Rl. Gillespie et Wp. Kemp, COMPARISON OF AGE STRUCTURE OF 3 MELANOPLUS SPP (ORTHOPTERA, ACRIDIDAE) IN WINTER-WHEAT AND ADJACENT RANGELAND, Canadian Entomologist, 126(6), 1994, pp. 1277-1285
Significant differences in age structure of grasshopper populations [M
elanoplus sanguinipes (Fabricius), M. bivittatus (Say), and M. packard
ii Scudder] occurred in winter wheat and adjacent rangeland. In 1988,
age structure differences were associated with density shifts in winte
r wheat between sample periods suggesting that older instars dispersed
into the crop but younger instars remained in rangeland. In 1989 ther
e was some partitioning of age classes between the two habitats, but n
o pattern emerged as in 1988. In 1990, significantly more older instar
s were collected in winter wheat than in rangeland. There were shifts
in percentage density of the three grasshopper species in winter wheat
but again no patterns emerged.