The European fire-bellied toad (''Bombina bombina'') is a species of
fire-bellied toad
The fire-bellied toads are a group of six species of small frogs (most species typically no longer than ) belonging to the genus ''Bombina''.
The name "fire-bellied" is derived from the brightly colored red- or yellow-and-black patterns on the ...
native to eastern parts of mainland
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
, where it can be found near waterbodies such as ponds and marshes.
It is known for its red colored belly used to ward off predators, an example of
aposematism
Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...
, and its distinctive "whoop" call.
Description
The European fire-bellied toad is a medium sized frog, growing up to approximately .
The dorsal coloration can vary from gray to brown to green, while the stomach is red with thick black
mottling
Mottle is a pattern of irregular marks, spots, streaks, blotches or patches of different shades or colours. It is commonly used to describe the surface of plants or the skin of animals. In plants, mottling usually consists of yellowish spots o ...
. The backs of these frogs are covered in warts.
When threatened by a predator, the fire-bellied toad will lift up its arms (sometimes flipping over) to expose its red coloration and show off its toxicity to the potential predator. This is known as
Unkenreflex
Unkenreflex – interchangeably referred to as unken reflex (''Unke'' is the German word for the genus of fire-bellied toads) – is a defensive posture adopted by several branches of the amphibian class – including salamanders, toads, and cert ...
, and is an example of
aposematism
Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...
.
Distribution
The European fire-bellied toad is found throughout
Central
Central is an adjective usually referring to being in the center of some place or (mathematical) object.
Central may also refer to:
Directions and generalised locations
* Central Africa, a region in the centre of Africa continent, also known as ...
and
Eastern Europe
Eastern Europe is a subregion of the Europe, European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural, and socio-economic connotations. The vast majority of the region is covered by Russ ...
.
More particularly, its range starts in eastern
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
(including eastern
Denmark
)
, song = ( en, "King Christian stood by the lofty mast")
, song_type = National and royal anthem
, image_map = EU-Denmark.svg
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Danish Realm, Kingdom of Denmark
...
and parts of southern Sweden), and then east to the
Volga District of
Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
where they are stopped by the
Ural Mountains
The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...
.
The frog's most southern range is
Bulgaria
Bulgaria (; bg, България, Bǎlgariya), officially the Republic of Bulgaria,, ) is a country in Southeast Europe. It is situated on the eastern flank of the Balkans, and is bordered by Romania to the north, Serbia and North Macedon ...
and the
Marmara Region
The Marmara Region ( Turkish: ''Marmara Bölgesi'') is a geographical region of Turkey.
Located in northwestern Turkey, it is bordered by Greece and the Aegean Sea to the west, Bulgaria and the Black Sea to the north, the Black Sea Region to the ...
of
Turkey
Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...
.
There is an
introduced population of European fire-bellied toads in
Lorraine
Lorraine , also , , ; Lorrain: ''Louréne''; Lorraine Franconian: ''Lottringe''; german: Lothringen ; lb, Loutrengen; nl, Lotharingen is a cultural and historical region in Northeastern France, now located in the administrative region of Gr ...
,
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, over away from their natural range in eastern
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
.
This population was first discovered in 2009 in
Moselle
The Moselle ( , ; german: Mosel ; lb, Musel ) is a river that rises in the Vosges mountains and flows through north-eastern France and Luxembourg to western Germany. It is a bank (geography), left bank tributary of the Rhine, which it jo ...
but has since been found in several other nearby locations up to away, which suggests they were moved by humans intentionally. They can potentially impact the local
yellow-bellied toad
The yellow-bellied toad (''Bombina variegata'') belongs to the order Anura, the family Bombinatoridae, and the genus of fire-bellied toads. The toad is distributed mainly across western Europe as well as a handful of countries in eastern Europ ...
s through hybridization.
While they are listed as "
Least Concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
" by the
ICUN, this frog has been suffering some losses throughout its range. For example, 15 known breeding populations of these frogs were identified in Denmark in 1974, but by 1988 only 8 of those populations remained. In the
Puszcza Romincka Landscape Park
Puszcza Romincka Landscape Park (''Park Krajobrazowy Puszczy Rominckiej'') is a protected area ( Landscape Park) in northern Poland, established in 1998, covering an area of . It takes its name from the Puszcza Romincka or Romincka Forest.
