole (insect)
In entomology, the term petiole is most commonly used to refer to the constricted first metasomal segment of members of the Hymenopteran suborder Apocrita; it may be used to refer to other insects with similar body shapes, where the metasomal base is constricted...
is formed by the first two segments of the abdomen, the first of which has a slight bulge on the tergite. In the male the postabdomen is highly characteristic, the sternite of the 5th postabdominal segment is shallow divided into 2 lobes, each of which bears two or three stout bristles at the tip; the entire structure is very similar to that of "Electrobata" tertiaria. The 6th sternite is triradiate like in Metopochetus, but like in Eurybatini not compressed laterally and with a trough-like channel in the middle. The subepandrial sclerite of male Badisis has a very small prominence with a minute setula at its tip. The aedeagus
Aedeagus
An aedeagus is a reproductive organ of male insects through which they secrete sperm from the testes during copulation with a female insect...
with its moderately long two-segmented distiphallus resembles that of Metopochetus subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
Crus
Crus (fly)
Metopochetus is a genus of stilt-legged fly. Crus is a subgenus. Species within Metopochetus are:* M. aequalis* M. aitkeni* M. aper* M. bickeli* M. clarus* M. corax* M. curvus* M. freyi* M. impar...
. On the other hand, the ejaculatory sclerite of Badisis is unlike that of any known Metopochetus, with a rod-like apodeme expanded at the tip like a mushroom-head. Females show the conventional postabdominal structure of stilt-legged flies.
Legs
The coxa of the forelegs has a tooth-like lobe on the lower forward end. Such a feature is apparently only found in Badisis and Metopochetus. The tibiae of mid- and hindlegs bear fine hairs (setulae) and numerous but scattered thicker bristles.Ecology and status
- See also: CoextinctionCoextinctionCoextinction of a species is the loss of a species as a consequence of the extinction of another. The term was originally used in the context of the extinction of parasitic insects following the loss of their specific hosts...
Myrtaceae
The Myrtaceae or Myrtle family are a family of dicotyledon plants, placed within the order Myrtales. Myrtle, clove, guava, feijoa, allspice, and eucalyptus belong here. All species are woody, with essential oils, and flower parts in multiples of four or five...
shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
Astartea fascicularis
Astartea fascicularis
Astartea fascicularis is a species of the botanical family Myrtaceae. This plant is endemic to the south west of Western Australia.An erect shrub to three, or five, metres in height, with white and pink flowers that appear throughout the year...
. If they feel threatened, they will try to escape by hopping and letting themselves drop down to the ground where they can hide.
The larvae have to date only been found in the pitchers of the Albany Pitcher Plant (Cephalotus follicularis). This carnivorous plant
Carnivorous plant
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...
has a limited range in southwestern Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
, effectively restricting the fly's range also. Most significantly, the plant is found in the Warren
Warren (biogeographic region)
Warren, also known as Karri Forest Region and the Jarrah-Karri forest and shrublands ecoregion, is a biogeographic region in southern Western Australia. Located in the southwest corner of Western Australia between Cape Naturaliste and Albany, it is bordered to the north and east by the Jarrah...
, Jarrah Forest
Jarrah Forest
Jarrah Forest is an Interim Biogeographic Regionalisation for Australia region in Western Australia.-Location and description:The ecoregion stands on the 300m high Yilgarn block inland plateau and includes wooded valleys such as those of Western Australia's Murray River and the Helena River near...
and Esperance Plains
Esperance Plains
Esperance Plains, also known as Eyre Botanical District, is a biogeographic region in southern Western Australia. Located on the south coast between the Avon Wheatbelt and Hampton regions, and bordered to the north by the Mallee region, it is a plain punctuated by granite and quartz outcrops and...
biogeographic region
Ecoregions in Australia
Ecoregions in Australia are geographically distinct plant and animal communities, defined by the World Wide Fund for Nature based on geology, soils, climate, and predominant vegetation....
s.
The conservation status
Conservation status
The conservation status of a group of organisms indicates whether the group is still extant and how likely the group is to become extinct in the near future...
of B. ambulans has not been evaluated yet. The Albany Pitcher Plant is classified as a Vulnerable species
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
by the IUCN. Its numbers are declining, mainly due to habitat destruction and collecting for horticulture
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
(though there is by now a good supply of culture-grown plants, which are also far easier to maintain than those collected from the wild). The Albany Pitcher Plant prefers somewhat moister habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
than the fairly arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
locations where adult B. ambulans have been collected. Thus, either that the adult flies are more mobile than their winglessness suggests, able to walk for prolonged distances, and consequently more resilient to local extinctions of the Albany Pitcher Plant. On the other hand, the flies might be restricted to the dry spectrum of the plant's habitat, making them more localized and consequently even more threatened than the plant is.