A PREDICTIVE MODEL FOR SEASONAL OCCURRENCE OF THREE GRASSHOPPER SPECIES IN SASKATCHEWAN (ORTHOPTERA: ACRIDIDAE)

Abstract

AbstractSeasonal occurrence of three important grasshopper species (Melanoplus sanguinipes (Fabr.), M. bivittatus (Say), and Camnula pellucida (Scudder)) is estimated. The predictions are based on the amount of embryonic development occurring in fall after oviposition and the rate of egg and nymphal development in spring. Embryonic development is calculated from heat units accumulated above 50°F (10 °C) from daily maximum and minimum temperatures from 1 August to 30 September. Egg and nymphal development during spring can be monitored by accumulating heat above 50°F (10 °C) using daily maximum and minimum temperatures from 1 April.The number of heat units required by each life stage is provided for comparison with current heat accumulations. The average date of occurrence from hatch to adults is provided based on 17 years of weather data from seven Saskatchewan weather stations.