Riodinidae is the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of metalmark

butterflies Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...

. The common name "metalmarks" refers to the small, metallic-looking spots commonly found on their wings. The 1,532 species are placed in 146 genera. Although mostly

Neotropical The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In biogeogra ...

in distribution, the family is also represented both in the Nearctic,

Palearctic The Palearctic or Palaearctic is a biogeographic realm of the Earth, the largest of eight. Confined almost entirely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa. Th ...

, Australasian ('' Dicallaneura''), Afrotropic ('' Afriodinia'', '' Saribia''), and

Indomalayan realm The Indomalayan realm is one of the eight biogeographic realms. It extends across most of South and Southeast Asia and into the southern parts of East Asia. Also called the Oriental realm by biogeographers, Indomalaya spreads all over the Ind ...

Description

The family includes small to medium-sized species, from 12 to 60 mm wingspan, often with vibrant structural colouring. The wing shape is very different within the family. They may resemble butterflies in other groups, some are similar to Satyrinae, some are bright yellow reminiscent of Coliadinae and others (examples '' Barbicornis'', '' Rhetus arcius'', '' Helicopis'', '' Chorinea'') have tails as do Papilionidae. The colouration ranges from muted colours in the temperate zone species to iridescent blue and green wings and transparent wings in tropical species. The golden or silvery metallic spots on the wings in many species of the Americas gave them the English common name "metalmarks". A number of species

mimic In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. In the simples ...

poisonous moths of several families and there are often extensive mimicry rings of similar-looking species, grouped around a model. Mimicry causes often closely related species to have completely different wing patterns, for example the genus '' Thisbe''. Many species mimic the stain and stripe pattern of toxic

Nymphalidae The Nymphalidae are the largest family of butterflies, with more than 6,000 species distributed throughout most of the world. Belonging to the superfamily Papilionoidea, they are usually medium-sized to large butterflies. Most species ha ...

. Batesian mimicry seems to be more common than in any other insect family of similar size. Reasons for this are unknown. Another example is '' Ithomeis'' where different subspecies resemble the species they mimic in different parts of the geographic range more than they resemble each other. The delimitation from the closely related

Lycaenidae Lycaenidae is the second-largest family (biology), family of butterflies (behind Nymphalidae, brush-footed butterflies), with over 6,000 species worldwide, whose members are also called gossamer-winged butterflies. They constitute about 30% of ...

by morphological

autapomorphy In phylogenetics, an autapomorphy is a distinctive feature, known as a Synapomorphy, derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or Outgroup (cladistics), outgroup taxa, not ...

is difficult. The first pair of legs of the males, which arises on the prothorax, is less than half as long as the legs of the pterothorax and they are not used for walking. The individual segments of the tarsus are sometimes fused together and fused with the tibia, and the pretarsi have no claws. This feature is also found in some Lycaenidae (and also the Monotrysia), but in these the legs are always much longer. The sensory hairs on the tarsi of the female forelimbs are arranged in a group. These groups which are arranged in pairs can be found in the other taxa of the Papilionoidea. The third problematic apomorphy is the absence of the rear projections (apophyses) of the female genitalia. This feature (absence) is found as well in some species of the subfamily of Poritiinae. In almost all Riodinidae, the coxae of the front legs are extended on males jutting out over the trochanter (only hinted at in ''Styx infernalis'' and ''Corrachia leucoplaga''). If there are similar projections in Lycaenidae (in genera ''Curetis'', ''Feniseca'' and ''Poritia''), they are built differently in detail and may be, for example, dorsally convex. In addition, almost all Riodinidae in contrast to the Lycaenidae have a humeral vein in the hindwings and the costa is thickened (exceptions in the subfamily Hamearinae). The head in relation to the eyes is wider than in Lycaenidae, making the antennal bases further away from the eye. The relatively long antennae often reach half of the front wing length. Riodinidae have an unusual variety in

chromosome A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...

numbers, only some very basal groups have the number typical for butterflies (between 29 and 31) or the number characteristic of Lycaenidae (23 to 24). Numbers between 9 and 110 occur. In some cases, representatives of a morphologically indistinguishable cryptospecies have different chromosome numbers and are reproductively isolated.

