Volume 96 T H E CANADIAN ENTOMOLOGIST 115.5 Hagen, K. S. 1962. Biology and ecology of predaceous Coccinellidae. Annu. Rev. Ent. 7: 289-326. Harrison, F. P. 1960. Corn earworm oviposition and the effect of D D T on the egg predator complex in corn silk. 1. econ. Ent. 53: 1088-1.094. Hodek, I., and J. Cerkasov. 1958. A rtudy of the imaginal hibernation of Se~nkdalia undecimxotata Schneid. (Coccinellidae, Col.) in the open. (In Czech; English summary.) Acta Soc. Zool. Bohemoslov. 22: 180-192. Hodek, I., and J . Cerkasov. 1961. Prcvention and artificial induction of imaginal diapause in Coccinel(a septmnplmctata 7, . (Cnl.: Coccincllidaei. Enr. exp. et appl. 4: 179-190. Hodek, I., P. Stwy and P. Stys. 1941. The natural enemy complex of Aphis fnbae and its efTectir-eness in control. Verh. X I int. Kongr. Ent., 1Pien (1960) 2: 747-749. Hudon. .\I. 1959. First record of Pcrilitrtr coccinellne (Schrank) (Hymenoptera: Braconidae) as a paraitc of Caccine.lln ~70z~e7motntn J-Ihr. and Colrome~qilla 7nrrcrilma lengi Timb. (Colcoptera: Coccinellidae) in Canada. Crmnd. En?. 91: 6344. Kaddou, I. l<. 1960. -The fecding bcha7-ior of I-lippndmnin qztinq?tcsignnta (Kirby) larvae. Unizs. Calif. Publ. Ent. 16: 181-232. Mote, D. C., J. Wilcox and E. G. Davis. 1926. Tmhe natural "cleaning up" habit of insects.
Saskatchewan had periodic outbreaks of grasshoppers long before the arrival of settlers. With the advent of agriculture these insects threatened the production of cereal and forage crops and necessitated the implementation of extensive control procedures. The effectiveness of control could be enhanced if farmers and government agencies were alerted and informed of the probable intensity and area of outbreak in the coming year. This lead to the initiation of forecasting the expected outbreaks, first, by questioning local persons as to the density, egg laying activities, and damage caused by local grasshopper populations and, secondly, by the inauguration of a special survey system of assessing abundance. Current populations of grasshopper adults or eggs were counted in all arable land areas of the province and rated in four categories of potential outbreak or hazard. The mapping of such ratings in their respective locations resulted in the production of a forecast map which indicated areas of probable light, moderate, severe, or very severe outbreak the following year. In Saskatchewan such maps have been produced annually since 1931 and are reproduced here. They represent the changing scene of grasshopper abundance in the past 36 years and have been accepted by agriculturists as a standard reference to be considered for sound agricultural production in the province.
The main objective of the present work was to investigate the ability of grasshopper nymphs to escape an environment devoid of food plants and to reach a suitable food supply, either as a result of random dispersal or by marching. The immediate interest was in movement over recently tilled surfaces. It was also desired to investigate the external factors that might influence such movement.
A pictorial and written description of the external morphology of embryos of a nondiapause form of M. bilituratus is given. Daily morphological changes, on each of the 17 days of embryological development, are recorded and related to the duration of incubation at 30° C. Development at 25° and 35° C was completed in 24 and 15 days, respectively.
The bioenergetics of annual populations of the dusky grasshopper, Encoptolophus sordidus costalis, on a natural grassland site were examined. Peak dry weight biomass of these insects reached 1.7 kg/ha (1.85 lb/at). Oxygen consumption ranged from 2.76 μl/h for first instar nymphs to 82 μl/h for adults, values that equated with an average consumption of 341 ml oxygen/m2 during the growing season. Energy values (cal/mg) of insect body tissue averaged 5.24 while those for exuviae, faeces, and plant material were 5.38, 4.08, and 4.39, respectively. The grasshoppers ingested 2% of the green shoot primary production, which, at the latitude of the Matador experimental site, was equal to 792 kcal/m2 in 1968–69. An additional 8% was cut and dropped so that a total of 10% of the green vegetation was removed by this insect species. Twenty-five percent of the ingested food was metabolized; the rest was voided as faeces. Respiration accounted for 51% of the metabolized energy. Exuviae made up 6 to 11% of secondary production. Ninety-seven percent of the potential energy of the green vegetation removed by the grasshoppers was returned to the "decomposer compartment" of the ecosystem, with only 3% removed or lost from the system.
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