Diel Flight Periodicity of Graminella nigrifrons (Homoptera: Cicadellidae)

Abstract

The effect of light intensity, temperature, and host-plant age on the diel flight periodicity of Graminella nigrifrons (Forbes) was evaluated under controlled laboratory conditions and in the field. In a controlled environment, leafhoppers reared on young and mature oats responded similarly to changes in light intensity when temperature was held at a constant 26.6 ± 1°C. Most leafhoppers were trapped under low light that simulated dusk and dawn. Activity was low at midday and at night. Temperature altered this flight pattern. When day temperature was 26.6 ± 1°C and night was 18.3 ± 1°C, most leafhoppers were trapped late in the day and peaked at dusk. Few leafhoppers flew at night, but there was a small peak at dawn. In these laboratory experiments, numbers of females and males trapped did not differ greatly. In the field, many more leafhoppers were trapped in July than in June or August. Peak flight for all months was at dusk and then declined to low numbers throughout the night, especially in July. There was little or no flight at dawn when temperatures were at their daily low or during warmer daylight hours. Considerably more males than females were trapped. Crepuscular flight reported here for G. nigrifrons is similar to that reported for leafhoppers and other insects.