Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/29/2012
Publication Date: 1/15/2013
Citation: Campbell, J.F. 2013. Influence of landscape pattern in flour residue amount and distribution on Tribolium castaneum (Herbst) response to traps baited with pheromone and kairomone. Journal of Stored Products Research. 52: 112-117. http://dx.doi.org/10.1016/j.jspr.2012.11.004.
Interpretive Summary: The red flour beetle is a major pest of flour mills and is typically monitored using traps that capture walking individuals, but the accumulation of flour on surfaces has the potential to influence beetle movement and response to traps. Different landscape patterns of a thin layer of flour residue were created that represented different patterns of surface coverage, and the response of individual beetles to traps baited with attractants (aggregation pheromone and food oil) or traps with no attractants was evaluated. There were no differences in number of beetles finding traps with attractants versus those without attractants on any of the landscapes alone or when all the landscapes were combined. However, on the combined fragmented landscapes, those with the flour divided into multiple small cells, greater numbers of beetles found traps with attractants (78%) than traps without (50%). When the flour was distributed into fewer and large groupings (clumped) there was no difference in beetles finding traps with and without attractants. The mechanism for this is not clear at this point since analysis of beetle movement did not reveal corresponding differences. The results suggest that the pattern of thin layers of flour residue can influence beetle captures in traps, with fragmented patterns in flour accumulation potentially increasing beetle response to traps, and this could impact the interpretation of pheromone monitoring programs.
Technical Abstract: Tribolium castaneum (Herbst), the red flour beetle, is a major pest of food facilities and is typically monitored using traps that capture walking individuals. In flour mills the accumulation of residues of flour on surfaces has the potential to influence beetle movement and response to trap attractants. Different flour residue landscapes of habitat (flour) within a matrix of no flour with the following characteristics were created: low abundance (10% coverage) and fragmented distribution, high abundance (30% coverage) and fragmented distribution, low abundance and clumped distribution, high abundance and clumped distribution, 0% coverage, and 100% coverage. Response of individual beetles to traps placed on these landscapes was evaluated; traps were either baited with aggregation pheromone and kairomone or contained no attractants. Encounters with the two types of traps were not significantly different for any of the specific landscapes, but greater numbers tended to encounter traps with attractants on fragmented landscapes and 100% flour landscapes. Combining landscape types, the proportion of beetles encountering pheromone- and kairomone-baited traps (0.61) was not greater than the proportion encountering empty traps (0.50). However, when combining just the fragmented landscapes there was a significantly greater response to traps with attractants (78%) than traps without (50%), but no difference in response on the combined clumped landscapes. Movement pathways, analyzed using video recordings of beetles, showed a general trend for 0% and 100% habitat landscapes to be most different from each other and 10% and 30% habitat landscapes tended to group together, but signifcant differences were observed only for maximum distance traveled in an interval, velocity, and mean turn angle. Results suggest that fragmented landscapes may have some impact on beetle response to attractants, but a potential mechanism for this needs further evaluation.