Pathways of Aphids and Grasshoppers to Radiate From Stress to New Species

Abstract

S. H. Hodjat

Environmental stress can evolve new insect species by epigenetic inheritance and changes in their morphology and physiology. Recent phylogenetic research has emphasized that the adaptation of insects to feed on plants increased their diversity. Discovery of many fossil aphid species trapped in tree resins proved that they started with sexual or holocyclic life cycles by overwintering in the egg stage during the winter. Adelgidae and Phylloxeridae appeared about 200 Mya after Coccoidea. They were rapidly adapted to feed on trees and herbaceous plants after the acquisition of cyclical parthenogenesis life cycle 140 Mya. The economic importance of aphids and grasshoppers and aphid relation to their host is by direct damage or carrying viral plant diseases. Phylogenetic research indicates that Orthoptera radiated 300 Mya and grasshoppers radiated in the Pliocene of the Cenozoic period about 59.3 Mya. The radiation of 40 Orthopteran orders representing 15 super- families of monophyletic insect group is composed of Ensifera and Caelifera suborders. In this article, the possible route for speciation in aphids and Chorthippus grasshoppers is discussed. Two articles in the appendix describe specific information about Gomphocerinae and Chorthippus species of Iran.

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