Grasshoppers in Grasshoppers in desert desert

grasslandsgrasslands

• Grasshopper population Grasshopper population dynamics are determined dynamics are determined primarily by weatherprimarily by weather

• However, weather impact However, weather impact varies with varies with latitudelatitude

Weather: Direct and Weather: Direct and Indirect Effects on Indirect Effects on

GrasshoppersGrasshoppers

•Slower developmentSlower development•More susceptible to More susceptible to diseases and diseases and natural natural enemiesenemies•Higher mortalityHigher mortality•Less eggs producedLess eggs produced

Less damagingLess damaging

Weather: Direct and Indirect EffectsWeather: Direct and Indirect Effects

•Faster developmentFaster development

•Less susceptible to diseases and Less susceptible to diseases and natural enemiesnatural enemies

•Lower mortalityLower mortality

•More eggs producedMore eggs produced

More damagingMore damaging

Weather: Direct and Indirect EffectsWeather: Direct and Indirect Effects

• In the Northern Great Plains, In the Northern Great Plains, summer summer temperaturestemperatures appear to be critical for appear to be critical for successful grasshopper developmentsuccessful grasshopper development

• Outbreaks in MT and WY usually occur after Outbreaks in MT and WY usually occur after several consecutive years of drought and several consecutive years of drought and above-average summer temperaturesabove-average summer temperatures

• In the desert grasslands of NM and AR the In the desert grasslands of NM and AR the situation is differentsituation is different

• Grasshopper populations increase after Grasshopper populations increase after above-average spring precipitation, above-average spring precipitation, followed by hot and dry summerfollowed by hot and dry summer

Favorable conditions for Favorable conditions for pest grasshoppers in pest grasshoppers in New Mexico desert New Mexico desert

grasslandsgrasslands• Mild autumn for egg-layingMild autumn for egg-laying

• Cool wet winter for good spring plant Cool wet winter for good spring plant growthgrowth

• Dry warm spring for grasshopper Dry warm spring for grasshopper nymphal developmentnymphal development

Main Grasshopper SpeciesMain Grasshopper Species

Pallidwinged grasshopperPallidwinged grasshopper

Main Grasshopper SpeciesMain Grasshopper Species

Cream grasshopperCream grasshopperCibolacris parvicepsCibolacris parviceps

Main Grasshopper SpeciesMain Grasshopper Species

Creosotebush grasshopperCreosotebush grasshopper

Main Grasshopper SpeciesMain Grasshopper Species

Arid spurthroated Arid spurthroated grasshoppergrasshopper

Main Grasshopper SpeciesMain Grasshopper Species

Migratory grasshopperMigratory grasshopper

Main Grasshopper SpeciesMain Grasshopper Species

Packard grasshopperPackard grasshopper

Main Grasshopper SpeciesMain Grasshopper Species

Spottedwinged grasshopperSpottedwinged grasshopper

Main Grasshopper SpeciesMain Grasshopper Species

Clearwinged grasshopperClearwinged grasshopper

Main Grasshopper SpeciesMain Grasshopper Species

Bigheaded grasshopperBigheaded grasshopper

Main Grasshopper SpeciesMain Grasshopper Species

Whitewhiskered grasshopperWhitewhiskered grasshopper