Leptodirus hochenwartii
Encyclopedia
Leptodirus hochenwartii, or L. hohenwarti, is a cave
beetle
in the family Leiodidae
and the only species
in the genus
Leptodirus. It is a true troglobite
, adapted to the life underground and unable to survive outside. Its distinguishing features are slender thorax
, elongated legs and antennae
, the absence of pigment
in the integument, and completely reduced eyes. But perhaps the most striking feature are the domed elytrae
which cover the abdomen completely and give it a round (so-called "physogastric") appearance.
It lives predominantly in large caves where the temperature does not exceed 12°C. Its ecology is largely unknown, but the specimens were seen feeding on carcasses of different cave animals and other organic material. Even less is known about its life history; the only study done so far determined that it reproduces and grows slowly. Females lay a small number of relatively large eggs
which take a long time to develop. The number of larva
l instar
s is reduced to only one, and the larvae do not feed before moulting
.
. Six subspecies
are currently recognized:
Of those, three are found in Slovenia, and the others are found in Croatia
. The southernmost known location is Velebit
range in Croatia where subspecies L. h. velebiticus was described, and subspecies L. h. reticulatus was originally found in Grota Noe near Trieste
(Italy
). The exact status of several subspecies and forms is problematic to determine because specimens can differ significantly in physical characteristics even within the same population.
The animal was first found in 1831 by Luka Čeč, an assistant to the lamplighter, when exploring the newly discovered inner portions of the Postojna cave
system in southwestern Slovenia
. He gave it to Earl Franz von Hohenwart who was unable to determine the species, and gave the specimen in turn to Ferdinand Schmidt, a naturalist from Ljubljana
. Schmidt recognized the beetle as a new species and described it in the paper Illyrisches Blatt (1832). He named it Leptodirus Hochenwartii after the donor, and also gave it Slovene name drobnovratnik and German
Enghalskäfer, both meaning "slender-necked (beetle)". The article represents the first formal description of a cave animal (the olm
, described in 1768, wasn't recognized as a cave animal at the time). Subsequent research by Schmidt revealed further previously unknown cave inhabitants, which aroused considerable interest among natural historians. For this reason, the discovery of L. hochenwartii (along with the olm) is considered as the starting point of speleobiology as a scientific discipline.
, despite the fact that density in some caves can be high. As such, the species is included in the Slovenian Red list of threatened species (category R). Additionally, it is included in the Annex II of the EU Habitats Directive (92/43/EEC); on this basis, 15 areas of conservation (pSCI) are established in Slovenia which include the majority of known localities.
Cave
A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...
beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
in the family Leiodidae
Leiodidae
Leiodidae is a family of beetles with around 3800 described species found worldwide. Members of this family are commonly called round fungus beetles due to the globular shape of many species, although some are more elongated in shape...
and the only 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...
in the genus
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...
Leptodirus. It is a true troglobite
Troglobite
Troglobites are small cave-dwelling animals that have adapted to their dark surroundings. Troglobite species include spiders, insects, fish and others. They live permanently underground and cannot survive outside the cave environment. Troglobite adaptations and characteristics include a heightened...
, adapted to the life underground and unable to survive outside. Its distinguishing features are slender thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
, elongated legs and antennae
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....
, the absence of pigment
Biological pigment
Biological pigments, also known simply as pigments or biochromes are substances produced by living organisms that have a color resulting from selective color absorption. Biological pigments include plant pigments and flower pigments...
in the integument, and completely reduced eyes. But perhaps the most striking feature are the domed elytrae
Elytron
An elytron is a modified, hardened forewing of certain insect orders, notably beetles and a few of the true bugs ; in most true bugs, the forewings are instead called hemelytra, as only the basal half is thickened while the apex is membranous...
which cover the abdomen completely and give it a round (so-called "physogastric") appearance.
