InsectNet forum

I was reading an enjoyable article on Danaus gilippus in LepSoc Journal Spring 2024 when the following map caught my eye:



Huh? Everyone knows that Danaus plexippus breeds all the way up into Canada. Right?

The purpose of the map is to demonstrate the lack of competition for foodplant between gilippus and plexippus; so no harm done to the point being made. Still, this seems to be a significant oversight concerning something that I consider common knowledge.

Am I missing something?

Maybe. I am sure D, plexippus is found here in Oregon. I just saw a news clip about a butterfly house in Hawaii and all they showed were
Monarchs, I don't think they occur there naturally, but I've never been. Perhaps it is just the comparison between the respective species, I had to look
up gilippus

D. plexippus has become naturalized across the Pacific, in every place where its host plant (milkweed) has also become naturalized. Monarchs reached Australia by the 1870s, and can now be found across much of the continent's southeast, along the entire east coast, and north into PNG.

Definitely breeds in Canada. Reaches some pretty northern locales. The map is just inaccurate.

It looks to be naturalized in western Europe and northern Africa as well. The range extends far south of Mexico as well. I've personally encountered them in Peru, although I'm not certain if this is an instance of the milkweed and butterfly having been introduced there or if it is native. As for Canada, the map is limited and inaccurate - The Travels of Monarch X was published in the 60's was it not? So it isn't as if better information hasn't been around.

I was surprised to meet Danaus plexippus in a Papuan village in the Baliem Valley in 2009.
I didn't know then that it was naturalized in New Guinea.

Danaus plexippus is all over the place.

I have captures from several locations in Solomon Islands.

University of Hawai'i on Oahu has a light morph, and on Maui can be found a dark morph.

I have seen D.plexippus in Costa Rica and Dominican Republic. It does not occur in Thailand or Laos, at least not yet, most of subspecies other than N.American nominate don’t migrate.