Vavilovian Mimicry - Classification and Comparisons

Classification and Comparisons

Vavilovian mimicry can be classified as reproductive, aggressive (parasitic) and, in the case of secondary crops, mutualistic. It is a form of disjunct mimicry with the model agreeable to the dupe. In disjunct mimicry complexes, three different species are involved as model, mimic and dupe—the weed, mimicking a protected crop model, with humans as signal receivers. Vavilovian mimicry bears considerable similarity to Batesian mimicry (where a harmless organism mimics a harmful species) in that the weed does not share the properties that give the model its protection, and both the model and the dupe (in this case people) are negatively affected by it. There are some key differences, though; in Batesian mimicry the model and signal receiver are enemies (the predator would eat the protected species if it could), whereas here the crop and its human growers are in a mutualistic relationship: the crop benefits from being dispersed and protected by people, despite being eaten by them. In fact, the crop's only 'protection' relevant here is its usefulness to humans. Secondly, the weed is not eaten, but simply killed (either directly or by not planting the seed). The only motivation for killing the weed is its effect on crop yields. Farmers would prefer to have no weeds at all, but a predator would die if it had no prey to eat, even if they might be difficult to identify. Finally, there is no known equivalent of Vavilovian mimicry in ecosystems unaltered by humans.

Many other cases of mimicry in plants are also known. In one class, flowers emit signals which cause insects to copulate with them, effecting pollination in the process. They may also resemble other organisms in defense, such as passion flower leaves mimicking the eggs of butterflies, which deters them from laying.

Delbert Wiens has suggested secondary crops cannot be classified as mimics because they result from artificial as opposed to natural selection, and because the selective agent is a machine. On this first point, Georges Pasteur points out that "indirect artificial selection" is involuntary and thus no different from natural selection. The signal receiver being an inanimate object certainly deviates from the normal case of a dupe perceiving the signal, but the result is no different from that of manual selection that has been occurring since the Neolithic Revolution.