BATS AND THE QUEEN SAGO PALM (Cycas circinalis)

Cycas circinalis, sometimes called the queen sago palm, does not have fruit because it does not have flowers. The tree does have seeds embedded in a tasty plum-flavoured flesh which is enjoyed by the seed-dispersing Marianas flying fox in the Mariana Islands and on Guam.

Despite its common name, Cycas circinalis is not a palm. Cycads are gymnosperms related to conifers, ginkos and Gnetophyta.

Cycads have a rich fossil history which attests to their vigour and abundance from the Permian period, about 240 million years ago, 100 million years before the appearance of flowering and fruiting plants, the angiosperms.

The seeds of the non-fruit of Cycas circinalis are used by the Chamorro people on the Pacific islands where this cycad grows. The potent poison in the seeds is removed by soaking the seeds in water. Water from the first seed-soaking will kill birds, goats, sheep and hogs. Water from the following soakings is said to be harmless.

After the final soaking, the seeds are dried and ground into flour. The flour is used to make highly acclaimed tortillas, tamales, soup and porridge.

During the 1960's researchers suggested that lytico-bodig, a debilitating disease found among the Chamorro people was caused by the remnant poison in the seeds and the concentration of that element in the flesh of fruit bats. The Chamorro people traditionally use cycad flour and ate the Marianas flying fox.

That theory has never been proved. The incidence of the disease has diminished although the seeds continue to be used. Fewer resident bats that feed on cycad seed pulp are eaten because their numbers were reduced by overhunting.

Australian aborigines may have developed the method for creating poison-free cycad flour about 13,000 years ago. Whenever or wherever the process was perfected, fatalities would have accompanied the earliest seed processing. The desire or need to use the seeds must have been strong.

Sturdy cycads are spared by the typhoons which destroy an island's agricultural crops and cycad seed preparations can be a valuable famine food.

In 1658 Georg Rumpf, an employee of the Dutch East India Company, saw cycads growing on India's Malabar coast and wrote the first known description of a cycad.

Cycads grow slowly. A Dioon edule, native to Mexico, that is less than five feet in height may be nearly 1000 years old.

Cycads grow sporadically. New leaves may appear at extended intervals or the tree may become dormant and not grow at all for a period of years.

The pollination of cycads is described as primitive. Despite the tree being a relict from the Paleozoic the botanical processes of a cycad are not crude. The maidenhair tree, Gingo biloba, and the cycad produce swimming sperm after pollination, two in each germinated pollen grain, a phenomenon unknown in any other seed plants.

References:

Fujita, M.S. 1991. Flying Fox (Chiroptera:Pteropodidae) Pollination, Seed Dispersal, and Economic Importance: A Tabular Summary of Current Knowledge, Resource Publication No. 2, Bat Conservation International

Hora, Bayard, editor. The Oxford Encyclopedia of Trees of the World, Oxford University Press

Jones, David, Cycads of the World. Washington, DC: Smithsonian Institution Press, 1993.

Sacks, Oliver, The Island of the Colour-blind and Cycad Island, Macmillan, 1996

THE PLANT

Family: Cycadaceae

Species: Cycas circinalis

THE BATS

Marianas flying fox (Pteropus mariannus)

Thank you to Dr. Merlin D. Tuttle, Founder and President of Bat Conservation International, Austin, Texas, for permission to use his photographs of the Marianas flying fox as a guide to drawing the illustrations. http://www.batcon.org

Thank you also to Forest and Kim Starr for permission to use photographs from their photo-library of plants growing in Hawaii.

http://www.hear.org/starr/hiplants/images/index.html

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