growth rate and development of the embryo within the leafhopper egg, with higher temperatures generally being proportionally related to quicker development. The optimal range of temperatures for the development of these insects is between . This means that development takes longer over winter for these insects as compared to spring and summer times. Since development is very closely related to temperature, researchers in the study also concluded that the number of leafhopper generations produced in a year may be related to the seasonal temperatures of their habitat. They found that under lab conditions, where the leafhoppers were raised in optimal temperatures of , as many as 15–16 generations of leafhoppers could be produced per year. However they cited that actual numbers of generations per year may be limited to up to eight generations in the warmer parts of the Southern United States. This may be partly because other factors like the seasonal availability of beet plants as food, may also impact the number of generations in a year. Generally beet plants are harvested in October which would limit food resources for the beet leafhopper in the fall. Life cycle The life cycle of the beet leafhopper consists of three stages: eggs, nymphs and adults. The insects grow through 5 different molts during development which provides 5 instars before they reach adulthood. The growth patterns in the size of the instars follow a sigmoidal curve which means that there is greatest increase in size among younger instars and the rate of growth decreases as the instars reach adulthood. Colouration Beet leafhoppers may show different coloration based on the time of year that they mature in. Generally, adults that mature during warmer temperatures in the spring and summer time show light green or yellowish colouration. This is different from adults that mature in the winter which generally show darker markings on their wings and pronotum. These changes in colouration may be due to changes in seasonal temperatures as sometimes leafhoppers who mature in colder spring temperatures also show darker colouration like that of winter leafhoppers. Some researchers believe that these changes in colouration occur according to the surrounding temperatures of the last leaf hopper instars as this is the stage during which wings develop. This may also be backed by the fact that adult leaf hopper do not change colour once they have matured regardless of the temperature of their environment. Vector