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Title: Movement behavior in response to landscape structure: the role of functional grain

item Romero, Susan
item Campbell, James - Jim
item Nechols, James
item With, Kimberly

Submitted to: Landscape Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2008
Publication Date: 10/5/2008
Publication URL:
Citation: Romero, S., Campbell, J.F., Nechols, J.R., With, K.A. 2008. Movement behavior in response to landscape structure: the role of functional grain. Landscape Ecology. 24(1): 39-51. Doi:

Interpretive Summary: The ability of the red flour beetle, Tribolium castaneum, to find and colonize small patches of food is a major contributor to its pest status in food processing and storage facilities such as flour mills, but this process is not well understood. Amount of food material and its pattern of distribution can influence beetle movement patterns and provide insight into how they perceive the structure of their environment. Model landscapes were created with different levels of total flour abundance and individual flour patch size, and beetle movement behavior on these landscapes was recorded and analyzed. As landscape structure changed, beetles were demonstrated to modify their movement behavior, indicating that they perceived some of the changes in the landscape and changed their search strategy. This study serves as an important first step in identifying behavioral rules of movement that may ultimately lead to more accurate predictions of how beetles use the environment and how the landscape pattern can be manipulated to reduce its suitability for this pest.

Technical Abstract: Landscape structure can influence the fine-scale movement behavior of dispersing animals, which ultimately may influence ecological patterns and processes at broader scales. Functional grain refers to the finest scale of interaction between organism and the landscape and may indicate the perceptive resolution at which an organism responds to heterogeneity. To determine the functional grain of a model insect, red flour beetle (Tribolium castaneum), we examined its movement behavior in response to experimental flour landscapes. Landscape structure was varied by manipulating habitat abundance (0, 10, 30, and 100%) and grain size of patches (fine-2 x 2 cm, intermediate-5 x 5 cm, and coarse-10 x 10 cm) in 50 x 50 cm landscapes. Lacunarity analysis of beetle pathways indicated an abrupt non-linear change in space use between the coarse-grained and both the intermediate- and fine-grained landscapes. Pathway metrics indicate that beetles used a similar proportion of all landscape types, but moved more slowly and tortuously (with many turns), and remained longer in both the overall landscape and individual patches, in fine-grained compared to coarse-grained landscapes. Pathway metrics calculated for intermediate-grained landscapes had values intermediate between the fine and coarse-grained landscapes. Our research demonstrates how detailed examination of movement pathways and measures of lacunarity in response to landscape structure can be useful in determining functional grain. Spatially explicit, organism-centered studies focusing on behavioral responses to different habitat configurations can serve as an important first step to identify behavioral rules of movement that may ultimately lead to more accurate predictions of space use in landscapes.