The Natural History of the Satyrine Butterfly, Mygona Irmina in Eastern Ecuador Author(S): Harold F
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First Description of the Early Stage Biology of the Genus Mygona: The Natural History of the Satyrine Butterfly, Mygona irmina in Eastern Ecuador Author(s): Harold F. Greeney, Lee A. Dyer and Tomasz W. Pyrcz Source: Journal of Insect Science, 11(5):1-11. 2011. Published By: Entomological Society of America DOI: http://dx.doi.org/10.1673/031.011.0105 URL: http://www.bioone.org/doi/full/10.1673/031.011.0105 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Journal of Insect Science: Vol. 11 | Article 5 Greeney et al. First description of the early stage biology of the genus Mygona: The natural history of the satyrine butterfly, Mygona irmina in eastern Ecuador Harold F. Greeney1a, Lee A. Dyer2b, and Tomasz W. Pyrcz3c 1Yanayacu Biological Station and Center for Creative Studies, Cosanga, Ecuador, c/o 721 Foch y Amazonas, Quito, Ecuador 2Biology 0314, University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557 3Zoological Museum of the Jagiellonian University, Ingardena 6, 30-060 Kraków, Poland Abstract The immature stages and natural history of Mygona irmina Doubleday (Lepidoptera: Nymphalidae: Satyrinae: Pronophilina) from northeastern Ecuadorian cloud forests are described based on 17 rearings. The dwarf bamboo, Chusquea c.f. scandens Kunth (Poaceae, Bambusoidea) is the larval food plant. Eggs are laid singly on the bottom side of mature host plant leaves. Larvae take 102-109 days to mature from egg to adult. Adults are encountered most frequently on sunny days, flying rapidly over areas dominated by their food plant or feeding on the ground at mammal feces. Males are often encountered inside large forest gaps near patches of bamboo guarding perches in the mid-canopy. Keywords: Andes, bamboo, Chusquea, cloud forest, larva, Poaceae, pupa Correspondence: a [email protected], b [email protected], c [email protected] Editor: Jim Miller was editor of this paper. Received: 15 November 2009, Accepted: 2 November 2010 Copyright : This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed. ISSN: 1536-2442 | Vol. 11, Number 5 Cite this paper as: Greeney HF, Dyer LA, Pyrcz TW. 2011. First description of the early stage biology of the genus Mygona: The natural history of the saturnid butterfly, Mygona irmina in eastern Ecuador. Journal of Insect Science 11:5 available online: insectscience.org/11.5 Journal of Insect Science | www.insectscience.org 1 Journal of Insect Science: Vol. 11 | Article 5 Greeney et al. Introduction the Andes in the north and on the eastern slopes in the north and central Andes. The The generic limits of the subtribe southern distributional limit is Rio Pastaza Pronophilina (Nymphalidae, Satyrinae) are valley. South of this distribution it is replaced still unclear and recent authors (e.g. Viloria by its ally M. poeania (Hewitson). To date 1998, 2003; Lamas et al. 2004; Pyrcz 2004; there are no recognised subspecies of M. Peña et al. 2006) have used several different irmina, yet some geographic races are fairly arrangements since Miller’s (1968) treatment distinct (TW Pyrcz unpublished observations). of the Satyrinae. The genus Mygona (Thieme) Nominotypical individuals are characterised is one of the genera that have been included by the noticeably smaller size compared to consistently in the Pronophilina, and is other populations, while those from the Chocó considered most closely related to Lasiophila slopes of the Colombian Western Cordillera (C. and R. Felder) based on adult morphology are generally larger and bear the largest blue (Pyrcz 1999). While D’Abrera (1988) patch on the dorsal hind wing. Specimens recognized seven species of Mygona, reared and collected as adults at the Yanayacu subsequent revisions consider the genus to Biological Station (YBS) do not differ include only three species (Lamas et al. 2004; markedly from other Ecuadorian populations. ! Pyrcz 2004). However, all these occur allopatrically, are morphologically similar, Almost nothing is known of the early stages and could be considered to represent one of any genus of Pronophilina with only a few widespread, polytypic species. Mygona irmina scattered records of food plant associations Doubleday (Lepidoptera: Nymphalidae: (e.g. Adams and Bernard 1981; Adams 1986; Satyrinae: Pronophilina) differs from all other Miller 1986; DeVries 1987; Pyrcz and congeners in the large, pale blue dorsal Wojtusiak 1999) and larval descriptions hindwing median patch, a pattern that is rather (Schultze 1929), mostly within the genus