Breadfruit

Breadfruit, Altocarpus altilis, belongs to the family Moraceae, which includes the mulberry and figs. Native to Malaysia and the western Pacific, the tree is now cultivated throughout the tropics.

Like many members of the Moraceae family, breadfruit has large tough leaves with a milky latex. In some regions, the latex of breadfruit is used for caulking boats.

The fruit is about the size of a small soccer ball. Rich in starch, it is a staple food in many regions. It can be roasted, baked, fried or boiled. With a little salt, it tastes more or less like a potato.

Breadfruit has been cultivated by humans for a long time, and many of the hybrids and cultivars are seedless. This means that they cannot be dispersed without the aid of humans. The fact that breadfruit is completely dependent on humans for dispersal has made this a useful tool for elucidating patterns of human migration in the Pacific Islands. By applying molecular dating techniques to hybrids and cultivars, scientists can trace the movement of breadfruit across the Pacific Islands through time. This data can then be combined with archeological information to infer migration patterns of humans.

Zerega, Nyree J. C., Diane Ragone and Timothy J. Motley. 2004. Complex origins of breadfruit (Artocarpus altilis, Moraceae): implications for human migrations in Oceania. American Journal of Botany 91:760-766.)

Passifloraceae

Passion plants (genus Passiflora, family Passifloraceae) have stunning, brightly colored flowers. The size and structure of the flower is optimized for pollination by hummingbirds. The species Passiflora edulis (not shown here) is cultivated throughout the tropics for its sweet and juicy fruit.

This genus includes about 500 species and is mostly tropical in distribution. Passiflora vines are most diverse in South America, but can also be found in Asia, New Guinea, Australia and New Zealand.

Wild Passiflora plants have several interesting strategies for deterring herbivores. The leaves contain cyanogenic glycosides and other secondary compounds that are toxic for most animals. Some insects, most notably caterpillars of the butterfly genus Heliconius, are adapted to feed on Passiflora. To deter Heliconius females from laying eggs on the plant, some Passiflora vines have pale spots on their leaves that mimic butterfly eggs. Because it is disadvantageous for their offspring to compete with other caterpillars for food, Heliconius females will avoid leaves that appear to have eggs on them. Passiflora also use extrafloral nectaries to attract ants and parasitoids that prey on Heliconius caterpillars.