Basic biology of Melanoplus aridus, Orthoptera: Acrididae a forbivorous grasshopper common on some southwestern rangelands

Melanoplus ar aridus (Scudder) (Orthoptera: Acrididae) is a common southwestern rangeland grasshopper that has rarely been described. Laboratory and field studies were initiated to determine morphological characteristics and to better understand the basic biology of this grasshopper. M. aridus has five nymphal instars. Definitive morphological characteristics were determined for each instar. These included the number of antennal segments, body and hind femur length, and wing pad shape and size. Phenologies at the study site and egg pod characteristics of laboratory-reared grasshoppers were similar to other Melanopline grasshoppers. M. aridus survived equally well on two species of snakeweed and can significantly reduce above ground biomass of these weeds. This grasshopper preferred threadlleaf snakeweed, Gutierrezia microcephala (DeCondolle) Gray, to all other plants tested in choice and no-choice experiments; however, it was able to survive on a variety of other plants.