Journal of Economic Entomology (2004) 97, 1148-1158

Fuji Jian, Digvir S. Jayas and Noel D.G. White (2004)
Movement and distribution of adult rusty grain beetle, Cryptolestes ferrugineus (Coleoptera: Laemophloeidae), in stored wheat in response to different temperature gradients and insect densities
Journal of Economic Entomology 97 (3), 1148-1158
Abstract: The movement and distribution of adult Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae) in grain provide important information for detection of insect pests and for simulations of their distribution in grain bins. Adult movement and distribution were determined in 100 by 100 by 1000-mm wheat (14.5 ± 0.2% moisture content) columns at four insect densities, three temperature gradients, and dynamic (changing) temperature conditions. Insect density was a minor factor influencing insect movement and distribution in grain columns with temperature gradients. Dispersal resulted in a uniform distribution at a higher insect density (higher than two adults per kilogram of wheat), and aggregation occurred at a low insect density. Adults wandered in the first 6 h after introduction, and there were fewer adults wandering in the vertical direction than in the horizontal direction. Adults moved faster in the vertical direction than in the horizontal direction, and the maximum speed of the movement was 6 m/d in the horizontal direction, and >10.8 m/d in the vertical direction through wheat. Adults could detect temperature gradients in <1 h and preferred warmer temperatures when they had a choice. Insect distribution in horizontal wheat columns at any temperature gradient was unstable for 24 h. Twenty-four hours after introduction, adults gradually overcame their positive geotactic behavior if the upper temperature was more biologically suitable or was not <27.5°C. Adults responded faster to higher temperature gradients than to lower temperature gradients. There was a similar pattern of adult distribution in 144 h.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Digvir S. Jayas

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
population dynamics/ epidemiology

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cryptolestes ferrugineus	Stored grain