Unfortunately no one knows. These Riodinids are excellent mimics of day flying Geometrid
moths like the Cyllopoda species (left) and Xanthyris flaveolata (right) so it could be their fate as Batesian mimics to be less common than their models for success as a species. Usually rare species of butterflies have very specialized ecological needs or the larvae feed on something (plants or animals) that has a spotty local distribution. Often rare species fly where they are not easily observed, like in the canopy or they have a short flight activity or are crepuscular. The following are accounts of some of these rare species.
Colaciticus johnstoni (Dannatt, 1904) Top – male from Pto. Inirida, Colombia (Courtesy: Pedro Alejandro Sarmiento Diaz) Bottom left – male, Villavicencio, Colombia. Bottom right – female, Villavicencio.
This species is rarely seen because it’s a canopy dweller. David Ahrenholz observed this species in Ecuador flying at a height of about 10 meters. Here in Villavicencio they were all seen between 2 and 3 meters high in trees. Their normal behavior probably changes when they fly through small forest fragments. Five males and one female were recorded during a 2 year period, all during the rainy season. The photos of the male taken by Pedro Alejandro Sarmiento Diaz in Puerto Inirida document the second locality known for this species in Colombia.
Colaciticus seitzi Salazar, Constantino & Rodriguez, 2010 The male holotype (Coutesy of Julian Salazar E.) Left – dorso. Right – ventral.
This is the only known specimen. It was collected on the east slope of the Cordillera Central near Fresno, Tolima at 800 meters. The species description is in the following publication:
Rodriguez, Gabriel, Julián A. Salazar-E., and Luis Miguel Constantino. 2011. “DESCRIPTION OF NEW SPECIES AND NEW RECORDS OF RIODINIDS (LEPIDOPTERA : RIODINIDAE ) FOR COLOMBIA.” Bol.cient.mus.hist.nat 14 (2): 215–237. download
Pachythone xanthe H. Bates, 1868 Top -female, Tachira, Venezuela. (Courtesy: Andres Miguel Orellana) Middle – female, Villavicencio, Colombia. Bottom – left, male; right. female, Villavicencio.
In the field the males of this species are very difficult to tell apart from a Mesene, especially the females of M. nola. The males were frequently seen at the study site but the female was a mystery. Identifying the first female was a problem, none of the experts consulted were sure of what species it was. It appears the female of xanthe was unknown until these females were captured. In the middle picture you can see the green colored eggs through the very thin integument of the female. The early stages and hostplants of all the species of Pachythone are unknown.
Pachythone bicolor (Godman & Salvin, 1886) All photos of specimens from Villavicencio, Colombia. Top left – dorsal, Top right ventral view. Bottom left-lateral view and right a head shot of the punk hairdo.
This interesting creature is one of those rare examples of a species that has a wide distribution but is rarely encontered anywhere. It has been collected in Guatemala, Panama, Colombia and Brazil but there are only 8 specimens in collections. Bicolor was described in 1886 and was only known from the type specimen for almost 80 years until a few specimens were collected in the 1960’s in Brazil, Guatemala in 1992 and recently in Colombia. The genus has changed over the years, first it was in Lepricornis, then Pheles and now Pachythone. The Colombian specimens were found in a fragment of secondary forest just outside of Villavicencio during the rainy season. They made short flights, perching between 1 and 2 meters high on the underside of tree leaves with their wings outspread. So far the female is unknown.
For a recent revision of the species see:
Dias Silva, Fernando Maia, Diego Rodrigo Dolibaina, Carlos Guilherme Costa Mielke, Olaf Hermann Hendrik Mielke, and Mirna Casagrande Martins. 2015. “Description of Two New Species of Pheles Herrich–Schäffer,  and Notes on the Taxonomic Position of Two Species Hitherto Included in the Genus (Riodinidae: Riodininae).” Zootaxa 3981 (2): 275–283. download