|Kemp, William - Bill|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/1998
Publication Date: N/A
Interpretive Summary: Each year across the Great Plains landscape, hundreds of species of grasshoppers hatch from eggs deposited in the soil during the previous summer and autumn. Any attempts to develop integrated pest management programs rely heavily on an understanding of the timing of this hatch each spring, especially in the case of economically important species like the white whiskered grasshopper. This manuscript describes a simple model whic uses maximum and minimum daily temperatures to explain how white whiskered grasshopper eggs develop, as the soil warms up, and subsequently hatch. Simple models of the type described here not only improve our understanding of important ecological relationships, but also provide models central to the development of management programs to these occasional threats to U.S. Agriculture.
Technical Abstract: Postdiapause development and field hatch of the white whiskered grasshopper, Ageneotettix deorum (Scudder) was studied in southwest Montana during a 3 year period. Postdiapause embryonic development rates were assembled into a developmental rate function after eggs were exposed to 12 different developmental temperatures, ranging from 9 degrees Celsius to 42 degrees Celsius. Forthright, the function and other components of the population model design system (PMDS) was used to predict hatch at 2 sites in southwestern Montana for 3 year Field emergence (first instars) was monitored by taking sweep net samples and used to assess the accuracy of the predictions. When simulated hatch was compared with field occurrence of first instars, the 50% occurrence dates were similar; within 2.6+/-1.4 d for all 5 comparisons. The results of our investigations should enhance the ability of decision support systems for grasshopper management to provide forecasts to land managers and pest advisors.