Hedylidae, the "American moth-butterflies", is a family of insects in the order Lepidoptera, formerly representing the superfamily Hedyloidea. They have traditionally been viewed as an Extant taxon sister group of the butterfly superfamily Papilionoidea, but a 2014 Phylogenetics analysis has suggested Hedylidae is a subgroup of Papilionoidea, and not a sister group, and are more accurately referred to as butterflies rather than moths.
Taxonomy and systematics
Hedylidae were previously treated as a tribe of
Geometridae: Oenochrominae, the "Hedylicae".
Prout
considered they might even merit treatment as their own family. Scoble first considered them to be a hitherto unrecognised group of butterflies and also suggested Hedylidae might possibly constitute the
sister group of the "true" butterflies (
Papilionoidea), rather than of (Hesperioidea + Papilionoidea). Weintraub and Miller
argued against this placement (but see
). In 1995, Weller and Pashley
found that molecular data did indeed place Hedylidae with the butterflies and a more comprehensive study in 2005
based on 57 exemplar
taxa, three
genes and 99 morphological characters, recovered the genus
Macrosoma as sister to the ("Papilionoidea" + Hesperioidea). However, the most recent
phylogeny analyses shows that skippers are true butterflies and therefore within the clade Papilionoidea, whereas the hedylids are a sister group that may be closely related to the obtectomeran moths.
This is contrary to some earlier studies that had shown both the skippers and hedylids as being nested within the Papilionoidea.
Since there are no obvious gaps between supposed species groups, according to basic morphological structure, Scoble (1986) synonymised the five pre-existing genera of Hedylidae (33 of which had been described in Phellinodes) into the single genus Macrosoma.
Nomenclatural notes
In zoological nomenclature, numerous junior homonyms of
Macrosoma (Hübner, 1818) exist,
(
Macrosoma Leach 1819 (a
reptile),
Macrosoma de Haan 1826 (
Odonata),
Macrosoma Robineau-Desvoidy 1830 (Diptera:
Muscidae),
Macrosoma Brandt 1835 (
Coelenterata),
Macrosoma Hope 1837 (
Coleoptera),
Macrosoma Lioy 1864 or 1865 (Diptera:
Sarcophagidae),
Macrosoma Hammer 1979
[Hammer, M. (1979). Investigations on the oribatid fauna of Java. K. Dan. Vidensk. Selsk. Biol. Skr., 22(9): 34.] (
Acarina: Oribatidae). To add to this potential confusion in lists of names, there exist two junior homonyms of
Hedyle Guenée, 1857:
Hedyle Bergh, 1895 (
Opisthobranchia, "Acochlidioidea",
Hedylopsidae;
currently placed in the genus
Hedylopsis Thiele, 1931),
and
Hedyle Malmgren 1865 (a
polychaete worm).
The sea slug family name "Hedylidae Bergh, 1895" (type species
Hedyle weberi Bergh, 1895) is thus also invalid.
Morphology and identification
The eggs of hedylid moths have an upright configuration and are variable in shape: in
Macrosoma inermis they are particularly narrow and spindle-shaped,
[Scoble, M.J. (1990a). A catalogue of the Hedylidae (Lepidoptera: Hedyloidea), with descriptions of two new species. Entomologica Scandinavica, 21: 113-119.] resembling those of some
Pieridae, and in the case of
M. tipulata they are more barrel-shaped,
like certain
Nymphalidae. The
resemble (probably convergently) those of
Apaturinae.
Adult hedylids resemble
Geometridae moths. They share many morphological and
Genetics characteristics with both the superfamilies
Papilionoidea and the
Hesperioidea. The abdomen is very long and slim, like many
Neotropical butterflies of the subfamilies
Nymphalidae and
Heliconiinae, hence the name of one
Macrosoma species "
heliconiaria". Unlike other butterflies, however, the antennae are un-clubbed, but rather filiform or bipectinate.
Unlike the family
Geometridae, in which they had been placed by the
Geometridae expert L.B.Prout, hedylids lack
Tympanal organ at the base of the abdomen, but have them on the wings (see under Behaviour). Unlike other butterflies, however (except the unique case of the remarkable Australian skipper butterfly
Euschemon rafflesia, whose males possess these structures), the single-spined frenulum and retinaculum are not lost or reduced in males, except in three
Macrosoma species where there is no functional wing coupling system. The retinaculum is always lost in females, and the frenulum may be
vestigial.
The family have been fully catalogued
and illustrated in an identification guide.
[Scoble, M.J. (1990b). An identification guide to the Hedylidae (Lepidoptera: Hedyloidea). Entomologica Scandinavica, 21: 121-158.]
Butterfly-like characteristics of Hedylidae
-
"Mesoscutum" with "secondary line of weakness" near median "notal" wing process,
[Minet, J. (1991). Tentative reconstruction of the ditrysian phylogeny (Lepidoptera:
]
Glossata).