It lives predominantly in large caves where the temperature does not exceed 12°C. Its ecology is largely unknown, but the specimens were seen feeding on carcasses of different cave animals and other organic material. Even less is known about its life history; the only study done so far determined that it reproduces and grows slowly. Females lay a small number of relatively large eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
which take a long time to develop. The number of larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
l 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...
s is reduced to only one, and the larvae do not feed before moulting
Ecdysis
Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...
.
Taxonomy and range
L. hochenwartii is endemic to western Dinaric AlpsDinaric Alps
The Dinaric Alps or Dinarides form a mountain chain in Southern Europe, spanning areas of Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Kosovo, Albania and Montenegro....
. Six subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
are currently recognized:
- L. hochenwartii hochenwartii Schmidt, 1832
- L. hochenwartii reticulatus J. Müller, 1906
- L. hochenwartii schmidti (Motschoulsky, 1856)
- L. hochenwartii croaticus Pretner, 1955
- L. hochenwartii velebiticus Pretner, 1970
- L. hochenwartii pretneri Müller, 1926
Of those, three are found in Slovenia, and the others are found in Croatia
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...
. The southernmost known location is Velebit
Velebit
Velebit is the largest though not the highest mountain range in Croatia. Its highest peak is the Vaganski vrh at 1757 m.The range forms a part of the Dinaric Alps and is located along the Adriatic coast, separating it from Lika in the interior...
range in Croatia where subspecies L. h. velebiticus was described, and subspecies L. h. reticulatus was originally found in Grota Noe near Trieste
Trieste
Trieste is a city and seaport in northeastern Italy. It is situated towards the end of a narrow strip of land lying between the Adriatic Sea and Italy's border with Slovenia, which lies almost immediately south and east of the city...
(Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
). The exact status of several subspecies and forms is problematic to determine because specimens can differ significantly in physical characteristics even within the same population.
Research history
Postojna Cave
Postojna Cave is a 20,570 m long Karst cave system near Postojna, Slovenia. It is the longest cave system in the country as well as one of its top tourism sites.-History:The caves were created by the Pivka River....
system in southwestern Slovenia
Slovenia
Slovenia , officially the Republic of Slovenia , is a country in Central and Southeastern Europe touching the Alps and bordering the Mediterranean. Slovenia borders Italy to the west, Croatia to the south and east, Hungary to the northeast, and Austria to the north, and also has a small portion of...
. He gave it to Earl Franz von Hohenwart who was unable to determine the species, and gave the specimen in turn to Ferdinand Schmidt, a naturalist from Ljubljana
Ljubljana
Ljubljana is the capital of Slovenia and its largest city. It is the centre of the City Municipality of Ljubljana. It is located in the centre of the country in the Ljubljana Basin, and is a mid-sized city of some 270,000 inhabitants...
. Schmidt recognized the beetle as a new species and described it in the paper Illyrisches Blatt (1832). He named it Leptodirus Hochenwartii after the donor, and also gave it Slovene name drobnovratnik and German
German language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
Enghalskäfer, both meaning "slender-necked (beetle)". The article represents the first formal description of a cave animal (the olm
Olm
The olm, or proteus , is a blind amphibian endemic to the subterranean waters of caves of the Dinaric karst of southern Europe. It lives in the waters that flow underground through this extensive limestone region including waters of the Soča river basin near Trieste in Italy, through to southern...
, described in 1768, wasn't recognized as a cave animal at the time). Subsequent research by Schmidt revealed further previously unknown cave inhabitants, which aroused considerable interest among natural historians. For this reason, the discovery of L. hochenwartii (along with the olm) is considered as the starting point of speleobiology as a scientific discipline.
Conservation
Due to its limited range and slow reproduction, L. hochenwartii is considered rare and vulnerableVulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
, despite the fact that density in some caves can be high. As such, the species is included in the Slovenian Red list of threatened species (category R). Additionally, it is included in the Annex II of the EU Habitats Directive (92/43/EEC); on this basis, 15 areas of conservation (pSCI) are established in Slovenia which include the majority of known localities.