Cercophana frauenfeldii Felder, 1862 (Lepidoptera: Saturniidae): Taxonomy, Ecology and Presence in the Far South of Chile

Once is not always the norm aboard the sailing vessel Milagro — and following Callisphyris leptopus Philippi: in mid-April 2026, with Ben, Milena, Gabriel, Damien and Lauriane, as we were leaving one of the arms of Bahía Tres Brazos, a bay located to the north-west of Gordon Island, we received a new visitor that would give us quite a headache: an adult male Cercophana frauenfeldii.

We will not hide from you that identifying this species was no easy feat — friends and acquaintances alike were all astonished by our photographs. We therefore searched the GBIF databases and, to our surprise: we hold the record for the southernmost specimen observed to date! Integrating our opportunistic observations into open databases such as iNaturalist.org thus makes it possible to document species in places where exploration is difficult.

Here a detailed spotlight on an uncommonly encountered nocturnal visitor in these waters!

Introduction

Cercophana frauenfeldii Felder, 1862 is a large Neotropical Saturniidae endemic to Chile, also known by the English common name "Andean Moon Moth" on account of its Andean range and its resemblance to a "lunar sphinx". This species is attracting growing interest in Chilean and South American entomology, both for its unusual biology and for its association with forests that are sometimes under threat.

In the second half of the 20th century, C. frauenfeldii was incorporated into syntheses on the Chilean Saturniidae fauna, particularly in revisional works on the family and the genera Cercophana and Neocercophana. More recent studies (2021) have complemented these approaches by describing the immature stages (egg, larva, caterpillar, cocoon…), the phenology, the species' distribution and its host plants.

Taxonomy, Morphological Characters and Developmental Stages

1. Original Description and Nomenclatural Status

The species was described by Felder in 1862 under the name Cercophana frauenfeldi, based on material from continental Chile, making it one of the first South American Saturniidae to be formally described. Modern catalogues of the Saturniidae family in Chile confirm this status, retaining the spelling frauenfeldii (with a double "i") as valid and placing it in the genus Cercophana Felder, 1862.

Revisions of the family in South America recognise Cercophana as a small Andean genus restricted to Chile, grouping C. frauenfeldii and a few closely related species including Cercophana venusta, distinct from the neighbouring genus Neocercophana described later for related taxa. Regional catalogues of Argentine Saturniidae also list this species as an element of the trans-border Andean fauna.

2. General Morphological Characters

Works on Chilean Saturniidae describe Cercophana frauenfeldii as a large nocturnal moth with broadly developed wings, varying from brown-ochre to greenish in colour, with lighter patterns and variable transparent or hyaline markings. In adults, sexual dimorphism is expressed through strongly bipectinate antennae in the male, adapted for pheromone detection, while females typically have a more voluminous abdomen associated with egg production.

A recent article in the Brazilian Journal of Entomology, dedicated to the immature stages, describes in detail the egg, the four larval stages, the pupa and the cocoon, providing a complete morphological basis for identification at all stages of development.

3. Immature Stages and Development

The detailed study of the immature stages of Cercophana frauenfeldii shows that larval development comprises four well-differentiated instars, generally spanning from November to late January throughout most of the species' range. The caterpillars feed on the leaves of their host plants, displaying primarily nocturnal activity and concealing themselves among foliage during the day.

Pupation occurs within a silken cocoon whose structure and location may vary depending on habitat conditions, but which is generally situated in the leaf litter or on low-hanging branches.

Geographical Distribution in Chile

1. Latitudinal Gradient and Biogeographical Provinces

Chilean catalogues and syntheses record Cercophana frauenfeldii from the centre of the country to the humid temperate regions of the south, particularly in the Maule, Biobío, La Araucanía, Los Lagos and Aysén regions. A recent compilation of field data and naturalist collections confirms that the species follows an Andean-coastal gradient associated with temperate forests.

The data we were able to consult reveal two major phenological and biogeographical groupings: the northern group, where adults fly mainly from February to mid-April, and the southern group (temperate rainforests), where the main flight period shifts to between April and June (the case of our visitor).

2. Southward Extension and the Magallanes Region

Works specifically addressing the Magallanes region highlight that C. frauenfeldii reaches the southern part of continental Chile, where it remains more localised. An article focused on the host plants of this moth confirms the presence of populations in temperate forests close to the southern limit of distribution of the host tree species, primarily belonging to three families: Gomortegaceae, Lauraceae and Winteraceae. The plants most represented in the studies conducted are Cryptocarya alba, Beilschmiedia miersii, Gomortega keule and Persea americana, all of which develop further north than our visitor.

While published records are concentrated mainly at sites further north than the Chilean Antarctic province where we explore, records from the Magallanes region make the species' presence in sub-Antarctic archipelagos plausible. According to observations made in 2003 in Parque Omora (Puerto Williams), this moth also uses the canelo or Magellan pepper (Drimys winteri) as a host plant, and this tree is ubiquitous in the Province of Cabo de Hornos.

The most recent works stress the need to better document the fine-scale distribution, phenotypic variability and population genetics of Cercophana frauenfeldii from the north-central to the far south of Chile.

Scientific Significance of This Local Record

Although this record has not yet been integrated into Chilean academic syntheses, it is fully consistent with the documented distribution as far as Magallanes and with the continuity of native forests. The absence of published data specific to the islands of the Cape Horn Biosphere Reserve, such as Gordon or Hoste, therefore reflects a sampling deficit in entomological surveys rather than a biogeographical impossibility, given the continuity of forest habitats.

Confirmation of this Saturniidae within the Cape Horn Biosphere Reserve would enrich the list of species present in the far south of Chile and would contribute to refining distribution models for forest Lepidoptera associated with Andean temperate forests. It would reinforce the idea that these archipelagos, long considered marginal, in fact constitute a functional southward extension of the South American temperate forest belt.

At the far south of Patagonia, targeted nocturnal sampling campaigns, combining light trapping with caterpillar surveys on potential host plants, would make it possible to confirm and quantify the presence of the species on Gordon Island and neighbouring islands. Onboard naturalist monitoring programmes such as those conducted on a small scale by the Karukinka association can play a decisive role in documenting these presences and feeding national and international entomological databases.

Bibliography

• Angulo, Andrés O., Lemaire, Claude, & Olivares, Tania S. Illustrated Catalogue of Saturniidae Species in Chile (Lepidoptera: Saturniidae). Gayana (Concepción), 68(1), 20–42, 2004.
• Monné, M. A., et al. Immature stages, phenology, distribution and host plants of the Andean Moon Moth Cercophana frauenfeldii Felder, 1862 (Lepidoptera: Saturniidae). Revista Brasileira de Entomologia, 65(2), 2021. Most comprehensive reference article on the immature stages, phenology, distribution and host plants of the species.
• Ureta R., E. La Familia Saturniidae (Heterocera) en Chile: Parte III. Boletín Museo Nacional de Historia Natural, 22, 49–64, 1944.
• Zúñiga-Reinoso, Á., Sepúlveda, J. Sobre la planta hospedera de Cercophana frauenfeldii (Felder) (Lepidoptera: Saturniidae) en Magallanes. Anales del Instituto de la Patagonia, Punta Arenas, v.44, n.2, p.81–83, 2016.