DISTRIBUTION:

The Automeris tridens moth (wingspan: males: 58-80mm; females: 84-94mm) flies from Mexico to Costa Rica and possibly further south. Lemaire lists
Mexico: Tamaulipas, San Luis Potosi, Veracruz, Oaxaca, Chiapas;
Belize: Toledo: Punta Gorda (NS);
Guatemala: Zacapa, Escuintla, Santa Rosa, (Izabal (JM));
El Salvador: Ahuachapan;
Honduras: Francisco Morazan (CL), Atlantida, Cortés, Francisco Morazán, Olancho and Yoro (RC);
Nicaragua: Nueva Segovia, Esteli, Jinotega, Matagalpa, Chinandega, Leon, Managua, Carazo, Granada, Chontales, Zelaya, Rio San Juan
and Costa Rica: Guanacaste, Heredia, San Jose, Cartago, Puntarenas (CL), Alajuela, Limon (IB).

Dan Janzen indicates (2012) that there are possibly two cryptic species in Guanacaste, Costa Rica, one inhabiting rain forest, and the other inhabiting dry forest areas. Samples from both areas are quite variable in appearance.

Automeris tridens male, 82mm, Cartago, Costa Rica,
courtesy of Kelly Price, tentative id by Bill Oehlke.

Lemaire groups randa, excreta, tridens, molonyei, oaxacensis and andicola based on genitalia and orange, non-ringed abdomen, and usually diffuse yellow ring of eyespot, and yellow hw postmedial line usually without black scaling internally, except for molonyei.

Automeris tridens has a rounded forewing, yellowish abdomen, postmedial and antemedial lines bordered with contrasting yellow. Females are larger and darker than males.

Visit Automeris tridens male, female and larva, Costa Rica, courtesy of Leroy Simon.

Automeris tridens female, Costa Rica, courtesy Dan Janzen.

Automeris tridens male, yellow form (verso), Costa Rica, courtesy Dan Janzen.

The forewing ground colour is variable from yellow to dull beige or buff with an orangey tint. The am and pm lines are thin, light brown and bordered with yellow on facing sides. The am line is irregular; the pm line preapical, slightly curved near the apex and then straight to the outer third of the inner margin. The cell is darker than its surroundings. The submarginal area is distinct and darker than the outlying area. The outer margin is quite straight.

Below is an unusual specimen. I do not know if the red/orange colouration has been light-bleached from the hindwing, or if this is just an aberrant specimen.

Automeris tridens female, Punta Gorda, Toledo, Belize, 86mm, courtesy of Art Gilbert and Norman Smith,
identification and significant digital wing repair by Bill oehlke.

The ground colour of the hindwing is normally reddish orange. The eyespot is ringed with yellow and the distinct black, slightly undulating pm line is inwardly lined with yellow, sometimes meeting the yellow ring surrounding the eyespot.

Visit Automeris tridens, Honduras, courtesy of Robert Lehman.

Automeris tridens female, Costa Rica, courtesy Dan Janzen.

Automeris tridens male, yellow form (verso), Costa Rica, courtesy Dan Janzen.

FLIGHT TIMES AND PREFERRED FOOD PLANTS:

Moths are on the wing in January, March, May-June-July-August-September, November-December.

Larvae feed on Ligustrum and Quercus in the lab and have been reported by Dan Janzen to feed on leguminous plants as well as plants from the following families: Connaraceae, Sterculiaceae, Boraginaceae, Bignoniaceae, Rubiaceae and Flacourtiaceae.

Thibaud Decaens has reared this species on Quercus robur.

Automeris tridens female copyright Kirby Wolfe.

Automeris tridens female, Costa Rica, courtesy Dan Janzen.

Automeris tridens female (verso), Costa Rica, courtesy Dan Janzen.

ECLOSION, SCENTING AND MATING:

Males use their more highly developed antennae to seek out females who release an airbourne pheromone into the night sky.

EGGS, LARVAE, COCOONS, AND PUPAE:

Eggs are deposited in clusters of 6-40+ on hostplant twigs. Larvae have urticating spines and are gregarious, especially in the early instars.

Larvae bulk up considerably for final instar and remain gregarious, often following each other, head to tail, in a long procession on host branches.

Automeris tridens sixth instar copyright Kirby Wolfe

Larval Food Plants

It is hoped that this alphabetical listing followed by the common name of the foodplant will prove useful. The list is not exhaustive. Experimenting with closely related foodplants is worthwhile.

Ligustrum Quercus Quercus robur.......

Privet Oak English oak

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