Factors affecting adult color polymorphism in the meadow grasshopper, Conocephalus maculatus (Orthoptera : Tettigoniidae)

Abstract

To examine the factors regulating the adult color morph of the meadow grasshopper, Conocephalus maculatus, we carried out 2 series of experiments. In Series I, crosses between green and brown morphs were carried out to investigate the genetic effect. The percentage of green morphs in F₁ hybrids between green females and green males was about 70% and the percentages in F₁ hybrids between parent pairs of different color morphs were significantly different. The results suggested that color polymorphism in C. maculatus was partly controlled by genetic factors. In Series II, the F₁ hybrids were also reared under different conditions with respect to temperature, photoperiod, background color and relative humidity, to assess the effects on the proportion of color morphs. The body coloration of F₁ hybrids was lighter and paler at 30°C than at 25°C, especially the brown morph, which shows that temperature affects the intensity of body color rather than color morph determination in adults.