Harmony and Conflict in the Living World - Alexander F. Skutch [77]
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too big for the smaller birds in this guild, but they too often plunder the nests of lesser birds. Bees occasionally raid neighboring hives of different species, stubbornly fighting the residents and, if victorious, carrying off their stores of nectar and pollen. Like most things in this perplexing world, the plant-pollinator-disperser association is not perfect, but it is nevertheless one of evolution's most admirable achievements, contributing immensely to nature's harmony and productivity, and, especially by flowers, birds, and butterflies, to its beauty. Moreover, directly or indirectly, the association provides nourishment for a large proportion of terrestrial life.
To learn how many species belong to the plant-pollinator-disperser association in any given area might require a prolonged study by a team of botanists, entomologists, ornithologists, and mammalogists, which to my knowledge has never anywhere been made. I surmise that in a tract of temperate zone woodland the association would include hundreds of species. In a similar area of tropical rain forest, where wind pollination is much rarer than in the temperate zones and more winged pollinators are needed, the number might run into thousands. Around this nucleus cluster other species that are neither pollinators nor dispersers. Among them are many insectivorous birds and other creatures that coexist harmoniously with the dispersers, and are indeed indispensable to them, for without the former, insects might devour all the foliage and kill the plants that yield the fruits and nectar.
Less closely allied to the plant-pollinator-disperser association, but living harmoniously with it, are many other animals; in tropical American forests, tinamous, guans, quails, pigeons, and, among raptors, the Laughing Falcon, that subsists almost wholly upon snakes. Parrots that digest seeds instead of the pulp that surrounds them may slightly reduce the reproduction of trees but neither injure them nor harm other birds. Among mammals, armadillos, anteaters, sloths, many primates, and others also belong to the compatible community. Not to be excluded are the indispensable but more obscure multitudes of small organisms that decompose dead tissues or otherwise contribute to the soil's ability to support the association, greatly swelling its numbers.
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Similar biocompatible associations are found in wetlands, prairies, Arctic tundra, and the oceans but apparently have not been investigated from this point of view. They appear to include fewer collaborators than those of woodlands. In the oceans, where the biomass of animals is very much greater in proportion to that of the chlorophyll-bearing plants that support them, the struggle for survival is fiercer and predation more rife, a truth to which the huge production of eggs of many marine creatures, far exceeding that of any terrestrial animals except possibly queen termites and bees, bears unimpeachable testimony. Nevertheless, in the oceans biocompatible associations do occur, as with cleaner fishes and their clients.
Preferential treatment of biocompatible associates would benefit the indispensable sustainers of terrestrial life but certainly not everything. It would protect neither invertebrate parasites nor parasitic cuckoos and cowbirds, all of which are only a froth (although often a smothering froth) on the surface of the living world. Whenever they seriously threaten human life or economic interests, vigorous, often costly efforts are made to exterminate them. Predatory vertebrates, especially among mammals and birds, present special problems. Mostly solitary, unsocial creatures, they do not fit into any