unusual among within the subtribe Pedaliodes (Butler, 1867) (Pelz 1997; Pronophilini. The only somewhat similarly Heredia and Viloria 2004; Greeney et al. patterned sympatric species is Oxeoschistus 2009). There is no published information on leucospilos Staudinger. In the past, another the life cycle of any species of Mygona, and species was associated with the genus here a description of the early stages of Mygona, originally described as Pronophila Mygona irmina is presented based on rearings propylea Hewitson (Adams, 1986) and in northeastern Ecuador. currently placed in the genus Proboscis Thieme (Pyrcz, 2004). Proboscis propylea Materials and Methods replaces M. irmina parapatrically at higher elevations, a fact noticed by Adams (1985). All rearing and field investigations were Mygona irmina (Figure 8c) flies at elevations carried out at the Yanayacu Biological Station of ca. 1800-2500 m and is distributed and Center for Creative Studies (00° 35.949 S, southward from Venezuela, occurring in the 77° 53.403 W), located in Napo Province, in Cordillera de la Costa (its type locality) in the the Andes of northeastern Ecuador. The study Cordillera de Merida and the Sierra de Perija, site is located approximately 5 km west of the throughout Colombia, and in Ecuador. In town of the town of Cosanga, adjacent to Ecuador it is found on the western slopes of Cabañas San Isidro, and encompasses about Journal of Insect Science | www.insectscience.org 2 Journal of Insect Science: Vol. 11 | Article 5 Greeney et al. 2000 hectares of primary cloud forest They most likely rest in dark areas of rotting bordered by cattle pasture and other disturbed vegetation trapped in tangles of the host plant habitats. A single oviposition event was or on rotting portions of the stem near the observed and this egg was reared through to ground or perhaps off the plant. eclosion. Subsequently, three mid-second instars were reared through to eclosion of the Egg (Figures 1A-B) imago. Landslides are common in the steep N = 1; approx. 1 mm diameter; 13 days. terrain surrounding YBS, most of which are Egg round, white, appear smooth but minute, dominated by Chusquea bamboo. Large irregular, vertically oriented striations visible patches of bamboo also form in flatter areas, under a dissecting scope (Figure 1A). Eggs especially along streams. For more complete are laid singly (n =1). Upon emergence, larvae site descriptions see Greeney (2008) and consume the entire egg shell. Valencia (1995). Larvae were collected at elevations ranging from 2000-2200 m, and First instar (Figures 1C-J, 1L) they were reared in glass jars at the ambient N = 1; 2-5.5 mm; 20 days. From a cephalad research lab, located at 2150 m. In the view, the head capsule nearly square and laboratory, fresh food plant leaves were added narrowing slightly dorsally and with a shallow as needed, and frass and old host plant leaves epicranial crease, light brown and shining, were removed daily. Larval measurements bearing sparse, forward-curved, dark setae were made the day prior to molting. laterally and dorsally, longest dorsally; body white upon emergence with very pale red- Results brown, thin longitudinal stripes on dorsum and sides, body widest around A1, tapering Larval behavior gradually posteriorly to very small, widely The dwarf bamboo, Chusquea c.f. scandens separated caudal tails, roughly round in cross- Kunth (Poaceae, Bambusoidea) is the larval section, body bare except for sparse, short, food plant of M. irmina in the studied area. dark setae, 1-3 per segment ventrolaterally, Larvae were found in patches of bamboo longest on T1, and A10; dorsal prothoracic along roads, streams, and in land slides. First shield thin, weakly scoleritized. Later in first and second instars rest and feed near the tip of stadia larvae appearing greenish from ingested mature leaves. Feeding damage is such that leaf material and with longitudinal stripes one margin of the leaf apex is left intact, and more prominent. The terminal 4-5 abdominal larvae rest near the tip of this thinned portion segments bear a rust-brown wash dorsally. of the leaf where they are very cryptic. Late Just prior to molting, the dorsum appears second, third, and fourth instars rest on the highlighted with whitish stripes (Fig.1J), and dorsal surface of leaves, often traveling to caudal tails become slightly more noticeable, adjacent leaves to feed. Their green coloration but remain short. makes them extremely cryptic on mature leaves, as they rest with their head tipped Second instar (Figures 1K, 1M-W) forward and scoli appressed to the leaf N = 4; to 10.5 mm; 13 days.