Movement of Cryptolestes ferrugineus (Coleoptera: Cucujidae) in grain columns containing pockets of high moisture content wheat and carbon dioxide gradients

Abstract

The movement of the adult rusty grain beetle, 'Cryptolestes ferrugineus ' (Stephens), in 100 cm long columns, filled with wheat of uniform moisture content (m.c.) of 12.1, 13.5 and 14.7%, was determined for horizontal and vertical placement of columns at 30C. Also, the insect movement in columns, filled with high moisture content wheat (above 16.5%) in the middle or top sections, and with uniform moisture content wheat (12 or 14.8%) in other sections, was determined. Insect movement was also determined under CO2 gradients (with CO2 introduced from either top or bottom) and no CO2 gradients (control) in columns filled with either uniform moisture content wheat (12 or 14.6%) or with pockets of high moisture content wheat (15.5, 16, 16.6 or 17%) in the middle, bottom or top three sections. Six columns made of polyvinyl chloride (PVC) were fabricated to hold wheat. 'Cryptolestes ferrugineus' adults up to 2 mo old were taken from laboratory cultures and 200 adults, 100 each--marked and unmarked, were introduced, either in the middle or at the top. The insect movement was determined in horizontal and vertical columns after 1, 3, 5, and 7 d, 1 and 5 d or 1 and 7 d. (Abstract shortened by UMI.)