Entomologica Scandinavica,
22: 69-95. as in some representatives of Papilionidea and Hesperioidea (potentially unique butterfly character;
-
Mesothorax aorta with horizontal chamber, as in other butterflies (not Papilionidae), but as also in Cossidae;
-
Metathorax "furca" resembling a blunt arrowhead;
-
Second median plate of forewing base lying partly under the base of vein "1A+2A", unlike the configuration in moths;
-
"Postspiracular bar" on first abdominal segment;
-
Female genitalic "anterior apophyses" reduced;
-
Male genitalia relatively "deep" dorso-ventrally;
-
Abdomen curved (especially in males), as in papilionoids;
-
Abdominal first Tergum segment is strongly "pouched" (Scoble 1986; as also in Drepanidae moths;
-
Arthropod leg sulcus joining "marginopleural" sulcus;
-
Male Arthropod leg lost, thus fused into two elements
-
Egg upright, spindle-shaped and ribbed
-
Larva with "anal comb",
-
Caterpillar with horn-like processes and a "bifid" tail as in many Nymphalidae;
-
Caterpillar with "secondary setae", as in Pieridae;
-
Ventral proleg "crochet" hooks not forming a complete circle, unlike configuration in hesperiids and papilionoids;
-
Pupa affixed to the substrate via a silken girdle around the 1st abdominal segment,
-
cocoon lost, as in papilionoids, and a few other groups of Lepidoptera;
-
"Temporal cleavage line" lost in the pupa (as in papilionoids).
Distribution
Hedylidae range in
North America south from central
Mexico and in
South America through the
Amazon basin from southern
Peru (where there are a full 26 species,
up to 12 at a single site:
to central
Bolivia and southwestern
Brazil). In the
Caribbean, they also occur in
Cuba,
Jamaica, and
Trinidad.
Behaviour
Hedylids are attracted to artificial lights, but occasionally some species can be found flying by day.
Thus, they may be involved in some mimicry complexes with
Nymphalidae (e.g. the female only of
Macrosoma lucivittata).
A few species are white
and resemble pierid butterflies (e.g.
Macrosoma napiaria). Based on a study of
Macrosoma heliconiaria, it has been found that hedylids have
Tympanal organ on their forewings for hearing
[ Organ of hearing] apparently homologous to the "Vogel's organ" in some
Papilionoidea that would help them evade bats at night. They have been shown to exhibit typical moth evasive behaviour towards bats such as erratic spiralling movements and dives.
The resting posture is often at a curious angle,
with the thorax tilted and the posterior edge of the hindwings nearly touching the substrate (Scoble, 1986). The larvae which lack the prominent horns in the first
instar tend to rest on the
midrib of the leaf and often skeletonise leaves or at either side produce an untidy patchwork of holes.
The elegant pupa is attached by a cremaster and silken girdle
and sometimes resembles a bird dropping.
List of species
This list of species is largely based on
Phenetics characters.
Biology and host plants
The life history of
Macrosoma heliconiaria was originally described from plants of
Byttneria aculeata in
Mexico.
This was a historical breakthrough into the biology of hedylids. In this study, Kendall commented notably "I thought the larvae might represent a satyr species, but when the first larva pupated I was sure it was a pierid. The first adult emerged as a complete surprise. The pupa...is secured by girdle and cremaster, not unlike a pierid".
Macrosoma cascaria was later also reared on this plant in
Panama.
More life histories are now known. From these data, known host plants span a wide range of (according to the APG II system)
rosid dicotyledonous plants, including the
rosid order
Myrtales family
Melastomataceae (genera
Miconia,
Melastomataceae, and
Melastomataceae), the
Rosids order
Malpighiales, families
Euphorbiaceae (
Croton), and
Malpighiaceae (
Byrsonima), the
Rosids orders
Sapindales, family
Rutaceae (
Zanthoxylum) and more commonly
, family
Malvaceae, tribes:
Malvaceae (
Ochroma),
Malvaceae (
Malvaceae and also
Hibiscus,
(
Byttneria aculeata,
Theobroma) and
Grewioideae (
Grewioideae). The "green lizard caterpillar"
Macrosoma tipulata attacks an economically important local fruit tree "Cupuaçu" (
Theobroma grandiflorum) in
Brazil and can defoliate saplings; the biology of this species has been studied and illustrated in some detail.
The larva of this species lives about 15 days in 5 instars, the pupal stage lasts about 7 days and the adult lives about 10 days.
M. tipulata and many other species can be found as adults through most of the year.
DNA sequences
A few species have been
DNA sequencing for the
mitochondrial genes "cytochrome oxidase I", and "ND1" and
"Wingless" and "Ef-1",
including
Macrosoma semiermis. Some species are currently being
DNA barcoding.
Cited literature
Sources
External links
