1. Introduction
The extant species in the planet have evolved for hundreds of millions of years. Evidence of climatic and environmental changes could be found through the adaptation of species and the historical development of the population within the species (Emerson et al ., 2001). Lucky individuals survived when the environment had changed dramatically. They migrated to the new habitat, and they settled, adapted and reproduced there. In the process of adaptation, new behavioral, physiological and genetic structure occurred (Avise et al ., 1998). Speciation duration is about 1-2 Myr, but morphological, physiological and behavioral changes may produce subspecies and species at almost any time (Hewitt et al. , 2000). The current distribution and the differentiation of species are compatible with the local geographical and climatic environment (Udvardy, 1981). Insects have the relatively rapid divergence rate (Orr et al ., 1998). Velarifictorus micado , selected in our study, is widely distributed in Asia, included China, Russia, Japan, Korea, Cambodia, Vietnam, Indonesia and nearby islands, covering the Palearctic and Oriental realm, and the distribution range of this cricket has gradually expanded since the introduction of V. micado to the United States in 1959 (Alexander and Walker, 1962; Bowles, 2018). Velarifictorus micado (Saussure, 1877) has been found to have two modes of life cycle. In a population that diapause as eggs, adults sing from August to October, and their eggs hatch after getting through the winter. In the other population that diapause as nymphs, adults sing in May-July, hatch quickly after mating and get through the winter as nymphs. Different adaptation types of V. micado lead to differentiation of reproductive modes and stimulate speciation among populations with different life cycle patterns (He and Takeda, 2013). Aimed to find out which gene markers can distinguish the two groups and the biogeographic boundary between them, figure out why V. micado differentiate into two modes of life cycle, mitochondrial fragments were extracted from the large sampling specimens and used in phylogenetic analysis, time estimation and demographic analysis.