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Manduca blackburni, Blackburn’s Sphinx Moth

Manduca blackburni: (5 inches/12cm wingspan). Hawaii’s largest native insect, this wonderful moth has long, narrow black banded wings on a background of grayish brown. It is adorned with 5 distinguished brilliant oranges spots running down both sides of its’ thick spindle shaped bodice. The large caterpillar stages are of two different color morphologies of either lime green or brownish gray. The lifecycle from egg to adult is quite rapid at an approximate duration of 56 days. During hot or dry weather conditions, the pupae can experience aestivate (underground hibernation) until conditions become suitable.

When Butler discovered the Blackburn’s Sphinx Moth in 1880, it was in abundant numbers all throughout six of the Hawaiian Islands. During the 1970’s, it seemed Blackburn’s sphinx illusiveness led conservation biologists to fear its extinction causing it to be the first unwilling participant from the state of Hawaii. Its rediscovery in 1984 was happily made in Maui, revealing a small population. Due to this newfound hope, heightened awareness led to further discoveries in Kahoolewan and the island of Hawaii.

The preferred environment for this amazing creature is in coastal, lowland, dryland forest that may receive only as little as 50 inches of rain. It has been found in elevations as low as sea level and, incredibly, as high as 2500 feet above sea level. In recent years, this unique dryland forest area has experienced a decline of an overwhelming 90 percent total loss. The decline in the Blackburn’s habitat is due to a myriad of factors including: fragmentation due to development, agricultural removal of host plants, and introduced species utilizing their habitat. Unfortunately, this decrease in land has had detrimental effects on the Aiea tree (current known moth populations located only where Aiea trees are found), the main diet for the Blackburn’s Sphinx larvae.

Not only are the larvae challenged by a reduced food source, they fall prey to parasitism from wasps and bees whose young feed on the innards of the unknowing larvae. They find themselves trampled on by the local domesticated animals, engage in competition for food from foreign species, and stolen by greedy collectors who are reducing their numbers at alarming rates. The fate of the Blackburn’s sphinx moth, with such restricted distribution, is prone to be completely wiped by natural catastrophes such as drought, fire and hurricanes.

As per the United States Fish and Wildlife Service (USFWS), the Blackburn’s sphinx is the only federally listed endangered insect listed for the state of Hawaii. Major funding has been diverted to the conservation of the Blackburn’s sphinx by establishing new populations, designation of seven new habitats by instituting sanctuaries and federally protecting lands. The USFWS have set aside money for the research of the Blackburn’s sphinx life by studying their specific habitat needs, assessing their population status and understanding their complete life history. Another vital aspect of the recovery process is monitoring the Blackburn’s sphinx by systematically taking population counts, surveying for potential future habitat areas, keeping statistics on their food sources and their populations, and monitoring the foreign species that could ultimately wipe out the entire population of the Hawaiian Islands first and only federally listed endangered species… the phenomenal Blackburn’s sphinx moth.


Written by: Tracey Gollwitzer, 2006

Image credit: NA