The Pa ...
in Poland, the fire-bellied toad was described as uncommon,
rare in the
Coastal Landscape Park
The Polish Coastal Landscape Park (''Nadmorski Park Krajobrazowy'') is a protected area (Landscape Park (Poland), Landscape Park) in northern Poland, established in 1978, covering an area of .
The Park lies within Pomeranian Voivodeship, in Puck ...
, and in an amphibian survey in
Warsaw
Warsaw ( pl, Warszawa, ), officially the Capital City of Warsaw,, abbreviation: ''m.st. Warszawa'' is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland, and its population is officia ...
the fire-bellied toad only made up 9% of the observed species. However, in some areas they are recovering through human intervention, such as in
Funen County
Funen County ( da, Fyns Amt) is a former county (Danish: ''amt'') in central Denmark, comprising the islands of Funen, Langeland, Tåsinge, Ærø, and approximately 90 other islands, of which only 25 are inhabited. The county was formed on 1 Apri ...
,
Denmark
)
, song = ( en, "King Christian stood by the lofty mast")
, song_type = National and royal anthem
, image_map = EU-Denmark.svg
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Danish Realm, Kingdom of Denmark
...
, where dozens of ponds were dug for the frogs to live and breed in, increasing their population approximately five-fold in a decade.
Ecology
This frog generally prefers to live in lowland areas such as
pond
A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from th ...
s and
marsh
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...
es without too much woody vegetation.
In larger lakes these frogs will stay on the edges ( deep) in
reed bed
A reedbed or reed bed is a natural habitat found in floodplains, waterlogged depressions and
estuaries. Reedbeds are part of a succession from young reeds colonising open water or wet ground through a gradation of increasingly dry ground. As ...
s and
floodplain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...
s.
They feed on all sorts of small
invertabrates, in particular
springtail
Springtails (Collembola) form the largest of the three lineages of modern hexapods that are no longer considered insects (the other two are the Protura and Diplura). Although the three orders are sometimes grouped together in a class called Ento ...
s,
beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s,
flies
Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...
, and
ant
Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22 ...
s. In return, the frogs are preyed on by many other animals such as
snake
Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...
s and
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s, while tadpoles are eaten by
leech
Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodie ...
es and
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
.
They will typically
hibernate
Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
once temperatures dip down to , during which they burrow into
soil
Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...
or a rotting log and remain in a state of
torpor
Torpor is a state of decreased physiological activity in an animal, usually marked by a reduced body temperature and metabolic rate. Torpor enables animals to survive periods of reduced food availability. The term "torpor" can refer to the time ...
until spring.
Breeding commences once temperatures reach and is usually done at night time or early morning, where females will deposit up to 15 to 40 eggs depending on their size.
Tadpole
A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found i ...
s are born in about a week and develop for approximately a month before
metamorphosing at a size of about ).
Evolution
The European fire-bellied toad (''B. bombina'') and yellow-bellied toad (''
B. variegata'') are the product of
clinal speciation.
They emerged from an ancient
divergence event, however they continue to
hybridise where they overlap geographically.
Yanchukov ''et al.'' 2006's survey of these species aids understanding of clinal speciation itself: Because different subpopulations carry different combinations of the
reproductive isolation mechanisms, and because they combine data from a new transect with four preceding
transect
A transect is a path along which one counts and records occurrences of the objects of study (e.g. plants).
There are several types of transect. Some are more effective than others.
It requires an observer to move along a fixed path and to count ...
s, their comparison and reanalysis of this speciation process helps to understand the contribution of
single-nucleotide polymorphism
In genetics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently lar ...
s to clinal speciation.
Clinal speciation is a challenging dynamic to study and so Yanchukov is one of the few to provide insight into this relationship.
Their speciation occurred during the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
epoch
In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured.
The moment of epoch is usually decided by ...
. The ancestor to both species was confined to southern Europe during the
Last Glacial Maximum
The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent.
Ice sheets covered much of Northern North America, Northern Eur ...
, where ''B. variegata'' evolved in the mountains in the west (
Apennine and
Balkans
The Balkans ( ), also known as the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throughout the who ...
