FORAGE LOSSES CAUSED BY RANGELAND GRASSHOPPERS 7 
Smith (1940) also supported the findings of 
Weese (1939). He collected insects in Oklahoma in 
five pastures, which were grazed at different in- 
tensities. He found that the total number of insects 
increased under conditions of overgrazing, but the 
total number of species declined, except the Or- 
thoptera, which was the only group to show an in- 
crease in both total number of species and total 
number of specimens. He reasoned that overgrazed 
pastures do not provide a favorable habitat for 
birds and small mammals that eat grasshoppers. 
Nerney (1958) reported that in a heavily grazed 
sparse grass area about 70 percent of the herbage 
was eaten by an average of about 16.5 grasshoppers 
per square meter in comparison with about 20 per- 
cent by equal numbers in a moderately grazed 
fairly good perennial grass area. Batcheler (1967) 
studied populations of the grasshopper Brachaspis 
collinus Hutton in alpine meadows in New Zealand. 
He reported that populations of the grasshopper 
weigh less than 1.1 kg/ha in dense grassland and up 
to 32.2 kg/ha where scree forms a high proportion 
of the total cover. Biomass of grasshoppers was 
much greater than that of deer and chamois in the 
greater part of the alpine grassland above 1,524 m. 
Modification of the habitat because of grazing and 
trampling by the introduced ungulates is also be- 
lieved to have favored grasshoppers, particularly in 
more dense grasslands. 
More recently, Campbell et al. (1974) collected 
grasshoppers in Kansas from pastures grazed at 
different intensities and pastures moderately 
grazed on a 3-year rotational deferred grazing sys- 
tem. He found nymphs and adults more abundant in 
the heavily grazed pastures and least abundant in 
the deferred and lightly grazed pastures. 
Human Influence 
Forage consumption by grasshoppers probably 
has been influenced greatly by man’s activities on 
rangeland. Ball (1936) stated that all ranges are 
overgrazed; however, this condition is no longer as 
widespread as during the early cattle days. Tre- 
herne and Buckell (1924) believed that early over- 
grazing by livestock was primarily responsible for 
the disappearance of the range grasses from Can- 
ada and that drought and the influence of grasshop- 
pers are secondary factors. 
Parker (1940) viewed the present land-use sys- 
tem in the Western States as more favorable for 
grasshoppers than during the early development of 
western agriculture. He stated that roadsides, 
fence rows, ditchbanks, grain stubble, idle land, 
untilled crops, and depleted ranges all provide 
more favorable egg-laying grounds than the origi- 
nal grasslands and that a more abundant supply of 
green food is provided for a longer period each sum- 
mer by the growing of agriculture crops. 
Riegert et al. (1965), from observing large popu- 
lations of Camnula pellucida in Canada, stated that 
severe infestations were usually associated with 
and dependent upon nearby cultivated crops. The 
native grasslands, in general, possess the neces- 
sary attribute of an oviposition habitat but do not 
provide the suitable food habitat for this species 
except for mountain meadows or native grass foot- 
hill areas. 
Bei-Bienko (1930) reported on plant association 
changes in Russia that because of grazing, woodcut- 
ting, and farming practices, resulted in a more 
favorable habitat for certain grasshopper species. 
He said grasshoppers migrate to the newly formed 
plant associations, and some species cause serious 
damage to cultivated crops in these areas. 
More recently, Hewitt and Rees (1974) found that 
certain land renovation practices, such as furrow- 
ing and scalping used in the Western United States, 
can provide an unfavorable habitat for some species 
of grasshoppers. Scoggan and Brusven (1973) also 
studied the grasshopper-plant community associa- 
tions in Idaho in relation to the natural and altered 
environment. Habitat alterations such as fire, soil 
tillage, sagebrush treatment, logging, road con- 
struction, and overgrazing all affected grasshopper 
distribution and abundance. Campbell et al. (1974) 
collected grasshoppers in Kansas in pastures that 
had been burned in early spring, midspring, and 
late spring. Both nymphs and adults were most 
abundant in the areas burned early in the spring. 
Weather Influence 
Attempts to make a direct correlation between 
the fluctuation of grasshopper numbers and 
weather, especially on a short-term basis, have 
mostly been unsuccessful. However, Nakamura et 
al. (1975) reported that adverse weather conditions 
during egg development and first instar develop- 
ment caused variation in grasshopper numbers dur- 
ing the sampling period. In general, the more warm 
or hot days in a summer the more time available for 
grasshopper feeding. As Parker (1954) pointed out, 
grasshoppers eat more in hot weather than in cool 
weather. 
Pepper and Hastings (1952) determined that 
