[8] The Io moth ranges from the southeast corner of Manitoba and in the southern extremes of Ontario, Quebec, New Brunswick and Nova Scotia in Canada, and in the US it is found from Montana, North Dakota, South Dakota, Nebraska, Colorado, New Mexico, Texas, Utah, east of those states and down to the southern end of Florida.

[4][10] Stinging spines of caterpillar Io moths have a very painful venom that is released with the slightest touch.

[14] Contacting the seta is not life-threatening for humans, but still causes irritation to the dermal tissue, resulting in an acute dermatitis called erucism.

[10][19][7] As the larvae develop, they will lose their orange color and will turn bright green and urticating, having many spines.

[20] When the caterpillars are ready, they spin a flimsy, valveless cocoon made from a dark, coarse silk.

[4] Adult Io moths normally emerge from their cocoons in late morning or early afternoon.

[19] After eclosing, the moths climb and hang on plants so that their furled wings can be inflated with fluid (hemolymph) pumped from the body.

Adult moths are strictly nocturnal, generally flying during the peak hours of the night.

[21] The females generally wait until nightfall and then extend a scent gland from the posterior region of the abdomen, in order to attract males via wind-borne pheromones.