Place：Lecture Hall B517, Institute of Zoology, Chinese Academy of Sciences

　　Contact: Dr.Zhishu Xiao, 010-64807110

　　SUMMARY The term coevolution was first used by Ehrlich and Raven in 1964 just to a study involving plants and insects (butterflies) and their evolutionary interactions. So, insects are the most implicated animals in the natural history of plants. The coevolution of insects and plants is the story of the way in which insects have lived for the last 300 million years, among and often directly on living and decaying plants and the varied means used by plants both to escape the depredations of insects and to benefit by their presence. More than a quarter of million species of vascular plants and 1 million species of insects have been described. In part this great number of species is the outcome of mutual adaptation between particular species of plants and insects. Feeding on leaves stems and roots led to preferences both for particular parts of the plant and for particular species of plants. Feeding on protein-rich spores led to pollination and the evolution of flowering plants. So, we can approach to the study of coevolution of plants and insects focusing in two main aspects: herbivory and pollination. The evolutionary history of flowering plants would have been different in absence of insects for it is the power of flight that makes insects effective vectors. In turn, the great diversity of pollinating and phytophagous insects is an evolutionary response to the existence of flowering plants. Predation and parasitism have led to numerous evolutionary strategies. Plants have protected themselves with structural barricades and chemicals, have evaded would-be predators or have bought protection from other insects. Some fungi have parasitized insects, while others live on the honeydew produced by plants-feeding insects. Insects have used the defensive chemicals of plants to defend themselves, and have cultivated fungi for food and air conditioning. Where the relationships between insects and plants are mutually beneficial, as in pollination, evident coadaptation can be seen. This is particularly obvious when the insects are using vision or scent within human range. On the other hand, ants which protect and are fed by myrmecophilous plants are not noticeable different from others ants, but as we do not find the food bodies and extra-floral nectaries particularly alluring, we may not be using the right senses. The ants may recognize fruiting bodies by touch and taste, factors much influenced by size. Mutual adaptation may develop between organisms, but commonly each member of a relationship adapts more or less completely to the most useful components of the other. The organism to which the relationships are most important is likely to alter most, and adaptation will be in the appropriate organs or behaviour. Several approaching ways to the coevolution studies can be used. One of these is a phylogenetic approach, including here the parallel cladogenesis, named Fahrenholz’s Rule (the principle that the phylogenies of parasites and their hosts generally evolve in parallel), evolutionary ecology (food chains or networks, defense relationships, biogeography, and so on), paleontological studies, genetics, etc. An emerging field in this context is the coextintions: the extinction of a partner implies the extinction of the other (verbigratia Agaonidae wasps and Ficus trees).