Monarch butterflies Minimize

November 2000. Information was sought from PestNet members on the status of the monarch butterfly (Danaus plexippus) populations in Pacific Islands. Monarchs were 'introduced' either accidentally, deliberately or under their own steam into the Pacific in the mid-1800. They spread throughout the Pacific and established on many Islands. Their current status has not been assessed, and this would be most useful for various reasons.

The following information was requested:

Island name, Island group (latitude and longitude if known), dates the informant was on the Island, stages of monarch butterfly seen (adults: how many: 1, 2, a few, many; immatures). Presence of milkweed (Asclepia sp. or Calotropis sp.).

The following countries noted the presence of the monarch butterfly and, in some cases, the presence of milkweeds:

New Caledonia - common
Tongatapu & Vava'u, Tonga - common
Oahi & Kauai, Hawaii - common
Fiji - common
Chuuk, ?Kosrae, Pohnpei, Yap,  FSM (recorded since mid-1800 in Pohnpei). See also Schreiner & Nafus (1997). Butterflies of Micronesia
Marchall Islands
Nauru - common
Tinian, Northern Marianas Islands - common

Distribution of milkweeds can be found in:

Asclepias curassavica: Weed Handbook of Western Polynesia by W Arthur Whistler (1983); page 20).

Weeds of the Pacific Islands' by John T Swarbrick (1997). Technical Paper No. 209, SPC, Noumea, New Caledonia. From surveys between 1988 and 1990 A currassavica was present in Cook Islands, Fiji, Kiribati, New Caledonia, Western and American Samoa, Solomon Islands, Tonga, Tuamotus, Tuvalu, Vanuatu, Wallis & Futuna, Guam, Pohnpei, Palau, Yap, Chuuk, Marshall Islands and Northern Marianas.