|Cordeiro, Erick M. - Kansas State University|
|Campbell, James - Jim|
|Phillips, Thomas - Kansas State University|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/27/2015
Publication Date: N/A
Interpretive Summary: The lesser grain borer is a major pest of wheat and is commonly found infesting bulk stored wheat, but little is known about the movement patterns of beetles within the grain mass and the factors that influence beetle behavior in the grain and ultimately their patterns of distribution. By documenting and analyzing the movement of individual lesser grain borer adults within a monolayer of wheat it was determined that age since adult emergence from an infested kernel, sex, strain, and wheat quality (percentage of lesser grain borer damaged wheat kernels) all influenced beetle movement pattern. Variation in movement pattern is likely to influence the formation of spatial distribution patterns in a grain bin and affect probability of beetles reaching the grain surface and dispersing from the grain. Understanding movement behavior within a grain bin is crucial to designing more targeted monitoring and application of control tactics.
Technical Abstract: Grain stored in bins is initially a relatively homogenous resource patch for stored-product insects, but over time spatial pattern in insect distribution can form, due in part to insect movement patterns. However, the factors that influence stored-product insect movement patterns in grain are not well understood. This research focused on the movement of Rhyzopertha dominica within a simulated wheat grain mass (vertical monolayer of wheat) and the identification of factors that contribute to overall and upward movement (age since adult emergence from an infested kernel (1, 7, and 14 days), sex, strain, and different levels of environment quality). We also used the model selection approach to select the most relevant factors and determine the relationships among them. Three week-old adults tended to stay closer to the surface compared to one or two week-old insects. Also, females tended to be more active and to explore a larger area compared to males. Explored area and daily displacement were also significantly strain dependent, and increasing grain infestation level decreased daily displacement and explored area. Variation in movement pattern is likely to influence the formation of spatial pattern and affect probability to disperse. Understanding movement behavior within a grain bin is crucial to designing better strategies to monitor and to control insect pests.