Miller Moth

With the Miller moth, the Laysan Millerbird also went extinct

The Miller moth, a nocturnal species also known as Miller or Laysan noctuid moth, was the main food source of the Laysan millerbird. When the moth went extinct, the bird disappeared as well.

The Miller moth occurred exclusively on Laysan, a subtropical Hawaiian island. On this island, which is only about four square kilometers in size, guano was mined in the late 19th and early 20th centuries. Guano consists of bird and bat droppings and, in combination with lime, was used among other things as fertilizer.

But guano mining itself did not cause the nocturnal moth’s extinction. Rather, rabbits destroyed the island’s entire vegetation within a very short time, and with it the host and food plants of the Miller moth.

There are two different theories about how the rabbits got to the island. One says that guano collectors released them on the island in 1903. Another possibility is that a German named Max Schlemmer, who lived on Laysan between 1894 and 1915, brought rabbits to the island in order to create supplies for a canned meat business.

No matter how the rabbits got there, the Miller moth—and probably also the moth Hypena laysanensis—lost both its food supply and its ability to reproduce when the vegetation disappeared. Caterpillars, which later become butterflies and moths, feed very differently from adult moths and are usually specialized on certain plants; without these they cannot develop. A similar fate befell the butterfly Xerces blue, which went extinct in the 1940s, as well as Sloane’s urania at the beginning of the 20th century.

Miller moth – fact sheet

alternative names	Miller, Laysan noctuid moth
scientific names	Agrotis laysanensis, Prodenia laysanensis
original range	Laysan (Pacific Ocean)
time of extinction	1911
causes of extinction	rabbits introduced to the island destroyed its food source
IUCN status	critically endangered (possibly extinct)

Missing since 1911

According to the NatureServe Explorer, the last record of the Miller moth dates from 1911. The International Union for Conservation of Nature, the IUCN, however, did not add the butterfly species to the Red List until 1986, and the United States Fish and Wildlife Service included it in its list of extinct insects in 1989.

Today, experts assume that the butterfly species is extinct, also because such species are sensitive to biological pest control agents. In addition, these were relatively large and conspicuous moths: females reached a wingspan of 4.2 centimeters and males 3.6 centimeters, making them hard to overlook. The island, now uninhabited, is also of manageable size.

The British zoologist Walter Rothschild described the Miller moth as Prodenia laysanensis in 1894 in Novitates Zoologicae: Some new Species of Lepidoptera.

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