Distinguishing features

Like the lycaenids, the males of this family have reduced forelegs while the females have full-sized, fully functional forelegs. The foreleg of males is often reduced and has a uniquely shaped first segment (the coxa) which extends beyond its joint with the second segment, rather than meeting it flush. They have a unique venation on the hindwing: the costa of the hindwing is thickened out to the humeral angle and the humeral vein is short.

Taxonomy and systematics

Riodinidae is currently treated as a distinct family within the superfamily

Papilionoidea Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...

, but in the past they were held to be the subfamily Riodininae of the

. Earlier, they were considered to be part of the now defunct family Erycinidae, whose species are divided between this family and the subfamily Libytheinae. Today, most systematists prefer to accept an independent family even if there are counter arguments. Based on morphological studies Ackery et al. in the manual of zoology (Kristensen 1998, cf. literature) placed Riodininae within the Lycaenidae. Kristensen et al. accepted the updating of the manual in 2007 raising the classification to family rank at least on a provisional basis.

Molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

(based on homologous DNA sequences) establishes a

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

relationship between the Riodinidae and the Lycaenidae accepted almost unanimously.

Subfamilies

The family Riodinidae has been historically been classified using a two subfamily (Stichel, 1928) or three subfamily (Callaghan and Lamas, 2004) system. Genetic data from Seraphim ''et al.'' (2018) supports the two subfamily interpretation, with the subfamily Euselasiinae being subsumed entirely within the Old World Nemeobiinae. Two subfamily model (Stichel, 1928) * Nemeobiinae * Riodininae Three subfamily model (Callaghan and Lamas, 2004) * Euselasiinae * Nemeobiinae * Riodininae The

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

genus '' Lithopsyche'' is sometimes placed here but sometimes within the

Biology

Species occur in a variety of habitats, but have a unique distribution focus in the tropical rain forests of South America. Many species are rarely found and have a relatively small distribution area. Species of the genus ''Charis'' were therefore used to reconstruct the history of the forest of the

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributary, tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries ...

: each of the 19 species has a vicariant distribution area, three originally separate forests (upper, lower Amazonas, Guyana) can be derived from the relationship between the species. The food plants for the caterpillars total more than 40 plant families. Mostly young leaves or flowers are used, and rarely fallen, dead leaves or lichen are eaten. The larvae feed mostly individually not gregariously. However, gregarious caterpillars are found within the Euselasiinae (''Euselasia''), Riodinini (''Melanis'') and Emesini (''Emesis''), with some species demonstrating processionary behaviours. Available evidence from ''Euselasia'' and ''Hades'' suggests the gregarious trait may be widespread among members of the subfamily Euselasiinae. The larva of ''Setabis lagus'' (Riodininae: Nymphidiini), is predatory. There are records of predation on larvae of ''Horiola'' species (family Membracidae) as well as scale insects ( Coccidae). Predatory feeding has also been shown in ''Alesa amesis''. A number of species associate with and are protected by ants during one or more stages of their life cycle. A study in Ecuador based on adult male feeding records for 124 species in 41 genera of Riodinidae (out of a total of 441 species in 85 genera collected in the study) demonstrated that rotting fish and other carrion was the most frequently used food source in terms of numbers of individuals and taxa, attracting 89 species from 32 genera. Other food substrates visited in this study included flowers, damp sand or

mud-puddling Puddling is a behaviour in which an organism seeks out nutrients in certain moist substances such as rotting plant matter, mud, and carrion, and sucks up the fluid. Where the conditions are suitable, conspicuous insects such as butterfly, butterf ...

Life cycle

The eggs vary in shape, but often appear round and flattened, some have the shape of a dome or turban. They are similar to the eggs of the Lycaenidae. The

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...

s are usually hairy and plump, and are the common overwintering stage. The caterpillars are usually longer than those of the Lycaenidae except in the myrmecophilous species.

