Pronophilina

Systematics and Taxonomy

Traditionally the name Pronophilini (or Pronophilidi) was used to describe a tribe of Neotropical Satyrines, but modern arrangement place them as a subtribe within the Satyrini tribe of the Satyrinae. The number of genera included in Pronophilina is disputed, since some genera were formally transferred to the Erebiina and Hypocystina (now part of Coenonymphina) subtribes, but some authors reject this arrangement.

Morphological analysis indicates there is a distinct core group of Pronophilina sensu stricto, and one or two additional groups (Neotropical Erebiina and Hypocistina in their original designation), but molecular analysis suggest they are each other's sister taxa and form a monophyletic group.

By the time Reuter proposed Pronophilidi as a formal tribe, there were some 230 described species. That number rose to 300 species by 1907, and 370 by 1970, primarily due to the work on museum and collection specimens by (in chronological order) William Chapman Hewitson, Cajetan Freiherr von Felder & Rudolf Felder, Arthur Gardiner Butler, Otto Staudinger, Theodor Otto Thieme and Gustav Weymer. More detailed field studies in the northern Andes by Adams and Bernard during the 1970s and 1980s resulted in many new taxa descriptions and a better understanding of their distribution and ecology and lead to an increased interest in this group after the 1990s. More than 100 species have been described since 1970, mostly due to contribution from A.L. Viloria, T.W. Pyrcz and G. Lamas, and it is estimated that the number of known taxa (including several yet unpublished species and subspecies descriptions) has nearly doubled in that period.

Description

The subtribe Pronophilina can be separated from other American satyrines by the following three external morphological synapomorphies: eyes always densely hairy; HW cross vein m1-m2 always curved or angled basally into the discal cell; maximum length of HW discal cell equal to or longer than half the total maximum length of HW (excluding tails). These characters separate the Pronophilina sensu stricto from other Neotropical montane satyrids previously included in the group. This arrangement has been adopted by Lamas, but phylogenetic analysis based on molecular data suggests a larger, more inclusive delimitation of Pronophilina is needed.

The background color of most species is dominated by brown, dark grey or black, with few and slight distinctive features in the wings, but some species show colorful variations between white, yellow, orange, red and iridescent blue.

Biology

The life cycle of pronophiline butterflies has been scarcely documented. Schultze described incomplete life histories for Pedaliodes phoenissa (Hewitson), Lymanopoda samius Westwood, and Junea doraete (Hewitson). Other authors have observed oviposition on Chusquea (Poaceae) or other woody bamboos, or loosely over grass dominated vegetation. Early stages of several species found in Costa Rica were published by DeVries. Recently, life cycle description have been documented for Parapedaliodes parepa (Hewitson) in Ecuador, Pedaliodes zingara Viloria & Heredia in Colombia, Pedaliodes poesia (Hewitson) and Corades medeba Doubleday in Ecuador, and Daedalma dinias emma Pyrcz & Greeney and Daedalma rubroreducta Pyrcz & Willmott.

Host plants

All reported host plants are in the Poaceae family, with the genus Chusquea featuring prominently, and a few records in Cynodon, Saccharum, Bambusa, Guada, Rhipidocladum, Merostachys and Zea, among others.

Parasitism

Parasitoids in the early stages of pronophiline butterflies have not been properly documented, although they might be locally important. Incidence of ectoparasitic Diptera (probably Ceratopogonidae) have been documented for seven species of the genera Corades, Lasiophila, Lymanopoda, Mygona and Pedaliodes.

Mimicry

There are 18 documented examples of convergent coloration patterns between coexisting pairs of pronophiline species from different genera (three examples), between pronophiline species and other satyrines (eight examples), and between pronophiline species and other butterflies or skippers (seven examples). Most examples involve species of Lymanopoda or Eretris. Some of these observations have been described as mimetic relationships, but the degree of resemblance is not so accurate as in other mimetic butterfly groups, there is no direct evidence of unpalatability of Pronophiline butterflies, and no clear understanding of the ecological consequences of such resemblance.

Diversity

Depending on the classification adopted, the pronophilini include between 592 and 711 species. This represents approximately 50-60% of the Neotropical, and 23-27% of the worldwide Satyrinae.

Most species have a geographically and altitudinally restricted distribution in the tropical and subtropical Andes, and other mountain ranges in Brasil, the Guayana Shield, Central America, and México. The genus Calisto has a Caribbean distribution, and some other genera are distributed in Patagonia.

Biogeography

The Pronophilines have been involved in diverse biogeographical discussions that aim to explain their current distribution, diversity and endemism. The high diversity within the Pronophilina, and the distinctive speciation patterns in mountain and caribbean taxa, has also motivated discussion about parapatric and sympatric speciation.

Origins

The affinities of the Pronophilina to other species-groups within the specious Satyrinae suggest different interpretations about its origin. Viloria reviewed morphological characters and separated three groups that might have different phylogenetic and biogeographic affinities: a major group of 39 true Neotropical Pronophilina, including the genus Calisto with a Caribbean distribution, eight genera related to the Holarctic Erebiina, and 19 genera which he placed as Neotropical representatives of the otherwise Australasian Hypocystina. This grouping would suggest an amphipacific distribution of the Hypocystina, and imply a Gondwanan origin according to a panbiogegraphic interpretations. This hypothesis was rebutted after a large phylogenetic analysis of the Satyrinae recovered a representative sample of Pronophiline genera as a monophyletic group, and suggested a completely Neotropical, or at least, a common origin for the group. However, the relationships of the group remain unresolved, as subsequent work has found that at least two genera -- Eretris, and the Caribbean Calisto—might be closer related to Holarctic Satyrines, but larger taxonomic sampling and a better integration of molecular and morphological data is needed to rule out analytical artifacts.

Speciation

It has been observed that most mountain species, especially in the species-rich genera close to Pedaliodes, have very narrow altitudinal ranges, and are restricted to one or few mountain ranges. This leads to high turn-over of species along altitudinal gradients within a mountain range, and high turn-over between ranges. Most species appear to be more closely related to those occupying a similar altitudinal range in neighboring mountains, than to the species below or above. A possible mechanism was proposed by Adams and extensively discussed by Viloria. This involves a series of alternative events of colonization and isolation that would be linked to repeated cycles of cold-wet and warm-dry climate (glaciations and interglaciation periods).

The genus Calisto also shows a distinctive radiation in the Caribbean, where it is the only representative of the Satyrinae. At least 54 named taxa have been recognized, most of them restricted to particular habitats in the island of Hispaniola, with fewer species in Cuba, Jamaica and Puerto Rico. The diversification of Calisto is referred to as an example of adaptive radiation into contrasting habitat types.