Overview

Brief Summary

Characteristics

Characteristics:

The chemical ecology of these butterflies is fairly well known. Larvae of basal Tithoreina feed on host plants in the family Apocynaceae, a host plant group shared with the related danaine butterflies. Most species, however feed on the Solanaceae, which is a very speciose and chemically diverse plant family. Most ithomiines are thought to be distasteful to predators, but interestingly some species do not sequester chemicals from their larval host plants (Brown 1984a & b). Instead the males collect pyrrolizidine alkaloids from flowers (especially Asteraceae) and rotting leaves (mainly of Boraginaceae). This may be an adaptation to reduce dependence on larval host plant chemicals (Brown, 1987).

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Introduction

The ithomiine butterflies are a diverse neotropical group of approximately 370 species that show huge diversity of colour pattern and form (Lamas 2004). Most species are involved in Müllerian mimicry with one another and serve as models in mimicry complexes with other Lepidoptera, including the heliconiines and the danaine genus Lycorea.

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Comprehensive Description

Nomenclature

Several generic names have been synonymized recently. These include:

  • Ceratiscada Brown & d'Almeida 1970 (synonymized with Episcada)
  • Dygoris Fox 1945 (synonymized with Godyris)
  • Garsauritis d'Almeida 1938 (synonymized with Hypothyris)
  • Hypomenitis Fox 1945 (synonymized with Greta)
  • Prittwitzia Brown & Ebert 1970 (synonymized with Episcada)
  • Rhodussa d'Almeida 1939 (synonymized with Hypothyris)
  • Roswellia Fox 1948 (synonymized with Athesis)
  • Talamancana Haber, Brown & Freitas 1994 (synonymized with Pteronymia)

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Characteristics

The chemical ecology of these butterflies is fairly well known. Larvae of relatively basal Tithoreina feed on host plants in the family Apocynaceae, a host plant group shared with the related danaine butterflies. Most species, however feed on the Solanaceae (nightshades), which is a very speciose and chemically diverse plant family. Most ithomiines are thought to be distasteful to predators, but interestingly some species do not sequester chemicals from their larval host plants (Brown 1984a & b). Instead the males collect pyrrolizidine alkaloids from flowers (especially Asteraceae) and rotting leaves (mainly of Boraginaceae). This may be an adaptation to reduce dependence on larval host plant chemicals (Brown, 1987).

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Evolution and Systematics

Evolution

Discussion of Phylogenetic Relationships

View Ithomiini Tree

The most recent revision of ithomiine sub-tribal and generic nomenclature is in the Checklist of Neotropical Lepidoptera (Lamas 2004), upon which the names in this tree and its subtrees are based. Lamas (2004), as well as Willmott and Freitas (2006) view Ithomiinae as a subfamily. Here, the clade is treated as a tribe, in order to accommodate the well-supported monophyly of (Danaini , Tellervini , Ithomiini) as a subfamily within Nymphalidae. Thus, Lamas' tribal names are listed here as subtribes.

The topology is derived from several recent works: the DNA sequence-based phylogenetic hypothesis of Brower et al. (2006), and the extensive morphological work of Willmott and Freitas (2006). It is based in part upon an unpublished combination of data from both. Relationships within Oleriina are based on de Silva et al. (2010). The phylogenetic affinities of three taxa (Eutresis, Haenschia and Aremfoxia) whose phylogenetic positions were not well resolved in Willmott and Freitas (2006) and were not sampled by Brower et al. (2006) are indicated as uncertain.

A few genera are likely paraphyletic with respect to others as currently circumscribed: molecular and morphological evidence both suggest that Pagyris is paraphyletic with respect to Placidina, Hypothyris is paraphyletic with respect to Hyalyris, Episcada is paraphyletic with respect to Ceratinia, Greta is paraphyletic with respect to Pseudoscada. The morphological data further suggests paraphyly of Godyris and Hypoleria.

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Wikipedia

Ithomiini

Ithomiini is a butterfly tribe in the nymphalid subfamily Danainae. Some authors consider the group to be a subfamily (Ithomiinae). These butterflies are exclusively Neotropical, found in humid forests from sea-level to 3000 m, from the southwestern United States to Argentina. There are around 370 species in some 40–45 genera.