) and ''B. bombina'' in the lowlands to the east (the
steppe
In physical geography, a steppe () is an ecoregion characterized by grassland plains without trees apart from those near rivers and lakes.
Steppe biomes may include:
* the montane grasslands and shrublands biome
* the temperate grasslands, ...
s around the
Black
Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white have o ...
and
Caspian Sea
The Caspian Sea is the world's largest inland body of water, often described as the world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia ...
). As the glaciers receded, both species spread out to the rest of Europe but
hybridized and
competed with each other until ''B. bombina'' occupied the lowlands and ''B. variegata'' the higher altitudes.
While the two frogs hybridize in narrow
hybrid zone
A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. Hybrid zones can form ''in situ'' due to the evolution of a new lineage but generally they result from secondary contact ...
s of approximately wide,
they generally avoid it by differing in their
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
* Morphology (archaeology), study of the shapes or forms of artifacts
* Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
and behavior. ''B. bombina'' prefers to breed in lowland
seasonal ponds, such as
wet meadow
A wet meadow is a type of wetland with soils that are saturated for part or all of the growing season. Debate exists whether a wet meadow is a type of marsh or a completely separate type of wetland. Wet prairies and wet savannas are hydrologically ...
s and
floodplain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...
s, but ones that are still close to nearby permanent waterbodies. On the other hand, ''B. variegata'' prefers to breed in higher elevations in
ephermal ponds that are quick to dry up.
''B. bombina'' also spends more time confined to a waterbody compared to ''B. variegata'', which is more terrestrial and has evolved longer legs and thicker skin to aid in their frequent migrations onto dry land.
[ MAFN ]ORCID
The ORCID (; Open Researcher and Contributor ID) is a nonproprietary alphanumeric code to uniquely identify authors and contributors of scholarly communication as well as ORCID's website and services to look up authors and their bibliographic ...
br>0000-0002-5400-4408
GSbr>5nkhrpUAAAAJ
Additionally, ''B. variegata'' is unable to sing as loudly as ''B. bombina'' due to their lack of internal
vocal sac
The vocal sac is the flexible membrane of skin possessed by most male frogs and toads. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call. The presence or development of the vocal sac is one way o ...
s, which forces them to find other breeding ponds without the other species of fire-bellied toad.
Secondary metabolites
Like its relatives – including ''
B. variegata''
and ''
B. orientalis''
– ''B. bombina'' produces
bombinins.
The H. Michl group in Vienna were the first to study ''B. bombina'' and ''B. variegata'', first publishing a partial bombinin amino acid sequence in Kiss & Michl 1962.
A few years later they discovered it was merely the
carboxy terminal
The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...
of a larger molecule in Csordás & Michl 1970, also showing
antibacterial
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...
effect.
The
antifungal
An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as crypto ...
effect of bombinins in the toads' skin makes them promising factors for
incorporation into food packaging to retard spoilage.
More recently Jilek ''et al.'' 2005 searched for
homologues of the
isomerase
Isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which bonds are broken and formed. The general form of such a reaction is as follows:
A–B ...
and found the closest in ''
Xenopus tropicalis
The western clawed frog (''Xenopus tropicalis'') is a species of frog in the family Pipidae, also known as tropical clawed frog. It is the only species in the genus ''Xenopus'' to have a diploid genome. Its genome has been sequenced, making it a ...
'', but also
finding predicted homologues in various other
vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s including the
chicken
The chicken (''Gallus gallus domesticus'') is a domesticated junglefowl species, with attributes of wild species such as the grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster or cock is a term for an adult m ...
(''Gallus domesticus'').
The
prokineticin family of compounds was first discovered in this species and ''B. variegata''.
These two species produce and subsequently other prokineticins have been isolated from other species in the genus, and predicted in ''
Rana temporaria
The common frog or grass frog (''Rana temporaria''), also known as the European common frog, European common brown frog, European grass frog, European Holarctic true frog, European pond frog or European brown frog, is a semi-aquatic amphibian ...
'' and ''
Pelophylax esculentus
The edible frog (''Pelophylax'' kl. ''esculentus'') is a species of common European frog, also known as the common water frog or green frog (however, this latter term is also used for the North American species ''Rana clamitans'').
It is used ...
''.
References
{{Authority control
Bombina
Amphibians described in 1761
Taxa named by Carl Linnaeus