Influence of the immediate environment on the dispersal of Sitona lineatus L. (Col., Curc.) during crop colonisation

Abstract

The factors favouring the colonisation of pea fields by Sitona lineatus L. were studied in three trapping experiments in fields of the ITCF Experimental Farm in Boigneville (Essonne, France). One trapping device was placed in an open environment, represented by a meadow. It showed that at the end of hibernation, S. lineatus populations dispersed mainly via air currents. The second device was located in a pea crop entirely surrounded by a wooded area used as place of hibernation. The distribution of S. lineatus caught in this protected environment reflected movements which were oriented towards directions not correlated with the wind direction. The third device was placed in a typical open environment of arable crops of the Paris Basin, and was used to determine the movements between three main types of environment occupied by the weevil: a hibernation zone (wooded area), a hibernation and/or feeding zone (clover) and a reproduction zone (pea). Crops on the ITCF experimental farm were colonised simultaneously at the beginning of spring, irrespective of environment, with two peaks in migration.