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

Abstract

Permission has been granted to the Library of the University of Manitoba to lend or seU copies of this thesis/practicum, to the Nationai Library of Canada to microfilm this thesis and to lend or seil copies of the film, and to University Microfhs Inc. to publisb an abstract of this thesidpracticum.This reproduction or copy of this thesis has been made available by authority of the copyright owner soleiy for the purpose of private stady and research, and may ody be repnidnced and copied as permitted by copyright iaws or with express d e n authorization from the copyright owner.The movement of the adult msty grain beetle, Cyptolestesfërrugineus (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 30°C. Also, the insect movement in columns, filled with hi& moisture content. wheat (above 16.5%) in the middle or top sections, and with uniform rnoisture content wheat (12 or 14.8%) in other sections, was determined. Insect movement was also determined under CO2 gradients (with COz introduced from either top or bottorn) and no CO, gradients (control) in columns filled with either uniform moisture content wheat (12 or 14.6%) or with pockets of high rnoisture 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 tàbricated to hold wheat. Each column (10 cm diameter) was divided into IO equal sections, each 10 cm long. One end of the column \vas closed and the o h -end remained opened to the atmosphere. Each section of the column had one port, except the two end sections, which had two ports each. The second port in the closed end section was for introducing CO, while the port at the open end was used for exit of gases. The first port in each section was used for introducing insects and for taking CO, sarnples. Carbon dioxide gradients were established in the cotumns by maintaining a flow o f 6 mumin fiom a compressed gas cylinder containing a mixture of 10% CO, and 90% air, by voIume. The gas concentration in each section was measured using a gas chromatopph. C~yptolestesfernigineus adults up to 2 rno old were taken fiom laboratoy 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.h horizontal columns Eilled with wheat of 13.5% uniform mec., 43% of aduh C. ferrugineus remained in the adjacent sections frorn their point of introduction, but afler 5 d, they exhibited the trend of distributing unifomly in h e columns. in vertical columns filled with 12 or 14.8% unifom moisture content, 63% of the insects moved downward showing positive geotaxism. tn horizontal or vertical coiumns containing pockets of high moisture content wheat, 55% of the beetles aggregated in the region of high moisture content, exhibiting hygrotactic response. Under CO? gradients in co...

Movement and Distribution of Cryptolestes ferrugineus (Coleoptera: Laemophloeidae) Adults Under Different Temperature Differences in Different Lengths of Horizontal Grain Columns

“…Results showed the preference of insects towards warmer regions of arena. Similar studies were reported on determining the preference of insects under major individual gradients like temperature ( Flinn et al 1992 , Kim et al 2015 , Henry and Wlodkowic 2020 ), moisture ( Parde et al 1998 , Collins and Conyers 2009 ), and gas concentration ( Navarro et al 1981 , White et al 1993 , Parde et al 2004 ). Directional movement of insects was assessed in one-dimensional (1D) and two-dimensional (2D) grain mass.…”

“…Therefore, our results confirmed the wandering movement behavior of the adults of C. ferrugineus as reported in literature ( Anukiruthika et al 2021 ). Adults of rusty grain beetles move to grain with 10% CO 2 concentration and wet grain ( Parde et al 2004 ) and avoid higher than 42.5°C grain area ( Jian et al 2002 ). Their vertical movement and distribution are significantly affected by the dockage percentage.…”