Weird and wonderful members of the plant kingdom - plant/animal relationships

Plants and animals evolved together, so it is not surprising that they share complex plant/animal relationships. Some relationships are beneficial to both parties, while others have a clear benefit for one at the expense, or even death, of the other. Browsers and grazers, from aphids and caterpillars to cows and camels, are familiar herbivores. Even insects and animals that eat seeds are considered herbivores. Some consume entire plants, or enough to kill them. Others only eat a portion of the plant, and so the plant can recover. The plant/herbivore relationship traditionally has been seen as lopsided, with the animal as the beneficiary and the plant as the loser. However, this may not be true - one example is canopy grazing by insects, which allows more light to penetrate into the lower layers of the forest.

Pollination is the transfer of the pollen from one flower to another, which results in fertilisation and, ultimately, the formation of seeds. The earliest plants were pollinated by wind, and for some modern plants this is still the most expedient method. Many trees, all grasses, and plants with inconspicuous flowers are designed for wind pollination. Bright, showy flowers evolved for another purpose - to attract a pollinator. Insects, birds, even mammals are important for perpetuating plants, such as:

1. Ants which pollinate many wildflowers, such as trilliums, bloodroot, violets
2. Birds which pollinate fleshy fruits and grains
3. Mammals which feed on, and excrete or dispose of the seeds of fruits, grains, nuts, berries. The baobab tree, for example relies on the baboon to eat and excrete its seeds. The baboon's digestive juices erode the tough seed coat and allow water to penetrate more easily. For the baobab this is important - baboons will only eat fresh seed, which means that if there have been several years of drought, only fresh seed which has the best chance of growing will get eaten, and will therefore sprout after passing through the ape!
4. Squirrel who store nuts are reckoned to recover only one third of their hoard, leaving two thirds to sprout in the ground and become new trees.

Baboon photograph by g-hat, used under a creative commons attribution licence