ARS | Publication request: Spatio-temporal distribution of stored-product inects around food processing and storage facilities

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 6, 2012
Publication Date: January 15, 2013
Citation: Semeao, A.A., Campbell, J.F., Hutchinson, J., Whitworth, R., Sloderbeck, P.E. 2013. Spatio-temporal distribution of stored-product inects around food processing and storage facilities. Agriculture, Ecosystems and Environment. 165: 151-162. http://dx.doi.org/10.1016/j.agee.2012.11.013.

Interpretive Summary: Stored-product insects can be found outside of facilities where grain is stored and processed, and these populations can potentially serve as a reservoir and source of food product infestation. Identifying the pattern of distribution of pest species and the factors that determine distribution could help in the targeting of monitoring and pest management programs. Pests were monitored using two types of food-baited traps at three food facilities, and the species captured were a mixture of both important grain and processed food pests and fungal feeding species more commonly associated with degraded grain. Although the types of insects captured were similar between inside and outside locations, more were captured per trap inside and fungal feeding species were proportionally more abundant outside. Features of the landscape around each outside trap were characterized to see which might predict locations with more insect activity. Increased captures in outside traps were primarily associated with proximity to buildings, but surprisingly not associated with presence of food spillage. Overall, there was evidence of considerable movement of insects in the landscape surrounding facilities, resulting in limited spatial pattern other than localized hot spots inside or near structures that varied in location overtime. This study provides a methodology for evaluation of external populations at food facilities, highlights the importance of understanding pest populations over larger spatial scales, and insight into where monitoring and pest management tactics need to be focused.

Technical Abstract: Grain storage and processing facilities consist of a landscape of indoor and outdoor habitats that can potentially support stored-product insect pests, and understanding patterns of species diversity and spatial distribution in the landscape surrounding structures can provide insight into how the outdoor environment can be more effectively monitored and managed. The spatial and temporal distribution of stored-product pests was assessed at three food processing facilities using two types of traps, and the influence of landscape features on their outside distribution was evaluated. For corrugated traps, targeting walking individuals, placed both inside and outside facilities, the predominant groups, accounting for 59% of captures, were Cryptolestes spp. (Coleoptera: Laemophloeidae), Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), and Sitophilus spp. (Coleoptera: Curculionidae). Numbers captured in outside corrugated traps tended to be less than captures inside structures, and while level of species diversity was similar fungal feeding species were more common in outside traps. In outside corrugated traps, Cryptolestes spp., Typhaea stercorea (L.) (Coleoptera: Mycetophagidae) and O. surinamensis were most abundant and in outside Lindgren traps that targeted flying individuals, T. stercorea, Cryptolestes spp., and Ahasverus advena (Waltl) (Coleoptera: Silvanidae) were most abundant. No correlation was observed between total captures and species diversity between inside and outside traps. Distribution of stored-product insects in corrugated traps tended not to be spatially clustered (global Moran's I values ranged from -0.25 to 0.22). However, Anselin local Moran's I indicated that at local level some traps with greatest captures had traps in the vicinity with similar values, but these specific locations were temporally variable. Landscape around each outside corrugated trap was characterized, and increased captures were associated with proximity to grain storage or processing structures, but not with presence of spillage as originally hypothesized. Overall, results support the hypothesis that there is considerable movement of insects in landscape surrounding facilities, resulting in limited spatial pattern other than temporally variable hot spots inside or near structures.