Megalodacne
Encyclopedia
Megalodacne is a genus
of fungivorous
beetles in the family Erotylidae
.
Distinguishing characteristics of the genus along with other members of the subfamily Megalodacninae include large eyes and a lack of depressions in the club joint of the antennae
. The first three tarsomeres are also cylindrical and of similar shape and size, while the fourth is significantly shorter.
Species of the genus Megalodacne very closely resembles members of the genera Episcapha and Episcaphula (some members of which were formerly classified under Megalodacne). They also often look superficially similar to several other beetles since the patterns of the markings of yellow, orange, or red on the elytra (called fascia) of Megalodacne are shared by many other beetle species.
An example of which is the sap beetle (Nitidulidae) genus Glischrochilus
. Their native ranges sometimes overlap as well, making it easy to confuse the two (as with Megalodacne fasciatus, Megalodacne heros, and the nitulidid Glischrochilus fasciatus from eastern North America
). The best way to tell them apart is by size, as sap beetles are generally small, ranging from 2 to 12 mm (0.078740157480315 to 0.47244094488189 ) in length. Glischrochilus reaches a maximum length of only 12 mm (0.47244094488189 in). Megalodacne on the other hand are large beetles ranging from 9 millimetre. The elytra of the sap beetles which most resemble Megalodacne also do not cover the whole abdomen and leave the last abdominal segment(s) exposed. The elytra of Megalodacne, on the other hand, completely cover the abdomen.
than smaller members of the family. The fungi eaten include Ganoderma
and Fomes
species.
Some tropical nocturnal species of Megalodacne are attracted to light.
e, like adults, also feed on the fruiting bodies
of bracket fungi by burrowing into it...
There are two kinds of larvae of Megalodacne depending on the species. In some species, the larvae are elongated and feed on fungi by drilling holes inside of it. In others, the larvae feed alongside adults by gnawing out shallow depressions on the fruiting bodies of fungi. The latter larvae are sluggish, heavily sclerotized
, and somewhat flattened. The larval stage takes about 2 to 3 months from egg to pupation
. It is not uncommon to see adults feeding along with larvae.
in 1873. The type species
is Ips fasciata (now known as Megalodacne fasciata). The genus Megalodacne is classified in the subfamily Megalodacninae, alongside the genera Episcapha and Episcaphula.
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...
of fungivorous
Fungivore
A fungivore or mycophage is any animal that primarily or solely feeds upon living members of the fungus kingdom. Fungivory is a type of predation, and is an important part of the soil food web...
beetles in the family Erotylidae
Erotylidae
Erotylidae is the pleasing fungus beetles, is a family of beetles containing over 100 genera. In the present circumscription, it includes the subfamilies Dacninae, Encaustinae, Erotylinae, Megalodacninae, and Tritominae. In other words, the narrowly-circumscribed Erotylidae correspond to the...
.
Description
Adult beetles of the genus Megalodacne range in size from 9 to 22 mm (0.354330708661417 to 0.866141732283465 ), making them among the larger members of the family.Distinguishing characteristics of the genus along with other members of the subfamily Megalodacninae include large eyes and a lack of depressions in the club joint of the 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 first three tarsomeres are also cylindrical and of similar shape and size, while the fourth is significantly shorter.
Species of the genus Megalodacne very closely resembles members of the genera Episcapha and Episcaphula (some members of which were formerly classified under Megalodacne). They also often look superficially similar to several other beetles since the patterns of the markings of yellow, orange, or red on the elytra (called fascia) of Megalodacne are shared by many other beetle species.
An example of which is the sap beetle (Nitidulidae) genus Glischrochilus
Glischrochilus
Glischrochilus is a genus of sap-feeding and predatory beetles under the family Nitidulidae, subfamily Cryptarchinae. Most members of this genus are commonly known as picnic beetles or beer bugs.-Description:...
. Their native ranges sometimes overlap as well, making it easy to confuse the two (as with Megalodacne fasciatus, Megalodacne heros, and the nitulidid Glischrochilus fasciatus from eastern North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
). The best way to tell them apart is by size, as sap beetles are generally small, ranging from 2 to 12 mm (0.078740157480315 to 0.47244094488189 ) in length. Glischrochilus reaches a maximum length of only 12 mm (0.47244094488189 in). Megalodacne on the other hand are large beetles ranging from 9 millimetre. The elytra of the sap beetles which most resemble Megalodacne also do not cover the whole abdomen and leave the last abdominal segment(s) exposed. The elytra of Megalodacne, on the other hand, completely cover the abdomen.
Ecology
Megalodacne species feed on harder bracket fungiBracket fungus
Bracket fungi, or shelf fungi, among many groups of the fungi in the phylum Basidiomycota. Characteristically, they produce shelf- or bracket-shaped fruiting bodies called conks that lie in a close planar grouping of separate or interconnected horizontal rows...
than smaller members of the family. The fungi eaten include Ganoderma
Ganoderma
Ganoderma is a genus of polypore mushrooms which grow on wood and include about 80 species, many from tropical regions. Because of their extensive use in traditional Asian medicines, and their potential in bioremediation, they are a very important genus economically. Ganoderma can be differentiated...
and Fomes
Fomes
Fomes is a genus of perennial woody fungi in the family Polyporaceae. Species are typically hoof-shaped . New growth each season is added to the margin, resulting in a downward extension of the hymenium. This often results in a zonate appearance of the upper surface, that is, marked by concentric...
species.
Some tropical nocturnal species of Megalodacne are attracted to light.
Life cycle
Megalodacne deposit eggs on the fungi on which they feed. Upon hatching, the larvaLarva
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...
e, like adults, also feed on the fruiting bodies
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
of bracket fungi by burrowing into it...
There are two kinds of larvae of Megalodacne depending on the species. In some species, the larvae are elongated and feed on fungi by drilling holes inside of it. In others, the larvae feed alongside adults by gnawing out shallow depressions on the fruiting bodies of fungi. The latter larvae are sluggish, heavily sclerotized
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....
, and somewhat flattened. The larval stage takes about 2 to 3 months from egg to pupation
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
. It is not uncommon to see adults feeding along with larvae.
Taxonomy and systematics
Megalodacne was first described by George Robert CrotchGeorge Robert Crotch
George Robert Crotch was a British entomologist.Born in Cambridge, England 1842 Crotch became interested in insects, especially Coleoptera, while an undergraduate at Cambridge University. He worked at the University Library, Cambridge...
in 1873. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Ips fasciata (now known as Megalodacne fasciata). The genus Megalodacne is classified in the subfamily Megalodacninae, alongside the genera Episcapha and Episcaphula.
List of species
Species of Megalodacne include:- Megalodacne bellula Lewis, 1883 - Japan, Korea, & China
- Megalodacne chinensis Crotch, 187- China
- Megalodacne elongatula Crotch, 1876 – Southeast Asia
- Megalodacne fasciata (Fabricius, 1777) – eastern North AmericaNorth AmericaNorth America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
- Megalodacne grandipennis (Fairmaire, 1891) – TanzaniaTanzaniaThe United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...
- Megalodacne grandis (Fabricius, 1792) - Africa
- Megalodacne heros (Say, 1823) – eastern North America
- Megalodacne immaculata Chûjô and Kiuchi, 1963 – Japan
- Megalodacne marginata Arrow, 1925 – Assam
- Megalodacne promensis Arrow, 1925 – Burma, China
- Megalodacne similima Crotch, 1876 – Sarawak, Sumatra
- Megalodacne varia Gorham, 1889 – Malaysia