Morphometrics reveal correlation between morphology and bioclimatic factors and population mixture in Tetrix japonica (Orthoptera: Tetrigidae)

Abstract The morphology of an organism is limited by genetic and environmental factors, and the precise mechanism is inconsistent between species. Tetrix japonica Bolivar, 1987, is a widely distributed pygmy grasshopper in East Asia. However, the population clustering and relationships between the morphology and bioclimatic factors have not been previously investigated. Here, 32 geographic populations were sampled from China, and morphometrics and multiple statistical analyses were applied to detect the population clustering and relationship between the morphology and bioclimatic factors. The results suggested that T. japonica with females are significantly bigger than males in the eight morphological traits. The 32 populations do not obviously cluster according to the natural geographic area. The body sizes of females are mainly related to the lowest temperature and precipitation; by contrast, males only have a significant relationship with the lowest temperature. The forewing size is significantly related to the maximum precipitation. Furthermore, the Mantel test showed that the morphological size variation of females has a weak positive correlation to geographic distance, but is insignificant in males. It was concluded that Chinese geographic populations of T. japonica mixed and that the size of the morphological structure is limited by bioclimatic factors.