Proceedings of the United States National Museum . portions of nearby States and Canada. These flights occurred duringan outbreak cycle, and a general population increase had preceded theflights. Drake and Tauber (1946) discussed flights which enteredIowa from the west in 1941 and earlier years. Corkins (1922) reported on extensive flights in 1920, mainly inBottineau and Renville Counties, N. Dak., and he noted their re-semblance to the historic flights of spretus. By the use of an airplaneone heavy swarm was examined and found to be most dense at analtitude of 500-800 feet, with a few individ
Proceedings of the United States National Museum . portions of nearby States and Canada. These flights occurred duringan outbreak cycle, and a general population increase had preceded theflights. Drake and Tauber (1946) discussed flights which enteredIowa from the west in 1941 and earlier years. Corkins (1922) reported on extensive flights in 1920, mainly inBottineau and Renville Counties, N. Dak., and he noted their re-semblance to the historic flights of spretus. By the use of an airplaneone heavy swarm was examined and found to be most dense at analtitude of 500-800 feet, with a few individuals at 1,650 feet. Nymphs as well as adults occasionally migrate (Parker, et al.,1955, p. 16; Shotwell, 1930, p. 24). Early papers (Herrick and Hadley, 1916; Shotwefl, 1930) gave theimpression that bilituratus bilituratus is almost omnivorous in its foodhabits. In recent years, however, entomologists have become keenlyaware that many grasshoppers are far from being the general feederswhich they were once thought to be, and several investigations. Figure 5.—Distribution of male specimens of Melanoplus bilituratus bilituratus examined from Alaska and Canada. GRASSHOPPERS—GURNET AND BROOKS 23 suggest that bilituratus bilituratus has definite responses and prefer-ences concerning food plants. In cage studies conducted in easternWyoming, Pfadt (1949) found that adults preferred dandelion andwheat to all other plants which he tested, that tansymustard anddandelion gave the most nymphal growth, and that dandelion, wheat,and tansymustard were most favorable to egg production. InManitoba, Smith, Hanford, and Chefurka (1952) fed certain plantsthrough three successive generations (in cages) and recorded survival,rate of development, and the number of eggs laid. They found thatwheat, barley, and dandelion were the most favorable food plants,and that Russian thistle and alfalfa were the least favorable. How-ever, Anderson and Wright (1952) found during Montana field studiesthat feeding
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