Pupa A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

e are hairy and attached with silk to either the host plant or to ground debris or leaf litter. No cocoon is seen. Several genera of Riodinidae have evolved intimate associations with ants, and their larvae are tended and defended by ant associates. This also is the case with several lineages of Lycaenidae and contributed to arguments for the uniting the two families. It is now recognized that myrmecophily arose several times among Riodinidae and Lycaenidae clades. Like their sister family Lycaenidae, numerous species of Riodinidae are myrmecophiles (involving about 280 ant species). The larvae of many species have special organs, which have a soothing or tempting effect on ants. Many Riodinidae larvae have so-called "tentacle nectary organs" on the eighth segment of the abdomen that secrete a fluid which is eaten by ants. Other tentacle organs on the third thoracic segment have been shown to emit allomones which influence ants. Studies suggest caterpillar acoustic signals are used to enhance their symbioses with ants (see singing caterpillars). The location of riodinid organs that function in caterpillar-ant symbioses differs from those found in the Lycaenidae, suggesting that the organs in these two families of butterflies are not homologous in origin.

Food plants

The larvae feed on plants of the families

Araceae The Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe (or leaf-like bract). Also ...

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

, Bromeliaceae, Bombacaceae, Cecropiaceae,

Clusiaceae The Clusiaceae or Guttiferae Juss. (1789) (''nom. alt. et cons.'' = alternative and valid name) are a family (biology), family of plants including 13 genera and ca 750 species. Several former members of Clusiacae are now placed in Calophyllaceae ...

, Dilleniaceae,

Euphorbiaceae Euphorbiaceae (), the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of Euphorbia, the type genus of the family. Most spurges, such as ''Euphorbia paralias'', ar ...

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

, Lecythidaceae,

Loranthaceae Loranthaceae, commonly known as the showy mistletoes, is a family of flowering plants. It consists of about 75 genera and 1,000 species of woody plants, many of them hemiparasites. The three terrestrial species are '' Nuytsia floribunda'' (the ...

, Malpighiaceae, Marantaceae,

Melastomataceae Melastomataceae () is a family of dicotyledonous flowering plants found mostly in the tropics (two-thirds of the genera are from the New World tropics) comprising c. 175 genera and c. 5115 known species. Melastomes are annual or perennial herbs ...

Myrtaceae Myrtaceae (), the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All ...

Orchidaceae Orchids are plants that belong to the family (biology), family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Orchids are cosmopolitan distribution, cosmopolitan plants that ...

Rubiaceae Rubiaceae () is a family (biology), family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with Petiole ( ...

Sapindaceae The Sapindaceae are a family (biology), family of flowering plants in the order Sapindales known as the soapberry family. It contains 138 genera and 1,858 accepted species. Examples include Aesculus, horse chestnut, maples, ackee and lychee. The ...

Zingiberaceae Zingiberaceae () or the ginger family is a family of flowering plants made up of about 50 genera with a total of about 1600 known species of aromatic perennial herbs with creeping horizontal or tuberous rhizomes distributed throughout tropical ...

as well as bryophytes and lichens.DeVries, P.J. (2001): iodinidae In Levin, S.A. (ed.): Encyclopaedia of Biodiversity. Academic Press.

Economic significance

The importance of Riodinidae species considered pests is very low. Some species of Euselasiinae feed on Myrtaceae of economic importance such as guava. A few Riodininae are specified as harmful to farmed Bromeliaceae or Orchidaceae.

References

* Borror, Donald J.; Triplehorn, Charles A. & Johnson, Norman F. (1989): ''An introduction to the study of insects'' (6th ed.). Philadelphia: Saunders College Pub. . * DeVries, P.J. (1997): Butterflies of Costa Rica and their natural history. Vol 2 Riodinidae. Princeton University Press. * Hall, J.P.W. (2004b): Metalmark Butterflies (Lepidoptera: Riodinidae), pp. 1383–1386. ''In'' J.L. Capinera (ed.) ''Encyclopedia of Entomology, Vol. 2.''
PDF
* Savela, Markku (2007)

Version of 7 August 2007. Retrieved 9 September 2007.

External links

* :fr:Riodinidae, Riodinidae in French
Images representing Riodinidae at eol

TOL
- Implied clade links to species lists.
TOL Images
3 pages.
LEPINDEX Taxonomy project of Natural History Museum, London

Barcode of Life
Includes images.

on the UF / IFAS Featured Creatures Web site
Mariposas mexicana
Excellent high resolution images of Mexican Riodinidae
Flickr Riodinidae

Metalmark Gallery

Images of type specimens
Butterflies and Moths of North America
{{Authority control Butterfly families Taxa named by Augustus Radcliffe Grote Papilionoidea Taxa described in 1895