Ithomiini biology[edit]

Ithomiines are unpalatable because their adults seek out and sequester pyrrolizidine alkaloids from plants that they visit, especially composit flowers (Asteraceae) and wilted borages (Boraginaceae). The slow-flying adults are Müllerian mimics of each other as well as of many other Lepidoptera. Henry Walter Bates referred to a "transparency group" of Amazon butterfly species. It was originally with seven species belonging to six different genera. Reginald Punnett suggested 28 species of this peculiar facies are known, though some are excessively rare. The majority are Ithomiines, but two species of the Danaine genus Lycorea , the Pierine Dismorphia orise the Swallow-tail Parides hahneli, and several species of diurnal moths belonging to different families also enter into the combination.Identification of adult ithomiines relies on hindwing venation and male androconial scales (sex brushes located on the hindwing costa).

The group has repeatedly been proposed as biological indicators of ecological conditions or biological diversity within neotropical forests, but individual sites harbor between 10 and 50 species, for the most part, and beta diversity is often great, even over relatively short distances.

Ithomiine larvae feed mostly on Solanaceae host plants. Exceptions are the more basal genera Tithorea, Aeria, and Elzunia that, like Tellervo and some Danainae, feed on Echiteae vines (Apocynaceae, Apocynoideae), as well as Megoleria and Hyposcada that feed on Gesneriaceae.

The local abundance of ithomiine butterflies in the Amazon forest, the lack of observations of predation, and their “peculiar smell” led Henry Walter Bates in 1867 to suggest that these organisms should be chemically defended. This was first experimentally demonstrated in 1889 when Thomas Belt fed ithomiines (that he called “Heliconii”) to birds, the spider Nephila, and the white faced monkey Cebus capucinus. The butterflies were consistently rejected, but other insects were eaten. Lincoln P. Brower in 1964 also showed that adults of Ithomia drymo pellucida were rejected by the bluejay Cyanocitta cristata bromia, and Haber showed that nine species of birds also rejected several ithomiine species. Besides, Vasconcellos-Neto and Lewinsohn demonstrated that the neotropical orb-weaving spider Nephila clavipes released unharmed 14 species of field-caught ithomiine butterflies.

The source of the protecting chemicals in the bodies of adult ithomiines proved not to be their larval host plants, as was first suggested, but rather in plants visited by the butterflies. Adults of ithomiine, mainly males, visit flowers of some Boraginaceae, (Tournefortia, Heliotropium), Asteraceae (mostly in the tribe Eupatorieae, and rarely on Senecio species), Apocynaceae (Prestonia, belonging to the tribe Echiteae) and Orchidaceae (Epidendrum paniculatum). Dead or withered plants are also visited and, when feeding on these plants, the butterflies scratch the tissues with their legs and suck the oozing sap. These plants are known to contain pyrrolizidine alkaloids, indicating their role as chemical sources for sequestration. Other butterfly and moth species that sequester pyrrolizidine alkaloids (Danainae, Ctenuchidae, and Arctiidae) also visit similar sources. The first demonstration that pyrrolizidine alkaloids were involved in the chemical defense of insects was given by Thomas Eisner, who showed that the spiders Nephila and Argiope rejected adults of the arctiid moth Utetheisa ornatrix that contain pyrrolizidine alkaloids from their larval host plant, Crotalaria (Fabaceae: Crotalarieae). Eisner's best-selling popular science book For love of insects tells the story of this exciting discovery.

Ithomiini classification[edit]

The subtribes in the Ithomiini help to organize the 43 recognized genera, but this group is the subject of ongoing molecular, phylogenetic, and morphological research, and the classification presented below will no doubt be refined in the near future.

The sister group to the tribe Ithomiini is either the small tribe Tellervini (containing the single Australasian genus Tellervo) or the larger tribe Danaini. The relationships of the three tribes in the subfamily Danainae are still unclear.

Tribe Ithomiini Godman & Salvin, 1879

See also[edit]

References[edit]

  • Lamas, G. (1999). Nymphalidae II Pt. 3 Ithomiinae. In: E. Bauer & T. Frankenbach (Eds.), Butterflies of the World. (pp. 1–17). Keltern, Germany: Goecke & Evers. ISBN 978-3-931374-66-2 16 colour plates - illustrates 252 specimens covering subset of the 320 known species, many of which are divided into subspecies.
  • Brown, Jr., K. S., and A. V. L. Freitas. 1994. Juvenile stages of Ithomiinae: overview and systematics (Lepidoptera: Nymphalidae). Tropical Lepidoptera 5(1): 9-20.pdf
  • See Links.
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